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The Coordination Committee formed by GR No. Abhyas - 2116/(Pra.Kra.43/16) SD - 4, Dated 25.4.2016 has given approval to prescribe this textbook in its meeting held on, 20.06.2019 and it has been decided to implement it from academic year 2019-20., , BIOLOGY, Standard XI, , 2019, , Maharashtra State Bureau of Textbook Production and, Curriculum Research, Pune., , Download DIKSHA App on your smartphone. If you scan the Q.R.Code on, this page of your textbook, you will be able to access full text. If you scan, the Q.R.Code provided, you will be able to access audio-visual study, material relevant to each lesson, provided as teaching and learning aids.

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The Constitution of India, , Preamble, WE, THE PEOPLE OF INDIA, having, solemnly resolved to constitute India into a, SOVEREIGN, SOCIALIST, SECULAR, DEMOCRATIC REPUBLIC and to secure to, all its citizens:, JUSTICE, social, economic and political;, LIBERTY of thought, expression, belief, faith, and worship;, EQUALITY of status and of opportunity;, and to promote among them all, FRATERNITY assuring the dignity of, the individual and the unity and integrity of the, Nation;, IN OUR CONSTITUENT ASSEMBLY this, twenty-sixth day of November, 1949, do HEREBY, ADOPT, ENACT AND GIVE TO OURSELVES, THIS CONSTITUTION.

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NATIONAL ANTHEM

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Preface, Dear Students,, We welcome you all to Std. XI. For the first time, you are being introduced to the subject of, Biology as a separate discipline. You have already been acquainted with some of the concepts of, Biological Sciences from Standard five onwards, especially in the subject of General Science up to, standard Eight and Science and Technology for standard Nine and Ten., This textbook aims to create awareness about the biological sciences specially Botany,, Zoology and allied aspects of biological sciences. The National Curriculum Framework (NCF), was formulated in 2005, followed by the State Curriculum Framework (SCF) in 2010. Based on, the given these two frameworks, reconstruction of the curriculum and preparation of a revised, syllabus has been undertaken which will be introduced from the academic year 2019-20. The, textbook incorporating the revised syllabus has been prepared and designed by the Maharashtra, State Bureau of Textbook Production and Curriculum Research, (Balbharati), Pune., The subject biology intends to give students understanding, and appreciation of the vast diversity, of living beings, their special adaptations to their environments and evolutionary relationships. No, compromise is made in any manner over the use of language in the Biology context, but at the same, time, the textbook is presented in a simple language. In addition, relevant diagrams, graphs, tables, used in the textbook will bring about more clarity in the understanding of various terminologies and, biological concepts. All the illustrations are in colour form. This will enable students to understand, various concepts of botany and zoology thoroughly and correlate this with their day-to-day, practical life. The new syllabus focuses on the conceptual principles of overall life processes, its, understanding, and application in day-to-day life and ability to solve different upcoming problems, and issues like conservation; different diseases and remedies, the application of technology, etc., The general teaching-learning objectives of the revised syllabus are further determined based on the, ‘principle of constructivism’ i.e. self-learning., The curriculum and syllabus confirms to the maxims of teaching such as moving from, concrete to abstract, known to unknown and from part to whole. For the first time, in the syllabus, of biology various independent activities have been introduced. These activities will not only help, to understand the content knowledge but also provide scope for gaining relevant and additional, application based knowledge on your own efforts. The detailed information of all concepts is also, provided for the better understanding of the subject. Q. R. Code have been introduced for gaining, the additional information, abstracts of chapters and practice questions/ activities., The efforts taken to prepare the textbook will not only enrich the meaningful learning experience, of the students, but also benefit other stakeholders such as teachers, parents as well as those aspiring, candidates preparing for the competitive examinations., We look forward to a positive response from the teachers and students., Our best wishes to all!, , Place : Pune, Date : 20 June 2019, Bharatiya Saur : 30 Jyestha 1941, , (Dr. Sunil Magar), Director, Maharashtra State Bureau of Textbook, Production and Curriculum Research,, Pune, 411004

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- For Teachers Dear Teachers,, We are happy to introduce the revised, textbook of Biology for Std XI. This book is a, sincere attempt to follow the maxims of teaching, as well as develop a ‘constructive’ approach to, enhance the quality of learning. The demand, for more activity based, experiential and, innovative learning opportunities is the need, of the hour. The present curriculum has been, restructured so as to bridge the credibility gap, that exists between what is taught and what, students learn from direct experience in the, outside world. Guidelines provided below will, help to enrich the teaching-learning process, and achieve the desired learning outcomes., • To begin with, get familiar with the, textbook yourself., • The present book has been prepared for, constructive and activity-based teaching., • Teachers must skillfully plan and organize, the activities provided in each chapter to, develop interest as well as to stimulate the, thought process among the students., • Always teach with proper planning., • Use teaching aids as required for the proper, understanding of the subject., • Do not finish the chapter in short., • Follow the order of the chapters strictly as, listed in the contents because the units are, introduced in a graded manner to facilitate, knowledge building., • Facilitate peer learning as much as, possible by reorganizing the class structure, frequently., • Teaching-learning interactions, processes, and participations of all students are very, essential and so is your active guidance., • Ask questions based on previous, knowledge of different concepts of lesson., • Do not use the boxes titled ‘Do you, know?’ for evaluation. However, teachers, must ensure that students read this extra, information., • Information provided in boxes with the, title ‘Can You Tell’, ‘Always Remember’, should be considered for evaluation., , •, , •, , •, •, , •, •, •, •, •, •, •, •, •, •, , Exercises provided after each unit are, prepared using different parameters like, observation, co-relation, critical thinking,, analytical reasoning etc., Evaluation pattern should be based on, the above mentioned parameters. Equal, weight age should be assigned to all the, topics. Use different combinations of, questions. Stereotype questions should be, avoided., Use demonstration, discussion method for, teaching., ‘Can You Recall’ is the first main starting, point of lesson which helps for the, introduction of topic. This will also helpful, for students regarding understanding the, content of lesson., Use QR Code given in the textbook., Keep checking the QR Code for updated, information., ‘Internet My Friend’ is used for collecting, extra important information related to topic., ‘Use Your Brain Power’ is used for the, application level questions in different, lessons., ‘Do Your Self’, ‘Find Out’, ‘Observe, and Discuss’ and ‘Try This’ are used for, activity based learning., ‘Know the Scientist’ is used for the, information of different scientist related to, concepts in lesson., ‘Activity’ is used in lesson and exercise for, better understanding and application of the, content which studied., Exercise is given at the end of lesson., In exercise different type of questions/, activities are given., Teacher should use their freedom to, acquaint the students with flora and fauna, of given region., Remember that mathematical and, statistical tools are also important to, understand biology, List of abbreviations are provided, towards the end of the textbook for further, clarification., Best wishes for a wonderful teaching, experience and fruitful welcome!

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Competency Statements, Standard XI, Unit, Diversity in, living world, , Cell structure, and functions, , Structural, organization, in organisms, , Plant, physiology, , Competency Statements, After studying the content in Textbook students will …, • Analyse basic characteristics of living and non-living., • Collect and analyse useful data by observing diversity of living organisms using, different tools., • Describe plants and animals in the surrounding on scientific basic and classify, them using taxonomic hierarchy., • Develop hobbies by watching and collecting the things (livings) and their, conservation using databases., • Classify different organisms based on cell structure, body organisation, mode of, nutrition etc., • Compare and analyse similarities and differences along with phylogeny amongst, different groups of organisms., • Recognize, analyse and compare structural similarities and differences and, progressive evolutionary changes in different plants and animals., • Explain and draw the structure and functions of different cell organelles., • Elaborate the role of nucleus in heredity and controlling characters with structure, of chromosome., • Compare cell division process and know their role in life cycle of organisms., • Analyse and specify different biomolecules of cell with their role in structural and, functional aspect of cell., • Explain basic morphology of dominant plant group of this era i.e. Angiosperms., • Compare morphological features of different plant parts in different plant families., • Draw floral parts and floral diagram., • Identify economic importance of Angiosperms with respect to fruit and seeds., • Compare morphological feature of two major classes of Angiosperms., • Explain different types of tissues in plants and reasons for growth viz. primary, and secondary., • Analyse basic differences in anatomy of different plants like dicot and monocots, with respect to root, stem and leaf., •, Elaborate different animal tissues and their role., • Explain and draw mechanisms of different physiological process like digestion, and excretion., • Review the contribution of different scientists in systematics and taxonomy., • Explain the scientific reasons behind the various physiological activities based, on relationship., •, , Understand the relationship between chemical reactions of molecules in daily, life and analyse them to solve various problems., , •, , Review the contribution made by different workers., , •, , Plan and implement programs about conservation of environment., , •, , Explain the importance of green energy and save energy in daily life.

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Animal, Physiology, , •, •, •, •, •, •, •, •, •, , Explain the need and importance of various physiological processes., Explain the structural modifications, observed in various living organisms to carry, out various physiological processes., Observe and correlate the histological structure of various organs with their, function., Comprehend mechanisms by which these physiological processes help maintain, homeostasis., Create memory maps, flow charts to depict major events in these processes., Develop insight about connection between life style/habits and physiological, disorders., Collect information about latest diagnostic tools and treatments for various, physiological disorders., Critically analyse given situational data and come up with rationale of possible, physiological disorders/suggest proper remedial measures., Perform various analytical tests to detect presence of certain components in food, materials/waste products., , Contents, Sr. No., , Name of the lesson, , Page No., , 1., , Living World, , 1-5, , 2., , Systematics of Living Organisms, , 6 - 18, , 3., , Kingdom Plantae, , 19 - 28, , 4., , Kingdom Animalia, , 29 - 43, , 5., , Cell Structure and Organization, , 44 - 58, , 6., , Biomolecules, , 59 - 75, , 7., , Cell Division, , 76 - 84, , 8., , Plant Tissues and Anatomy, , 85 - 96, , 9., , Morphology of Flowering Plants, , 97 - 115, , 10., , Animal Tissue, , 116 - 126, , 11., , Study of Animal Type : Cockroach, , 127 - 137, , 12., , Photosynthesis, , 138 - 150, , 13., , Respiration and Energy Transfer, , 151 - 160, , 14., , Human Nutrition, , 161 - 173, , 15., , Excretion and Osmoregulation, , 174 - 192, , 16., , Skeleton and Movement, , 193 - 214, , DISCLAIMER Note : All attempts have been made to contact copy right/s (©) but we have not heard from them. We, will be pleased to acknowledge the copy right holder (s) in our next edition if we learn from them.

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1. Living World, Can you recall?, , There is immense diversity in living, organisms. Since time immemorial, variety of, organisms are living together on earth. In order, to understand the interrelations between living, and non-living as well as between two living, beings or groups, systematic study of these is, essential. This data is also important for various, industries and agriculture. Intensive laboratory, and field studies in order to identify and classify, the organisms form strong basis for meaningful, use of the collected data. If we need to study this, diversity, certain aids called taxonomical aids, can be used. These includes herbaria, botanical, gardens, museums, biodiversity parks, etc., , 1. What is the difference between living and, non-living things?, 2. Enlist the characters of living organisms., 3. Whether all organism are similar? Justify, your answer., Planet earth is made up of abiotic and, biotic components. The biotic components are, obviously the living beings present around us., The question is why do we call them living and, how do they differ from non-living?, 1.1, Basic principles of life :, A. The living being once produced / born has, to survive. For survival, it needs energy and, many chemical molecules. For energy, it has to, perform metabolism. Metabolism is breaking, of molecules (catabolism) and making of new, molecules (anabolism)., B. From birth onwards, organisms show, tendency of growth and development. This, growth is a well-orchestrated process. You, might have observed sand mounds, boulders, grow, etc.This growth is not from within and, hence these are not living beings., C. Growth and development are not the, processes which have unlimited time span. At, certain point of time, the molecules, organs,, systems begin to loose their effective working, and become old. This is ageing process of the, body., D. Life has to continue hence the organism, tries to produce a young one like itself. It, is possible due to reproduction (asexual or, sexual). This ensures continuity of race. Mules,, sterile worker bees do not reproduce; yet are, living. Can we call reproduction as inclusive, characteristic of life?, E. As the body looses it's capacity to perform, metabolism, the organism dies., F. Any living being responds to thermal,, chemical or biological changes in the, surrounding. This is unique property of living, beings., , Can you tell?, 1., 1. How can we study large number of, organisms at a glance?, 2. Weather all organisms prepare their own, food?, 3. Which feature can be considered as all, inclusive characteristic of life? Why?, Think about it, 1. Can metabolic reactions demonstrated in, a test tube (called ‘in vitro’ tests) be called, living?, 2. Now a days patients are declared ‘brain, dead’ and are on life support. They do not, show any sign of self-consciousness. Are, they living or non - living?, 1.2, , Herbarium :, The word herbarium (plural-herbaria), was coined by Pitton de Tournefort in the, book ‘Elemens’. The art of herbarium was, initiated by an Italian taxonomist Luca Ghini, (1490-1556). Herbaria are effective tools in, taxonomic studies. A herbarium is essentially, a dried plant specimen that is pressed, treated, and mounted on standard size sheet in order to, preserve it., , 1

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Date, place of collection along with, detailed classification and highlighting with its, ecological peculiarities, characters of the plant, are recorded on the same sheet. Local names, and name of the collector may be added. This, information is given at lower right corner of, sheet and is called 'label'., , Know the scientists, In 1543, first, botanical garden of the, world was established, by an Italian Prof., Luca Ghini (A. D., 1490-1556) at Pisa,, Italy. Botanical garden, at Kew in England, is known for largest, collection of more Prof. Luca Ghini, than 30,000 specimens (preserved plants) and, more than 7 million herbaria., , Internet my friend, Collect information about Prof., Almeida, Prof. V. N. Naik, Dr. A. V. Sathe,, Dr. P. G. Patwardhan with reference to, their taxonomic work and biodiversity, conservation., , Fig. 1.1 Herbarium, 1.3, , Botanical Gardens :, Botanical gardens are the places where, plants of different varieties collected from, different parts of the world, are grown in a, scientific and systematic in a in vivo manner., Plants are labeled. The label-board shows, scientific as well as common name of the plant., , Fig. 1.2 Botanical Garden : Kolkata 255 years old Banyan tree, , 2

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1.5, , Zoological Parks :, Zoological Park generally known as, zoo, is a place of interest for common man., In a zoo, wild animals are kept in captivity., They are protected and care is taken to provide, conditions similar to their natural habitat. (exsitu) In a zoo, a naturalist can study food habits, and behavior of animals., Flora, manuals, Monographs and, Catalogue are some other tools of maintaining, biodiversity records. Flora is the plant, life occurring in a particular area on time., A Monograph describes any one selected, biological group where as manual provides, information, keys about identification of species, found in a particular area., , Conservation of Biodiversity :, Biodiversity is the degree of variation, of life forms in an ecosystem. Biodiversity, is essential to maintain ecological stability., The extent of complexity and density of, biodiversity can be regarded as a measure, of health of an ecosystem. Population, explosion and over exploitation of resources, has resulted in loss of biodiversity at an, alarming rate. Conservation involves, attempting to slow down, stop or even reverse, the loss in the natural habitat of organism., This is known as in- situ conservation. Why, does the loss of biodiversity matter? For, many people, it is a simple moral or ethical, issue. We share our planet with a huge range, of other organisms and we have no right to, harm them. Biodiversity helps to maintain, stability in an ecosystem. Loss of one variety, of organisms can affect entire ecosystem., 1.4, , Museum :, Museums are the places where,, collections of preserved plant and animal, specimens are kept. Plant and animal, specimens may be preserved in formalin (10%, to 40% formaledehyde) in transperent jars., Jars are labelled. Larger animals like birds and, mammals are usually stuffed and preserved., This science is known as taxidermy. Specimens, in dried form are also kept in museum., We can even find systematic collections, of shells, skeletons of animals, insect boxes in, museums., Thus,, biological, museums, in, educational institutes are reference hubs of, biodiversity studies., , Fig. 1.4 Zoological Park, , 1., , Can you tell?, , 1. What are the, essentials of a good herbarium?, 2. Why should we visit botanical gardens,, museums and zoo?, 3. What is ' ex- situ' and ' in- situ' conservation?, , 1.6, , Biodiversity parks :, It is an ecological assemblage of, species that form self-sustaining communities, on degraded / barren landscape e.g. Late, Uttamrao Patil biodiversity park Gureghar,, Mahabaleshwar. This park is the best model, for conservation of natural heritage in urban, landscape., , Fig. 1.3 Biological Museum, , 3

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Systematic classification of living, organisms is helpful in understanding, the interrelations. In order to understand, interrelations between organisms and maintain, harmony on planet earth, study of biodiversity, is a must., , 1.7, , Key :, Key is taxonomical aid used for, classification of plants and animals. The keys, are based on contrasting characters. One of the, contrasting characters gets accepted and other, rejected. The statement in key is called a lead., Normally keys are analytical in nature. Let us, study about classification of living organisms, in next chapter., , Know the scientists, Dr. S. P. Agharkar, One of the leading, botanists of India, Dr., S. P. Agharkar was born, in November 1884 in, Malvan, Maharashtra. He, explored biodiversity of, Western Ghats where he, came across a species of freshwater jellyfish,, which was until then only known to be found, in Africa. These findings were published, in scientific journal Nature in 1912. Dr., Annandale, the Superintendent of the Indian, Museum in Kolkata, helped Dr.Agharkar in, his further endeavours to collect, preserve and, conduct microscopic examinations of animal, and plant specimens. The institute ARI, Pune, has been named after his name., , Do you know ?, When plants from any forest locality, are conserved on the name of holy place it is, called as sacred grove these also considered, as sacred natural sites by IUCN., , Internet my friend, 1., , Collect information about botanical gardens, zoological parks and biodiversity hot, spots in India., 2. Collect information of endemic flora and, fauna of India., , Find out, Human being is at key position in maintaining biodiversity of earth. Find out more, information about the following., 1. Laws to protect and conserve biodiversity in India., 2. Environmental effects of ambitious projects like connecting rivers or connecting cities by, constructing roads., 3. Did Bauxite mining in Western Ghats affect critically endangered species like – Black, panther, different Ceropegia spp., E riocanlon spp.?, , 4

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Exercise, 1. Choose correct option, A. Which is not a property of living being?, a., b., c., d., , E. What do you understand from terms like, in situ and ex situ conservation?, , Metabolism, Decay, Growth, Reproduction, , 4. Write short notes, A. Role of human being in biodiversity, conservation., B. Importance of botanical garden., , B. A particular plant is strictly seasonal plant., Which one of the following is best suited, if it is to be studied in the laboratory?, a., b., c., d., , 5. How can you, as an individual, prevent the, loss of Biodiversity?, , Herbarium, Museum, Botanical garden, Flower exhibition, , Practical / Project :, 1. Make herbarium under the guidance of, your teacher., 2. Find out information about any one, sacred grove (devrai) in Maharashtra., , C. A group of students found two, cockroaches in the classroom. They had, a debate whether they are alive or dead., Which life property will help them to do, so?, a., b., c., d., , Metabolism, Growth, Irritability, Reproduction, , 2. Distinguish between botanical gardens,, zoological park and biodiversity park, with reference to characteristics, 3. Answer the following questions, A. Jijamata Udyan, the famous zoo in, Mumbai has acclimatised humbolt, penguins. Why should penguins be, acclimatised when kept at a place away, from their natural habitat?, B. Riya found peculiar plant on her visit to, Himachal Pradesh. What are the ways, she can show it to her biology teacher and, get information about it?, C. At Andaman, authorities do not allow, tourists to collect shells from beaches., Why it must be so?, D. Why do we have green house in botanical, gardens?, , 5

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2. Systematics of Living Organisms, Natural : It is the classification which is based, on objectively significant rather than being, selected for convenience like artificial system, of classification e.g. Bentham and Hooker's, system of classification., Phylogenetic : It is the classification based on, common evolutionary descent. e.g. Engler and, prantles classification., In the system of classification the, terms like ‘taxa’ and ‘categories’ are often, used. Each category is referred to as a unit of, classification. In fact, it represents a rank and, is commonly termed as taxon., , Can you recall?, What is five kingdom system of, classification?, There is great diversity of organisms, around us. Since time immemorial, we, humans have been exploiting this wealth for, our own benefit. During this process man, tried to differentiate between and identify, the organisms. Eventually this evolved into, a branch of biology known as systematics or, classification. The methods of classification, dates back to ancient time when Indian, Greek, and Roman philosophers have contributed their, might to systematise science., 2.1, Systematics :, ‘‘Systematics is the study of kinds and, diversity of organisms and their comparative, and evolutionary relationship’’(G. Simpson,, 1961)., Taxonomy :, Taxonomy, means, classification, following certain rules or principles. Word, Taxonomy comes from two Greek words,, taxis – meaning arrangement and nomous, meaning law or rule. The term taxonomy was, first introduced by A. P. de Candolle (Swiss, Botanist) [1778-1841]., , Archaea, Bacteria, , Eukaryota, , Common ancestor, Fig 2.1 Phylogenetic descent, 2.3, , Three domains of life :, It is believed that the life originated on, earth in its very simple form. Constant struggle, of the early living beings gave rise to more and, more perfect forms of life. This struggle and, progress is evolution which led to formation of, diverse life forms. Carl Woese in 1990 proposed, three domains of life to classify life forms. They, are Archaea, Bacteria and Eukarya. Domain is, an unit larger than Kingdom in the system of, classification., Bacteria and Archaea both have, prokaryotic cells where as Eukarya have, eukaryotic cell. All the three domains have, very unique ribosomal RNA (rRNA). Archaea, are known for their survival in very extreme, conditions like high tempreature, salinity,, acidic conditions, etc. Bacteria, though are, prokaryotes differ from Archaea in structure of, cell wall., , 2.2, , Classification :, It is the arrangement of organisms, or groups of organisms in distinct categories, in accordance with a particular and well, established plan. This classification is based, on similarities and dissimilarities among the, organisms., Artificial :, It is the classification that is based on, few easily observable and non-evolutionary, featurs such as habit, colour, form, etc.; often, irrespective of their affinity (relationship), with other organisms. e.g. Linnaeus system of, classification., , 6

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2.4, , Chemotaxonomy :, It is method of biological classification, based on similarities and differences in, structure of certain compounds present among, the organisms being classified. In short, it is the, classification based on chemical constituents, of organisms. e.g. Archaea cell wall is without, peptidoglycan and that of Prokarya is with, peptidoglycan. Among Eukarya, fungi have, chitinous cell wall while plants have cellulosic, cell wall., , It helps to study newly identified, species as well as understanding ecological, and evolutionary relationships between living, beings. The process of DNA barcoding includes, two basic steps: (a) collecting DNA barcode, data of known species and (b) matching the, barcode sequence of the unknown sample, against the barcode library for identification., DNA barcoding has many applications. A, few to mention are, protection of endangered, species, preservation of natural resources,, pest control in agriculture, identifying disease, vectors, authentication of natural health, products and identification of medicinal plants., , 2.5, , Numerical taxonomy :, The system is based on quantification, of characters and develops an algorithm for, classification. The basic aim of this taxonomy, was to create a taxonomy using numeric, algorithms like cluster analysis rather than, using subjective evaluation of their propertise., This system was first proposed by Sokel and, Sneath in 1963., , Can you tell?, 1. Which characters of organisms are visible, characters?, 2. Name the recent approaches in taxonomy., 3. What is DNA barcoding?, 4. What is evolution?, 5. Enlist uses of taxonomy., , 2.6, , Cladogram :, It is a typical branching pattern. As, shown on previous page, a diagram of three, domains of life is a cladogram. It represents, a hypothetical relationship denoting a, comparison of organisms and their common, ancestors., , 2.9, , Taxonomic Categories :, Classification is not a single step, process but involves hierarchy of steps in which, each step represents a rank or category. Since, the category is a part of overall taxonomic, arrangement it is called taxonomic category, and all categories together constitute the, taxonomic hierarchy. Kingdom, division, class,, order, family, genus, species are the categories, in hirarchial sequence. These are compulsory, categories. Besides, there are some facultative, categories like sub-order, sub-family, etc. to be, used as per need., , 2.7, , Phylogeny :, It is evolutionary relationship of, organism. It is an important tool in classification, as it takes into account not merely the, morphological status but also the relationship, of one group of organism with other groups, of life. The system helps to understand the, evolution and also focuses on the similarities, of their metabolic functioning. Woese’s three, domain concept as well as Whittakar’s five, kingdom system are very good examples of, phylogenetic relationship., , 2.10, , Taxonomic Hierarchy :, Taxon : A taxon is the taxonomic group, of any rank in the system of classification, (H.J. Lam 1948) e.g. in plant kingdom each, one of the following such as Angiosperms,, Dicotyledonae,, Polypetalae,, Malvaceae, represents a taxonomic group i.e. a taxon., , 2.8, , DNA barcoding :, DNA barcoding, is a new method for, the identification of any species based on its, DNA sequence from a tiny tissue sample of the, organism under study., , 7

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Category, Kingdom, Division/Phylum, Class, Sub-class, Series, , Taxon, Plantae, Angiospermae, Dicotyledonae, Polypetalae, Thalamiflorae, , Taxon, Animalia, Chordata, Reptilia, Diapsida, -, , Order, Family, Genus, Species, , Malvales, Malvaceae, H ibiscus, rosa- sinensis, , Squamata, Elapidae, N aj a, naj a, , •, Cohort / Order : It is taxonomic rank, used in the classification of organisms and, recognised by nomenclature codes. An order, is a group of closely related families showing, definite affinities. Order thus is a step above, family in taxonomic hierarchy. Members, belonging to same order but different families, may show very few dis similarities. e.g. family, - Papavaraceae, Brassicaceae, Capparidaceae,, etc with parietal plancentation are grouped, in order Parietales. Families of dogs and cats, though are different, they belong to same order, Carnivora., •, Class : The class is the distinct, taxonomic rank of biological classification, having its own distinctive name. A group of, higher taxonomic rank than order. Class is the, assemblage of closely allied orders. Orders, Carnivora and order Primates belong to class, Mammalia. Thus monkeys, gorillas, gibbons, (Primates) and dogs, cats, tigers (Carnivora), belong to same class., •, Division / Phylom : The division is, a category composed of related classes e.g., division. Angiospermae includes two classes, - Dicotyledonae and Monocotyledonae (In, animal classification division is a sub-unit of, Category / Phylum)., •, Sub-kingdom : Different divisions, having some similarities form sub-kingdom., e.g. The divisions Angiospermae and, Gymnospermae will the sub-kingdom, Phanerogams or Spermatophyta., •, Kingdom : It is the highest taxonomic, category composed of different subkingdoms. e.g. sub-kingdom Phanerogams, and Cryptogams form the Plant kingdom or, Plantae which includes all the plants while all, animals are included in kindom Animalia., The taxonomic categories we have, considered so far are broad categories., Scientists have added sub-categories to these, in order to place organisms in more scientific, manner. You will observe that as we go higher, in taxonomical ladder, number of common, characters go on decreasing., , Table 2.2 Classification of China-rose and, Cobra, 2.11 Units of Classification :, •, Species : Species is the principal, natural taxonomic unit, ranking below a genus, and denoted by latin binomial (considered as, the basic) unit of classification. It is a group, of organisms that can interbreed under natural, condition to produce fertile offspring. It was, thought to be an indivisible, stable and static, unit. However in the modern taxonomy, subdivision of species such as sub-species, varities, and populations are seen and given more, importance., •, Genus : Genus is a taxonomic rank, or category larger than species used in the, biological classification of living and fossil, organisms. Genus is a group of species bearing, close resemblance to one another in their, morphological characters but they do not, interbreed. e.g. Tiger, Leopard, Lion all three, belong to same genus Panthera. They have, common characters yet are different from each, other because their genus is same but species is, different. Another example is genus Solanum., Brinjal and potato both belong to this genus., •, Family : It is one of the major, hierarchial taxonomic rank. A family represents, a group of closely related genera. e.g. genera, like H ibiscus, Gossypium, Sida, Bombax are, included in same family Malvaceae. Cat also, belongs to family of leopards, tigers and lions,, family Felidae but dog belongs to different, family Canidae., , 8

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If we are comparing two organisms, that are related to each other only at division or, phylum level, their classification may become, difficult., , Before 2011, the code which was set up, to confirm the scientific names was ICBN, means International Code of Botanical, Nomenclature. Recently XIX International, Botanical Congress (IBC) was held in, Shenzhen, China in July 2017. This code, is also called "Shenzhen code", so the old, code ICBN has been changed to ICNAFP, means "International Code of Nomenclature, for Algae, Fungi and Plants". This code was, published on 26th June 2018., According to this system the scientific, name of sunflower is H elianthus annus. In the, above H elianthus indicates name of the genus, (generic name) and second word annus denotes, name of the species., The Binomial Nomenclature system follows, certain rules., y Name of organism is composed of two, Latin / Greek words., y Generic name is a simple noun. It should, come first and begin with capital letter., y Specific name is the descriptive adjective, which should come later and begin with, small letter., y Scientific names must be underlined, separately if hand written and must be, printed in italics., y The generic and specific name should not, have less than three letters and more than, thirteen letters., y Usually the name of the author who names, a plant or animal is also written in full or, abbreviated form after scientific name. e.g., Mangif era indica L. Where L stands for, Linnaeus., , Can you tell?, 1. Why horse and ass are considered to be, two different species or animals?, 2. Make a flow chart showing taxonomic, hierarchy., 2.12, , Nomenclature :, Any object that becomes known to, human intelligence must possess a name. It, may not be possible or convenient to describe it, in order to communicate ideas about it. The art, of naming the objects is in fact, a science called, nomenclature. All living organisms are known, by a particular name., 1. Vernacular / Local names / Common, names: Widely distributed organisms have, a large number of common names. Pansy, (V iola tricolor L. ) grown in most European, and American gardens has about 50 common, English names. In a multilingual country like, India, almost all useful plants have local names, which differ from language to language and, even from dialect to dialect. As in Ayurveda,, mango (Mangif era indica L. ) is known by over, 50 different names, all in the Sanskrit language., Hence the common names obviously have, limited usage and for universal applications, a, unique name for a particular individual is very, much essential., 2. Scientific Names : To overcome the, difficulties raised by common names, scientists, have given scientific names to all the known, organisms. These are systematic, thus provide, means for international communication., Initially the polynomial system was used, but Carl Linnaeus used binomial system of, nomenclature. He introduced this system in his, book ‘‘Species Plantarum’’ published in 1753., International Code of Botanical Nomenclature, (ICBN) has been set up to confirm the scientific, names., , Internet my friend, 1. Collect the information about most, recent system of classification of living, organisms and Kingdom System of, Classification. e.g. Search for APG, system of classification for Plants., 2. Collect, the, information, about, classification systems for all types of, organisms., , 9

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Membrane bound organelles e.g., mitochondria,, chloroplast,, endoplasmic, reticulum are absent. Ribosomes are smaller in, size (70S) than in eukaryotic cells. The mode of, reproduction in monera is asexual or with the, help of binary fission or budding. Very rarely,, sexual reproduction is by conjugation method., Morphologicaly,, bacteria, are, categorised into four groups, the sphericalCoccus, the rod-shaped bacillus, the comma or, kidney shaped- vibrio and the spiral- spirillum., On the basis of evolution, bacteria can, be classified as Archaebacteria and Eubacteria., , Know the scientists, Carl Linnaeus classified living, organisms in two kingdoms based on mode, of nutrition, whether they are migratory,, sedentary, etc. But this broad classification, as Kingdom Plantae and Kingdom Animalia, was found inadequate. It could not classify, the organisms that show characters of both the, Kingdoms for ex. Bacteria, Fungi, Euglena, etc. Hence to avoid confusion scientist R.H., Whittaker (1969) proposed Five Kingdom, system of classification. This system shows, the Phylogenetic relationship between the, organisms. The five kingdoms are., , a. Archebacteria :, These are differentiated from other, bacteria on the basis of their different cellular, features. These bacteria are mostly found, in the extreme environments; hence termed, extremophiles. They are found in a variety, of places from volcanic craters to salty lakes, and hot springs. Their ability to withstand such, hostile environment speaks of their capacity, to survive in very severe conditions. Bacteria, that can withstand high salinities are called, halophiles while those that withstand extreme, temperature are known as thermophiles. A, very common example is of methanogenic, bacteria found in gut of ruminants (cows and, buffaloes). These bacteria help in production of, methane in biogas plants., , 1. Kingdom Monera, 2. Kingdom Protista, 3. Kingdom Plantae, 4. Kingdom Fungi, 5. Kingdom Animalia, R. H. Whittaker, , 2.13, , Salient features of Five Kingdoms :, , 1. Kingdom Monera :, It contains unicellular organisms with, prokaryotic cellular organization. Monera, includes unicellular prokaryotic organisms., These are omnipresent. They are found in all, types of environment which are not generally, inhabited by other living beings. Few are, photoautotrophs or chemoautotrophs; but, majority are heterotrophic in nature. These, organisms do not have well defined nucleus., DNA exists as a simple double stranded, circular single chromosome called as nucleoid., Smaller circular molecules of DNA as extrachromosomal genetic elements called plasmids, are often present. Cell wall is made up of, peptidoglycan (also called murein) which is a, polymer of sugars and amino acids., , Coccus Coccobacillus, , Spirillum, , Vibrio, , Bacillus, , Spirochete, , Fig. 2.3 Different shapes of bacterial cells, b. Eubacteria :, These are commonly referred as true, bacteria. They have cell wall of peptidoglycan., They are found as autotrophs and heterotrophs., The autotrophs can be photosynthetic like, Chlorobium (Green sulphur bacteria) and, Chromatium or chemosynthetic like sulphur, bacteria., , 10

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2. Kingdom Protista :, This group includes all the unicellular, but eukaryotic organisms. These organisms, show link with all eukaryotic Kingdoms like, Plantae, Fungi and Animalia., , These are mostly multicellular, filamentous forms living in fresh water. The, body is covered by mucilagenous sheath., The genetic material is typical prokaryotic., Chl-a, Chl-b, carotenes and xanthothylls are, the photosynthetic pigments. Filaments show, heterocyst which helps in nitrogen fixation., Heterotrophs are the most abundant., Most of them are decomposers and known, for breaking down large molecules in simple, molecules or minerals. They can be anaerobes, helping in curdling of milk (L actobacilli),, fixation of nitrogen (Az otobacter), antibiotic, production (Streptomyces), composting and, degrading oil. But the story doesn’t end here,, some of them are pathogens i.e. causing disease, (typhoid, cholera, tuberculosis, tetanus)., , a. Plant like protista :, They are also termed Chrysophytes., They are commonly termed phyto-planktons., They are microscopic and mostly photosynthetic, and are major producers in oceans. Most of, them are referred to as diatoms as the have, body wall made up of two soap-box like fitting, silica covers. “Diatomaceous earth" is nothing, but these shells left behind for so many years., Diatomaceous earth is granular hence finds use, in polishing and filtration., , Heterocyst, Mucilagenous, sheath, , Fig. 2.5 Diatoms, b. Animal like Protista :- They are also termed, protozoans. They lack cell wall. They are, heterotrophs. They are believed to be primitive, animal forms. Amoeboid protozoans have, pseudopodia as locomotory organs. Amoeba is, free living form but Entamoeba is endoparasite, and causes amoebic dysentery. Flagellated, protozoans have flagella as locomotory, organ. Trypanosoma is a common flagellated, pathogen which causes sleeping sickness., Paramoecium is a cilliate protozoan, having cilia for locomotion. In Paramoecium,, gullet (a cavity) opens on the cell surface., Plasmodium is a sporozoan protozoa. It causes, malaria. It forms spores in one of its life stage., , Fig. 2.4 Cynaobacterium (N ostoc), Can you tell?, 1. What are salient features of Monera?, 2. What will be the shape of a bacillus and, coccus type of bacteria?, 3. Write a note on useful and harmful, bacteria., Mycoplasma :, These are smallest of the living forms., They do not have cell wall. Many forms are, pathogenic. They are found resistant to, common antibiotics due to absence of cell wall., , 11

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Micronucleus, , Macronucleus, , e. Euglenoids :- They lack cell wall but have a, tough covering of proteinaceous pellicle., They possess two flagella, one short, and other long. They behave as heterotrophs in, absence of light but possess pigments, similar, to that of higher plants, for photosynthesis., , Contractile, vacuole, , Food, Vacuoles, Cilia, Cytopyge, Lysosomes, , Gullet, Oral, Groove, Trichocyst, , Nucleus Nucleolus, , Fig. 2.6 Param oeciu m, , Flagellum, , Stored, carbohydrate, , c. Dinoflagellates :- These are aquatic (mostly, marine) and photosynthetic. The cell wall, is made up of cellulosic stiff plates. They, possess a pair of flagella. They have a wide, range photosynthetic pigments, which can be, yellow, green, brown, blue and red. Gonyaulax, is dinoflagellate that is responsible for famous, ‘red tide’. It makes even sea appear red., , Endoplasmic, reticulum, Photoreceptor, , 3. Kingdom Plantae:, The kingdom is dominated by, autotrophs. It also includes some semiautotrophic members, the insectivorous plants, like Venus fly trap, pitcher plant, bladderwort,, as well as heterotrophic parasitic members, like Cuscuta. Members of this kingdom, are multicellular, having eukaryotic cells, containing chlorophyll. Cells have cell wall, mostly made up of cellulose. Plants exhibit, alternation of generation i.e., life cycle has two, distinct phases. Kingdom Plantae is divided into, two major groups Cryptogamae / Cryptogams, and Phanerogamae / Phanerogams., We will study this kingdom in detail in, next chapter., , Epitheca, Cingulum, Plates, , Flagella, , Golgi apparatus, Contractile vacuole, , Fig. 2.8 Eu g l ena, , Apical horn, Flagellar pore (s), , Hypotheca, , Mitochondria, Chloroplasts, , Sulcus, Ventral view, , Anatomical horns, , Dorsal view, , Fig. 2.7 G ony au l ax, , 4. Kingdom Fungi : These are eukaryotic, heterotrophs showing extracellular digestion., They are found in warm and humid places. They, have simple body which may be unicellular or, made up of long thread like structures called, hyphae. Large fungi such as mushrooms have, a compact mass of cells. Unicellular organisms, have a protoplast with many nuclei. e.g., Rhiz opus, Saccharomyces (Yeast-unicellular, fungus)., , d. Fungi like protista :- They are commonly, from the group Myxomycetes. These are, saprophytic organisms found on decaying, leaves. Their cells aggregate to form a large, cell mass called plasmodium (not a malaria, parasite). The spores produced by plasmodium, are very tough and survive even very harsh, conditions., , 12

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Filamentous fungi consist of a body, called mycellium in which hyphae are present., The hyphae may be with septa or without, septa. They may be uni or multinucleate. The, non-septate multinucleate hyphae are called, coenocytic hyphae. The cell wall in fungi is, composed of chitin, a polysaccharide or fungal, cellulose. The fungi exhibit hetrotrophic mode, of nutrition. Mostly they are saprophytic, some, are parasitic or predators. They reproduce, sexually as well as asexually. Asexual, reproduction takes place by fragmentation,, fission and budding. Some fungi are symbiotic;, either live with algae as lichens or as mycorrhiza, in association with roots of higher plants., They are useful as well as harmful., Mushrooms are consumed as food, yeast is, used in bakery and breweries. Penicillium, a, fungus, is well known for antibiotic production., Harmful fungi cause diseases in plants and, animals. e.g. Puccinia., The fungi are further classified on the, basis of their structure, mode of spore formation, and fruiting bodies as follows-, , b. Ascomycetes :, These are called as sac-fungi. These, fungi are mostly multicellular. Rarely, unicellular varieties include yeast. The hyphae, are branched and septate. Sac fungi can be, decomposers, parasites or coprophilous (grow, on dung). Morels and truffles are varieties, of sac fungi that are consumed as delicacies., N eurospora is useful in genetic and biochemical, assays., Ex. Aspergillus, Penicillium, Claviceps,, N eurospora, Saccharomyces., , a. Phycomycetes :, These are commonly called algal fungi., Mycelium is made up of aseptate coenocytic, hyphae. They commonly grow in moist and, damp habitats, on decaying organic matter as, well as in aquatic habitats or as parasites on, plants., e.g. Mucor, Rhiz opus (bread mould),, Albugo (parasitic fungus on mustard)., , c. Basidiomycetes :, These are commonly called club fungi., They have branched, septate hyphae. e.g., Agaricus (mushrooms), Ganoderma (bracket, fungi), U stilago (smuts), Puccinia (rusts), etc., , Fig. 2.10 A spe rgi l l u s, , Sporangium, Sporangiophore, Hypha, , Fig. 2.11 Mushroom, d. Deuteromycetes :, These are called imperfect fungi, which, are known to reproduce only asexually., e.g. Alternaria, Colletotrichum., , Fig. 2.9 M u cor, , 13

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2.14 Acellular organisms :, a. Viruses : Viruses were named so by Louis, Pasteur; considering the meaning, Venom or, poison. These obligate parasites were given, the name 'virus' by M. J. Beijernek, after, observation that they were able to migrate in, an agar gel. Thus, being and infectious soluble, agent, he called the filtrate as 'contagium, vivum fluidum'. It was scientist Stanley who, demonstrated that viruses are inert outside, the host cell and can be crystallised. They are, made up of proteins., Viruses lack their own cell machinery., They have protein coat (capsid) around nucleic, acid strand, thus considered to be acellular, organisms. Viruses are inactive outside a host, cell; but once they enter their specific host cell,, they take charge of cellular machinery of host, cell and duplicate themselves. Viruses thus can, be called infectious nucleoprotein particles., , Fig. 2.12 A l ternaria, Can you tell?, 1. Write a note on economic importance of, fungi., 2. Why are fungi considered as heterotrophic, organisms?, 3. What are coenocytic hyphae?, 4. Classify fungi into their types., 5. Kingdom Animalia : Members of this, kingdom are heterotrophs; adapted to holozoic, nutrition. Most of them have capacity of, locomotion. They are multicellular eukaryotes, where cells lack chlorophyll as well as cell, wall. Growth is determinate (follow definite, pattern)., In chapter four, we will study, about Kingdom- Animalia and its further, classification., , Types of viruses :, As per genetic material, viruses are, grouped as DNA or RNA viruses., Do you know ?, Viruses have either DNA or RNA as, their genetic material but never DNA as well, as RNA., , Can you tell?, 1. Differentiate between Plantae and, Animalia., 2. How are fungi different from plants?, 3. Have you seen any diseased plant in your, farm?, Hollow core, , Do you know ?, , o, , RNA, , New variety of Banana seedlings, produced by tissue culture technique like, ‘Shrimanti’, Basarai, G-9 are virus free, varieties., , Radius 40 A, Capsomeres, , RNA, , Viruses, Viroids are groups of acellular, organisms that are not included in Whitaker’s, Five Kingdom classification., , o, , Pitch 23 A, , Fig. 2.13 Tobacco mosaic virus (TMV), , 14

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c. Lichens : Lichen is co-existence of algae, and fungi for mutual benefit. Algal member,, the phycobiont as it is called, mostly belongs, to cyanobacteria (blue-green algae) or green, algae. Fungal member is called mycobiont., They are excellent example of symbiosis. The, algal component of lichens provides food to, fungal part while fungus provides shelter to, alga and also absorbed water and minerals to, alga. The association is intense and it is difficult, to identify them as separate living beings., Though found in extreme environments, like snow clad poles, lichens are sensitive, to pollution. They are not found in polluted, regions, hence are considered as pollution, indicators. Lichens also play important, role in soil formation by using specific acid, productions., , Protein coat called capsid is made up of, smaller units, the capsomeres. Capsomeres are, arranged in polyhedral or helical forms. Capsid, protects genetic material., The genetic material in viruses is either, single-stranded RNA or single or doublestranded RNA or double-stranded DNA., Viruses that infect bacterial cells are called, bacteriophages which normally have doublestranded DNA., Head, Collar, , Core, Sheath, , Baseplate, Tail fibers, , Fig. 2.14 Bacteriophage, Viruses cause disorders like leaf curling,, yellowing, mosaic formation etc. in plants. You, have heard of foot and mouth disease in animals, or swine flu which are viral diseases. Small, pox, mumps, herpes to common cold, viruses, are the causative agents of many diseases in, humans. The list includes AIDS too!, b. Viroids : Potato spindle tuber disease was, found to be caused by single stranded RNA, which lacks protein coat. T. O. Diener in 1971, reported that this is low molecular weight, RNA and smaller in size than viruses. These, infectious RNA strands are called viroids., , Fig. 2.15 Lichens, Can you tell?, 1. Why are viruses called infectious, nucleoproteins?, 2. Describe genetic material in plant, and animal viruses as well as in, bacteriophages., 3. Differentiate between viruses and viroids., , o, , Internet my friend, , Prions : In modern medicine, certain infectious neurological, diseases were found to be transmitted by abnormally folded proteins. These proteins are called, prions. The word prion comes from ‘proteinaceous infectious particle’. e.g. mad cow disease in, cattle, Jacob's disease in human. Find more information about prions., , 15

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Monera, Prokaryotic, , Complete the following table on the basis of previous, knowledge., Protista, Fungi, Plantae, Animalia, Eukaryotic, Eukaryotic, Eukaryotic, Eukaryotic, , -------Absent, , Present in some, organisms, Present, , Unicellular, , ................., , Observe and Discuss, Characters, Cell type, Cell wall, Nuclear, membrane, Body, organization, Mode, nutrition, , of, ............., , Ecological, role, , Decomposers, , Autotrophic, Photosynthetic, Heterotrophic, ...................., , ..............., Present, , Present, (cellulose), ................, , Multicellular/ Tissue /organ, loose tissue, ..................., , Autotrophic, (Photosynthetic), , Decomposers, , ................., , ..............., Present, Tissue/, organ, /system, -------Consumers, , Do Yourself, Complete the following table through collecting information about sunflower,, tiger with characteristic features., Taxon, , Characteristics, , Category, Kingdom, , Taxon, , Characteristics, , Tiger, , Sunflower, , Category, Kingdom, , 16

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Exercise, 1. Choose correct option, A. Which of the following shows single, stranded RNA and lacks protein coat?, a. Bacteriophage, b. Plant virus, c. Viroid, d. Animal virus, B. Causative agent of red tide is, _____________., a. Dinoflagellate, b. Euglenoid, c. Chrysophyte, d. Lichen, C. Select odd one out for Heterotrophic, bacteria., a. Nitrogen fixing bacteria, b. Lactobacilli, c. Methanogens, d. Antibiotic production, D. Paramoecium : Ciliated Protist, Plasmodium : ____________, a. Amoeboid protozoan b. Ciliophora, c. Flagellate protozoan d. Sporozoan, , 5. Draw neat labelled diagrams, A. Paramoecium, B. Euglena, C. TMV, 6. Complete chart and explain in your word, , Types of Viruses, , Animals, , 7. Identify the following diagrams, label, them and write detail information in, your words, , 2. Answer the following, A. What are the salient features of monera?, B. What will be the shape of bacillus and, coccus type of bacteria?, C. Why is binomial nomenclature, important?, , A, , 3. Write short notes, A. Useful and harmful bacteria., B. Five Kingdom system, C. Useful Fungi, 4. Complete tree diagram in detail, Fungi, , B, Protista, , 17

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8. The scientific name of sunflower is given, below. Identify the correctly written, name., A. H elianthus annus, B. H elianthus Annus, 9. Match the following., Kingdom, i. Monera, ii. Protista, iii. Plantae, iv. Fungi, , C, , Examples, a. Lichen, b. Cyanobacteria, c. Rhiz opus, d. Spirogyra, , 10. Complete the following, A. Plant-like Protista B., , - Entamoeba, , Practical / Project :, 1. Make a group of students. Observe, living organisms in your school/college, campus and try to write their characters, with respect to habit, habitat, mode, of nutrition, growth- determinate or, indeterminate, type of reproduction, - vegetative reproduction - asexual, reproduction - Sexual reproduction., With the help of similarity and, dissimilarity, try to classify organisms, into different categories. Similar work, should implement for animal group., 2. Find out types of lichens and its economic, importance., , D, , E, , F, , 18

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3. Kingdom Plantae, Can you recall?, , Observe and Discuss, , 1. Why do we call as plants producers on, land ?, 2. What, are, differences, between, sub-kingdoms, Cryptogamae, and, Phanerogamae?, 3. Differentiate between Thallophytes and, Bryophytes., 4. Give any two examples of Pteridophyta., , Collect different water samples of, fresh water. Mount them on a glass slide and, observe under a compound microscope. Try, to identify the organisms which are visible, under it., , 3.2, , 3.1, , Kingdom plantae :, In earlier chapter, we have studied, different aspects of classification., Kingdom Plantae is further classified, on the basis of characteristics like absence, or presence of seeds, vascular tissues,, differentiation of plant body, etc., • Phanerogams are commonly called seed, producing plants. They produce special, reproductive structures that are visible, (Phaneros – visible), • Cryptogams are spore producing plants, and do not produce seeds and flowers., They reproduce sexually by gametes but, sex organs are concealed (kryptos : hidden,, gamos : marriage)., , Salient features of major plant, groups under Cryptogams :, , A., Division : Thallophyta - Members, are mostly aquatic, few grow on other plants, as epiphytes. Some grow symbiotically and, epizoic i.e. growing or living non-parasitically, on the exterior of living organisms. Aquatic, algae grow in marine or fresh water. Most of, them are free living while some are symbiotic., Plant body is thalloid i.e. undifferentiated, into root, stem and leaves. They may be small,, unicellular, microscopic like Chlorella (nonmotile), Chlamydomonas (motile). They can, be multicellular, unbranched, filamentous like, Spirogyra or branched, filamentous like Chara., Sargassum, a huge macroscopic sea weed, which measures more than 60 meters in length, is also an alga., , Classification of Kingdom Plantae is, represented as follows :, Kingdom- Plantae, Cryptogams, Non-Vascular Plants, Thallophyta, , Phanerogams, , Vascular Plants, Bryophyta, , Pteridophyta, , Vascular Plants, Gymnosperms, Dicotyledonae, , Chart 3.1 Classification of Kingdom Plantae, , 19, , Angiosperms, Monocotyledonae

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The algal cell wall contains either, polysacchrides like cellulose / glucose or a, verity of proteins or both. Reserve food is in the, form of starch and its other forms. Reprocuction, takes place by vegetative asexual and sexual, way. The life cycle shows phenomenon of, alternation of generation, dominant haploid and, reduced diploid phases. Algae are classified as, per its pigments like chlorophyll, xanthophylls, and phycobilin., , Pyrenoids are located on Chloroplast., Members are rich in protein, so used as food;, used even by space travellers. e.g. Chlorella., Chlamydomonas, Spirogyra, Chara, V olvox,, U lothrix etc., Internet my friend, 1. Make a list of green algae with their, characteristic shape of chloroplast., 2. Enlist the forms of filamentous algae., 3. Write different pigments found algae., , a. Chlorophyceae (green algae) :, These are mostly fresh water (few, brackish water and marine)., Plant body is unicellular, colonial, filamentous., Cell wall contains cellulose., Chloroplasts are of various shapes, like discoid, plate-like, reticulate, cup-shaped,, ribbon-shaped or spiral with chlorophyll a and, b. The stored food is in the form of starch., , b. Phaeophyceae (Brown algae) :, Plant body : Mostly marine, rarely, fresh water. Simple branched / filamentous (e.g., Ectocarpus) / profusely branched (Petalonia)., Cell wall has cellulose, fucans, and algin. Photosynthetic pigments like, chlorophyll-a, -c and fucoxanthin are present., Mannitol, laminarin and starch are stored, food materials. Body is usually differentiated, into holdfast, stalk called stipe and leaf-like, photosynthetic organ called frond. Many, species of marine algae are used as food. e.g., Porphyra, L aminaria, Sargassum. Some species, are used for production of hydrocolloids. e.g., Ectocarpus, F ucus, etc., , Chloroplast, Nucleus, , C hl am y dom, , onas, , Pyrenoid (starch storage), Mitochondria (Amino acid synthesis), , Oogonium, (contains eggs), , Lamina, , C hara, Antheridium, (contains sperm), , Stipe, Holdfast, , Gametophyte, Mucilage Cell membrane, Cytoplasm, Cell wall, , Cytoplasm, Nucleus Pyrenoid, strand Chloroplast Vacuole, , L am inaria, , S pi rogy ra, , S argas su m, , F u cu s, , Fig. 3.2 Chlorophyceae, , Fig. 3.3 Phaeophyceae, , 20

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c. Rhodophyceae (Red algae) :, Plant body These are found in marine, as well as fresh water on the surface, deep sea, and brakish water. Plant body is thalloid. Cells, contain chlorophyll a, d and phycoerythrin., Cell wall is made up of cellulose and pectin, glued with other carbohydrates. Stored food is, in the form of Floridean starch. Commercially, important agar-agar which is used as solidifying, agent in tissue culture medium is obtained from, red algae. e.g. Chondrus, Batrachospermum, Porphyra, Gelidium , Gracillaria, Polysiphonia,, etc., , Can you tell?, 1. What are the three major groups of, Cryptogams ?, 2. Name the accessory pigments of algae., 3. Give salient features of algae., Differentiate between Chlorophyceae and, Phaeophyceae., 4. Enlist examples of Chlorophyceae and, Rhodophyceae., Observe and Discuss, You may have seen F unaria plant in, rainy season. Why is it called amphibious, plant?, , B atrachospe rm u m, , B. Bryophyta, (Bryon : moss ; phyton : plant), Bryophytes are mostly terrestrial, plants. They are found in moist shady places., But they need water for fertilization and, completion of their life cycle. Hence they, are called ‘amphibious plants’. They include, approximately 960 genera and about 25,000, species., Life cycle of Bryophytes shows, sporophytic and gametophytic stages., Vegetative plant body is thalloid or leafy which, represents gametophytic generation. Spore, producing capsule represents sporophytic, generation., Bryophytes have root-like structures, called rhizoids. Rhizoids are unicellular in, liverworts while multicellular in mosses., Rhizoids absorb water and minerals and also, help in fixation of thallus on the substratum., Bryophytes are divided into two groups :, liverworts and mosses., a. Liverworts (Hepaticeae) :, These are lower members of Bryophyta., These are primitive group of Bryophytes., Gametophyte possesses flat plant body called, thallus. The thallus is green, dorsiventral,, prostrate with unicellular rhizoids. e.g. Riccia,, Marchantia., , G racil l aria, , Pol y siph onia, , Fig. 3.4 Rhodophyceae, Internet my friend, 1. Economic importance of algae., 2. Role of algae in environment., 3. Different forms of green, red, brown and, blue green algae., Do you know ?, Brown algae- kelps may grow up, to 100 meters in height. Find out more, information about Sargasso sea., , 21

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Hornworts (Anthocerotae) - These member, possess flattened thallus. The thallus produces, horny structures which are called sporophytes, hence the name hornworts. e.g. Anthoceros., b. Mosses (Musci) :, These are advanced members of, Bryophyta which possess erect plant body., Gametophytic phase of the life cycle, includes two stages namely; protonema stage, and leafy stage. The protonema is prostrate, green, branched and filamentous (it is also, called juvenile gametophyte). It bears many, buds. Leafy stage is produced from each, bud. Thus protonema helps in the vegetative, propagation. The leafy stage has erect, slender, stem like (Cauloid) main axis bearing spiral, leaf like structures (Phylloid). It is fixed in soil, by multicellular branched rhizoids. This stage, bears sex organs. Vegetative reproduction, takes place by fragmentation and budding in, secondary protonema., e.g. F unaria, P olytrichum, Sphagnum , etc., , Economic importance Some mosses provide food for, herbivorous mammals, birds, etc. Species of, Sphagnum, a moss; provides peat used as fuel., Mosses are also used as packing material for, transport of living materials because they, have significant water holding capacity. Just, like lichens, mosses are the first living beings, to grow on rocks. They decompose rocks to, form soil and make them suitable for growth, of higher plants. Dense layers of mosses help, in prevention of soil erosion, thus act as soil, binders., C. Pteridophyta, (Pteron : feather, phyton : plant), Evolutionarily, Pteridophytes are the, first vascular and true land plants. Hence, considered as the first successful terrestrial, plants with true roots, stem and leaves. These, plants have a primitive conducting system and, they are the only Cryptogams with vascular, tissues. The late Paleozoic era is regarded as the, age of Pteridophytes. The group has about 400, genera and 11,000 species. The plants consist, of pinnate (feather like) leaves. Leaves may, be small called microphylls (e.g. Selaginella), or large called macrophylls (e.g. N ephrolepis /, fern)., Blade, , A nthoceros, , R iccia (Liverworts), , Frond, Capsule, , Seta, , Sporophyte, Rhizome, , foot, , Back side, , Roots, , Front side, , Gametophyte, , F u naria, , Main axis, , Rhizoids, , Fig. 3.5 Mosses, , Fig. 3.6 N eph rol epi s (Fern), , 22

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Observe and Discuss, , Observe and Discuss, , You may have seen the various plants, which do not bear flowers, fruits and seeds, but they have well developed root, stem and, leaves. Discuss., , Observe all garden plants like Cycas,, Thuja, Pinus, Sunflower, Canna and compare, them. Note similarities and dissimilarities, among them. Which differences did you notice, between Gymnosperms and Angiosperms?, , Pteridophytes grow in moist and shady, places. Pteridophytes show sporophytic and, gametophytic stages in life cycle. e.g. Ferns,, Horsetail. Some are aquatic (Az olla, Marsilea),, xerophytic, (Equisetum), and, epiphytic, (L ycopodium)., Pteriodphytes show heteromorphic, alternation of generations in which the, sporophyte is diploid, dominant, autotrophic, and independent. It is differentiated into root,, stem and leaves. The primary root is short lived, and soon replaced by adventitious roots while, the stem may be aerial or underground. Leaves, may be scaly (Equisetum) simple and sessile, (L ycopodium) or large and pinnately compound, (N ephrolepis / Ferns)., In these members Xylem consists of, only tracheids and Phloem consists of only, sieve cells. Secondary growth is not seen in, Pteridophytes due to absence of cambium., Pteridophytes are classified as Psilopsida- (Psilotum), Lycopsida - (Selaginella, and L ycopodium), Sphenopsida - (Equiesetum), and Pteropsida - (Dryopteris, Pteris and, Adiantum), , 3.3, , Salient features of major plant groups, under Phanerogams, , A. Gymnospermae, (Gymnos : naked, sperma : seed) :There are about 70 genera and 1000, living species of Gymnosperms in world. In, India it is represented by 16 genera and 53, species., Scale, leaves, , Stem, , a. C y cas plant, body, , b. Scale leaf, in C y cas, , Economic importance - Pteridophytes are, Used for medicinal purpose and as soil binders., Many varieties are grown as ornamental plants., Can you tell?, 1. Distinguish between Bryophyta and, Pteridophyta., 2. Why Bryophyta are called amphibians of, Plant Kingdom?, 3. Pteridophytes are also known as vascular, Cryptogams - Justify., 4. Give one example of aquatic and, xerophytic Pteridophytes., , c. Coralloid roots of, C y cas, d. Megasporophyll, of C y cas, , 23, , Fig. 3.7 C y cas plant, details

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Most of the Gymnosperms are, evergreen, shrubs or woody trees. These are, primitive group of flowering plants producing, naked seeds. Seeds are not covered by fruit i.e., ovary. They are vascular plants having Xylem, with tracheids and Phloem with sieve cells., , Do you know ?, Gymnosperms like Ginkgo biloba is, called living fossil. It is because the plant is, found in living as well as fossil form and the, number of fossil forms is much more than the, living forms., Gymnosperms vary in their size. e.g., Sequoia sempervirens is the tallest living plant, in the world. It is commonly called coast red, wood of California. The height of the plant is, about 366 feet. Taxodium mucronatum has a, girth of about 125 feet. Zamia pygmaea is the, smallest Gymnosperms and is about 25 cm, only., , The plant body is sporophyte. It is, differentiated into root, stem and leaves. The, root system is tap root type. In some, roots form, symbiotic association with other life forms., Coralloid roots of Cycas show association, with blue green algae and roots of Pinus, show association with endophytic fungi called, mycorrhizae., In Gymnosperms, stem is mostly erect,, aerial, solid and cylindrical. Secondary growth, is seen in Gymnosperms due to presence of, cambium. In Cycas it is usually unbranched,, while in conifers it is branched. The leaves, are diamorphic. The foliage leaves are green,, simple needle like or pinnately compound,, where as scale leaves are small, membranous, and brown. Spores are produced by, microsporophyll (Male) and megasporophyll, (Female)., , Try this, Study the leaves of H ibiscus, Peepal,, Canna, Grass and Tulsi. Classify them as, Monocot and Dicot., , Can you recall?, 1. What are the salient features of, Angiosperms?, 2. What is double fertilization ?, 3. Explain in brief two classes of, Angiosperms? Draw and label one, example of each class., , Economic importance - Cycas is grown as, ornamental plant. Pinus is used as source of, pine wood, turpentine oil and pine resin., , B. Angiospermae (Angios : enclosed :, vessel, Sperma : seed), Angiosperms are the most advanced, group of flowering plants. In these plants the, seeds are enclosed within the fruit i.e. ovary., Angiosperms is a group of highly evolved, plants, primarily adapted to terrestrial habitat., They vary in size., Angiosperms show heteromorphic, alternation of generation in which the, sporophyte is diploid, dominant, autotrophic, and independent. The gametophytes (male or, female) are recessive, haploid and dependent, on the sporophyte., , Fig. 3.8 Pinu s tree with cones, , 24

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Angiosperms, are, heterosporous., Microspores (commonly called pollens) are, formed in microsporangia (or anthers). They, develop in highly specialized microsporophyll, or stamens while megaspores are formed in, megasporangia (or ovules) borne on highly, specialized megasporophyll called carpel., Besides the essential whorls of, microsporophylls, (Androecium), and, megasporophylls (Gynoecium) there are, accessory whorls namely calyx (sepals) and, corolla (petals) arranged together to form, flowers., , a. Monocotyledonae : These plants have, single cotyledon in their embryo. They have, adventitious root system and stem is rarely, branched. Leaves generally have sheathing leaf, base and parallel venation while the flowers, are generally trimerous., The vascular bundles are conjoint,, collateral and closed type. In Monocots, except, few plants secondary growth is absent. e.g. Zea, mays (Maize), Sorghum vulgare (Jowar)., Tassel, , Corn seed, , Silks, , Leaf blade, , Do you know ?, Wolffia is the smallest Angiosperm,, 1mm in size and Eucalyptus grows to over, 100 meters., , Ear, , Angiosperms are subdivided into two classes:, a. Dicotyledonae : These plants have two, cotyledons in their embryo. They have a tap, root system and the stem is branched. Leaves, show reticulate venation while the flowers, show tetra or pentamerous symmetry., Vascular bundles are conjoint, collateral, and open type. Cambium is present between, Xylem and Phloem for secondary growth. In, Dicots secondary growth is commonly found., e.g. H elianthus annus (sunflower), H ibiscus, rosa- sinensis (China rose)., , Roots, , Fig. 3.10 Z ea m ay s (Maize), Can you tell?, 1. Give general characters of Gymnosperms, and Angiosperms., 2. Distinguish between Dicotyledonae and, Monocotyledonae., 3. Why do Dicots show secondary growth, while Monocots don't?, 3.4, , Plant life cycle and alternation of, generations:, Life cycle of a plant includes two phases, or distinct generations namely sporophyte, (diploid : 2n) and gametophyte (haploid : n)., Some special diploid cells of sporophyte divide, by meiosis to produce haploid cells. These, haploid cells divide mitotically to give rise, to gametophyte. The gametophyte produces, male and female gametes which fuse during, fertilization to produce diploid zygote. It, divides by mitosis to form diploid sporophyte., The sporophytic and gametophytic generations, generally occur alternately in the life cycle of, a plant. This phenomenon is called alternation, of generations., , Seeds, , Ray florets, Disk florets, , Stem, Tap root, , Inflorescence, of Sunflower, Fig. 3.9 H el ianthu s annu s (Sunflower), , 25

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Distinct alternation of these two, generations is observed in Bryophytes, and Pteridophytes. In Gymnosperms and, Angiosperms, gametophyte is much reduced, and exists within sporophyte. In algae, based, upon the nature of dominant phase in life, cycle, it is called haplontic, diplontic or haplodiplontic life cycle., In Bryophytes haploid gametophyte, is dominant. It is photosynthetic, independent, thalloid or erect phase. Sporophyte is short, lived, multicellular and depends totally, or partially on gametophyte for nutrition, and anchorage. Whereas in Pteridophytes,, sporophyte is dominant, independent and, vascular plant body. Haploid multicellular, gametophyte is generally autotrophic and short, lived. It alternates with Sporophyte., , Fertilization, , Gametes, (1n), , 2n, , Can you tell?, 1. What is alternation of generations?, 2. Which phase is dominant in the life cycle, of Bryophyta and Pteridophyta ?, , Fertilization, , Diploid, multicellular, In animals organism, Mitosis, , Meiosis, , Fungi and, some algae, , or, , Gametes, , es, , Haplo-Diplontic, Haploid multicellular, organism, Mitosis, Mitosis, , or, , Meiosis, , Spores, (1n), , Fig. 3.11 Alternation of generation, , Sp, , Fertilization, , Meiosis, , Gametophyte (1n), , Haplontic, Haploid single-cell or, multicellular organism, Mitosis, Mitosis, , Gametes, , Sporophyte, phase, Gametophyte, phase, , es, , n, , Zygote, (2n), , Sp, , Diplontic, , Sporophyte (2n), , Fertilization, , Plants and, some algae, , Meiosis, Diploid, multicellular, organism, , Fig. 3.12 Types of life cycle, Diplontic :, Here, mitotic, divisions occurs only in, diploid, cells., Gametes, formed through meiosis are, haploid in nature. The diploid, zygote divide mitotically., In this process production, of, multicellular, diploid, organism or in the production, of many diploid single cells, takes place. E.g. Animals., , Haplontic :, Here, mitosis, occurs, in haploid cells. It results in the, formation of single haploid cells or, a multicellular haploid organism., These forms produce the gametes, through mitosis. Zygote is formed, After fertilization. This cell is the, only diploid cell in the entire life, cycle of the organism. Thus the same, zygotic cell later undergoes meiosis., E.g. Some Algae and Fungi., , 26, , Haplo-diplontic :, Here, mitosis, occur in both diploid, and haploid cells. These, organisms undergo through, a phase in which they are, multicellular and haploid, (the gametophyte), and a, phase in which they are, multicellular and diploid, (the sporophyte). E.g. Land, plants and in many algae.

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Exercise, 4. Differentiate between Dicotyledonae and, Monocotyledonae based on the following, characters, a. Type of roots, b. Venation in the leaves, c. Symmetry of flower, , 1. Choose correct option, A. Which is the dominant phase in Pteridophytes?, a. Capsule, b. Gametophyte, c. Sporophyte, d. Embryo, B. The tallest living gymnosperm among, the following is .........., a. Sequoia sempervirens, b. Taxodium mucronatum, c. Zamia pygmaea, d. Ginkgo biloba, , 5. Answer the following questions, A. We observe that land becomes barren, soon after monsoon. But in the next, monsoon it flourishes again with, varieties we observed in season earlier., How you think it takes place?, B. Fern is a vascular plant. Yet it is not, considered a Phanerogams. Why?, C. Chlamydomonas is microscopic whereas, Sargassum is macroscopic; both are, algae. Which characters of these plants, includes them in one group?, D. Which of the following nuts will not, be enclosed in fruits? What are the, peculiar characteristics of these plants?, Betel nut/ Areca nut, pine nut, walnut,, almond, cashew nut, nutmeg., , C. In Bryophytes .........., a. Sporophyte and gametophyte, generation are independent, b. Sporophyte is partially dependent, upon gametophyte, c. Gametophyte is dependent upon, Sporophyte, d. Ginlgo biloba, D. A characteristic of Angiosperm is ........., a. Colloteral vascular bundles, b. Radial vascular bundles, c. Seed formation, d. Double fertilization, E. Angiosperms and Gymnosperms, resemble in having .........., a. Vessels in wood, b. Mode of nutrition, c. Siphonogamy, d. Nature of seed, , 6. Girth of a Maize plant does not increase, over a period of time. Justify, 7. Radha observed a plant in rainy season, on the compound wall of her school. The, plant did not have true roots but rootlike, structures were present. Vascular tissue, was absent. To which group the plant, may belong?, , 2. How you place the pea, jawar and fern, at its proper systematic position? Draw a, flow chart with example of., 3. Complete the following table, Groups of algae, 1. Stored food, 2. Cell Wall, , Chlorophyceae, Starch, , Phaeophyceae, , Rhodophyceae, , Cellulose and algin, , 3. Major pigments, , Chl- a, d and Phycoerythrin, , 27

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8. Draw neat labelled diagrams, A. Spirogyra, B. Chlamydomonas, C. F unaria, D. N ephrolepis, E. Haplontic and haplodiplontic life cycle, , 10. Observe the following diagram. Correct, it and write the information in your, words., Sporophyte (2n), Gametes, (1n), , 9. Identify the plant groups on the basis of, following features., A. Seed producing plants, B. Spore producing plants, C. Plant body undifferenciated into Root,, Stem and leaves, D. Plant need water for fertilization, E. First vascular plants, , Meiosis, , Gametophyte, phase, Sporophyte, phase, , Zygote, (2n), , Spores, (1n), , Practical / Project :, 1. Study the N eph rol epi s plant in detail., 2. Study the coralloid roots, scale leaf, and megasporophyll of cycas in, detail., , 28, , Fertilization

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4. Kingdom Animalia, Can you recall?, , c. Tube within tube body plan : Digestive, system is present in tube-like body cavity., Mouth and anus are present at two separate, ends of digestive system. Annelida onwards all, phyla show this type of body plan., , 1. What is the basis for classification ?, 2. Who, proposed, Five, Kingdom, classification system?, 3. What is the need and importance of, classification?, You are familiar with animals, their, general characteristics and great diversity, observed in this group. Let us learn about how, this diverse group is classified systematically., 4.1, Criteria used for animal classification:, Grades of organization - Cellular,, Cell-Tissue, Tissue-Organ, Body SymmetryAssymmetry, Radial Symmetry, Bilateral, Symmetry, Body Cavity - Acoelomate,, Pseudocoelomate, Coelomate. Germ Layers, -Diploblastic, Triploblastic. SegmentationUnsegmented, Segmented., , Fig. 4.3 Fish, Observe and Discuss, Observe the diagram given below and, discuss the criterias of classification., Triploblast, , Diploblast, Endoderm, , 4.2, Animal body plan :, a. Cell aggregate plan : In this body plan, cells, do not form tissues or organs. Their is minimal, differentiation and division of labour among, cells. It is found in porifera., , Digestive, cavity, Ectoderm, Non-living layer, , Mesoderm, , Fig. 4.1 Sponge, b. Blind sac body plan : In this body plan,, body is like a sac with single opening. Digestion, is carried out in this sac-like structure where, ingestion and egestion takes place through same, opening. e.g. Members of Phylum Cnidaria., , Asymmetry, , Radial, , Bilateral, , Types of Symmetry, 4.3, Animal Classification :, 1. Phylum : Porifera, (pori-pores; feron-bearing), e.g. Scypha, Euspongia (Bath sponge),, Euplectella (Venus' flower basket), These are aquatic animals, most of, them are marine and few are fresh water. They, are also called 'sponges'., , Mouth, , Fig. 4.2 H y dr a, , 29

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They reproduce asexually as well as, sexually. Asexual reproduction is performed by, fragmentation and gemmule formation. These, animals have ability of regeneration. Sexual, reproduction is performed by formation of, gametes. Fertilization is internal. Development, takes place through indirect larval stage., , Most of them have asymmetrical body., Body of these animals consists of many cells, with little division of labour. Hence their body, is considered as a colony of different types of, cells., These are sedentary animals. On their, body, they bear numerous minute pores called, 'ostia' through which water enters in the body, cavity- spongocoel. Water leaves the body, through single large opening called 'osculum'., Water is circulated in the body through, the 'canal system'. During its circulation, cells, of the animal body absorb food, exchange, respiratory gases and release excretory, products., , Osculum, Silica spicules, Ostium, , central, cavity, , Osculum, , Mesohyl, (semi fluid, matrix), Epidermis, , Collar, , Choanocyte, , Ostia, holdfast, , Choanocyte, Body, , Flagellum, , Nucleus, , Fig. 4.5 Typical Sponge body, , Apopyle, , Internet my friend, Common, Base, , Which are the larval stages of Porifera?, , a. S y con, , b. Eu sp ong ia, , 2. Phylum : Cnidaria, e.g. H ydra, Aurelia (Jelly fish), Physalia, (Portuguese man-of-war), Adamsia (sea, anemone), Diploria (Brain coral), Gorgonia, (sea fan)., They are aquatic, mostly marine and, few are fresh water forms. They are sessile or, free swimming. They show radial symmetry, and are diploblastic with blind-sac body, plan. Animals exhibit two body forms. Polyp, is cylindrical form (H ydra) and medusa is, umbrella-like (Aurelia - Jelly fish)., , c. Eu p l ectel l a, , Umbrelar surface, , Fig. 4.4 Animals - Porifera, , Marginal lappet, Subumbrelar, surface, , Spongocoel is lined by special, flagellated cells called 'choanocytes' or 'collar, cells'. Beating of flagella creates water current., Body of these animals is supported, by calcareous or siliceous 'spicules' or, proteinaceous 'spongin fibers'., , Oral arm, , Marginal tentacles, , A u rel ia, Fig. 4.6 Animal of Cnidaria, , 30

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Body cavity is meant for circulation as, well as digestion. Hence called gastrovascular, cavity or coelenteron. Tentacles bear cnidoblasts, or stinging cells which are meant for anchorage,, offence and defence. Cnidarians reproduce both, asexually and sexually. Asexually reproduction, takes place by budding and regeneration., Sexual reproduction takes place by gamete, formation. They exhibit alternation of polypoid, generation with medusoid generation. This, phenomenon is called metagenesis i.e. polyps, produce medusae asexually and medusae, produce polyps sexually. (e.g. Obelia), Spines, , Secretory (adhesive), granules, Adhesive, granule, Radiating fibre, Covering cell, Spiral filament, (nucleus), Straight filament, (nucleus), , Nucleus, Root, , Mesenchyme, , Spiral, filament, Synapse, Neuron, , C ol l ob l ast, , Thread tube, , Stylet, , Operculum, , Refractile rods, Lasso, , Pl eu rob rachia, , Cytoplasm, Before discharge, , Fig. 4.8 Animal of Ctenophora, , Nucleus, After discharge, , 4. Phylum : Platyhelminthes, (platy -flat, helminth -worms), e.g. Planaria, Taenia (Tapeworm),, F asciola (Liver fluke)., Body of these animals is dorsoventrally flattened, hence are called as flat, worms. Animals are acoelomate, triploblastic, showing organ-system grade of organization., Mostly endoparasitic and few are free-living., Parasitic forms shows presence of hooks and, suckers for attachment to the body of host., Body is covered by cuticle (in parasites) or, cilia (in free-living forms). Digestive system is, generally absent in parasitic forms, but in freeliving forms, it is incomplete (blind-sac plan)., Animals have flame cells or protonephridia,, helpful for excretion and osmoregulation., Animals are hermaphrodite (bisexual). Self, fertilization is seen. Few have high power of, regeneration and show polyembryony., , Fig. 4.7 Cnidoblast, Find out, Information about coral reef and sea fan., , 3. Phylum : Ctenophora, These are commonly called comb jellies, or sea walnuts. These are exclusively marine,, free swimming animals. Body is diploblastic,, radially symmetrical with blind-sac body, plan. Animals have tissue-level organisation., Locomotion is carried out by eight rows of, cilliated comb plates. Characteristic feature, of ctenophores is bioluminescence. Like, cnidarians, ctenophores also exhibit extra, and intracellular digestion. Reproduction is, sexual with indirect development. Cnidoblasts, are absent hence these are called acnidarians., Instead, they have colloblasts (sticky cells) to, capture the prey. Ctenophora is represented by, very few members, hence it is considered as, one of the minor phyla. e.g. Pleurobrachia ,, Ctenoplana., , 31

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Oral, Sucker, , Mouth, , Gastrovascular, Cavity, , Pharynx, Head lobe, , Eyespots, , Immature, proglottid, , Neck, Sucker, hook, , Mature, proglottid, Gravid, proglottid, Ventral nerve cords c. Pl anaria, , a. F asciol a, b. T aenia, , Excretory pore, , Fig. 4.9 Animals of platyhelminthes, 5. Phylum : Aschelminthes (ascus-sac,, helminth-worm) / Nemathelminthes, (nema-thread), e.g. Ascaris (Roundworm), W uchereria, (filarial worm), Ancylostoma (hook worm)., These are mostly parasitic, few forms, are free-living. Body is long, cylindrical, thread, like, circular in cross-section, hence are called, round worms. They are triploblastic, bilaterally, symmetrical, pseudocoelmate, with tube within, tube body plan. Body is covered by tough and, resistant cuticle. Body wall has longitudinal, muscles but no circular muscles. Alimentary, canal is complete with mouth and anus at, opposite ends. Pharynx is well developed and, muscular. Excretion takes place by canals or, gland cells. Excretory products are eliminated, through excretory pore. Nervous system has, nerve ring and nerves. Animals are unisexual, i.e. sexes are separate. Animals like Ascaris, shows sexual dimorphism. Usually female is, longer and broader and have straight posterior, end. Male is shorter and narrower and has, curved posterior end with a pair of penial, setae for copulation. Fertilization is internal., Development may or may not include larval, stage., Tail, Anal pore, , Anus, , Tail, , Dorsal lip, , Mouth, , Ventral lip, , Cloaca, Tail, , Head, Male, Cuticle, a. Ascaris, , Head, Female, , b. Ancylostoma hookworm, , Fig. 4.11 Animals of Aschelminthes, Can you tell?, 1. State parasitic adaptations in liverfluke, and Ascaris., 2. Give example of free living platyhelminth., 6. Phylum : Annelida (Annulus : Ring), e.g. N ereis, Pheretima (Earthworm),, H irudinaria (Leech)., They are commonly called ring worms, or segmented worms. Animals may be aquatic, and few may be ectoparasitic or free living or, burrowing in moist soil. They show bilateral, symmetry with metameric segmentation., , Mouth, Sheath, , Fig. 4.10 Wuchereria, , 32

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A special region of the body called clitellum is present. Locomotion is with the, help of longitudinal and circular muscles., Locomotory structures like setae (earthworm),, parapodia (N ereis) or suckers (leech) are, present. Alimentary canal is complete., Exchange of gases takes place through body, wall. Circulatory system is of closed type., Excretion and osmoregulation is carried out, with the help of nephridia. Nervous system, consists of nerve ring and ventral nerve cord., Nerve cord is ventral, solid and ganglionated., Mostly hermaphrodites and few are dioecious, (N ereis)., , This is largest phylum of kingdom, animalia. These animals have jointed, appendages, hence the name -Arthropoda., These are omnipresent and solitary or colonial,, most of them are free-living (Barnacles are, sedentary). Few are parasitic and sanguivorous, (female mosquito, bed bug). Their body, is bilaterally symmetrical, triploblastic,, eucoelomate, metamerically segmented with, tube within tube body plan and organ-system, level of organization. Body is covered by, tough, non-living chitinous exoskeleton. Hence,, they need periodic moulting (ecdysis). Body is, divided into head, thorax and abdomen., , a. N ereis, , a. Peripl aneta, , b. A rchispi rostrept u s, , c. H ottentotta, c. Pheretim a, , b. H iru do, , Fig. 4.13 Animals of Arthropoda, , Fig. 4.12 Animals of Annelida, Always Remember, All animals from Annelida onwards, are triploblastic, coelmate with organ system, level of organization., Find out, 1., 1. What are the merits and demerits of, hermaphroditism?, 2. Why are leeches used in Ayurveda?, 3. What is the role of earthworms in, agriculture? What is vermicompost?, 7. Phylum : Arthropoda (Arthros : Joint,, Podos : leg), e.g. Cockroach, Butterfly, Scorpion,, Millipede , Prawn., , 33, , Digestive, system, is, complete., Circulatory system is of open type, blood flows, through body cavity (haemocoel). Respiratory, organs are gills, trachea, book lungs, book gills., Excretion takes by green glands, Malpighian, tubules or coxal glands. Nervous system is, formed by nerve ring and double, ventral,, ganglionated nerve cord. Sense organs are, well developed in the form of antennae, simple, or compound eyes, various receptors. Sexes, are separate showing sexual dimorphism,, fertilization is generally internal, development, is direct or indirect by metamorphosis. In some, arthropods like honey bees, bugs etc. offsprings, are produced by parthenogenesis. Some insects, exhibit polymorphism e.g. honey bee, ants,, termites etc. Some arthropods are economically, important such as Apis (honey bees) for their, honey and wax.

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Lac is produced by L accif er lacca (Lac, insect). Lobsters, prawns and crabs are edible,, silk worms produce silk. Some arthropods are, harmful which acts as vector e.g. mosquito., L ocusta (locust) is a gregarious pest. L imulus, (King crab) is known as living fossil., , Digestive system is well developed,, complete with anterior mouth and posterior, anus. Buccal cavity has a rasping organ called, radula which is provided with transverse rows, of teeth. Aquatic forms show numerous feather, like gills called ctenidia, useful for aquatic, respiration. Gills are present in mantle cavity., (space between visceral mass and mantle), Terrestrial forms may show presence of lungs., Circulatory system is of open type, (except Sepia, which possesses closed type)., Blood contains a copper containing blue, respiratory pigment called haemocyanin., Excretion occurs by kidneys, also called as organ, of Bojanus. Nervous system is formed by three, pairs of ganglia. Ganglia are interconnected, by commissures and connectives. Sense organs, such as eyes for vision, tentacles for tactile, sensation, osphradia for testing purity of water, are present. Sexes are separate, animals are, mostly oviparous, development is direct or, indirect., , Find out, 1., 1. Why is phylum arthropoda considered as, most successful phylum?, 2. What do we mean by parthenogenesis?, 3. What do we mean by living fossil?, 4. How the bees produce honey?, 5. What will happen if arthropods do not, moult?, 8. Phylum : Mollusca (Mollis : soft), e.g. Pila, Bivalve, Octopus (devil fish),, Sepia (cuttle fish), Chaetopleura (Chiton),, Pinctada (Pearl oyster), L oligo (Squid), Aplysia, (Sea hare), Dentalium (Tusk shell)., This is second largest phylum. Molluscs, are either free living or sedentary. They are, aquatic or seen in marshy places. Few are, terrestrial. These are soft bodied and show tube, within tube body plan. These are bilaterally, symmetrical, but few are asymmetrical due, to torsion (twisting). Body is divisible into, head, foot and visceral mass. Visceral mass, is enclosed in thick muscular fold of body, wall called mantle. Mantle secretes a hard, calcareous shell, the shell may be external or, internal or absent. Muscular foot is present on, ventral side., , a. S p isu l a, , Economic importance Pearl, oyster, gives precious pearls. Many molluscs are, edible. Shells of molluscs are rich source of, calcium., Can you tell?, 1. Explain the term metameric segmentation., 2. Give characteristics of Arthropoda., 3. Enlist harmful Arthropods., 4. Why do Molluscs have shell?, , b. C haetop l eu ra, , c. Pil a, , e. O ctop u s, , d. S ep ia, , Fig. 4.14 Animals of Mollusca, , 34

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9. Phylum : Echinodermata, (Echinus - Spines, derma - skin), e.g. Asterias (Sea star), Cucumaria (Sea, cucumber), Echinus (Sea urchin), Antedon (sea, lily), Ophiothrix (Brittle star)., These are exclusively marine, solitary,, sedentary or free-living and gregarious,, benthic., These are radially symmetrical, animals with pentamerous symmetry. Body, may be spherical, elongated or star-shaped., Endoskeleton is made up of calcareous ossicles., Spines are present on the body, hence the name, echinodermata. The body is without definite, body divisions, instead, there are two sides as, oral and aboral., The peculiar character is presence of, water vascular system in which water enters, through madreporite. This system is used, in locomotion, food capturing, respiration,, etc. Digestive system is complete. Mouth is, ventrally present on oral surface and anus on, aboral surface., Respiration is performed by peristomial, gills, papillae, respiratory tree, etc. Circulatory, system and excretory system is absent., , Nervous system is simple with a nerve, ring around mouth and radial nerves in the, arms. Sexes are separate (sometimes bisexual),, fertilization is external, development is indirect., They show high power of regeneration., 10. Phylum : Hemichordata (Hemi : Half,, Chordata : Rod), e.g. Balanoglossus, Saccoglossus., Earlier, this Phylum was considered, as sub-phylum of Chordata because buccal, diverticulum was considered as notochord., But, now it is placed as a separate phylum of, Non-chordata. These are exclusively marine, animals, usually living at the bottom of sea in, burrows. Mostly these are free living but the, animals like Rhabdopleura are sedentary. Body, is soft, vermiform, unsegmented and divided, into three parts - proboscis, collar and trunk., Buccal cavity gives rise to rod-like buccal, diverticulum which is considered as notochord, by some scientists., Proboscis, Anus, Collar, , Branchial region, , Genital region, , a. A ntedon, , b. O ph iothrix, , Hepatic region, , a. B al anogl ossu s, , c. A sterias, d. C u cu m aria, Fig. 4.15 Animals of Echirodemata, , b. S accogl ossu s, Fig. 4.16 Animals of Hemichordata, , 35

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Alimentary canal is complete, straight, or 'U' shaped. Respiration occurs by numerous, gills, arranged in two longitudinal rows,, present in the pharyngeal region. Gills open by, gill slits., Circulatory system is simple and, open type. Excretion occurs with the help of, glomerulus. Nervous tissue is embedded in, epidermis on both dorsal and ventral sides., The sexes are separate (sometimes bisexual)., Fertilization is external and development is, indirect through free swimming larva. This, phylum is the connecting link between nonchordata and chordata., , 11. Phylum : Chordata, Chordates are characterised by, presence of cartilagenous notochord at least, in early embryonic life, presence of gill slits, in the pharyngeal (neck) region, presence of, hollow, dorsal nerve cord running through out, the length of body and ventral heart., Phylum Chordata is divided into three, subphyla-Urochordata, Cephalochordata and, Vertebrata. Urochordata and Cephalochordata, are collectively called Protochordates., a. Subphylum : Urochordata or Tunicata, e.g. H erdmania, Sal pa, D oliolum., These are also called as tunicates or, ascidians. They are exclusively marine. Body, is soft and covered by 'test' or 'tunic' which is, made up of tunicine. Notochord is present only, in the tail of larva, hence the name, urochordata., Notochord is lost during metamorphosis., Pharynx has many gill slits. Closed circulatory, system is present. Development is indirect., , Can you tell?, 1. Give salient features of Phylum, Echinodermata., 2. Hemichordata is the connecting link, between non-chordata and chordata., Give reasons., Observe and Discuss, Compare and contrast, Chordates and Non-chordates., Non-Chordate, , Gill slits, , Pulsating dorsal, blood vessel, , Exoskeleton, , Digestive tube, , Nerve cord, Chordate, , Heart, , between, , Anus, , a. H erd m ania, , Anus, Notochord, , b. A scid ia, , Fig. 4.17 Animals of Urochordata, b. Subphylum : Cephalochordata, e.g. Branchiostoma (Amphioxus or L ancelet), They are exclusively marine. These are, also called as lancelet, which are small fish, like animals that rarely exceed 5 cm in length., , Post-anal tail, , Find out, , Why Balanoglossus, is considered as connecting link between, Non-Chordates and Chordates?, , Lancelets partly live burried in, soft marine sediments. Notochord extends, throughout the length of body and present, throughout the life. Myotomes (muscle blocks), are present. Post-anal tail is present. Closed, circulatory system is present. Blood is without, pigment., , Do you know ?, , Notochord is, flexible rod-like structure of vacuolated cells., It is located along the dorsal side of chordate, embryos. It gives support to the body and, provides attachment to muscles., , 36

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Digestive system lacks stomach., Respiration occurs by 6 to 15 pairs of gills slits., Gills slits are without operculum. Heart is two, chambered with one auricle and one ventricle., Gonad is single, large and without gonoduct., Fertilization is external. They are anadromous, i.e. migrate for spawning to fresh water from, their marine habitat. After spawning, they die, within few days. Larvae metamorphose and, then migrate to ocean., , Buccal cirri, Vestibule, Pharynx, Gill slits, , Notochord, Dorsal hollow, nerve cord, , Midgut diverticulum, Atriopore, , Midgut, , Myotomes, Anus, Caudal fin, , A m p hioxu s, , Can you tell?, 1. H erdmania is called a Chordate. Explain., 2. Give characteristics of Petromyz on., Comment on its mode of nutrition., , Fig. 4.18 Animal from Cephalochordata, c. Subphylum : Vertebrata, In these chordates, notochord is replaced, by cartilaginous or bony vertebral column. It is, divided into two divisions - A gn athostom ata, (no jaws) and G nathostom ata (jaws present)., 1. Division : A gn athostom ata, This division includes the lowest or, most primitive vertebrates, which are without, jaws. They include only one class of living, vertebrates - the Cyclostomata., Class : Cyclostomata (Cyclos : Circular, Stoma, - mouth) L at/ Grk., e.g. Petromyz on (Lamprey), Myxine (Hagfish)., Cyclostomes are jawless and eellike animals. Skin is soft, smooth containing, unicellular mucus glands, but no scales. Median, fins are present but paired fins are absent., They are ectoparasites. They have sucking, and circular mouth without jaws. Cranium and, vertebral column made up of cartilage., , 2. Division : Gnathostomata, It is divided into two superclasses Pisces (bear fins) and tetrapoda (bear four, limbs)., A. Superclass : Pisces, These are aquatic animals. These are, poikilothermic (body temperature changes, according to the change in surrounding, temperature). Lateral line system is present, which shows presence of rheoreceptores for, detection of water current. Locomotion is, by body muscles and fins. Caudal fin acts as, steering wheel. Exoskeleton is of dermal scales., Endoskeleton is either bony or cartilagenous., Body is streamlined and boat shaped. This, feature offers minimum resistance during, swimming. Respiration is by gills. Heart is two, chambered and is ventral in position. It shows, single and closed circulation. Heart always, shows presence of deoxygenated blood, so it, is described as venous heart. They have well, developed brain with large olfactory lobes., Sexes are separate. Most fishes are oviparous, and some are viviparous., Superclass Pisces is divided into two, classes as below., 1. Class Chondrichthyes :, (chondron : cartilage, ichthyes : fish), e.g. Scoliodon (dog fish), Pristis, (sawfish), Electric ray, Common skate,, Hammer headed shark., , Sea lamprey, , Detail of mouth, , Fig 4.19 Petrom y z on, , 37

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Exocoetus (flying fish), H ippocampus, (sea-horse), Pomphret, L abeo rohita (Rohu),, Catla (Katla), Clarias (Magur), Aquarium, fishes. Betta -(fighting fish), Pterophyllum, (Angle fish)., Osteichthyes includes fishes in which, bony endoskeleton is present, hence called as, bony fishes. These are aquatic, present in both, fresh and marine waters. Exoskeleton is formed, of cycloid and ctenoid scales. Mouth is mostly, terminal in position. They show two dorsal, fins. Tail fin is formed by two equal lobes, i.e. homoceral (symmetrical). Four pairs of, gill slits are present, covered with operculum., Air bladder is present to maintain buoyancy., Claspers are absent. Fertilization is external., These fishes are oviparous., , Carcanodon (great white shark), Trygon, (Sting ray), Dorsal fin, Eye, , Lateral line, , Caudal fin, , Mouth, Gill clefts, , Pelvic fin, Median ventral fin, , a. S col iod on, , Operculum, , b. A noxy p ristis, , Dorsal fin, , Eye, , Fig 4.20 Animals from chondrichthyes, , Forked tail, , Chondrichthyes includes the animals, in which endoskeleton is cartilagenous. These, are exclusively marine. Exoskeleton is formed, of placoid scales. Teeth are modified placoid, scales which are backwardly directed. Mouth, is ventral in position. There is single dorsal fin, and 2 pairs of lateral fins (pectoral and Pelvic)., Caudal fin is heterocercal (Asymmetrical). Five, to seven pairs of gill slits are present. They are, not covered by operculum. Air bladder is absent, hence these fishes need to swim constantly so, that they do not sink. They are predatory fishes., Some of them have electric organs e.g. Torpedo, - (electric ray) and some have poison sting e.g., Trygon - (sting ray) as organs of offence ans, defence. Male copulatory organs called claspers, are present. Fertilization is internal. Many of, them are viviparous., , Mouth, , a. C atl a, , b. Exocoetu s, (flying fish), , Lung, , Pelvic fin, , c. H ip p ocam p u s, (sea-horse), , Fig 4.21 Animals from Osteichthyes, Can you tell?, 1. Differentiate between Chondrichthyes, and Osteichthyes on the basis of scales, and caudal fin., 2. What is the lateral line system?, 3. Why Piscian heart is called a venous, heart?, , 2. Class : Osteichthyes, (Osteon : bone , ichthyes : fish), e.g. Bombay duck,, (Protopterus, L epidosiren), , Ventral fin, Pectoral fin, , fishes, , 38

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B. Superclass : T etrapoda, These animals bear two pairs of, appendages. Some animals like snakes are, secondarily limbless., Superclass tetrapoda includes four, classes namely, Amphibia, Reptilia, and, Mammalia., , 2. Class : Reptilia, (Repere : to creep or to crawl), e.g. N aj a naj a (Cobra), H emidactylus, (Wall lizard), Chelonia ( Turtle), Crocodilus, (Crocodile), Testudo (Tortoise), Chameleon, (Tree lizard), Bangarus (Krait), V ipera (viper)., a. Lizard, , 1. Class : Amphibia, (Amphi : both, bias : life), e.g. Rana (Frog), Buf o (Toad), Salamandra, (Salamander),, I chthyophis, (Limbless, amphibian), H yla (Tree frog)., Amphibia include the animals which, live on land as well as in water (fresh water, only). They are poikilothermic animals. Body, is differentiated into head and trunk. Neck, and tail is usually absent in many adults with, few exceptions. Two pairs of limbs arise from, pectoral and pelvic girdles respectively. These, help in locomotion. Skin is moist, glandular, with mucous glands. Exoskeleton is absent., Eyelids are present. Tympanum represents the, ear. Excretory products, digestive wastes and, gametes are released through common chamber, called cloaca. Circulatory system is of closed, type. Heart is three chambered and ventral in, position. RBCs are biconvex and nucleated., Respiration is by skin, lungs and buccopharynx., Nervous system is well developed. Sexes are, separate. These are oviparous. Fertilization, is external. Development is indirect through, aquatic larval stage. They show metamorphosis., , a. A nu ra, , b. Crocodile, , c. Tortoise, , Fig 4.23 Animals from Reptilia, Reptilia includes crawling animals., These are the first true terrestrial vertebrates., Few may be aquatic or semi-aquatic, also, found in marshy area. Locomotion occurs by, limbs. The limbs are pentadactyl and digits, bear claws. Limbs help the animal to walk or, creep. Snakes are limbless. Snakes crawl on, their belly. Reptiles are poikilotherms. Skin is, dry, non-glandular and covered by exoskeleton, of epidermal scales or scutes, shields or plates., Lizards and snakes shed their skin periodically., Tympanum is present. Heart has two complete, auricles, but ventricles are incompletely, partitioned. So heart is not perfectly four, chambered (except crocodile). Brain is well, developed. The olfactory lobes and cerebellum, are better developed than those of amphibians., Sexes are separate and show prominent sexual, dimorphism. Fertilization is internal. They are, oviparous (except viper, it is viviparous) and, show parental care. ., , b. B u f o, , c. S al am and er, , Fig 4.22 Animals from Amphibia, , 39

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Body is differentiated into head, neck,, trunk and tail. Skin is thin, dry, non-glandular, except oil gland at the base of tail (uropygial, gland). Bones are hollow (pneumatic) with, air cavities to reduce body weight. Jaws are, without teeth and modified into beak. Crop, and gizzard are present in digestive system., Blood is red in colour due to presence of red, blood cells. RBCs are biconvex and nucleated., Heart is perfectly four chambered. They show, double circulation. Respiration takes place by, lungs, having air sacs to increase the buoyancy., Brain is enlarged and has well developed, cerebellum for equillibrium. Sexes are separate, with prominent sexual dimorphism. These are, oviparous. Fertilization is internal. Parental, care is very well developed. Seasonal migration, is seen in some birds., , Can you tell?, 1. Amphibians do not have exoskeleton., Give reason., 2. Why are amphibians and reptilians called, poikilotherms?, 3. Class : Aves (Avis : bird), e.g. Columba (Pigeon), Psittacula, (Parrot), Flight less birds like Struthio (ostrich),, K iw i, Aptenodytes (Penguin), Corvus (crow),, N eophron (Vulture), Passer (sparrow)., a. S try thio, , b. Passer, , Special features :- The urinary bladder is, absent. The female shows presence of only left, ovary and left oviduct. This helps to reduce, body weight., , c. Psittacoide a, , 4. Class : Mammalia (mammae :, breasts, nipples), e.g. Bat, Rattus (Rat), Macaca (Monkey),, Camelus (Camel), Whale, Human being,, Cannis (dog), F elis (Cat), Elephas (Elephant),, Equus (Horse), Pteropus (flying fox)., Oviparous - Ornithorhynchus (Platypus)., Viviparous - Macropus (Kangaroo)., Mammalia includes the animals having, mammary glands (milk producing glands), for the nourishment of young ones. These, are omnipresent. Mostly terrestrial, some, are aquatic and few are aerial and arboreal., Limbs are the organs of locomotion and used, for walking, flying, climbing, burrowing,, swimming, etc. Body is differentiated into head,, neck, trunk and tail. These are homeotherms., Exoskeleton is in the form of hair, fur, nails,, hooves, horns, etc. Skin is glandular having, sweat glands and sebaceous glands (oil glands)., Mammary glands are modified sweat glands., , d. N ecrosy rtes, , e. Pav o, Fig 4.24 Aves, Forelimbs are modified into wings for, flying (some birds have lost the capacity to fly, e.g. Ostrich), hind limbs are used for walking,, clasping tree branches and running. Aquatic, birds have webs between their toes (e.g. Duck)., Body is streamlined (Boat shaped) to reduce, resistance during flight. These are homeotherms, i.e. their body temperature remains constant., Exoskeleton is made up of feathers. Scales are, present on hind limbs., , 40

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They have external ear (pinna). They, show heterodont dentition. RBCs are biconcave, and enucleated. Blood is red in colour. Heart, is ventral in position and four chambered., Respiration takes place by lungs. Brain is highly, developed. Cerebrum shows a transverse band, called corpus callosum. Few mammals are, oviparous (e.g. Duck billed platypus). Some, have pouches for the development of immature, young ones, these are called marsupials e.g., Kangaroo. Majority of mammals are placental, and viviparous., , a. C am el u s, , d. M acrop u s, , b. O rnithorhy nchu s, , c. T rachy p ithecu s, , Fig 4.25 Mammals, Can you tell?, 1. Give adaptations in aves for flying., 2. Aves and mammals are homeotherms. Give reason., 3. How mammals differ from other groups of animals., Do yourself, Observe different animals in your surrounding, write detailed classification and, write down the characteristics of animals in following format., Picture / Photograph, , Classification, , 41, , Characteristics

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Exercise, 1. Choose correct option, , E. Birds need to keep their body light to help, in flying. Hence, they show presence of, some organs only on one side. How their, skeleton helps in reducing their weight?, , A. Which of the following belongs to a, minor phylum?, a. Comb jelly b. Jelly fish, c. H erdmania d. Salpa, , F. Cnidarians and Ctenophorans are both, diploblastic. Which other character do, they have in common, which is not found, in other Phyla?, , B. Select the animal having venous heart., a. Crocodile, b. Salamander, c. Rohu, d. Toad, , G. Crab and Snail both have a protective, covering. Is it made up of the same, material?, , C. In Ascaris, __________________., a. mesoglea is present, b. endoderm is a discontinuous layer, c. mesoderm is present in patches, d. body cavity is absent, , H. Sponge and sea star show calcareous, protective material. Do they belong to the, same Phylum?, , D. Which of the following is incorrect in, case of birds?, a. Presence of teeth, b. Presence of scales, c. Nucleated RBCs, d. Hollow bones, , I. Fish and snake both have scales. How do, these scales differ from each other?, J. Lower Phyla like Arthropods and, Cnidarians show metamorphosis. Is it also, found in any class of Phylum Chordata?, 3. Draw neat labelled diagram, , E. Chitinous exoskeleton is a characteristic, of ___________., a. Dentalium, b. Antedon, c. Millipede, d. Sea urchin, , A. Sycon, B. Aurelia, C. Amphioxus, D. Catla, , 2. Answer the following questions, , E. Balanoglossus, , A. Reptiles are known for having three, chambered heart. Which animal shows a, near four chambered condition in reptiles?, , F. Scolidon, 4. Match the following, , B. The circulatory system has evolved from, open to closed type in Animal kingdom., Which Phylum can be called first to, represents closed circulation?, , Phylum, i. Annelida, ii. Mollusca, iii. Ctenophora, iv. Porifera, v. Echinodermata, , C. Pinna is part of external ear and it is found, in mammals. Do aves and reptiles show, external ear in any form?, D. Fish and frog can respire in water. Can, they respire through their skin? If yes,, why do they have gills?, , 42, , Characters, a. Tube feet, b. Ostia, c. Radula, d. Parapodia, e. Comb plates

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5. Identify the animals given in pictures and, write features of its phylum / class, , 6. Observe and identify body symmetry of, given animals, , Practical / Project :, , B, , A, , Study different animals in kingdom, anamalia and prepare the chart with detail, scientific information., , C, , D, , E, , F, , G, , H, , I, , 43

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5. Cell Structure And Organization, 1. Can you recall?, 1. Who observed cells under the microscope for the first time?, 2. Who made the first microscope?, 3. How do onion peel cells and our body cells differ?, 4. Why bacterial nucleus is said to be primitive?, 5.1, , Cell :, Cell is called a structural and functional, unit of life of all living organisms capable of, independent existence and can perform all, functions of life., To see cells clearly we need a, microscope. Larger cells can be seen through, simple microscope but to see smaller cells, we require compound microscope. Simple, microscope can magnify image 50 to 100 times, but a compound microscope can do so 1000, times or more. In the microscope we use in, the laboratory, a beam of light is used to make, things visible hence it is light microscope. To, see interior of cell we need electron microscope., It can magnify image 500000 times., , There is no typical shape of a cell., Cells may be spherical, rectangular, flattened,, polygonal, oval, triangular, conical, columnar,, etc., Cell size varies greatly in various, plants and animals. Some of them are not, visible to naked eye. Some are barely visible, while some are macroscopic. The smallest cell, size can be seen in mycoplasma (0.3 µm in, length), bacterial cell size is 3 to 5 µm, while, the largest size of cell is seen in Ostrich egg, (nearly 15cms). Longest cells are nerve cells., You already know that cell theory was, proposed by Schwann and Schleiden. However,, in this theory, there was no explanation about, formation of new cells. It was Rudolf Virchow, (1855) who explained for the first time that, new cells are formed by cell division from pre, existing cells (Omnis cellula- e- cellulla)., In later years, advanced research in, cytology led to modification in cell theory,, which is now known as Modern Cell Theory., , Leeuwenhoek, Microscope, (circa late 1600s), , Fig. 5.1 Microscope, Find out, , Flu virus, Mitochondria, , C60 Protein, , Red, blood Animal, cell, cell, , Human, egg, , Atom, Lipids, , 0.1 nm, , 1 nm, , Bacteria, 10 nm, , 100 nm, , 1 µm, , Pollen, , Plant cell, , 10 µm, , Fig. 5.2 Cell size, , 44, , 100 µm, , Frog, egg, 1 mm, , 1. How, do, a, combination, of, lenses helps in higher, magnification?, 2. When, do, we, use, plane, and, concave mirror and, diaphragm?, 3. What, is, the, difference between, magnification and, resolution?

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Cell envelop is a three-layered structure, with outer glycocalyx, middle cell wall and, inner plasma membrane. Glycocalyx is present, as either slime layer (loose sheath) or capsule, (tough). Bacteria are better observed when, stained., The most followed staining method, is ‘Gram staining’ developed by Danish, bacteriologist Hans Christian Gram. The, cell wall is made up of peptidoglycan (in, Gram positive bacteria) and murein (in Gram, negative bacteria). It gives mechanical strength, to the cell. Cell membrane is a phospholipid, bilayer. All these structures give protection to, the cell and also help in inter-cellular transport., In motile bacteria either cilia or flagella are, found. Both are driven by rotatory movement, produced by basal body (which works as, motor). Other parts are filament and hook., Some other surface projections are, the tubular pili (which help in inter-cellular, communication) and fimbriae (for clinging to, support)., The cell membrane shows infoldings, called mesosomes, which help in cell wall, formation and DNA replication. Some bacteria, especially photosynthetic cyanobacteria show, more longer extensions called chromatophores., They carry photosynthetic pigments. The, cytoplasm contains dense particles called, ribosomes helping in protein synthesis., Ribosomes are described by their sedimentation, rate in Svedberg units. Bacterial ribosome, are 70S (composed of a larger subunit 50S +, smaller subunit 30S)., , Totipotency : It is the capacity or the potential, of living nucleated cell to differentiate and, divide to form any other type of cell and thereby, a complete new organism., A cell is totipotent because it has the, entire genetic information of the organism in its, nucleus. Embryonic animal cells are totipotent, and termed as stem cells. Stem cells have, great medical applications including cure for, diseases., Know the scientists, A German botanist Matthias, Schleiden (1838) examined number of plants, and concluded that various tissues of plants, are composed of different types cells. At that, time, a British zoologist Theodore Schwann, (1839) proposed that cells are bound by a, thin membrane. He also explained about, existence of cell wall as a unique character, of plant cell. On the basis of his observation,, he proposed that animals and plants are made, up of cells and products of cells., •, •, •, •, •, •, , Postulates of modern cell theory,, All living organisms are made up of cells., Living cells arise from pre-existing cells., A cell is the structural and functional unit, of life., Total activities of cells are responsible for, activity of an organism., Cells show transformation of energy., Cells contain nucleic acids; DNA and, RNA in the nucleus and cytoplasm., , 5.2, , Kinds of cells :, Living organisms are grouped into, two main categories the Prokaryotes and, Eukaryotes. The prokaryotes have simple, cellular organization while eukaryotes exhibit, high degree of organization., , Chromosome (nucleoid region), Pili, Ribosomes, Food granule, , A. Prokaryotic cells :, The cell in prokaryotes show following, main features. It has chemically complex, protective cell envelop. However, it does not, have well-defined nucleus and other membrane, bound cell organelles., , Flagellum, , Capsule or, Slime layer, Cell wall, Plasma membrane, Cytosol, Plasmid (DNA), , Fig. 5.3 Prokaryotic cell, , 45

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Use your brain power, , Find out, , Why do basal body, of bacterial flagella considered as smallest, motor in the world?, , Describe major differences between, prokaryotic and eukaryotic cells., B., , ·, •, •, •, •, •, •, •, •, •, , Eukaryotic Cells :, Cells in which the nucleus has a definite, nuclear membrane are known as Eukaryotic, cells. These cells exhibit presence of membrane, bound cell organelles. e.g. Cells of Protists,, Plants, Animals and Fungi., The eukaryotic cells have different, shape, size and physiology but all the cells, are typically composed of plasma membrane,, cytoplasm and its organelles viz. Mitochondria,, Endoplasmic Reticulum, Ribosomes, Golgi, complex, etc. and a true nucleus., , Do you know ?, The term cell was first used by Robert, Hooke (1665) in his book ‘‘Micrographic’’., Purkinje and Mohl (1835-37) discovered, protoplasm., Camillo Golgi (1838) discovered the Golgi, apparatus., Robert Brown (1881) discovered the, Nucleus., Balbiani (1881) discovered chromosomes, in salivary glands of Chironomus larva., Flemming (1882) studied cell division in, detail and coined the term Mitosis., Porter (1945) discovered Endoplasmic, Reticulum., C. Benda gave the name Mitochondria., C. de Duve (1955) discovered Lysosomes., , 5.3, Components of Eukaryotic cell :, 1. Cell wall:, It is rigid, supportive and, protective outer covering of plasma membrane, of plant cells, fungi and some protists. Algae, show presence of cellulose, galactans,, mannans and minerals like calcium carbonate, in cell wall. In other plants, it is made up of, hemicelluloses, pectin, lipids and protein., Microfibrils of plant cell wall show presence of, cellulose which is responsible for rigidity. Some, of the depositions of cell wall are silica (grass, stem), cutin (epidermal walls of land plants),, suberin (endodermal cells of root), wax, lignin., It gives shape to the cell and protects from, mechanical injury and infections., , Always Remember, Genetic material in bacterium is a, single chromosome made up of circular and, coiled DNA. It remains attached to mesosome., This DNA undergoes a very typical replication, pattern called as theta model of replication., The DNA is not associated with histone, proteins (as in eukaryotes) hence not referred, to as chromatin. Besides chromosomal DNA, many bacteria show plasmids which are small, circular DNA molecules carrying few genes., They are termed as extrachromosomal selfreplicating DNA molecules. They are of two, basic types F – plasmid for reproduction and, R – plasmid for resistance against antibiotics., Cytoplasm of prokaryotes is a pool of all, necessary materials like water, enzymes,, elements, amino acids, etc. Some inclusion, bodies in form of organic (cyanophycean, starch and glycogen) and inorganic granules, (phosphate and sulphur) are also found., , Cell wall, Cell membrane, Golgi, apparatus, Chloroplast, Vacuole, membrane, Raphide, crystal, Druse, crystal, Mitochondrion, , Golgi vesicles, Ribosome, Smooth ER, (no ribosomes), Nucleolus, Nucleus, Rough ER, (endoplasmic, reticulum), Large central, vacuole, Amyloplast, (starch grain), , Cytoplasm, , Fig. 5.4 Plant cell, , 46

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Pinocytotic vesicle, , 2. Cell membrane / Plasma membrane/, biomembrane :, It is thin, quasifluid structure present, both extracellularly and intracellularly., Extracellularly, it is present around protoplast, and intracellularly, it is present around most, of the cell organelles in eukaryotic cell. It, separates cell organelles from cytosol., Thickness of biomembrane is about 75, o, ., A Under electron microscope, cell membrane, appears trilaminar (made up of three, layers). It shows presence of lipids (mostly, phospholipids) arranged in bilayer. Lipids, posses one hydrophilic polar head and two, hydrophobic non-polar tails. So, phospholipids, are amphipathic. Lipid molecules are arranged, in two layers (bilayer) in such a way that their, tails are sandwitched in between heads. Due, to this, tails never come in direct contact with, aqueous surrounding., Cell membrane also shows presence of, proteins and carbohydrates. Ratio of proteins, and lipids varies in different cells. For examplein human beings, RBCs show approximately, 52% protein and 40% lipids., , Mitochondrion, , Lysosome, Golgi vesicles, , Golgi, apparatus, , Rough ER, (endoplasmic, reticulum), , Nucleolus, Nucleus, , Smooth ER, (no ribosomes), , Centrioles, Microtubules, , Cell (plasma), membrane, , Cytoplasm, Ribosome, , Fig. 5.5 Animal cell, In plants, cell wall shows middle, lamella, primary wall and secondary wall., Middle lamella : It is thin and lies between two, adjacent cells. It is the first structure formed, from cell plate during cytokinesis. It is mainly, made up of pectin, calcium and magnesium, pectate. Softening of ripe fruit is due to, solubilization of pectin., Primary wall : In young plant cell, it is capable, of growth. It is laid inside to middle lamella., It is the only wall seen in meristematic tissue,, mesophyll, pith, etc., Secondary wall : It is present inner to primary, wall. Once the growth of primary wall, stopps, secondary wall is laid. At some places, thickening is absent which leads to formation, of pits., Plasmodesmata, are, cytoplasmic, bridges between neighbouring cells. It shows, pores between cell wall and middle lamella., , Glycoprotein, , Middle, lamella, , Pectin, , Primary, cell wall, , Cellulose, microfibril, , Lipid, bilayer of, Plasma, membrane, , Fluid mosaic model :, It is most accepted model of cell, membrane. It was proposed by Singer and, Nicholson in 1972., According to this model, it is made up, of phospholipid bilayer and proteins. Proteins, are like icebergs in the sea of lipids. Proteins, can change their position. Some proteins are, intrinsic i.e. occur at different depths of bilayer., Phospholipid, bilayer, , Glycolipid, , Hemicellulose, Protein in, plasma, membrane, , Peripheral, Protein, Integral, membrane, channel, membrane Cytoskeletal, protein, filament Cholesterol, proteins, , Fig. 5.6 Cell wall of plant cell, , Fig. 5.7 Fluid mosaic model, , 47

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It helps in distribution and exchange of, materials between various cell organelles., Cell organelles are nothing but, compartments in the cell that carry out specific, functions. Some of them coordinate with each, other and complete specific tasks for the cell., Nuclear membrane, endoplasmic reticulum,, Golgi complex, lysosomes and various types of, vesicles and vacuoles form such a group and, are together considered as endomembrane, system of the cell. Organelles having distinct, functions are not included in endomembrane, system. e.g. mitochondria or chloroplast carry, out specific type of energy conversions in the, cell., 4. Endoplasmic Reticulum (ER):, This little network within the cytosol, is present in all eukaryotic cells except ova, and mature red blood corpuscles. Under the, electron microscope, it appears like network of, membranous tubules and sacs called cisternae., It forms more than 50% of the total membrane, of a eukaryotic cell. This divides the cytoplasm, in two parts viz; one within the lumen of ER, called, laminal cytoplasm and non-laminal, cytoplasm that lies outside ER., Membrane of Endoplasmic reticulum, is continuous with nuclear envelope at one end, and extends till cell membrane., It thus acts as intracellular supporting, framework and helps in maintaining position, of various cell organelles in the cytoplasm., The outer surface of endoplasmic reticular, membrane may or may not be studded with, ribosomes. Accordingly, it is called rough or, smooth ER. Smooth and rough ER differ in, their functions., Smooth ER is involved in various, processes in different cells. Depending on cell, type, it helps in synthesis of lipids (ex. steroid, secreting cells of cortical region of adrenal, gland, testes and ovaries), detoxification of, drugs and poisons (liver cells) and storage of, calcium ions (muscle cells)., , They span the entire thickness of the, membrane. So, they are called transmembrane, proteins. They form channels for passage of, water. Extrinsic or peripheral proteins are, found on two surfaces of the membrane., Quasifluid nature of lipid enables, lateral movement of proteins. This ability to, move within the membrane is measured as, fluidity., Main function of plasma membrane, is transport of molecules across it. This, membrane is selectively permeable. During, passive transport, many molecules move across, the membrane without spending energy. Some, solutes move by simple diffusion along the, concentration gradient (from higher to lower, concentration). Neutral solutes may move, across the membrane by the process of simple, diffusion This is called the passive transport., Water may also move by osmosis., During active transport, few ions or, molecules are transported against concentration, gradient (from lower to higher concentration)., It requires energy. So, ATP is utilized. As such, a transport is an energy dependent process, in which ATP is utilized, it is called Active, transport e.g. Na+/K+ pump. Polar molecules, cannot pass through non-polar lipid bilayer., So, they require carrier proteins., 3. Cytoplasm :, The cell contains ground substance, called cytoplasmic matrix or cytosol. This, colloidal jelly like material is not static. It shows, streaming movements called cyclosis. The, cytoplasm contains water as major component, along with organic and inorganic molecules, like sugars, amino acids, vitamins, enzymes,, nucleotides, minerals and waste products., It also contains various cell organelles, like endoplasmic reticulum, Golgi complex,, mitochondria, plastids, nucleus, microbodies, and cytoskeletal elements like microtubules., Cytoplasm acts as a source of raw materials, as well as seat for various metabolic activities, taking place in the cell., , 48

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Ribosomes, , Nuclear envelope, , "Receiving" side of Golgi, apparatus (cis face), , Nucleus, , Vesicle, from ER, , New vesicle, forming, , Rough endoplastic, reticulum, Smooth endoplastic reticulum, , trans face, , Fig. 5.8 Endoplasmic reticulum, , Fig. 5.9 Golgi complex, , Rough ER is primarily involved in, protein synthesis. (e.g. pancreatic cells that, secrete insulin). These proteins are secreted by, ribosomes attached to rough ER and are called, secretory proteins. These proteins get wrapped, in membrane that buds off from transitional, region of ER. Such membrane bound proteins, depart from ER as transport vesicles. Rough, ER is also involved in formation of membrane, for the cell. The ER membrane grows in, place by addition of membrane proteins and, phospholipids to its own membrane. Portions, of this expanded membrane are transferred to, other components of endomembrane system., , This explains why Golgi bodies are, usually located near ER. Modified and, condensed secretions leave Golgi through trans, face again as membrane bound vesicles., Golgi body carries out two types, of functions, modification of secretions of, ER and production of its own secretions., Cisternae contain specific enzymes for specific, functions. Refining of product takes place in an, orderly manner. For example, glycolipids and, glycoproteins that are brought from ER loose, certain sugars and regain other, thus forming a, variety of products., Golgi bodies also manufacture their, own products. Golgi bodies in many plant cells, produce non-cellulose polysaccharides like, pectin. Manufactured or modified, all products, of Golgi complex leave cisternae from trans, face as transport vesicles., , 5. Golgi complex :, Golgi complex or Golgi apparatus or, Golgi body; various terms are used to denote, this assembly, manufacturing cum packaging, and transport unit of cell., Golgi complex essentially consists of, stacks of membranous sacs called cisternae., Diameter of cisternae varies from 0.5 to 1, µm. A cell may have few to several cisternae, depending on its function., The, thickness, and, molecular, composition of two membranes of a Golgi sac, differ from each other. The Golgi sacs show, specific orientation in the cell. Each cisterna, has a forming or ‘cis’ face (cis: on the same, side) and maturing or ‘ trans’ face (trans: the, opposite side)., Transport vesicles that pinch off from, transitional ER merge with cis face of Golgi, cisterna and add its contents into the lumen., , Always Remember, The cisternae in Golgi body are not, physically connected to each other as that are, in ER., According to recent studies it is, proposed that cisternae of Golgi body, themselves mature moving from cis to trans, face. It is called ‘Cisternal maturation model’., It is also said that some vesicles recycle their, enzymes that have been carried forward by, moving cisternae back to less mature region., , 49

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While they are leaving from the Golgi,, certain markers may get impregnated on their, membrane so that they can identify their, specific target cell or cell organelle., 6. Lysosomes :, Lysosomes can be considered as, dismantling and restructuring units of a cell., These are membrane bound vesicles containing, hydrolytic enzymes. The enzymes in lysosomes, are used by most eukaryotic cells to digest, (hydrolyse) macromolecules. The lysosomal, enzymes show optimal activity in acidic, pH. Lysosomes arise from Golgi associated, endoplasmic reticulum., The list of lysosomal enzymes includes, all types of hydrolases viz, amylases, proteases, and lipases. These enzymes are in inactive state, and are activated only when a lysosome comes, in contact with another particular organelle to, form a hybrid structure., After the action of enzymes is over, the, lysosome is reformed and re-used. Lysosomes, are thus found in various structural forms and, carry out various functions for the cell., , Lysosomes are polymorphic in nature., We can classify lysosomes as, Primary, lysosomes; which are nothing but membrane, bound vesicles in which enzymes are in inactive, state., Secondary lysosomes or hybrid, lysosomes, which are formed by fusion of, lysosome with endocytic vesicle containing, materials to be digested, represented as, heterophagic vesicle. This is larger in size than, primary lysosome., Residual body is the vesicle containing, undigested remains left over in the heterophagic, vesicle after releasing the products of digestion, in the cytosol., Lysosomes which bring about digestion, of cells own organic material like a damaged, cell organelle, are called autophagic vesicles, (or suicide bags). An autophagic vesicle, essentially consists of lysosome fused with, membrane bound old cell organelle or organic, molecules to be recycled. Remember, every, week, a human liver cell recycles half of its, macromolecules., Lysosomes bring about intracellular, and extracellular digestion. The intracellular, digestion is brought about by autophagic, vesicle or secondary lysosomes which contain, foreign materials brought in by processes like, phagocytosis. e.g. Food vacuole in amoeba or, macrophages in human blood that engulf and, destroy harmful microbes that enter the body., , Lysosome structure, Single-wall, membrane, , Always Remember, , Enzyme complexes, , Plasma, membrane, , Lysosomal enzymes do not digest their, own membrane proteins. Three-dimensional, shape of these proteins probably protects the, membrane., Accidental release of lysosomal, enzymes in limited amount does not harm the, cell because pH of cytosol is near neutral., Any insufficiency in secretion of, lysosomal enzymes leads to disorders e.g. in, genetic disorder, Tey Sach’s disease, due to, insufficiency of lipase, brain gets impaired, due to accumulation of fats., , Rough ER, Transport vesicle, Golgi, apparatus, Lysosomes, , Food, , Autophagy, Phagocytosis, , Food, vacuole, , Fig. 5.10 Lysosomes, , 50

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Extracellular digestion is brought about, by release of lysosomal enzymes outside the, cell. e.g. acrosome, a cap like structure in, human sperm is a modified lysosome which, contain various enzymes like Hyaluronidase., These enzymes bring about fertilization, by dissolving protective layers of ovum., During metamorphosis process found, in many organisms, lysosomal enzymes help in, reusing the tissues of redundant organs. They, also help in destruction of malignant cells. e.g., T-lymphocytes., , In addition to endomembrane system,, there are several other cell organelles, bound by single layer of plasma membrane, in the cell., Microbodies : Microbodies are found in both, plant and animal cells. These are minute, membrane bound sacs. Microbodies contain, various types of enzymes based on which, they are classified into different types; few of, which are explained here :, Sphaerosomes : These are found mainly in, cells involved in synthesis and storage of fats., e. g. endosperm of oil seeds. The membrane, of sphaerosome is half unit membrane i.e. this, membrane has only one phospholipid layer., Peroxisomes : Peroxisomes contain enzymes, that remove hydrogen atoms from substrate, and produce toxic hydrogen peroxide by, utilisation of oxygen. At the same time, peroxisome also contains enzymes that, convert toxic H2O2 to water. Conversion of, toxic substances like alcohol takes place in, liver cells by peroxisomes., , 7. Vacuoles :, Vacuoles are membrane bound sacs, prominently found in plant cells. In animal, cells, whenever present they are few in number, and smaller in size. Generally, there are two or, three permanent vacuoles in a plant cell., In some large plant cells, a single large, vacuole occupies the central part of the cell. It, is called central vacuole. In such cells vacuole, can occupy as much as 90% of the total volume, of the cell., The, vacuoles, are, bound, by, semipermeable membrane, called tonoplast, membrane. This membrane helps in maintaining, the composition of vacuolar fluid; the cell sap,, different from that of the cytosol. Composition, of cell sap differs in different types of cells. The, cell sap of central vacuole is a store house of, various ions and thus is hypertonic to cytosol., Small vacuoles in seeds of certain plants store, organic materials like proteins. Vacuoles store, excretory products or even compounds that are, harmful or unpalatable to herbivores, thereby, protecting the plants. Attractive colours of the, petals are due to storage of such pigments in, vacuoles., Intake of food or foreign particle by, phagocytosis involves formation of food, vacuole. In fresh water unicellular forms like, Paramoecium, excretion and osmoregulation, takes place by contractile vacuoles. Vacuoles, maintain turgidity of the cell., , 8. Glyoxysomes :, These membrane bound organelles, contain enzymes that convert fatty acids, to sugar. They can be observed in cells of, germinating seeds where the cells utilise, stored fats as source of sugar till it starts, photosynthesising on its own., Membrane, Matrix, Core, , Fig. 5.11 Glyoxysomes, , 51

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9. Mitochondria (Singular :, Mitochondrion) :, These are important cell organelles, involved in aerobic respiration. Mitochondria, are absent in prokaryotic cells and red blood, corpuscles (RBCs). Their shape may be oval or, spherical or spiral strip like., It is a double membrane bound, organelle. Outer membrane is permeable to, various metabolites due to presence of a protein, -Porin or Parson’s particles. Inner membrane is, selectively permeable to few substances only., Both membranes are separated by a spaceouter chamber., Inner membrane shows several finger like, or plate like folds- cristae. Inner membrane, bears numerous particles- oxysomes and, cytochromes / electron carriers., Inner membrane encloses a cavity- inner, chamber, containing a fluid- matrix. Matrix, contains few coils of circular DNA, RNA, 70S, types of ribosomes, lipids and various enzymes, of Krebs cycle and other pathways., DNA, , Ribosomes, Matrix, , Use your brain power, 1. Why do we call mitochondria as power, house of cell? Explain in detail. Hint:, Refer chapter Cellular Respiration., 2. Are mitochondria present in all, eukaryotic cells?, Oxysomes :, Inner membrane of mitochondria, bears numerous particles - Oxysomes (F1-F0, / Fernandez - Moran / Elementary particles /, mitochondrial particles). Each particle consists, of head and stalk / foot. Head (F1) / lollipop, head faces towards matrix and foot (F0) is, embedded in inner membrane. Head acts as, an enzyme ATP synthase and foot as proton, channel. Oxysomes are involved in proton, pumping and ATP synthesis., 10. Plastids :, Like mitochondria, plastids too are, double walled organelles containing DNA,, RNA and 70S ribosomes. But they are larger, in size and can be observed under light, microscope. Plastids are classified according, to the pigments present in it as leucoplasts,, chromoplasts and chloroplasts., Leucoplasts do not contain any, pigments, they are of various shapes and sizes., These are meant for storage of nutrients. e.g., Amyloplasts that store starch, Elaioplasts that, store oils and Aleuroplasts that store proteins., , Outer membrane, Inner membrane, Intermembrane, space, , F0 portion, F1 portion, , Cristae, Head (F1), Pedicel (F0), , Perimitochondrial space, Outer chamber, Protein layer, Lipid layer, , Inner, membrane, Outer membrane, , Internal membrane, Plastoglobule, Intermembrane space, Ribosome, External membrane, , Base, , Granum, Chloroplast, DNA, , F1 particles, , Respiratory, chain and, enzymes, Intracristal, space, Mitochondrial crista, F1 particles, , Stroma, Thylakoid, Thylakoid, Lumen membrane, Lamella, , Fig. 5.13 Chloroplast, , Fig. 5.12 Mitochondrion, , 52

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lamellae. Space outside thylakoids is is filled, with stroma. The stroma, and the space inside, thylakoids contain various enzymes essential, for photosynthesis. Like other plastids,, stroma of chloroplast also contains DNA and, ribosomes., , Something, interesting, :, Both, mitochondria and chloroplast are double, walled organelles, they have DNA and, ribosomes and can duplicate within the, cell on their own! It is considered that, primitive eukaryotic cell engulfed an aerobic, nonphotosynthetic prokaryotic cell. This, guest cell developd symbiotic relationship, with the host cell. In course of evolution, both, merged as a single cell with a mitochondrion., One of these cells might have engulfed, photosynthetic prokaryote and evolved into, photosynthetic eukaryotic cells. This is called, ‘Endosymbiont theory’ i.e. coexistence of cell, within cell!, , 11. Ribosomes :, You are aware that ribosomes are, protein factories of the cell. They use the, genetic information to synthesise proteins., Ribosomes were first observed as dense, particles in electron micrograph of a cell by, scientist Pallade in 1953. Ribosomes are made, up of Ribosomal RNA and proteins. They do, not have any membranous covering around, them., , Chromoplasts contain pigments like, carotene and xanthophyll, etc. They impart red,, yellow or orange colour to flowers and fruits., Now you must have understood why potato, looks white in colour and shoe flower petals are, red. Both leucoplasts and amyloplasts donot, contain photosynthetic apparatus we find in, chloroplasts. Let us now study the chloroplast, in details., Plant cells, cells of algae and few, protists like Euglena contain chloroplasts. You, have observed ribbon shaped chloroplast in, Spirogyra. It differs in size, number and shape, in various cells in which it is found. In plants, it, is found in green regions; mainly in mesophyll, of leaf. This chloroplast is lens shaped. But, it can also be oval, spherical, discoid or, ribbon like. A cell may contain single large, chloroplast as in Chlamydomonas or there are, 20 to 40 chloroplasts per cell seen in mesophyll, cells. Chloroplasts contain green pigment chlorophyll along with other enzymes that help, in production of sugar by photosynthesis., Inner membrane of double walled, chlorophyll is comparatively less permeable., Inside the cavity of inner membrane, there, is another set of membranous sacs called, thylakoids. Thylakoids are arranged in the, form of stacks called grana (singular: granum)., The grana are connected to each other by, means of membranous tubules called stroma, , Prokaryotes, 30S, subunit, , 50S, subunit, , 70S, , 16S rRNA, 21 proteins, , Eukaryotes, , Small, subunit, , Large, subunit, , 18S rRNA, 33 proteins, , 40S, subunit, , 28S rRNA, 5.8S rRNA, 5S rRNA, 50 proteins, , 23S rRNA, 5S rRNA, 34 proteins, , Complete, ribosome, , 60S, subunit, , 80S, , Fig. 5.14 Ribosome, In a eukaryotic cell, ribosomes are, present in mitochondria, plastids and in cytosol., Ribosomes in cytoplasm are either found, attached to outer surface of Rough Endoplasmic, Reticulum and nuclear membrane or freely, suspended in cytoplasm. Both are similar in, structure and are 80S type. Each ribosome is, made up of two subunits; a large and a small, subunit., Bound ribosomes generally produce, proteins that are transported outside the cell, after processing in ER and Golgi body. e.g., Bound ribosomes of acinar cells of pancreas, produce pancreatic digestive enzymes. Free, ribosome come together and form chains called, polyribosomes for protein synthesis., , 53

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Free ribosomes generally produce, enzymatic proteins that are used up in cytoplasm, like enzymes required for breakdown of sugar., Both types of ribosomes can interchange, position and function. Number of ribosomes, is high in cells actively engaged in protein, synthesis., , Nucleoplasm, , Nuclear, membrane, , Nucleolus, Nuclear pore, , Always Remember, , Fig. 5.15 Nucleus, , The particle size of ribosomes is, measured in terms of Svedberg unit (S). It is a, measure of sedimentation rate of a particle in, ultracentrifuge. It is thus a measure of density, and size of a particle., 1S = 10-13 sec., , The nucleoplasm or karyolymph, contains various substances like nucleic, acids, protein molecules, minerals and salts., It contains chromatin network and nucleolus., Nucleolus is another component which is not, bound by cell membrane., Nucleolus is made up of rRNA and, ribosomal proteins and it is best known as the, site of ribosome biogenesis. Depending on, synthetic activity of a cell, there are one or more, nucleoli present in the nucleoplasm. For ex:, cells of oocyte contain large nucleolus whereas, sperm cells contain small inconspicuous, one. They appear as dense spherical bodies, present near chromatin network. They produce, rRNA and ribosomal proteins which are then, transported to cytoplasm and are assembled, together to form ribosomes., , Know the scientists, Venkatraman Ramakrishnan : Won, Nobel Prize in Chemistry in the year 2009,, for explaining the structure and working of, ribosomes. He shared the prize with Yonath, (Israel) and Thomas Steitz (USA)., 12. Nucleus :, Structure of nucleus of a eukaryotic, cell becomes distinct in a non-dividing cell or, during interphase. Such an interphase nucleus, is made up of nuclear envelope, nucleoplasm,, nucleolus and chromatin network., Nuclear envelope is a double walled, delimiting membrane of nucleus. Two, membranes are separated from each other, by perinuclear space (10 to 50nm). Outer, membrane is connected with endoplasmic, reticulum at places. It also harbours ribosomes, on it. The inner membrane is lined by nuclear, lamina- a network of protein fibres that helps, in maintaining shape of the nucleus. The two, membranes along with perinuclear space help, in separating nucleoplasm from cytoplasm., However, nuclear membrane is not continuous., At places, there are small openings called, nucleopores. The nucleopores are guarded, by pore complexes which regulate flow of, substances from nucleus to cytoplasm and in, reverse direction., , Can you recall?, 1. Consider the following cells and comment, about the position, shape and number, of nuclei in a eukaryotic cell. Add more, examples from your previous knowledge, about cell and nucleus., - Cuboidal epithelial cell, different types, of blood corpuscles, skeletal muscle fibre,, adipocyte., 2. Why nucleus is considered as control unit, of a cell., 3. Can cells like Xylem or mature human, RBCs called living?, 4. What is a syncytium and coenocyte?, , 54

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Chromatin material :, Nucleus contains genetic information, in the form of chromosomes which are nothing, but DNA molecules associated with proteins., In a nondividing cell, the chromosomes appear, as thread like network and cannot be identified, individually. This network is called chromatin, material. The chromatin material contains, DNA, histone and non-histone proteins and, RNA. In some regions of chromatin, DNA, is more and is genetically active called, euchromatin. Some regions that contain more, of proteins and less DNA and are genetically, inert, are called heterochromatin., , 13. Cytoskeleton :, With advancement in light and electron, microscopy, scientists revealed presence of, network of fibrils throughout the cytoplasm., It is called cytoskeleton. Cytoskeleton, consists of microtubules, microfilaments and, intermediate filaments. Microtubules are made, up of protein- tubulin. Microfilaments are, made up of actin and intermediate filaments, are composed of fibrous proteins. Cytoskeleton, helps in maintenance of shape of cell,, contraction of cell, mobility of cell and cell, organelles, changes in shape of the cells and, cell division., Cilia and flagella :, They are fine hair like membrane bound, protoplasmic outgrowths that occur on the free, surface of the cell. They generate a current, in fluid medium for passage of material and, locomotion. Cilia are small in size and many in, number. Cilia act as oars causing movement of, cell., Flagella are longer and few in number., Flagella present in prokaryotic bacteria are, structurally different from that of eukaryotic, flagella. Cilium or flagellum consists of basal, body, basal plate and shaft., Basal body is placed in outer part, of cytoplasm. It is derived from centriole. It, has nine peripheral triplets of fibrils. Shaft is, exposed part of cilia or flagella. It consists of, two parts- sheath and axoneme. Sheath is, covering membrane of cilium or flagellum., , Outer nuclear membrane, Inner nuclear, Nucleolus, membrane, Nuclear, pore, Perinuclear, space, Heterochromatin, Chromatin, threads, Chromocentre, Karyolymph, Karyosome, , Fig. 5.16 Ultrastructure of nucleus, When the cell prepares to divide, the, chromosomes coil and get condensed. At, metaphase stage, they become distinct and can, be clearly identified. You will study this process, as well as structure and types of chromosome, in other chapters. Every species of living, organism has specific number of chromosomes, like normal human cell has 46., The nucleus contains entire genetic, information, hence play important role in, heredity and variation. It is the site for synthesis, of DNA, RNA and ribosomes. It plays important, role in protein synthesis. Chromosome number, being constant for a species, it is important in, phylogenetic studies. Nucleus thus is the master, cell organelle., , Central microtubules, Plasma, membrane, , Dynein, arms, , Radial spokes, Inner sheath, Nexin, , B tubule, A tubule, Doublet microtubule, , Fig. 5.17 Structure of Cilia, , 55

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Core called axoneme possesses 11, fibrils running parallel to long axis. It shows, 9 peripheral doublets and two single central, fibrils (9+2). The central tubules are enclosed, by central sheath., , Microtubule triplet, , Connecting, fibers, , This sheath is connected to one of the, tubules of peripheral doublets by a radial spoke., Central tubules are connected to each other by, bridges. The peripheral doublets are connected, to each other through linkers or interdoublet, bridge., , A-C Linder, , Centrioles and centrosomes :, Centrosome is usually found near the, nucleus of an animal cell. It contains a pair, of cylindrical structures called centrioles., The cylinders are perpendicular to each other, and are surrounded by amorphous substance, called pericentriolar material. Each cylinder, of centriole is made up of nine sets of triplet, microtubules made up of tubulin. Evenly, spaced triplets are connected to each other by, means of non-tubulin proteins., , Microtubule, triplet, , Foot, Radial, fibre, (spoke), , Fig. 5.18 Structure of Centriole, At the proximal end of centriole, there, is a set of tubules called hub. The peripheral, triplets are connected to hub by means of radial, spokes. Due to this proximal end of centriole, looks like a cartwheel. The centrosomes help, in assembly of spindle apparatus during cell, division. It forms basal body of cilia and, flagella., , Do Yourself, Prepare a concept map of cell structure., , 56

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Exercise, 1. Choose currect option, I. Golgi body is absent in, a. Prokaryotes, b. Mature mammalian RBC, c. Alkaryotes, d. All of the above, , A. Growth of cell wall during cell, elongation take place by ............., a. Apposition b. Intussusception, c. Both a & b d. Super position, B. Cell Membrane is composed of, a. Proteins and cellulose, b. Proteins and Phospholipid, c. Proteins and carbohydrates, d. Proteins, Phospholipid and some, carbohydrates, , 2. Answer the following questions, A. Plants have no circulatory system?, Then how cells manage intercellular, transport?, B. Is nucleolus covered by membrane?, C. Fluid mosaic model proposed by Singer, and Nicolson replaced Sandwich model, proposed by Danielli and Davson?, Why?, D. The RBC surface normally shows, glycoprotein molecules. When, determining blood group do they play, any role?, E. How cytoplasm differs from, nucleoplasm in chemical composition?, , C. Plasma membrane is Fluid structure due, to presence of, a. Carbohydrates, b. Lipid, c. Glycoprotein, d. Polysaccharide, D. Cell Wall is present in, a. Plant cell, b. Prokaryotic cell, c. Algal cell d. All of the above, E. Plasma membrane is, a. Selectively permeable, b. Permeable, c. Impermeable, d. Semipermeable, , 3. Answer the following questions, A. Distinguish between smooth and rough, endoplasmic reticulum., B. Mitochondria are power house of cell., Give reason., C. What are types of plastids?, , F. Mitochondria DNA is, a. Naked, b. Circular, c. Double stranded d. All of the above, G. Lysosomes are not help full in, a. Osteogenesis, b. Cellular digestion, c. Metamorphosis, d. Lipogenesis, , 4. Label the diagrams and write down the, details of concept in your word, , A, , H. Which of the following set of organelles, contain DNA, a. Mitochondria, Peroxysome, b. Plasma membrane, ribosome, c. Mitochondria, chloroplast, d. Chloroplast, dictyosome, , 57

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6. Label the A, B, C, and D in above diagram, and write the functions of organells A and, B., , B, , A, B, , C, D, , C, , 7. Identify each cell structures or organelle, from it's description below., i. Manufactares ribosomes, ii. Carrys out photosynthesis, iii. Can bud of vesicles, which form the, golgi apparatus., iv. Manufactures ATP in animal and plant, cells., v. Selectivelly permeable., , D, , 8. Onion cells have no chloroplast. How can, we tell they are plants?, Practical / Project :, 1. Observe the cells of Onion root tip under, microscope., 2. Observe the cells from buccal epithelium, stained with Giemsa under microscope., , 5. Complete the flow chart, Transport vesicle, , Golgi apparatus, , Autophagy, , 58

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6. Biomolecules, Can you recall?, , Chemically all living organisms, have basic three types of macromolecules,, which are polymers of simple subunits, called monomers. The polysaccharides, (carbohydrates),, polypeptides, (proteins), and polynucleotides (nucleic acids) are the, polymers of monosaccharides, amino acids and, nucleotides respectively (Figure 6.1). Lipids, are water insoluble and small molecular weight, compounds as compared to macromolecules., , 1. Which are different cell components?, 2. What is the role of each component of cell?, , Our planet is having a wide diversity, of living organisms that are classified as, unicellular (consisting of a single cell; including, bacteria and yeast) or multicellular having, many cells (e.g. plants and animals). You have, also learnt that living organisms have cell as, the basic structural and functional unit. The, cells have protoplasm containing numerous, chemical molecules, the biomolecules., Biochemistry is biological chemistry, that provides us the idea of the chemistry, of living organisms and molecular basis for, changes taking place in plants, animals and, microbial cells. It develops the foundation, for understanding all biological processes, and communication within and between cells, as well as chemical basis of inheritance and, diseases in animals and plants., Chemical analysis of all living, organisms indicates presence of the most, common elements like carbon, hydrogen,, nitrogen, oxygen, sulphur, calcium, phosphorus,, magnesium and others with their respective, content per unit mass of a living tissue., , 6.2, Biomolecules in the cell, A. Carbohydrates :, The word carbohydrates means, ‘hydrates of carbon’. They are also called, saccharides. They are biomolecules made, from just three elements: carbon, hydrogen, and oxygen with the general formula (CH2O)n., They contain hydrogen and oxygen in the same, ratio as in water (2:1). Carbohydrates can be, broken down (oxidized) to release energy., Based on number of sugar units,, carbohydrates are classified into three types, namely, monosaccharides, disaccharides and, polysaccharides (Table 6.2)., , Biomolecules, Organic, Macromolecules, Polysaccharides, Simple, sugar, , Inorganic, Micromolecules, , Polynucleotides, , Lipids, , Polypeptides, , Glycerol Alkaloids, Phenolics, Terpenoids, Saturated fatty Unsaturated Essential oils, Toxins, acids, fatty acids, Lectins, , Nucleotide, Amino, acid, , Secondary, metabolites, , Fatty, acids, , Prime, elements, Carbon (C), Hydrogen (H), Oxygen (O), Present in air /, water, , Macro, elements, , Trace, elements, , Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S), , Boron (B), Chlorine (Cl), Zinc (Zn),, Copper (Cu), Iron (Fe), Sodium, (Na), Molybdenum (Mo), Nickel, Fig.6.1 Biomolecules in living system (Ni), Silicon (Si), Cobalt (Co), , 59

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Carbohydrates, Monosaccharides, (Simple sugars), 1. Triose-3carbons, (e.g. Glyceraldehyde), 2. Tetrose-4 carbons, (e.g. Erythrose), 3. Pentose-5 carbons, (e.g. Ribose in RNA and, deoxyribose in DNA), 4. Hexose- 6 carbons, (e.g. Glucose- blood sugar,, Fructose-fruit sugar and, Galactose-product of lactose), 5. Heptose-7 carbons, (e.g. Sedoheptulose), , Disaccharides, (Two monosaccharides), 1. Sucrose (cane sugar), on hydrolysis, it produces, Glucose and Fructose, 2. Lactose (milk sugar), on hydrolysis, it produces, Glucose and Galactose, 3. Maltose (malt sugar), on hydrolysis, it produces, two units of Glucose, , Polysaccharides, (Polymer of monosaccharides), a. Homopolysaccharides:, polymer of one type of, monosaccharides, e.g. Starch - plant storage, molecule, e.g. Cellulose - cell wall, component, e.g. Glycogen - animal storage, molecule, b. Heteropolysaccharides:, polymer of different types of, monosaccharides e.g. Hyaluronic, acid, heparin, blood group, substances, chondroitin sulphate, Table 6.2 Classification of Carbohydrates, a ketone(-C=O) group are classified as ketoses., eg. ribulose, fructose., , 1. Monosaccharides : These are the simplest, sugars having crystalline structure, sweet, taste and soluble in water. They cannot be, further hydrolysed into smaller molecules., They are the building blocks or monomers of, complex carbohydrates. They have the general, molecular formula (CH2O)n, where n can be 3,, 4, 5, 6 and 7. They can be classified as triose,, tetrose, pentose, etc. according to the number, of carbon atoms in a molecule as mentioned in, the table 6.2., Monosaccharides, containing, the, aldehyde (-CHO) group are classified, as aldoses e.g. glucose, xylose, and those with, , a. Glucose : It is the most important fuel in, living cells. Its concentration in the human, blood is about 90mg per 100ml of blood. The, small size and solubility in water of glucose, molecules allows them to pass through the, cell membrane into the cell. Energy is released, when the molecules are metabolised by cellular, respiration., b. Galactose : It looks very similar to glucose, molecules. They can also exist in α and β, forms. Galactose react with glucose to form, the dissacharide lactose. However, glucose and, galactose cannot be easily converted into one, another. Galactose cannot play the same role, in respiration as glucose., c. Fructose : It is the fruit sugar and chemically, it is ketohexose but it has a five-atom ring, rather than a six-atom ring. Fructose reacts with, glucose to form the sucrose, a disaccharide., , Fig. 6.3 Structure of Glucose, , All monosaccharides are reducing, sugars due to presence of free aldehyde or, ketone group. These sugars reduce the Benedict's, reagent (Cu2+ to Cu+) since they are capable, of transferring hydrogens (electrons) to other, compounds, a process called reduction., , 2. Disaccharides : Monosaccharides are rare, in nature. Most sugars found in nature are, disaccharides. Disaccharide is formed when, two monosaccharide react by condensation, , 60

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reaction releasing a water molecule. This, process requires energy. A glycosidic, bond forms and holds the two monosaccharide, units together., Sucrose, lactose and maltose are, examples of disaccharides. Sucrose is a nonreducing sugar since it lacks free aldehyde or, ketone group. Lactose and maltose are reducing, sugars. Lactose also exists in beta form, which, is made from β-galactose and β-glucose., Disaccharides are soluble in water,, but they are too big to pass through the cell, membrane by diffusion. They are broken down, in the small intestine during digestion. Thus, formed monosaccharides then pass into the, blood and through cell membranes into the, cells., , monosaccharides. The properties of a, polysaccharide molecule depend on its length,, branching, folding and coiling., a. Starch : Starch is a stored food in the plants. It, exists in two forms: amylose and amylopectin., Both are made from α-glucose. Amylose is, an unbranched polymer of α-glucose. The, molecules coil into a helical structure. It forms a, colloidal suspension in hot water. Amylopectin, is a branched polymer of α-glucose. It is, completely insoluble in water., , Amylose, , Amylopectin, , hydrolysis, , C12H22O11 + H2O, Disaccharide + Water, , C6H12O6 + C6H12O6, monosaccharide + monosaccharide, , Fig. 6.5 Starch, , b. Glycogen : It is amylopectin with very short, distances between the branching side-chains., Glycogen is stored in animal body particularly, in liver and muscles from where it is hydrolysed, as per need to produce glucose., Fig. 6.4 Maltose, Monosaccharides are used very quickly, by cells but if a cell is not in need of all the, energy released immediately then it may get, stored. Monosaccharides are converted into, disaccharides in the cell by condensation, reactions, which result in the formation of, polysaccharides as macromolecules. These are, too big to escape from the cell., , c. Cellulose : It is a polymer made from, β-glucose molecules and the polymer molecules, are 'straight'. Cellulose serves to form the cell, walls in plant cells. These are much tougher, than cell membranes. This toughness is due to, the arrangement of glucose units in the polymer, chain and the hydrogen-bonding between, neighbouring chains., Biological significance of Carbohydrates:, It supplies energy for metabolism., Glucose is the main substrate for ATP, synthesis. Lactose, a disaccharide is present, in milk provides energy to lactating babies., Polysaccharide serves as structural component, of cell membrane, cell wall and reserved food, as starch and glycogen., , 3. Polysaccharides :, Monosaccharides can undergo a series, of condensation reactions, adding one unit, after the other to the chain till a very large, molecule (polysaccharide) is formed. This, is called polymerization. Polysaccharides, are broken down by hydrolysis into, , 61

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Unsaturated Fatty Acids are with, one or more double bonds between the carbon, atoms of the hydrocarbon chain. Oleic acid, found in nearly all fats and linoleic acid found, in many seed oils are examples of unsaturated, fatty acids., These fatty acids are basic molecules, which form different kinds of lipids. Lipids, may be classified as simple, compound and, derived lipids., , Can you tell?, 1. Enlist the natural sources, structural, units and functions of the following, polysaccharides., a. starch b. cellulose c. glycogen, 2. The exoskeleton of insects is made up of, chitin. This is a ......., a. mucoprotein b. lipid, c. lipoprotein d. polysaccharide, 3. List names of structural polysaccharides, 4. What are carbohydrates?, 5. Write a note on oligosaccharide and, glycosidic bond., , Simple Lipids : These are esters of fatty acids, with various alcohols. Fats and waxes are, simple lipids. Fats are esters of fatty acids, with, glycerol, (CH2OH-CHOH-CH2OH)., Triglycerides are three molecules of fatty acids, and one molecule of glycerol. Generally,, unsaturated fats are liquid at room temperature, and are called oils. Unsaturated fatty acids are, hydrogenated to produce fats e.g. Vanaspati, ghee., Fats are a nutritional source with high, calorific value. Fats act as reserved food, materials. In plants it is stored in seeds to, nourish embryo during germination. In animals, fat is stored in the adipocytes of the adipose, tissue. Fats deposited in subcutaneous tissue, act as an insulator and minimise loss of body, heat. Fats deposited around the internal organs, act as cushions to absorb mechanical shocks., Wax is another example of simple lipid., They are esters of long chain fatty acids with, long chain alcohols. They are most abundant, in the blood, the gonads and the sebaceous, glands of the skin. Waxes are not as readily, hydrolysed as fats. They are solid at ordinary, temperature., , B. Lipids :, These are group of substances with, greasy consistency with long hydrocarbon, chain containing carbon, hydrogen and oxygen., In lipids, hydrogen to oxygen ratio is greater, than 2:1 (in carbohydrates it is always 2:1)., Lipid is a broader term used for fatty acids and, their derivatives. They are soluble in organic, solvents (non-polar solvents). Let’s understand, what fatty acids are., Fatty acids are organic acids which, are composed of hydrocarbon chain ending, in carboxyl group (-COOH). They can be, saturated fatty acids with no double bonds, between the carbon atoms of the hydrocarbon, chain. Palmitic and stearic acids found in all, animal and plant fats are examples of saturated, fatty acids., , Fig. 6.6 Saturated and unsaturated fatty acid, , Fig. 6.7 Triglyceride, , 62

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Waxes form water insoluble coating on, hair and skin in animals, waxes form an outer, coating on stems, leaves and fruits., , Adrenocorticoids,, sex, hormones, (progesterone, testosterone) and vitamin D, are synthesised from cholesterol. Cholesterol, is not found in plants. In plants, sterols exist, chiefly as Phytosterols. Yam Plant (Dioscorea), produces a steroid compound called diosgenin., It is used in the manufacture of antifertility, pills. i.e. birth control pills., , Fig. 6.8 Wax in, bee hive, , Find out, , Compound lipids : These are ester of fatty, acids containing other groups like phosphate, (Phospholipids), sugar (glycolipids), etc. They, contain a molecule of glycerol, two molecules, of fatty acids and a phosphate group or simple, sugar. Some phospholipids such as lecithin, also have a nitrogenous compound attached, to the phosphate group. Phospholipids have, both hydrophilic polar groups (phosphate and, nitrogenous group) and hydrophobic non-polar, groups (hydrocarbon chains of fatty acids)., Phospholipids contribute in the formation of, cell membrane. Glycolipids contain glycerol,, fatty acids, simple sugars such as galactose, and nitrogenous base. They are also called, cerebrosides. Large amounts of them have, been found in the brain white matter and myelin, sheath., , 1. Why do high cholesterol level in the blood, cause heart diseases?, 2. Polyunsaturated fatty acids are believed, to decrease blood cholesterol level. How?, , Can you tell?, 1. Differentiate between the saturated and, unsaturated fats., 2. What are lipids? Classify them and give at, least one example of each., , C. Proteins :, The term 'protein' (Gk. proteious, meaning first or of primary importance) was, suggested by Berzelius (1830). Mulder adopted, the term protein to refer to the complex organic, nitrogenous substances found in the cell of all, animals and plants., Characteristics : Proteins are large molecules, containing amino acid units ranging from 100, to 3000. Proteins have high molecular weights., In proteins, amino acids are linked together by, peptide bonds which join the carboxyl group of, one amino acid residue to the amino group of, another residue. A protein molecule consists of, one or more polypeptide chains. Proteins can, contain any or all of the 20 naturally occurring, amino acid types., The linear sequence of amino acids, in polypeptide chain of a protein forms its, primary structure. Functional proteins have, 3-dimensional conformation. Some proteins, such as keratin of hair consists of polypeptide, chain arranged like a spiral helix., , Water, , Nonpolar tails, Polar head, group, Phospolipid molecules, , Water, , Fig. 6.9 Lipid bilayer in aqueous medium, , Sterols : They are derived lipids. They are, composed of fused hydrocarbon rings (steroid, nucleus) and a long hydrocarbon side chain., One of the most common sterol is cholesterol., It is widely distributed in all cells of the, animal body, but particularly in nervous tissue., Cholesterol exists either free or as cholesterol, ester., , 63

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Simple proteins : Simple proteins on hydrolysis, yield only amino acids. These are soluble in, one or more solvents. Simple proteins may be, soluble in water. Histones of nucleoproteins, are soluble in water. Globular molecules of, histones are not coagulated by heat. Albumins, are also soluble in water but they get coagulated, on heating. Albumins are widely distributed, e.g. egg albumin, serum albumin and legumelin, of pulses are albumins., , Such spirals are in some cases righthanded called a-helix, in others left-handed, called β-helix. The spiral configuration is held, together by hydrogen bonds. The sequence, of amino acids in the polypeptide chain also, determines the location of its bend or fold and, the position of formation of hydrogen bonds, between different portions of the chain or, between different chains. Due to formation, of hydrogen bonds peptide chains assume a, secondary structure., In some proteins, two or more peptide, chains are linked together by intermolecular, hydrogen bonds. Such structures are called, pleated sheet. Pleated sheet structure is found, in protein of silk fibres. In large proteins such, as myoglobin and enzymes, peptide chains, are much looped, twisted and folded back on, themselves due to formation of disulphide, bonds. Such loops and bends give the protein, a tertiary structure. Whereas in haemoglobin,, protein subunits are held together to form, quaternary structure., Proteins are extremely reactive and, highly specific in behaviour. Proteins are, amphoteric in nature i.e. they act as both acids, and bases. The behaviour of proteins is strongly, influenced by pH. Like amino acids, proteins, are dipolar ions at the isoelectric point i.e. the, sum of the positive charges is equal to the sum of, the negative charges and the net charge is zero., The ionic groups of a protein are contributed by, the side chains of the polyvalent amino acids., A protein consists of more basic amino acids, such as lysine and arginine exists as a cation, and behaves as a base at the physiological pH, of 7.4. Such proteins are called basic proteins., Histones of nucleoproteins are basic proteins., A protein rich in acidic amino acids exists as, an anion and behaves as an acid. Such proteins, are called acidic proteins. Most of the blood, proteins are acidic proteins., Classification of proteins :, On the basis of structure, proteins are, classified into three categories:, , Conjugated proteins : Conjugated proteins, consist of a simple protein united with some, non-protein substance. The non-protein group, is called prosthetic group e.g. haemoglobin., Globin is the protein and the iron containing, pigment haem is the prosthetic group. Similarly,, nucleoproteins have nucleic acids as prosthetic, group. On this basis, proteins are classified as, glycoproteins and mucoproteins. Mucoproteins, are carbohydrate-protein complexes e.g. mucin, of saliva and heparin of blood. Lipopoteins are, lipid-protein complexes e.g. conjugate protein, found in brain, plasma membrane, milk etc., Derived proteins : These proteins are not found, in nature as such. These proteins are derived, from native protein molecules on hydrolysis., Metaproteins, peptones are derived proteins., , Can you tell?, 1. All proteins are made up of the same, amino acids; then how proteins found, in human beings and animals may be, different from those of other ?, 2. What are conjugated proteins? How do, they differ from simple ones? Give one, example of each., 3. Which of the following is a simple, protein, a. nucleoprotein, b. mucoprotein, c. chromoprotein, d. globulin, , 64

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1. Structure of DNA :, DNA is a very long chain made up of, alternate sugar and phosphate groups. The, sugar is always deoxyribose and it always, joined to the phosphate in the same way, so that, the long chain is perfectly regular, repeating, the same phosphate-sugar sequence over and, over again. Each sugar of the sugar-phosphate, chain has a 'base' attached to it and the base is, not always the same. This unit which consists, of a sugar, phosphate and a base is called, nucleotide. The nitrogenous base and a sugar, of a nucleotide form- a molecule, nucleoside., Thus, nucleoside does not contain phosphate, group. Four types of nucleosides are found in, DNA molecule. In a nucleoside, nitrogenous, base is attached to the first carbon atom (C-1), of the sugar and when a phosphate group gets, attached with that of the carbon (C-5) atom, of the sugar molecule a nucleotide molecule is, formed., , D. Nucleic Acids :, Know the scientists, Swiss, biochemist,, Friederich, Miescher (1869) discovered and isolated, nucleic acids from the pus cells. By 1938, it, became evident that nucleic acids are of two, types- deoxyribose nucleic acid (DNA) and, ribose nucleic acid (RNA). DNA is found in, chloroplasts and mitochondria. DNA is the, hereditary material in most of the organisms., The nucleic acids are among the largest of, all molecules found in living beings. They, contain three types of molecules a) 5 carbon, sugar, b) Phosphoric acid and c) Nitrogen, containing bases. Three join together to form, a nucleotide of nucleic acid., Fuelgen, (1924), showed, that, chromosomes contain DNA. He established, that nucleic acids contain two pyrimidine, (cytosine and thymine) and two purine (adenine, and guanine) bases. Wilkins and co-workers, showed that the purine and pyrimidine bases are, placed regularlyo along the DNA molecules at a, distance of 3.4 A , DNA is composed of : Sugar, molecule (It is a pentose sugar of deoxyribose, type) Phosphoric acid (also called phosphates, when in chemical combination) Nitrogen, containing bases (these are nitrogen containing, organic ring compounds). Principally bases are, of two types: (a) pyrimidine bases (b) purine, bases, Pyrimidine bases are single ring, (monocyclic) nitrogenous bases. Cytosine,, Thymine and Uracil are pyrimidines. Purine, are double ring (dicyclic) nitrogenous bases, Adenine and guanine are purines., Erwin Chargaff (1950) estimated the, relative amounts of the four nitrogenous bases, viz. adenine, thymine, cytosine and guanine in, DNA. They observed that the pyrimidine and, purine always occur in equal amount in DNA., They also found that the base ratio i.e. A+T /, G+ C may vary in the DNA of different groups, of animals and plants but A+T/ G+C ratio, remains constant for a particular species., , Purines, , Pyrimidines, , Fig. 6.10 Nitrogen bases in Nucleic acid, , A single strand of DNA consists of, several thousands of nucleotides one above, the other. The phosphate group of the lower, nucleotide attached with the 5th carbon atom of, the deoxyribose sugar forms phospho-di-ester, bond with that of the, 3rd carbon atom of the, deoxyribose sugar of the nucleotide placed just, above it., , 65

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DNA Model :, According to Watson and Crick, DNA, molecule consists of two strands twisted around, each other in the form of a double helix. The two, strands i.e. polynucleotide chains are supposed, to be in opposite direction so end of one chain, having 3’ lies beside the 5' end of the other. One, turn of the double helix of the DNA measures, o, about 34A . It consists paired nucleotides and, the distance between, two neighbouring pair, o, nucleotides is 3.4A . The diameter of the DNA, o, molecule has been found be 20A., There are certain organisms like, Bacteriophage ϕ x 174 and several bacterial, viruses which possess single stranded DNA., , Major groove, , Minor groove, , Hydrogen bond, , Fig. 6.11 Structure of DNA, , 2. Ribonucleic Acid (RNA) :, Another nucleic acid found in the living, organisms is Ribose nucleic acid. In most of, the organisms it is not found to be hereditary, material but in certain organisms like tobacco, mosaic virus, it is the hereditary material., Like DNA, ribose nucleic acid also consists, of polynucleotide chain with the difference, that it consists of single strand. In some cases, e.g. Reovirus and wound tumour virus, RNA is, double stranded. The nucleotides of RNA have, ribose sugar instead of the deoxyribose sugar, as in the case of DNA., , Single long chain of polynucleotides of, DNA consists of one end with sugar molecules, not connected with another nucleotide having, C-3 carbon not connected with phosphate, group, similarly the other end having C-5 of the, sugar is not connected with any more phosphate, group. These two ends of the polynucleotide, chain are called as 3' and 5' ends respectively., The single polynucleotide strand of DNA is not, straight but helical in shape. The DNA molecule, consists of such two helical polynucleotide, chains which are complementary to each other., The two complementary polynucleotide chains, of DNA are held together by the weak hydrogen, bonds. Adenine always pairs with thymine,, and guanine with cytosine ( a pyrimidine with, a purine). Adenine-thymine pair consists of, two hydrogen bonds and guanine-cytosine pair, consists of three hydrogen bonds (Thus, if the, sequence of bases of a polynucleotide chain is, known, that of the other can be determined)., , Uracil, , Ribonucleotide, , Do you know ?, Watson and Crick did not conduct, any experiment on DNA. Crick was expert in, physics, X-ray crystallography and Watson, in viral and bacterial genetics. They only, analyzed and comprehended the results of, experiments performed by scientists like R., Franklin, M. Wilkins, etc., , Cytosine, , Fig. 6.12 Single strand of RNA, , 66

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In case of RNA, Uracil substitutes, thymine of DNA. Purine, pyrimidine equality is, not found in RNA molecule because of its single, stranded structure. RNA strand is usually found, folded upon itself in certain regions or entirely., These foldings helps in stability of the RNA, molecule. Most of the RNA polynucleotide, chains start either with adenine or guanine., Three types of cellular RNAs have been, distinguished: (a) messenger RNA (mRNA) or, template RNA, (b) ribosomal RNA (rRNA), (c), transfer RNA (tRNA) or soluble RNA., mRNA carries genetic information for, arranging amino acids in definite sequence. It, is a linear polynucleotide. It accounts 3% of, cellular RNA. Its molecular weight is several, million. mRNA molecule carrying information, to form a complete polypeptide chain is called, cistron. Size of mRNA is related to the size of, message it contains. Synthesis of mRNA begins, at 5’ end of DNA strand and terminates at 3’, end., Cistron, 5', , It is also single stranded but to number, of complementary base sequences after pairing,, it is shaped like clover-leaf (Holley,1965)., Each tRNA can pick up particular amino, acid. Following four parts can be recognized, on tRNA 1) DHU arm (Dihydroxyuracil loop, / amino acid recognition site 2) Amino acid, binding site 3) Anticodon loop / codon, recognition site, 4) Ribosome recognition, site. In the anticodon loop of tRNA, three, unpaired nucleotides are present called as, anticodon which pair with codon present on, mRNA. The specific amino acids is attached, at the 3' end in acceptor stem of clover leaf of, tRNA., 3', , Amino acid, attachment side, , 5', Acceptor, stem, D-loop, T loop, , 3', Termination codon, , Initiation codon, , Fig. 6.13 The mRNA, Variable loop, , rRNA form 50-60% part of ribosomes., It accounts 80-90% of the cellular RNA. It, is synthesized in nucleus. Kurland (1960), discovered it. It gets coiled here and there due, to intrachain complementary base pairing., , Anticodon, loop, , Anticodon, Fig. 6.15 The tRNA, , Sugar-phosphate backbone, , Can you tell?, D, 1. Describe the structure of DNA molecule, as proposed by Watson and Crick., 2. Difference between DNA and RNA is, because of, a. sugar and base, b. sugar and phosphate, c. phosphate and base, d. sugar only, 3. Differentiate between DNA and RNA., 4. What is nucleotide? How is it formed?, Mention the names of all nucleotides., , Hydrogen, bond, , Bases, , Fig. 6.14 The rRNA, , tRNA molecules are much smaller, consisting of 70-80 nucleotides., , 67

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E. Enzymes :, Thousands of different chemical, reactions take place automatically at a given, time in a tiny living cell. The reactions take, place at the body temperature. If these enzymes, were not present in the cell, either the reactions, would not occur or if they occur they would, occur at a very very slow rate., , The prosthetic group is firmly bound to, the protein component by chemical bonds and, is not removed by hydrolysis. If the prosthetic, group is removed the protein part of the enzyme, becomes inactive., There are enzymes which require certain, organic compounds and inorganic ions for, their activity. The organic compounds that are, tightly attached to the protein part are called coenzymes whereas the inorganic ions which are, loosely attached to the protein part are called, co-factors. Some of the organic co-enzymes, are nicotinamide-adenine-dinucleotide (NAD), and flavin mononucleotide (FMN). Inorganic, ions of metals which act as co-factors include, magnesium, copper, zinc, iron, manganese etc., Iron (Fe++) is a co-factor of enzyme catalase,, manganese is a co-factor of peptidases. Often, metal co-factors are referred to as enzyme, activators., Properties of Enzymes :, Proteinaceous Nature : All enzymes are, basically made up of protein., , Know the scientists, German chemist Edward Buchner, discovered enzymes by accident. Buchner, discovered that living cells were not, necessary but that yeast extract could bring, about fermentation. He then coined the term, Enzyme (Gk. En = in, zyma = yeast i.e. in, yeast). This term is now commonly used for, all biocatalysts., Each enzyme catalyzes a small number, of reactions, specifically perhaps only one., The substance upon which an enzyme acts is, termed as the substrate. The enzymes which, act within the cell in which they are synthesized, are known as endo-enzymes e.g., enzymes, produced in the chloroplast and mitochondria,, if they act outside the cell in which they are, synthesized, they are known as exo-enzymes, e.g., enzymes released by many fungi. These, enzymes, synthesised by living cell, retain their, catalytic property even when extracted from, cells., , Three-Dimensional conformation : All, enzymes, have, specific, 3-dimensional, conformation. They have one or more active, sites to which substrate (reactant) combines., The points of active site where the substrate, joins with the enzyme is called substratebinding site., Catalytic Property : Enzymes are like, inorganic catalysts and influence the speed of, biochemical reactions but themselves remain, unchanged. After completion of the reaction, and release of the product they remain active, to catalyse again., A small quantity of enzymes can, catalyse the transformation of a very large, quantity of the substrate into an end product., For example, sucrase can hydrolyse 100000, times of sucrose as compared with its own, weight., Specificity of action : The ability of an enzyme, to catalyse one specific reaction and essentially, no other is perhaps its most significant property., , Do you know ?, Rennet tablets used for coagulating, milk protein casein (cheese) contain renin, enzyme that is obtained from the stomach of, calf., Nature of Enzymes :, On the basis of chemical composition,, enzymes can be put into two categories., (i) Purely proteinaceous enzymes e.g., proteases that spilt protein (ii) Conjugated, enzymes are made up of a protein to which a, non-protein prosthetic group is attached., , 68

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Each enzyme acts upon a specific, substrate or a specific group of substrates., , acid. Similarly, the enzyme glutamate pyruvate, transaminase catalyses the transfer of an amino, group from the substrate glutamate to another, substrate pyruvate., , Reversibility of action : Enzymes are very, sensitive to temperature and pH. Each enzyme, exhibits its highest activity at a specific pH,, called optimum pH. Any increase or decrease, in pH causes decline in enzyme activity e.g., enzyme pepsin (secreted in stomach) shows, highest activity at an optimum pH of 2 (acidic)., Trypsin (in duodenum) is most active at an, optimum pH of 9.5 (alkaline). Both these, enzymes viz. pepsin and trypsin are protein, digesting enzymes., , Classification of Enzymes :, Oxidoreductases : These are enzymes, catalyzing oxidation and reduction reactions, by the transfer of hydrogen and/or oxygen. e.g., alcohol dehydrogenase, alcohol, , Alcohol + NAD+, , dehydrogenase, , Aldehyde + NADH2, , Transferases : These enzymes catalyse, the transfer of certain groups between two, molecules. e.g. glucokinase, , Temperature : Enzymes are destroyed at, higher temperature of 60-70°C or below, they, are not destroyed but become inactive. This, inactive state is temporary and the enzyme can, become active at suitable temperature. Most of, the enzymes work at an optimum temperature, between 20°C and 35oC., , Glucose + ATP, , Glucokinase, , Glu-6-Phosphate + ADP, , Hydrolases: These are enzymes catalyse, hydrolytic reactions. This class includes, amylases, proteases, lipases etc. eg. Sucrase, , Nomenclature of Enzymes :, There are various ways of naming, enzymes. Enzymes are named by adding the, suffix-‘ase’ to the name of the substrate on, which they act e.g. protease, sucrase, nuclease, etc. which break up proteins, sucrose and, nucleic acids respectively., The enzymes can be named according, to the type of function they perform e.g., dehydrogenase remove hydrogen, carboxylase, add CO; decarboxylases remove CO2, oxidases, helping in oxidation., Some enzymes are named according, to the source from which they are obtained, e.g. papain from papaya, bromelain from the, member of Bromeliaceae family, pineapple., According, to international, code, of enzyme nomenclature, the name of each, enzyme ends with an -ase and consists of, double name. The first name indicates the, nature of substrate upon which the enzyme acts, and the second name indicates the reaction, catalysed e.g. pyruvic decarboxylase catalyses, the removal of CO2 from the substrate pyruvic, , Sucrose, , Sucrase, , Glucose + Fructose, , Lyases : These enzymes are involved in, elimination reactions resulting in the removal, of a group of atoms from substrate molecule, to leave a double bond. It includes aldolases,, decarboxylases, and dehydratases, e.g, fumarate hydratase., Histidine, , Histidine, , decarboxylase, , Histamine + CO2, , Isomerases : These enzymes catalyze, structural rearrangements within a molecule., Their nomenclature is based on the type of, isomerism. Thus these enzymes are identified as, racemases, epimerases, isomerases, mutases,, e.g. xylose isomerase., Glu-6-Phosphate, , Isomerase, , Fructose-6-Phosphate, , Ligases or Synthetases : These are the, enzymes which catalyse the covalent linkage, of the molecules utilizing the energy obtained, from hydrolysis of an energy-rich compound, , 69

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like ATP, GTP e.g. glutathione synthetase,, Pyruvate carboxylase. Pyruvate, Pyruvate + CO2 + ATP, , Mechanism of enzyme action :, The basic mechanism by which enzymes, catalyze chemical reactions begins with the, binding of the substrate (or substrates) to the, active site on the enzyme. The active site is the, specific region of the enzyme which combines, with the substrate., The binding of the substrate to the, enzyme causes changes in the distribution of, electrons in the chemical bonds of the substrate, and ultimately causes the reactions that lead, to the formation of products. The products are, released from the enzyme surface to regenerate, the enzyme for another reaction cycle. There, are two models to explain the mechanism, of forming Enzyme-Substrate complex, as, described below:, , carboxylase, , Oxaloacetate + ADP + Pi, , Can you tell?, D, 1. Which enzyme is needed to digest food, reserve in caster seed?, a. amylase, b. diastase, c. lipase, d. protease, 2. Co-enzyme is --------a often a metal b. often a vitamin, c. always as organic molecule, d. always an inorganic molecule, 3. List the important properties of enzymes., 4. Name the chemical found in the living, cell which has necessary message for the, production of all enzymes required by it., Try this, , To demonstrate the, effect of heat on the activities of inorganic, catalysts and enzymes., Procedure : Take 2 ml of hydrogen peroxide, (H2O2) in two test tubes, Add a pinch of, manganese dioxide (MnO2) powder to one, and a small piece of potato (to provide, enzyme catalase) or fresh liver (to provide, enzyme peroxidase) to other test tube. Keep, the tubes at room temperature in summer and, at 38°C in winter. You will find that bubbles, of oxygen evolve in both the test tubes. Both, MnO2 and cellular enzymes (catalase or, peroxidase) cause breakdown of H2O2 and, evolution of oxygen. Now take two fresh test, tubes and repeat the experiment. This time, use, boiled and cooled manganese dioxide and the, liver/potato piece. You will find that oxygen, evolves in the hydrogen peroxide solution, containing boiled and cooled manganese, dioxide. But oxygen does not evolve in the, other tube containing boiled and cooled liver/, potato piece. This activity confirms that heat, does not affect catalytic action of inorganic, catalyst but inactivates the enzyme., , Fig. 6.16 Mechanism of enzyme action, , Lock and Key model:, The specific action of an enzyme with a, single substrate can be explained using a Lock, and Key analogy first postulated in 1894 by, Emil Fischer. In this analogy, the lock is the, enzyme and the key is the substrate. Only the, correctly sized key (substrate) fits into the key, hole (active site) of the lock (enzyme)., , Fig. 6.17 Lock and key model, , 70

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Induced Fit model (Flexible Model):, , Km or the Michaelis-Menten constant, is defined as the substrate concentration, (expressed in moles/lit) to produce half of, maximum velocity in an enzyme catalysed, reaction. It indicates that half of the enzyme, molecules (i.e. 50%) are bound with the, substrate molecules when the substrate, concentration equals the Km value., Km value is a constant and a, characteristic feature of a given enzyme. It is, a representative for measuring the strength of, ES complex. A low Km value indicates a strong, affinity between enzyme and substrate, whereas, a high Km value reflects a weak affinity between, them. For majority of enzymes, the Km values, are in the range of 10-5 to 10-2 moles., , Koshland (1959) proposed the induced, fit theory, which states that approach of a, substrate induces a conformational change in, the enzyme. It is the more accepted model to, understand mode of action of enzyme. Unlike, the lock-and-key model, the induced fit model, shows that enzymes are rather flexible structures, in which the active site continually reshapes by, its interactions with the substrate until the time, the substrate is completely bound to it (it is also, the point at which the final form and shape of, the enzyme is determined)., , 2., , Enzyme Concentration :, The rate of an enzymatic reaction, is directly proportional to the concentration, of the substrate. The rate of reaction is also, directly proportional to the square root of the, concentration of enzymes. It means that the rate, of reaction also increases with the increasing, concentration of enzyme. And the rate of, reaction can also decreased by decreasing the, concentration of enzyme., , Fig. 6.18 Complex Flexible model, , Factors Affecting Enzyme Activity :, Following factors affect enzyme, activity :, 1., Concentration of Substrate :, Increase in the substrate concentration, gradually increases the velocity of enzyme, activity within the limited range of substrate, levels. A rectangular hyperbola is obtained, when velocity is plotted against the substrate, concentration. Three distinct phases (A, B and, C) of the reaction are observed in the graph., Where V = Measured velocity, Vmax = Maximum, velocity, S = Substrate concentration, Km =, Michaelis-Menten constant., , Graph 6.20 Effect of enzyme, concentration, 3., Temperature :, The enzymatic reaction occurs best at, or around 37oC which is the average normal, body temperature in homeotherms. The rate, chemical reaction is increased by a rise in, temperature but this is true only over a limited, range of temperature. Enzymes rapidly, denature at temperature above 40oC., , Graph 6.19 Effect of substrate, concentration on enzyme activity, , 71

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Concept of Metabolism: Metabolism is the, sum of the chemical reactions that take place, within each cell of a living organism and, provide energy for vital processes and for, synthesizing new organic material., It involves continuous process of, breakdown and synthesis of biomolecules, through chemical reactions. Each of the, metabolic reaction results in a transformation, of biomolecules. Most of these metabolic, reactions do not occur in isolation but are, always linked with some other reactions., In living systems, cells are ‘work, centres’ where metabolism involves two, following types of pathways., a. Catabolic pathways lead to formation of, simpler structure from a complex biomolecules, e.g. when we eat wheat, bread or chapati, our, gastrointestinal tract digests (hydrolyses) the, starch to glucose units with help of enzymes, and releases energy in form of ATP (Adenosine, triphosphate)., b. Anabolic pathway is called biosynthetic, pathway that involves formation of a more, complex biomolecules from a simpler structure,, e.g., synthesis of glycogen from glucose and, protein from amino acids. These pathways, consume energy., , The activity of enzymes is reduced at, low temperature. The temperature at which, the enzymes show maximum activity is, called Optimum temperature., , Graph 6.21 Effect of temperature on, enzyme activity, , 4., , Effect of pH :, Similar to temperature, there is also, pH at which an enzyme will catalyze the, reaction at the maximum rate. Every enzyme, has different optimum pH value. The enzyme, cannot perform its function beyond the range, of its pH value., , Metabolic pool : It is the reservoir of, biomolecules in the cell on which enzymes can, act to produce useful products as per the need, of the cell. The concept of metabolic pool is, significant in cell biology because it allows one, type of molecule to change into another type, e.g. carbohydrates can be converted to fats and, vice-versa., Catabolic chemical reaction of, glycolysis and Krebs cycle only provide ATP, but also makes available metabolic pool of, biomolecules that can be utilized for synthesis, of many important cellular components. The, metabolites can be added or withdrawn from, this pool according to the need of the cell. The, balance between catabolism and anabolism, maintain homeostasis in the cell as well as in, the whole body., , pH, , Graph 6.22 Effect of pH on enzyme, activity, , 5., , Other Substances :, The enzymes action is also increased, or decreased in the presence of some other, substances such as co-enzymes, activators and, inhibitors. Most of the enzymes are combination, of a co-enzyme and an apo-enzyme. Activators, are the inorganic substances which increase, the enzyme activity. Inhibitor is the substance, which reduces the enzyme activity., , 72

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CO2 and H2O, , Fig. 6.22 Catabolic and anabolic reactions, , Economic importance -, , Secondary metabolites (SMs) : Secondary, metabolisms are small organic molecules, produced by organisms that are not essential for, their growth, development and reproductions., Several types of bacteria, fungi and plants, produce secondary metabolism., Secondary metabolites can be classified on, the basis of chemical structure (e.g. SMs, containing rings, sugar), composition (with or, without nitrogen), their solubility in various, solvents, or the pathway by which they are, synthesized (e.g.phenylpropanoid produces, tannins). A simple way of classifying secondary, metabolites includes three main groups such as,, , Secondary metabolites :, 1. Secondary, metabolites from natural, sources have made a significant, contribution for millennia. In modern, medicine, drugs developed from secondary, metabolites have been used to treat, infectious diseases, cancer, hypertension, and inflammation., 2. Morphine was the first alkaloid isolated, from plant Papaver somnif erum. It is used, as pain reliever and cough suppressant., 3. SMs like alkaloids nicotine and cocaine, and the terpenes cannabinol are widely, used for recreation and stimulation., 4. Flavours of secondary metabolites, improve our food preference., 5. Characteristic flavours and aroma of, cabbage and its relatives are caused, by nitrogen and sulphur-containing, chemicals, glucosinolates, protect these, plants from many pests., 6. Tannins are added to wines and chocolate, for improving astringency., 7. Since most of secondary metabolites are, having antibiotic properties, they are also, used as food preservatives., , 1. Terpenes : Made from mevalonic acid, that is composed mainly of carbon and, hydrogen, 2. Phenolics : Made from simple sugars, containing benzene rings, hydrogen and, oxygen., 3. Nitrogen-containg, compounds, :, Extremely diverse class may also contain, sulphur., , 73

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Exercise, 1. Choose correct option, , 2. Solve the following questions, A. Observe the following figure and name, the type of bond shown by arrow in the, structure., , A. Sugar, amino acids and nucleotides unite, to their respective subunits to form-------a. bioelements, b. micromolecules, c. macromolecules d. all of these, , P, , B. Glycosidic bond is found in ---------------., a. Disaccharide, b. Nucleosides, c. Polysaccharide, d. all of theses, , A, , T, , S, , G, , C, , S, , S, , T, , A, , S, , S, , C, , G, , S, , P, P, , C. Amino acids in a polypeptide are joined, by ---------------bond., a. Disulphide, b. glycosidic, c. hydrogen bond, d. none of these, , P, P, , P, P, P, P, P, , 3. Answer the following questions, A. What are building blocks of life?, B. Explain the peptide bond., C. How many types of polysaccharides you, know?, D. Enlist the significance of carbohydrates., E. What is reducing sugar?, F. What is the basic difference between, saturated and unsaturated fatty acid?, G. Enlist the examples of simple protein and, add their significance., H. Explain the secondary structure of protein, with examples., I. Explain the induced fit model for mode of, enzyme action., J. What is RNA? Enlist types of RNA., K. Describe the concept of metabolic pool., L. How do secondary metabolites useful for, mankind?, , D. Lipids associated with cell membrane, are ------------., a. Spingomyelin b. Isoprenoids, c. Phospolipids, d. Cholesterol, E. Linoleic, Linolenic and -------------------acids are referred as essential fatty acids, since they cannot be synthesized by the, body and hence must be included in daily, diet., a. Arachidonic, b. Oleic, c. Steric, d. Palmitic, F. Haemoglobin is a type of -------------protein, which plays indispensible part in, respiration., a. simple, b. derived, c. conjugated, d. complex, G. When inorganic ions, molecules bind to, together form-----a. isoenzyme, c. denatured enzyme, , S, , S, , or metallo-organic, apoenzyme, they, , 4. Solve the following questions, A. Complete the following chart., , b. holoenzyme, d. none of these, , Protein, Physiological role, Collagen, ............................, ..........................., Responsible for muscle, contraction, Immunoglobulin ..............................., IgG, ....................., Significant in respiration, Fibrinogen, ................................, , H. In enzyme kinetics, Km= Vmax/2. If Km, value is lower, it indicates ---------------a. Enzyme has less affinity for substrate, b. Enzyme has higher affinity towards, substrate, c. There will be no product formation, d. All active sites of enzyme are saturated., , 74

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B. Answer the questions with reference to, the following figure., , I. What are nucleic acids? Enlist the point, of differences among DNA and RNA., J. What are the types of RNA? Mention the, role of each class of RNA., K. What is metabolism? How metabolic, pool is formed in the cell., , Polypeptide, Oxidation, Reduction, Polypeptide, , 6. If double stranded DNA has 14% C, (cytosine) what percent A (adenine), T, (thymine) and G (gaunine) would you, expect?, , i. Name the type of bond formed, between two polypeptides., ii. Which amino acid is involved in the, formation of such bond?, iii. Amongst I, II, III and IV structural, level of protein, which level of, structure includes such bond?, , 7. Name, i. The term that describes all the chemical, reactions taking place in an organism., ii. The form in which carbohydrate is, transported in a plant., iii. The reagent used for testing for reducing, sugar., , C. Match the following items given in, column I and II., Column I, i. RNA, ii. Yam plant, iii. Koshland, iv. Omega-3-fatty acid, v. Sucrase, , Column II, a. Induced fit model, b.Flax seeds, c. Hydrolase, d. Uracil, e. Anti-fertility pills, , Practical / Project :, 1. Perform an experiment to study starch, granules isolated from potato., 2. Study the action of enzyme urease on, urea., , 5. Long answer questions, A. What are biomolecules? Explain the, building blocks of life., B. Explain the classes of carbohydrates, with examples., C. Describe the types of lipids and mention, their biological significance., D. Explain the chemical nature, structure, and role of phospholipids in biological, membrane., E. Describe classes of proteins with their, importance., F. What are enzymes? How are they, classified? Mention example of each, class., G. Explain the properties of enzyme?, Describe the models for enzyme actions., H. Describe the factors affecting enzyme, action., , 75

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7. Cell Division, Daughter cells, G1 (8 hours or more), , Can you recall?, Cytokinesis, , 1. How do your wounds heal?, 2. What is the difference between growth of, non-living material and living organism?, , Interphase, Mitosis, (1-3 hours), , p, lo, Te, , • Cell growth, • Normal cell, ap, ha, function, Meta, s, phas e, • Organelle, Propha e, duplication, se, , se, , Life of all multicellular organisms, starts from single cell i.e. zygote. Growth of, every living organism depends on cell division., As stated in the cell theory, every cell arises, from the pre-existing cell., 7.1, Cell cycle :, Sequential events occurring in the life, of a cell is called cell cycle. There are two, phases of cell cycle as interphase and M-phase., During interphase, cell undergoes growth or, rest as per the need. During M-phase, the cell, undergoes division. Interphase alternates with, the period of division., , ha, , An, , • Protein, synthesis, , on, , ati, , •, , A, DN, , c, pli, , re, , G2 (2-5 hours), , S (6-8 hours), , Fig. 7.1 Cell cycle, , Interphase : Interphase is the stage between, two successive cell divisions. It is the longest, phase of cell cycle during which the cell is highly, active and prepares itself for cell division. The, interphase is divisible into three sub-phases as, G1 -phase, S-phase and G2 -phase., G1-phase : This is also known as first gap period, or first growth period. It starts immediately, after cell division. Cell performs RNA synthesis, (mRNA, rRNA and t-RNA), protein synthesis, and synthesis of membranes during this phase., S-phase : It is synthesis phase in which DNA, is synthesized or replicated, so that amount of, DNA per cell doubles. Histone proteins are also, synthesized during this phase., G2 phase : G2 is the second growth phase,, during which nucleus increases in volume., Metabolic activities essential for cell division, occur during this phase. Various proteins, necessary for cell division are synthesized, during this phase. Besides, RNA synthesis, also occur during this phase. In animal cells,, a daughter pair of centrioles appear near the, pre-existing pair., , 76, , Discuss with Teacher, Some cells do not have gap phase, in their cell cycle whereas some cells spend, maximum part of their life in gap phase., Search for such cells. Some cells are said to, be in their G0 phase. What is this G0 phase?, M-phase or period of division : 'M' stands, for mitosis or meiosis. M-phase involves, karyokinesis and cytokinesis. Karyokinesis is, the division of nucleus into two daughter nuclei, whereas cytokinesis is division of cytoplasm, resulting in two daughter cells., 7.2, , Types of cell division :, Three kinds of cell division are found, in animal cells. They are amitosis or direct, division, mitosis or indirect division and, meiosis or reductional division. Mitosis can be, performed by haploid as well as diploid cells, but meiosis can be performed by diploid cells, only. In honey bee, drones develop from haploid, unfertilized eggs whereas in Marchantia,, haploid spores form gametophyte by mitosis.

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A., Amitosis : It is the simplest mode of cell, division. During amitosis, nucleus elongates, and a constriction appears somewhere along its, length. This constriction deepens and divides, the nucleus into two daughter nuclei. This, is followed by the division of the cytoplasm, which results in the formation of two daughter, cells. This division occurs in unicellular, organisms, abnormal cells, old cells and in, foetal membrane cells., , Due to condensation, each chromosome, becomes visible under light microscope, which can be seen with its sister-chromatids, connected by centromere. The nucleolus starts, to disappear. Nuclear membrane disintegrates, and disappeares gradually. Centrosome which, had undergone duplication during interphase, begins to move towards opposite poles of the, cell. Mitotic apparatus is almost completely, formed., 2. Metaphase : In this phase, chromosomes, are completely condensed so that they appear, very short. Sister-chromatids and centromere, become very prominent. All the chromosomes, lie at equatorial plane of the cell. This is, called metaphase plate. Mitotic spindle is, fully formed. Centromere of each chromosome, divides into two, each being associated with a, chromatid., , Internet my friend, What is Karyogram or Karyotype?, B., Mitosis : This is a type of cell division, in which a cell divides to form two similar, daughter cells which are identical to the parent, cell. It is completed in two steps as karyokinesis, and cytokinesis., Karyokinesis is nuclear division which, is sub-divided into prophase, metaphase,, anaphase, and telephase. Although for the, sake of convenience above mentioned steps, are used, it must be remembered that mitosis, is a continuous process that starts with the, disappearance of nuclear membrane in, prophase and ends with separation of two fully, formed cells after cytokinesis., 1. Prophase : This phase involves condensation, of chromatin material, migration of, centrosomes, appearance of mitotic apparatus, and disappearance of nuclear membrane., , Spindle fibres, , Fig. 7.3 Metaphase, , 3. Anaphase : The chromatids of each, chromosome separate and form two, chromosomes called daughter chromosomes., The formed chromosomes are pulled away, in opposite direction by spindle apparatus., Chromosomes being pulled away appear like a, bunch of banana during midway of anaphase., Each set of chromosomes reach at opposite, poles of the cells marks the end of anaphase., , Early prophase, Duplicated, centriole, , Nucleolus, , Nuclear, membrane, , Metaphase plate, , Chromosome, , Late prophase, Chromatids, moving to, opposite, poles, , Nuclear, membrane, disappears, , Condensed, chromosomes, , Fig. 7.2 Prophase, , Fig. 7.4 Anaphase, , 77

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4. Telophase : The telophase is the final, stage of karyokinesis. The chromosomes with, their centromeres at the poles begin to uncoil,, lengthen and loose their individuality. The, nucleolus begins to reappear. The nuclear, membrane begins to appear around the, chromosomes. Spindle fibres break down, and get absorbed in the cytoplasm. Thus two, daughter nuclei are formed in a cell., , Cytokinesis : The division of the cytoplasm, into two daughter cells is called cytokinesis., The division starts with a constriction. This, constriction gradually deepens and ultimately, joins in the centre dividing into two daughter, cells. This process of division of cytoplasm is, perpendicular to the spindle. This mechanism, of cytokinesis is characteristic of animal cells., However, plant cells are covered by a, relatively non-flexible cell wall. Due to this,, furrow can not be formed. Instead, cell wall/, partition starts to appear at the centre of the, cell and grows outward to meet the existing, lateral walls. The formation of the new cell, wall begins with the formation of a simple, precursor, called the 'cell-plate' that represents, the middle lamella between the walls of two, adjacent cells., At the time of cytoplasmic division,, organelles like mitochondria and plastids get, distributed between the two daughter cells., , Newly formed daughter nuclei, , Daughter cells, , Fig. 7.5 Telophase, , Significance of mitosis : As mitosis is, equational division, the chromosome number, is maintained constant. It ensures equal, distribution of the nuclear and the cytoplasmic, content between the daughter cells, both, quantitatively and qualitatively. The hereditary, material (DNA) is also equally distributed., It helps in the growth and development of, organisms., , Do you know ?, Pulling, away, of, daughter, chromosomes is achieved by elongation and, shortening of two types of spindle fibres., Spindle fibre present between centriole and, centromere, called as kinetochore fibres, contract and the spindle fibres present, between two opposite centrioles, called as, polar fibres elongate., Cytokinesis, in animal, cell, , Cleavage furrow, , Contractile ring, of microfilaments, , Cytokinesis, in plant cell, , Vesicles forming Wall of, parent cell Cell plate, cell plate, , New cell, wall, Daughter cells, , Daughter cells, , Fig. 7.6 Cytokinesis, , 78

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1. First meiotic division or Heterotypic, division – (Meiosis I), 2. Second meiotic division or Homotypic, division (Meiosis II), A. First meiotic division or Heterotypic, division (Meiosis I), During 1st meiotic division, diploid cell, is divided into two haploid cells. The daughter, cells resulting from this division are different, from the parent cell in chromosome number., Hence this division is also called heterotypic, division., It consists of the phases like prophase-I,, metaphase-I, anaphase-I, telophase-I and, cytokinesis-I, Prophase-I : This phase has longer duration., Significant features which are peculiar to, meiosis occurs in this phase. This phase, can be sub-divided into five sub-stages as, Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis., Leptotene : The volume of nucleus increases., The chromosomes become distinct, long, thread-like and coiled. They take up a specific, orientation- the 'bouquet stage' inside the, nucleus. This is characterised with the ends, of chromosomes converged towards that side, of the nucleus where the centrosome lies., The centriole divides into two and migrate to, opposite poles., Zygotene : Intimate pairing of non-sister, chromatids of homologous chromosomes, takes place by formation of synaptonemal, complex. This pairing is called synapsis. Each, pair consists of a maternal chromosome and a, paternal chromosome. Chromosomal pairs are, called bivalents or tetrads., Pachytene : Each individual chromosome, begins to split longitudinally into two similar, chromatids. At this stage, tetrads become, more clear in appearance because of presence, of four visible chromatids. The homologous, chromosomes of each pair begin to separate, from each other. However, they do not, completely separate but remain attached, together at one or more points., , Old and worn-out cells are replaced, through mitosis. It helps in the asexual, reproduction of organisms and vegetative, propagation in plants. The process of mitosis, also maintains the nucleo-cytoplasmic ratio., Although mitosis is a very reliable process, for preserving the genetic make-up of cells or, organisms, it cannot introduce variation or new, combination of existing genes., Can you tell?, D, 1. What is cell cycle?, 2. Which processes occur during interphase?, 3. Which are the steps of mitosis?, Internet my friend, How the life span of a cell is decided?, Death of cell : You may think of it as a bad, for cells in your body to die. In many cases,, that's true: it's not good for cells to die because, of an injury (for example, due to scrape or a, harmful chemical), which is called necrosis., However, some cells of our body die; not, randomly but in a carefully controlled way. For, example, during the embryonic development,, the cells between the embryonic fingers died, in a process called apoptosis to give a definite, shape to the fingers. This is a common form, of programmed cell death where cells undergo, "cellular suicide" when they receive certain, signals. Apoptosis involves the cell death, but it, benefits the organism as a whole (for instance,, by letting fingers develop or by eliminating, potential cancer cells)., C. Meiosis : The term meiosis was coined, by J. B. Farmer in 1905. It takes place only, in reproductive cells during the formation, of gametes. By this division, the number of, chromosomes is reduced to half, hence it is also, called reductional division. The cells in which, meiosis take place are termed as meiocytes., Meiosis produces four haploid daughter cells, from a diploid parent cell. Meiosis is of two, subtypes :, , 79

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These points appear like a cross (X) Diakinesis : In this phase, the chiasmata beings, known as chiasmata. Chromatids break at these to move along the length of chromosomes, points and broken segments are exchanged from the centromere towards the ends of, between non-sister chromatids of homologous chromosomes. The displacement of chiasmata, chromosomes. This is called as crossing-over is termed as terminalization. The terminal, or recombination., chiasmata exist till the metaphase., The nucleolus disappears and the, Diplotene : Though chiasmata are formed, nuclear, membrane also begins to disappear., in pachytene, they become clearly visible in, diplotene due to the beginning of repulsion Spindle fibres starts to appear in the cytoplasm., between synapsed homologous chromosomes., This is called desynapsis. It involves, disappearence of synaptonemal complex., Leptotene Zygotene Pachytene Diplotene Diakinesis, Do yourself, Write down the explanation, of prophase I in your words., , Fig. 7.7 Prophase I, , Metaphase-I : The spindle fibres become well, developed. The tetrads move towards the equator, and they orient themselves on the equator in, such a way that centromeres of homologous, tetrads lie towards the poles and arms towards, the equator. Due to increasing repulsive forces, between homologous chromosomes, they are, ready to separate from each other., , This is reductional division. The, sister chromatids of each chromosome are, connected by a common centromere. Both, sister chromatids of each chromosome are now, different in terms of genetic content as one of, them has undergone the recombination., Astral rays, , Pole, , Recombined, chromosomes, , Spindle, apparatus, Chromosomes, with sister, chromatids, , Interpolar, fibres, , Tetrad, , Chromosomal, fibres, , Fig. 7.8 Metaphase-I, , Fig. 7.9 Anaphase-I, , Anaphase-I : In this phase, homologous, chromosomes are pulled away from each, other and carried towards opposite poles by, spindle apparatus. This is disjunction. The two, sister chromatids of each chromosome do not, separate in meiosis-I., , Telophase-I : The haploid number of, chromosomes after reaching their respective, poles, become uncoiled and elongated. The, nuclear membrane and the nucleolus reappear, and thus two daughter nuclei are formed., , 80

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Cytokinesis-I : After the karyokinesis,, cytokinesis occurs and two haploid cells are, formed., In many cases, these daughter cells, pass through a short resting phase or interphase, / interkinesis. In some cases, the changes of the, telophase may not occur. The anaphase directly, leads to the prophase of meiosis II., , It consists of the following phases, : prophase-II, metaphase-II, anaphase-II,, telophase-II and cytokinesis-II., Prophase-II : The chromosomes are distinct, with two chromatids. Each centriole divides, into two resulting in the formation of two, centrioles which migrate to opposite poles and, form asters. Spindle fibres are formed between, the centrioles. The nuclear membrane and, nucleolus disappear., , Nuclear membrane, reappear, , Metaphase-II : Chromosomes gets arranged, at the equator. The two chromatids of each, chromosome are separated by the division of the, centromere. Some spindle fibres are attached to, the centromeres and some are arranged end to, end between two opposite centrioles., , Daughter cells, , Fig. 7.10 Cytokinesis-I, , Anaphase-II : The separated chromatids, B. Second meiotic division or Homotypic become daughter chromosomes and move to, Division (Meiosis II), opposite poles due to the contraction of the, During this division, two haploid cells spindle fibres attached to centromeres., formed during first meiotic division divide, Telophase-II : During this stage the daughter, further into four haploid cells. This division is, chromosomes uncoil. The nuclear membrane, similar to mitosis. The daughter cells formed, surrounds each group of chromosomes and the, in second meiotic division are similar to their, nucleolus reappears., parent cells with respect to the chromosome, number formed in meiosis-I. Hence this division, is called homotypic division., Curiosity box:, 1. What is exact structure of synaptonemal complex?, 2. What is structure of chiasmata?, 3. Which type of proteins are involved in formation of spindle fibres?, 4. Why and how some spindle fibres elongate and some contract?, 5. What is the role of centrioles in formation of spindle apparatus?, 6. What would have happened in absence of meiosis?, , Telophase I, (and cytokinesis), , Prophase II, , Metaphase II, , Fig. 7.11 Meiosis II, , 81, , Anaphase II, , Telophase II

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Cytokinesis-II : Cytokinesis occurs after, nuclear division. Two haploid cells are formed, from each haploid cell. Thus, in all, four haploid, daughter cells are formed. These cells undergo, further changes to develop into gametes., , Internet my friend, Different types of proteins like, cyclins, maturation promoting factor (MPF),, cyclosomes, enzymes like cyclin dependent, kinases (CDK) play important role in control of, cell cycle. Collect more information about these, proteins and enzymes from internet, prepare a, power-point presentation and present it in the, class., , Significance of Meiosis : Meiotic division, produces gametes. If it is absent, the number, of chromosome would double or quadruple, resulting in the formation of monstrosities, (abnormal forms). The constant number, of chromosomes in a given species across, generations is maintained by meiosis. Because, of crossing over, exchange of genetic material, takes place leading to genetic variations, which, are the raw materials for evolution., , Can you tell?, D, 1. What is difference between mitosis and meiosis?, 2. What is difference between meiosis-I and meiosis-II?, 3. Elaborate the process of recombination., , Do Yourself, Prepare a concept map on cell division in following box., , 82

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Exercise, 1. Choose correct option, I. Histone proteins are synthesized during, ......, a. G1 phase, b. S-phase, c. G2 phase, d. Interphase, , A. The connecting link between Meiosis-I, and Meiosis-II is ..............., a. interphase-I, b. interphase-II, c. interkinesis d. anaphase-I, , 2. Answer the following questions, A. While observing a slide, student observed, many cells with nuclei. But some of the, nuclei were bigger as compared to others, but their nuclear membrane was not so, clear. Teacher inferred it as one of the, phase in the cell division. Which phase, may be inferred by teacher?, B. Students prepared a slide of onion root, tip. There were many cells seen under, microscope. There was a cell with two, groups of chromosomes at opposite ends, of the cell. This cell is in which phase of, mitosis?, C. Students were shown some slides, of cancerous cells. Teacher made a, comment as if there would have been, a control at one of its cell cycle phase,, there wouldn’t have been a condition, like this. Which phase the teacher was, referring to?, D. Some Mendelian crossing experimental, results were shown to the students., Teacher informed that there are two, genes located on the same chromosome., He enquired if they will be ever separated, from each other?, E. Students were observing a film on, Paramoecium. It underwent a process, of reproduction. Teacher said it is due, to cell division. But students objected, and said that there was no disappearnce, of nuclear membrane and no spindle, formation, how can it be cell division?, Can you clarify?, , B. Synapsis is pairing of ............., a. any two chromosomes, b. non-homologous chromosomes, c. sister chromatids, d. homologous chromosomes, C. Spindle apparatus is formed during which, stage of mitosis?, a. Prophase. b. Metaphase., c. Anaphase. d. Telophase., D. Chromosome number of a cell is almost, doubled up during ..............., a. G1-phase b. S-phase, c. G2-phase d. G0-phase, E. How many meiotic divisions are, necessary for formation of 80 sperms?, a. 80 b. 40 c. 20 d. 10, F. How many chromatides are present in, anaphase-I of meiosis-I of a diploid cell, having 20 chromosomes?, a. 4, b. 6, c. 20 d. 40, G. In which of the following phase of mitosis, chromosomes are arranged at equatorial, plane?, a. Prophase, b. Metaphase, c. Anaphase, d. Telophase, H. Find incorrect statement a. Condensation of chromatin material, occurs in prophase., b. Daughter chromatids are formed in, anaphase., c. Daughter nuclei are formed at, metaphase., d. Nuclear membrane reappears in, telophase., , 83

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6. If an onion has 16 chromosomes in its leaf, cell, how many chromosomes will be there, in its root cell and pollen grain., , F. Is the meiosis responsible for evolution?, Justify your answer., G. Why mitosis and meiosis-II are called, as homotypic division?, H. Write the significance of mitosis., I. Enlist the different stages of prophase-I., , 7. Identify the following phases of mitosis, and label the 'A' and 'B' given in diagrams, , 3. Draw labelled digrams and write, explanation, A. With the help of suitable diagram,, describe the cell cycle., B. Distinguish between mitosis and, meiosis., C. Draw the diagram of metaphase., , Spindle fibres, A, , 4. Match the following column-A with, column-B, Column-A, (phases), , Column-B, (Their events), , a. Leptotene, b. Zygotene, c. Pachytene, d. Diplotene, , 1. Crossing over, 2. Desynapsis, 3. Synapsis, 4. Bouquet stage, , B, , 5. Is a given figure correct? why?, , Practical / Project :, Fix the onion root tips at different, durations of the day starting from 6am up to, 9am at the intervals of half an hour. Prepare, the slide of each fixed root tip and analyse the, relation between time and phase of mitosis., , 84

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8. Plant Tissues and Anatomy, Can you recall?, , 1. Origin :, Primordial meristem or promeristem, is also called as embryonic meristem. Usually, occupying very minute area at the tip of root, and shoot. Primary meristem originates from, the primordial meristem and occurs in the, plant body from the beginning, at the root and, shoot apices. Cells are dividing and different, permanent tissues are produced from primary, meristems. Secondary meristematic tissues, develop from living permanent tissues during, later stages of plant growth; hence are called, as secondary meristems. This tissue occurs in, the mature regions of root and shoot of many, plants. Secondary meristem is always lateral, (to the central axis) in position e.g. fascicular, cambium, inter fascicular cambium, cork, cambium., 2. Position : Apical meristem is produced, from promeristem and forms growing point of, apices of root, shoot and their lateral branches., It brings about increase in length of plant body, and called as apical initials. Shoot apical, meristem is terminal in position whereas in root, it is subterminal i.e. located below the root cap., Intercalary meristematic tissue is present in, the top or base area of node. Their activity is, mainly seen in monocots. These are short lived., , 1. Which component bring about important, processes in the living organisms?, 2. What is tissue?, 3. Explain simple and complex tissue., 4. Complete the flow chart., Organisms, organs, Cells, 8.1, , Tissue :, Anatomy is the study of internal, structure of organism. Organs are made up, of group of cells. A group of cells having, essentially a common function and origin is, called as tissue. Plant tissues are grouped as, meristematic tissue and permanent tissue on, the basis of its ability to divide., 8.2, , Meristematic Tissue :, It is a group of young cells. These are, living cells with ability to divide in the regions, where they are persent. These are polyhedral, or isodiametric in shape without intercellular, spaces. Cell wall is thin, elastic, mainly, composed of cellulose. Protoplasm is dense, with distinct nucleus at the center and vacuoles, if present, are very small. Cells show high rate, of metabolism. These cells are immature., , Apical meristem, , Cell wall, Nucleus, Cytoplasm, , Intercalary, meristem, , Fig. 8.1 Meristematic cells, A., Classification of Meristem : Following, criterias are used for classification of meristems, viz. origin, function and position as follows-, , Lateral, meristem, , Fig. 8.2 Location of meristematic tissue, , 85

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Lateral meristem is present along, the sides of central axis of organs. It takes, part in increasing girth of stem or root., eg. intrafascicular cambium. It is found in, vascular bundles of gymnosperms and dicot, angiosperms., , Parenchyma has distinct intercellular, spaces. Sometimes, cells may show compact, arrangement. The cytoplasm of adjacent cells, is interconnected through plasmodesmata, and thus forms a continuous tissue. These, cells are distributed in all the parts of plant, body viz. epidermis, cortex, pericycle, pith,, mesophyll cells, endosperm, xylem and, phloem. These cells store food, water, help in, gaseous exchange, increase buoyancy, perform, photosynthesis and different functions in plant, body. Dedifferentiation in parenchyma cells, develops vascular cambium and cork cambium, at the time of secondary growth., , 3. Function : Young growing region of the plant, has Protoderm that forms protective covering, like epidermis arround the various organs., Meristem called Procambium is involved, in developing primary vascular tissue while, the other structures like cortex, endodermis,, pericycle medullary rays, pith are formed from, the region of Ground meristem. These are, three groups of meristem based on function., , Cytoplasm, Vacoule, Nucleus, , Can you tell?, Intercellular, air spaces, , 1. Enlist the characteristics of meristematic, tissue., 2. Classify meristematic tissue on the basis, of origin., , Thin primary cell wall, , 8.3, , Permanent tissue :, This is group of cells which have lost, the capacity of division and aquired permanent, size, shape and functions. It is due to different, morphological, physiological and functional, changes that occur during maturation of the, cell. Depending upon types of cells, there are, two types as simple and complex permanent, tissues., , Fig. 8.3 Simple permanent tissue, 2. Collenchyma : It is a simple permanent, tissue made up of living cells. The cell wall, is cellulosic but shows uneven deposition of, cellulose and pectin especially at corners. The, walls may show presence of pits. Cells are, similar like parenchyma containing cytoplasm,, nucleus and vacuoles but small in size and, without intercellular gaps. Thus appears to, be compactly packed. The cells are either, circular, oval or angular in transverse section., Collenchyma is living mechanical tissue and, serves different functions in plants. It gives, mechanical strength to young stem and parts, like petiole of leaf. It allows bending and pulling, action in plant parts and also prevents tearing, of leaf. Growth of organs and elongation are, other functions. Collenchyma is usually absent, in monocots and roots of dicot plant., , A. Simple permanent tissues :, These are made up of only one type of, cells carrying similar functions. This tissue is, either living or dead. Following are the types of, simple permanent tissues namely, Parenchyma,, Collenchyma and Sclerenchyma., 1. Parenchyma : Cells in this tissue are thin, walled, isodiametric, round, oval to polygonal, or elongated in shape. Cell wall is composed, of cellulose. Cells are living with prominent, nucleus and cytoplasm with large vacuole., This is less specialized permanent tissue., , 86

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B. Complex permanent tissues : This tissue, is heterogenous comprising of more than one, type of cells and all function as a single unit., This tissue is involved in conducting the sap, and food from source to sink area. Xylem, and phloem are the complex tissues present in, plants., 1. Xylem : It is a dead complex tissue., Components of xylem are tracheids, vessels,, xylem parenchyma and xylem fibres., , Vacoule, Nucleus, , Cell wall, , Fig. 8.4 Collenchyma, , Perforation, plates, , 3. Sclerenchyma : It is simple permanent tissue, made up of compactly arranged thick walled, dead cells. The cells are living at the time of, production but at maturity they become dead., As cells are devoid of cytoplasm their thickened, walls are due to uniform deposition of lignin., Cells remain interconnected through several, pits. It is of two types viz. fibres and sclerids., Fibres are thread-like, elongated and narrow, structures with tapering and interlocking end, walls. These are mostly in bundles, pits are, narrow, unbranched and oblique. They provide, mechanical strength. Sclerids are usually, broad, with blunt end walls. These occur, singly or in loose groups and their pits are deep, branched and straight. These are developed, due to secondary thickening of parenchyma, cells and provide stiffness only., , Simple pit, pair, , Vessel, member, , Tracheids, , a. Xylem tissue, Crushed, phloem, Common cell, Xylem, parenchyma, Protoxylem, Metaxylem, , Narrow, lumen, , Protoxylem, cavity, , Lumen, (cavity), Lignified thick, cell wall, Transverse section, , Fibre, , b. Vascular bundle, Fig. 8.6 Xylem tissue and Vascular bundle, , Longitudianl, section, , The xylem also provides mechanical, strength to the plant body. Tracheids and, vessels conduct water and minerals. These, are also known as hadrome. In pteridophytes, and gymnosperms tracheids are conducting, elements and vessels in angiosperms,, Selaginella (Pteridophyte) and Gnetum, (Gymnosperm) show presence of vessels., , Fig. 8.5 Sclerenchyma, This tissue functions as the main, mechanical tissue. It permits bending, shearing, and pulling. It gives rigidity to leaves and, prevents it from falling. It also gives rigidity to, epicarps and seeds. Commercial fibres are also, produced from sclerenchyma fibres. e.g. jute,, flax, hemp., , 87

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Tracheids are elongated, tubular and, dead cells. The ends are oblique and tapering., The cell walls are uniformly thickened, and lignified. This provides mechanical, strength. Tracheids contribute 95% of wood, in Gymnosperms and 5% in Angiosperms., The different types of thickening patterns are, seen on their walls such as annular (in the, form of rings), spiral (in the form of spring/, helix), scalarif orm (ladder like), pitted is most, advanced type (small circular area) which may, be simple or bordered., , Xylem fibres are sclerenchymatous, cells and serve mainly mechanical support., These are called wood fibres. These are also, elongated, narrow and spindle shaped. Cells, are tapering at both the ends and their walls, are lignified., Phloem : This is a living tissue. It is also called, as bast. Phloem is responsible for conduction, of organic food material from source (leaf, generally) to a sink (other plant parts). Phloem, was named as leptome by Haberlandt as, similar to xylem. On the basis of origin, it is, proto (first formed) and meta (laterly formed), phloem. It is composed of sieve cells, sieve, tubes, companion cells, phloem parenchyma, and phloem fibres., , Vessels are longer than tracheids with, perforated or dissolved ends and formed by, union of several vessels end to end. These are, involved in conduction of water and minerals., Their lumen is wider than tracheids and the, thickening is due to lignin and similar to, tracheids. In monocots, vessels are rounded, where as they are angular in dicot angiosperms., The first formed xylem vessels (protoxylem), are small and have either annular or spiral, thickenings while latter formed have larger, vessels (metaxylem) have reticulate or pitted, thickenings. When protoxylem is arranged, towards pith and metaxylem towards periphery, it is called as endarch e.g. in stem and when, the position is revert as in the roots is called as, exarch., , Annular, , Spiral, , Sieve plate, , Companion cell, Ground tissue cell, , Nucleus, Sieve tube, , Fig. 8.8 Leptome, Sieve tubes are long tubular conducting, channel of phloem. These are placed end to end, with bulging at end walls. The sieve tube has, sieve plate formed by septa with small pores., The sieve plates connect protoplast of adjacent, sieve tube cells. The sieve tube cell is a living, cell with a thin layer of cytoplasm but loses, its nucleus at maturity. The sieve tube cell is, connected to companion cell through phloem, parenchyma by plasmodesmata. Sieve cells are, found in lower plants like pteridophytes and, gymnosperms. The cells are narrow, elongated, with tapering ends and sieve area located, laterally., , Scalariform Simple Bordered, Reticulate Pitted, , Fig. 8.7 Tracheids, Xylem parenchyma cells are small, associated with tracheids and vessels. This, is the only living tissue among this complex, tissue. The function is to store food (starch) and, sometimes tannins. Parenchyma are involved, in lateral or radial conduction of water or sap., , Companion cells are narrow elongated, and living. These cells are laterally associated, with sieve tube elements. Companion cells, have dense cytoplasm and prominent nucleus., , 88

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Sieve tube, , Epidermis, , Cuticle, , companion, cell, , Stoma, , Phloem, parenchyma, , A, , Mesophyll, , Waxy layer, , Sieve plate, A. Phloem in T. S., , Guard cells, Sub-stomatal, chamber, , Cuticle, , Cuticular pegs, , B. Phloem in L. S., Epidermis, , Fig. 8.9 Phloem tissue, Nucleus of companion cell regulates, functions of sieve tube cells through simple, pits. From origin point of view, sieve tube cells, and companion cell are derived from same cell., Death of the one results in death of the other, type., Phloem parenchyma cells are living,, elongated found associated with sieve tube and, companion cells. The chief function is to store, food, latex, resins, mucilage, etc. The cells, carry out lateral conduction of food material., These cells are absent in most of the monocots., Phloem fibres are the only dead tissue, among this unit. These are sclerenchymatous., Generally absent in primary phloem, but, present in secondary phloem. These cells are, with lignified walls and provide mechanical, support. These are used in making ropes and, rough clothes., , Anticlinar, walls of, Epidermal, cells, , B, , Fig. 8.10 Epidermal tissue system, Subsidiary cells, Epidermal cells, , Inner thick wall, Nucleus, Stomatal pore, Guard cell, , Fig. 8.11 Epidermal cells, A. Epidermal tissue system : It forms the, outer covering of plant body and is derived, from protoderm or dermatogen. The two types, of structures are seen in epidermal tissue system, viz epidermis and epidermal appendages., Epidermis is the outermost protective, cell layer made up of compactly arranged, cells without intercellular spaces. Cells, show presence of central large vacuole, thin, cyctoplasm and a nucleus. The outer side of the, epidermis is often covered with a waxy thick, layer called the cuticle which prevents the loss, of water. It may bear hairs. Root epidermis has, root hairs. These are unicellular elongated and, involved in absorption of sap from the soil. In, stem, epidermal hairs are called trichomes., , Can you tell?, 1. Write a note on parenchyma., 2. Describe schlerenchyma fibres., 3. Sketch and label T.S. of phloem tissue., , 8.4, Tissue Systems : Plant tissues are, derived from meristems and their structure and, functions depend on the position. On the basis, of their structure and location, three types of, tissue systems are present viz. Epidermal tissue, system, ground tissue system and vascular, tissue system., , 89

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These are generally multicellular, branched, or unbranched, stiff or soft or even secretory., These help in preventing water loss due to, transpiration., Small gateways in the epidermal cells, are called as stoma. Such stoma are controlled, or guarded by specially modified cells called, guard cells. These guard cells may be kidney, shaped (dicot) or dumbbell shaped (monocot),, collectively called as Stomata. Stoma, guard, cells and subsidiary cells form a unit called, stomatal apparatus. Stomata are further, covered by subsidiary cells. Guard cells have, chloroplasts to carry out photosynthesis. Guard, cells change their turgor pressure causing its, opening and closing, thus they play a vital role, in exchange of gases and water vapour., , Phloem (outer), Cambium, (outer), Phloem, Xylem, Phloem (inner), Xylem, Cambium (inner), Collateral closed, Collateral open Bicollateral open, Phloem, Phloem, Cambium, , Xylem, Hadrocentric, , Xylem, Leptocentric, , Radial, , Fig. 8.12 Vascular bundles, It is a feature of family Cucurbitaceae., When one vascular tissue is completely, encircling the other, it is called as concentric, vascular bundle, this may be leptocentric, (phloem encircled by xylem) or hadrocentric, (xylem encircled by phloem). When one, complex tissue is encircling on both the faces, of the other it is amphicribral (xylem encircled, by phloem on both faces) and amphivasal, (phloem encircled by xylem on both faces)., , B. Ground tissue system : All the plant, tissues excluding epidermal and vascular, tissue is ground tissue. It is made up of simple, permanent tissue e.g. paranchyma. It is present, in cortex, pericycle, pith and medullary rays, in the primary stem and root. Collenchyma, and schlerenchyma in the hypodermis and, chloroplasts containing mesophyll tissue in, leaves is also ground tissue., , 8.5, , Secondary growth in plants :, The vertical growth of the roots and, stems in length with the help of apical meristem, is called as primary growth. Dicotyledonous, plants and gymnosperms exhibit increase, in girth of root and stem. In dicot stem,, secondary growth begins with the formation, of a continuous cambium ring. The cambium, present between the primary xylem and, primary phloem of a vascular bundle is called, intraf asicular cambium. The cells of medullary, rays adjoining these intrafascicular cambium, strips become meristematic (regain the, capacity to divide) and form the interf ascicular, cambium. Thus a complete and continous ring, of vascular cambium is formed., The cambium ring cuts off new cells,, towards both the sides, inner and outer. The, cells that are cut-off towards pith (inner side), mature into secondary xylem and cells that, are cut-off towards periphery mature into, secondary phloem. Generally, amount of, secondary xylem is more than the secondary, phloem., , Vascular tissue system : These are the distinct, patches of the complex tissue viz. Xylem and, phloem. On the basis of their arrangement, in the plant body these are radial when both, the complex tissue are situated separately, on separate radius as separate bundle. This, is a common feature of roots. In the stem,, the complex tissue is collectively present as, neighbours of each other on the same radius in, the form of xylem inside and phloem outside, hence called conj oint, collateral, vascular, bundles., These bundles may be further of open, type (secondary growth takes place) containing, cambium in between them and closed, type if cambium is not present (secondary, growth absent). When phloem is present in, a vascular bundle on both the sides of xylem, and intervening cambium tissue, it is called, bicollateral vascular bundle., , 90

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8.6, , Wood :, During favourable conditions, spring, w ood (early wood) is formed which has, broader xylem bands, lighter colour, tracheids, with thin wall and wide lumen, fibres are, less in number, low density. Whereas, during, unfavourable season autumn w ood (late wood), is formed which has narrow xylem band,, darker in colour, lumen is narrow and walls are, thick with abundant fibres are present of high, density. Tracheary elements of heartwood are, plugged by in-growth of adjacent parenchyma, cells i.e. tyloses. They are filled by oils, gums,, resins, tannins called as extractives. Thus inner, non-functinal, durable part which is resistant, to pathogens is called duramen or heartwood., Outer light, functional part of secondary xylem,, cells are living, no deposition, lighter and less, durable, more susceptible to pathogens and, involved in conduction of sap is called as sap, w ood (alburnum)., , In woody plants, secondary tissues, constitute the bulk of the body. This provides, support, conduction of water and minerals and, protection. Lateral meristems play a major role, in development of secondary tissues., Formation of cambial ring : With the onset, of favourable season, meristematic cells, of intrafascicular cambium become active., Simultaneously, the ray parenchyma cells,, both fusiform initials and ray initials become, meristematic. This is known as dedif f erentiation., These form patch of cambial cells (meristematic, cells) in between the adjacent bundles and, produce interfascicular cambium. Now both, intrafascicular and interfascicular cambium, join and form a complete ring. This is known, as cambial ring. This is possible because they, lie in one plane., Secondary, phloem, , Primary, phloem Cork, , Bark, , Pith, , 8.7, , Cork cambium and secondary, growth:, Increase in diameter of stem by, secondary growth is mainly due to the activity, of vascular cambium present the outer cortical, layer. When epidermis gets ruptured, it, becomes necessary to replace these cells by, new cells. Phellogen (cork cambium) develops, in extrastelar region of stem. The outer cortical, cells of cortex become meristematic and produce, a layer of thin walled, rectangular cells. These, cells cut off new cells on both sides. The cells, produced on outer side develop phellem (cork), wheras on the inner side produce phelloderm, (secondary cortex). The cork is impervious in, nature and does not allow entry of water due to, suberized walls., Secondary cortex is parenchymatous, in nature. Phellogen, phellem and phelloderm, constitute periderm. Activity of cork cambium, develops a pressure on the other cells and these, cells die. Bark is non-technical term refering, to all cell types found external to vascular, cambium including secondary phloem. Bark of, early season is soft and of the late season is, hard., , Vascular, Cortex, cambium, Phloem, Epidermis, Primary, Xylem, xylem Secondary Cork, xylem cambium, Sclerenchyma, , Fig. 8.13 Secondary growth in, Dicot stem, Secondary growth in roots : It is also observed, in most of the dicot and gymnospermic roots, by producing secondary vascular tissue and, periderm. Secondary growth is produced, by vascular cambium and cork cambium, respectively., Conjuctive parenchyma cells present, on the inner edges of primary phloem bundles, become meristematic. These cells add, secondary xylem and secondary phloem on the, inner and outer side respectively. These events, are similar to secondary growth in stems., , 91

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Lenticles are aerating pores present as, (raised scars) the surface of bark. These are, portions of periderm, where phellogen activity, is more, lenticles are means for gaseous and, water vapour exchange., Monocot stems lack cambium hence, secondary growth does not take place. But, accessory cambium development in plants, like, Dracena, Agave, Palms and root of sweet, potato show presence of secondary growth., This is called as anomalous secondary growth., , Root hair, Epiblema, Exodermis, , Cortex, , Endodermis, Pericycle, Phloem, , Can you tell?, , Metaxylem, , 1. Concentric vascular bundles are always, closed. Describe., 2. How is the arrangement of vascular bundles in dicot and monocot stem?, 3. How is the structure of vascular bundles, of the root?, 4. Why vascular bundles of dicot stem are, described as conjoint collateral and open?, , Protoxylem, , Fig. 8.14 T. S. of dicot root, The central part of stele or vascular, cylinder is called Pith. It is narrow and made, up of parenchymatous cells, with or without, intercellular spaces. At later stage, a cambium, ring develops between xylem and phloem, which causes secondary growth in thickness., B. Anatomy of monocot root :, It resembles that of a dicot root in its, basic plan. However, it possesses more than, six xylem bundles (polyarch condition). Pith is, large and well-developed. Secondary growth is, absent., , 8.8, Anatomy of Root, Stem and Leaf :, A. Anatomy of Dicot Root :, The transverse section of a typical, dicotyledonous, root, shows, following, anatomical features. The outermost single layer, of cells without cuticle is Epiblema. Some of, its cells are prolonged into unicellular root hair., Next to it is the Cortex which consists of several, layers of typical parenchymatous cells. After, the death of epiblema, outer layer of cortex, become cutinized and is called Exodermis., The cortical cells store food and water. The, innermost layer of cortex is called Endodermis., The cells are barrel-shaped and their radial, walls bear Casparian strip or Casparian bands, composed of suberin. Near the protoxylem,, there are unthickened passage cells. A single, layer of parenchymatous Pericycle is present, just below endodermis which bounds the stele, or vascular cylinder. Stele consists of 2 to, 6 radial vascular bundles. Xylem is exarch., Based on the number of groups of xylem and, phloem, the stele may be diarch to hexarch., A parenchymatous connective tissue, or conjunction tissue is present between xylem, and phloem., , Root hair, Epiblema, , Cortex, , Endodermis, Pericycle, Protoxylem, Metaxylem, Phloem, Pith, , Fig. 8.15 T. S. of Monocot root, , 92

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C. Anatomy of Dicot Stem (Sunflower) :, A transverse section of dicot stem, shows the following structures : Epidermis, is single, outermost layer with multicellular, outgrowth called trichomes. A layer of cuticle, is usually present towards the outer surface, of epidermis. Cortex is situated below the, epidermis and is usually differentiated into, three regions namely, hypodermis, general, cortex and endodermis. Hypodermis is situated, just below the epidermis and is made of 3-5, layers of collenchymatous cells. Intercellular, spaces are absent. General cortex is made, up of several layers of large parenchymatous, cells with intercellular spaces. Endodermis is, an innermost layer of cortex which is made up, of barrel shaped cells. It is also called starch, sheath., , Stele is the central core of tissues, differentiated into pericycle, vascular bundles, and pith. Pericycle is the outermost layer, of vascular system situated between the, endodermis and vascular bundles. In sunflower,, it is multilayered and also called hard bast., Vascular bundles are conjoint, collateral,, open, and are arranged in a ring. Each one is, composed of xylem, phloem and cambium., Xylem is endarch. A strip of cambium is, present between xylem and phloem. Pith is, situated in the center of the young stem and is, made up of large-sized parenchymatous cells, with conspicuous intercellular spaces., D. Anatomy of Monocot Stem :, It differs from dicot. Epidermis is, without trichomes and the hypodermis is, sclerenchymatous. Vascular bundles are, numerous and are scattered in ground tissue., Each vascular bundle is surrounded by a, sclerenchymatous bundle sheath. Vascular, bundles are conjoint, collateral and closed, (without cambium). Xylem is endarch and, shows lysigenous cavity. Pith is absent., Secondary growth is also absent., Epidermis, Hypodermis, , (Diagrammatic), , Vascular bundle, , Hair, Epidermis, , Ground tissue, Starch Grains, , Cuticle, Hypodermis, (sclerenchyma), , General, Cortex, (Parenchyma), Hyprodermis, (Collenchyma), Endodermis, , Phloem, Metaxylem, , Phloem, Cambium, , Protoxylem, , Metaxylem, Medullary rays, , Epidermis, , Protoxylem cavity, , Protoxylem, , Bundle sheath, , Wood, parenchyma, , Ground tissue, (parenchyma), , (Part enlarged), Fig. 8.16 T. S. of Dicot stem, , Fig. 8.17 T. S. of Monocot stem, , 93

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E. Anatomy of Leaf : Dorsiventral Leaf is, very common in dicotyledonous plants where, the mesophyll tissue is differentiated into, palisade and spongy parenchyma. The leaves, are commonly horizontal in orientation with, distinct upper and lower surfaces. The upper, surface which faces the sun is darker than the, lower surface., , Vascular system is made up of a number, of vascular bundles of varying size depending, upon the venation. Each one is surrounded by, a thin layer of parenchymatous cells called, bundle sheath. Vascular bundles are closed and, xylem towards upper epidermis and phloem, towards lower epidermis. Cambium is absent, hence no secondary growth in the leaf., Lower epidermis consists of a single, layer of compactly arranged rectangular,, parenchymatous cells. A thin layer of cuticle, is also present. The lower epidermis contains, a large number of microscopic pores called, stomata. There is an air-space called substomatal chamber at each stoma., , V. S. of Typical dicot leaf :, Upper epidermis consists of a single, layer of tightly packed rectangular, barrel, shaped, parenchymatous cells which are, devoid of chloroplast. A distinct layer of cuticle, lies on the outside of the epidermis. Stomata, are generally absent. Between upper and lower, epidermis, there is chloroplast-containing, photosynthetic tissue called Mesophyll., Mesophyll is differentiated into, palisade and spongy tissue. Palisade, parenchyma is present below upper epidermis, and consists of closely packed elongated cells., The cells contain abundant chloroplasts and, help in photosynthesis. Spongy parenchyma, is present below palisade tissue and consists of, loosely arranged irregularly shaped cells with, intercellular spaces. The spongy parenchyma, cells contain chloroplast and are in contact, with atmosphere through stomata., Bundle sheath, Xylem, Phloem, , F. Isobilateral Leaf : In this leaf both the, surfaces are equally illuminated as both the, surface can face the sun, and show similar, structure. The two surfaces are equally green., Generally monocotyledonous plants have, isobilateral leaves., A typical monocot leaf : resembles a dicot leaf, in its anatomical structure. However, it shows, stomata on both the surfaces and mesophyll, is not differentiated into palisade and spongy, tissue. It has parallel veins. These are conjoint,, collateral and closed., , Adaxial, epidermis, , Bulliform cells help in leaf rolling, , Palisade, mesophyll, , Amphistomatic, leaf with, stomata, on both, epidermis., , Air cavity, Spongy, mesophyll, Sub-stomatal, cavity, Stoma, , Abaxial, epidermis, , Fig. 8.18 V. S. of Monocot leaf, , Fig. 8.17 V. S. of dicot leaf, , 94

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Exercise, 1. Choose the correct option, A. Location or position of meristematic, regions is divided into ................... types, a. one, b. two, c. three, d. none of the above, , D. There were two cut logs of wood lying, in the campus. One had growth rings, and other didn’t. Teacher said it is due, to differences in their pattern of growth, which is dependent on season. How?, E. While on the trip to Kashmir, Pintoo, observed that cut portions of large trees, shows distinct rings, which he never, found in Maharashtra. Why is so?, F. A student was observing a slide with no, label under microscope. The section had, some vascular bundles scattered in the, ground tissue. It is section of a monocot, stem! He exclaimed. No! it is section, of fern rachis, said the teacher. Teacher, told to observe vascular bundle again., Student agreed, Why?, G. Student found a wooden stopper in lab., He was told by an old lab attendant, that it is there for many years. He kept, thinking how it did not rot?, H. Student while observing a slide of leaf, section observed many stomata on the, upper surface. He thought he has placed, slide upside down. Teacher confirmed it, is rightly placed. Explain., , B. Cambium is also called ................, a. apical meristem, b. intercalary meristem, c. lateral meristem, d. none of the above, C. Collenchyma is a type of ................., tissue., a. living, b. dead, c. living and dead d. none of the above, D. ..................... is a complex permanent, tissue., a. Parenchyma, b. Sclerenchyma, c. Chlorenchyma, d. Xylem, E. Mesophyll tissue is present in................, a. root, b. stem, c. leaf, d. flower, 2. Answer the following questions, A. A fresh section was taken by a student but, he was very disappointed because there, were only few green and most colourless, cells. Teacher provided a pink colour, solution. The section was immersed in, this solution and when observed it was, much clearer. What is the magic?, B. While observing a section many scattered, vascular bundles could be seen. Teacher, said but in spite of this large number the, stem cannot grow in girth. Why?, C. A section of the stem had vascular, bundles, where one tissue was wrapped, around the other. How will you, technically describe it?, , 3. Write short notes on the following points, A. Structure of stomata, B. Secondary growth, C. Peculiarity of a sclerenchyma cell wall, 4. Differentiate, A. Vascular bundle of monocot and dicot, B. Xylem and Phloem functioning, C. Internal or anatomical difference, between monocots and dicots., , 95

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8. Distinguish between Dicot and Monocot, leaf on the basis of following characters., , 5. Draw neat labelled diagrams, A. T. S. of Dicot leaf., B. T. S. of Monocot root., C. T. S. of dicot stem., 6. Write the information related to diagrams, given below, , Characters, Stomata, , Dicot leaf, ............., , Monocot leaf, ............., , Intercellular, space, Venation, , ............., , ............., , Vascular, bundle, Mesophyll, cells, , ............., ............., , ............., , ............., , ............., , Practical / Project :, 1. Prepare detail anatomical charts with, digramatic representation of dicot and, monocot plants., 2. Observe different slides related to, anatomy of flowering plants under the, guidence of teacher., , 7. Identify the following diagrams, label it and prepare a chart of characteristics., , c., , b., a., , 96, , d.

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9. Morphology of Flowering Plants, Can you recall?, , 9.2, , Morphology :, Morphologically plant shows vegetative, structures like root, stem, leaf and reproductive, structures such as flowers, fruits and seeds., , You have learnt the diversity and, structure of Angiospermic plant in 6th standared., , 9.1, , Angiosperms :, Our earth has a vast diversity of, plants. The flowering plants dominate the, world of plants as they are well adapted to the, environmental conditions. These plants show, considerable variation in their general external, and internal characters with respect to their, habitat. Such variations help the plant body to, carry out different functions. You have studied, a broad classification of kingdom Plantae., Angiosperms are one of flowering plants from, phanerogams., Angiosperms can be classified into, different types on the basis of habitat and it can, be represented as follows :, , Flower, Fruit, Stem, Leaf, , Primary roots, Secondary roots, , Angiosperms, , Hydrophytes - Growing in, aquatic habitat e.g. H ydrilla, , Shoot, system, , Root, system, , Fig. 9.2 Typical Angiospermic plant, , A. Root : Root is descending axis of plant body, which is positively geotropic and hydrotropic, but negatively phototropic and aerotropic. Root, grows beneath the soil surface towards gravity., Roots are generally non-green, cylindrical and, without nodes and internodes., , Xerophytes - Growing in, regions with scanty or no, rainfall like desert e.g. Opuntia, Psammophytes - Growing in, sandy soil e.g. Elymus, , Typical Root Structure : A typical root has, different regions :-, , Lithophytes - Growing on rock, e.g. Couchidium, , Region of, maturation, , Halophytes - Growing in saline, soil e.g. Mangroove plants like, Rhiz ophora, , Region of, root hairs, Region of cell, elongation, , Chart 9.1 Angiosperm classificationbased on habitat, , Meristematic, region, , In angiosperms seed germinates under, favourable environmental conditions and, produces a seedling which develops into a new, plant., , Region of, root cap, , Fig. 9.3 Regions of root, , 97

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A, parenchymatous, multicellular, structure in the form of cap, present over young, growing root apex is known as root cap. Cell, of root cap secrete mucilage for lubricating, passage of root through the soil. Cells of, root cap show presence of starch granules, which help in graviperception and geotropic, movement of root. Usually single root cap is, present in plants. But in plants like Pandanus, or screw pine multiple root caps are present., In hydrophytes root caps are replaced by root, pocket e.g. Pistia, Eichhornia etc. Due to, presence of root cap the growing apex of root is, subterminal in position. The apex of the root is, a growing point about 1 mm in length protected, by root cap. This region is called as region, of cell division or meristematic region. The, structure is developed by compactly arranged, thin walled actively dividing meristematic cells., These cells bring about longitudinal growth of, root. It is followed by Region of elongation., This region of cells is present just above zone, of cell division. The cells are newly formed, and show rapid elongation to bring about, increase in length of the root. The cells help in, absorption of mineral salts. A Region of root, hair / absorption/piliferous zone is made up of, numerous hair like outgrowths. The epiblema, or piliferous layer produces tubular elongated, unicellular structures known as root hair. They, are in close contact with soil particles and, increase surface area for absorption of water., Root hair are short lived or ephimeral and are, replaced after every 10 to 15 days. Region of, cell maturation or differentiation is major, portion of root is developed by this region., The cells of this region are quite impermeable, to water due to thick walled nature. The cells, show differentiation and form different types, of tissues. This region helps in fixation of, plant and conduction of absorbed substances., Development of lateral roots also takes place, from this region., Function of Root : Roots carry out several, functions which can be categorized into primary, and secondary functions. Primary functions of, , root are, fixation or anchorage of plant body in, the soil, absorption of water and minerals from, soil and conduction of absorbed materials up to, the stem base etc., Types of Root :, On the basis of origin, roots can be, classified as Tap roots or true roots and, Adventitious roots., a. Tap root : The root which develops from the, radicle of an embryo during seed germination, is known as tap root or true root. The main root, is called as primary root; its branches of first, order are called as secondary roots whereas, branches of second order are called as tertiary, roots e.g. Pea, Bean, Sunflower etc., The main root with all its branches is, known as tap root system. Tap root system is, commonly seen in dicotyledonous plants., b. Adventitious roots : A root that develops, from any part other than radicle is known as, adventitious root. Such root may develop from, the base of the stem, nodes or from leaves. In, monocots, radicle is short lived and from the, base of stem a thick cluster of equal sized roots, arise. This is adventitious root system. eg., Maize, Wheat, Sugarcane etc. It is also known, as fibrous root system as they look like fibre., The growth of roots is superficial. Adventitious, root in some plants are used for vegetative, propagation. eg. Euphorbia, Carapichea, ipecacuanha (Ipecac) etc., , a. Tap root, b. Adventitious, system, root system, Fig. 9.4 Types of root, , Modification of root : When roots have to, perform some special type of function in, addition to or instead of their normal function, they develop some structural changes. Such, roots are called as metamorphosed roots., , 98

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Modifications of tap root, a. Food storage : When tap root stores food, it becomes swollen fleshy and also develops, definite shape. Main or primary root is the, main storage organ but sometimes hypocotyl, part of embryo axis also joins the main root., Secondary roots remain thin. Stem in such, cases remain reduced, discoid and leaves are, radicle leaves. On the basis of shape swollen, tap roots are classified as Fusiform, Conical, and Napiform., The fusiform root is swollen in, the middle and tapering towards both ends, forming spindle shaped structure. e.g. Radish, (Raphanus sativus) The conical root is broad, at its morphological base and narrows down, towards its apex is called as conical root. e.g., Carrot (Daucus carota) In napiform root, base, of root is highly swollen, almost spherical in, shape and abruptly narrows down towards its, apex. e.g. Beet (Beta vulgaris), , Conical root, , Fusiform root, , Pneumatophores, , Lenticles, , Roots, , Fig. 9.6 Respiratory roots, , The roots show presence of lenticels, i.e. minute pores for gaseous exchange, ( Pneuamatic - Hollow, phore - stalk) e.g., Rhiz ophora, Avicennia, Sonneratia, H eritiera, (ver. sundri) etc., Modifications of Adventitious Roots :, a. Food storage : Fibrous roots also show food, storage like tap root but the main difference is, that fibrous root usually do not develop definite, shape. These roots are further classified as, Simple tuberous, Fasciculated tuberous,, Beaded and Nodulose roots., , Napiform root, Simple, , Fig. 9.5 Swollen tap roots, , Fasciculated, , Moniliform, , Fig. 9.7 Tuberous root, , b. For Respiration : Pneumatophores or, Respiratory Roots : Halophytes are the plants, which grow in saline swamps, marshy places, and salt lakes. These plants produce special, kind of roots called as pneumatophores or, breathing roots. The main root system of these, plants do not get sufficient air for respiration, as soil is water logged. Due to this, mineral, absorption of plant also gets affected., To overcome this problem underground, roots develop special roots which are negatively, geotropic; growing vertically upward. These, roots are conical projections present around, main trunk of plant., , Simple tuberous roots become swollen, and do not show definite shape. They are, produced singly. The roots arise from nodes, over the stem and penetrate into the soil. E.g., sweet potato or shakarkand (I pomoea batatas)., A cluster of roots arising from one point which, becomes thick and fleshy due to storage of food, is known as fasciculated tuberous root. These, clusters are seen at the base of the stem. E.g., Dahlia, Asparagus, etc. These beaded roots are, also called as moniliform roots. These roots, are swellings at regular intervals like beads, of a necklace. e.g. Spinacia oleracea (Indian, Spinach)., , 99

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The cluster of long slender roots become, enlarged at the tips forming nodules is known, as nodulose roots. E.g. Arrow (Maranta root), Amhaldi (Curcuma amada)., Nodulose root, , Fig. 9.10 Maize plant roots, , These roots provide additional support, to the plant body. In Screwpine or Pandanus, (Kewada), stilt roots arise only from the, lower surface of obliquely growing stem for, additional support. These roots show multiple, root caps., , Fig. 9.8 Nodulose root, , Do you know ?, , A banyan tree, growing in the Indian Botanical Garden, howrah, (Kolkata) has nearly 1700 such prop roots. The, crown of tree has a large circumference. The, tree is about 200 years old., , b. For mechanical support :, 1. Prop roots : These roots arise from, horizontal branches of tree like Banyan tree, (F icus benghalensis) and grow vertically, downwards till they penetrate the soil. These, prop roots show secondary growth, become, thick, act like pillars to provide mechanical, support to the heavy branches., , 3. Climbing roots : Different climbers with, weak stem produce roots at their nodes by, means of which they attach themselves to, support and there by raise themselves above, the ground e.g. Betel leaf or Pan, black pepper, or Piper nigrum (Kali Mirch), Pothos or money, plant., , Climbing roots, , Fig. 9.9 Banyan tree, 2. Stilt roots : These roots normally arise from, a few lower nodes of a weak stem in some, monocots shrubs and small trees. They show, obliquely downward growth penetrating soil, and provide mechanical support to the plant. In, the members of family Poaceae, the plants like, Maize, Jowar, Sugarcane etc. produce stilt root, in whorl around the node., , Fig. 9.11 Climbing roots, 4. Clinging Roots : These tiny roots develop, along internodes, show disc at tips, which, exude sticky substance. This substance enables, plant to get attached with walls of buildings., They do not damage substratum. e.g. English, Ivy (H edera helix)., , 100, , Fig. 9.12 Clinging roots

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5. Plank Roots/Buttresses : Often develop, at the base of large trees form plank like, extensions around stem. e.g. Silk cotton, Pipal, etc., , Fig. 9.13 Plank roots, , 2. Sucking roots or Haustoria : Specialised, microscopic sucking roots developed by, parasitic plants to absorb nourishment from, the host. V iscum album is a partial parasite., It develops haustoria which penetrate into, xylem of host plant for absoptional food. In, Cuscuta reflexa or Dodder (Amarvel) haustoria, penetrates vascular strand and suck food from, phloem, water and minerals from xylem., Cuscuta is leafless plant with yellow stem. It is, a total parasite., , 6. Buoyont roots : Roots developed at the, nodes of aquatic herbs like (J ussiaea repens),, become highly inflated and spongy providing, buoyancy and helping the plant to float., , Fig. 9.16 Sucking roots, , Fig. 9.14 Spongy roots, , c. For special functions :, 1. Epiphytic roots : Small epiphytic plants, such as orchids growing on the branches of, huge trees in dense rain forests and are unable to, obtain soil moisture. They produce specialized, root to hang in the air. The roots are provided, with a spongy membranous absorbent covering, of the velamen tissue. The cells of velamen, that absorb moisture from air. A tissues are, hygroscopic and have porous walls The roots, may be silvery white or green but without root, cap e.g. V anda, Dendrobium etc., , B. Stem : The aerial part of the plant body is, know as shoot system. Stem is the main axis of, this shoot system. Stem is the ascending part, of the plant body which develops from plumule, and reproductive units and is differentiated, into nodes and internodes. It is usually, positively photorophic, negatively geotropic, and negatively hydrotropic. It shows different, types of buds (axillary, apical, accessory, etc.)., At nodes it produces dissimilar organs such as, leaves and flowers and similar organs such as, branches. Young stem is green and capable of, photosynthesis., The primary functions of the stem are to, produce and support branches, leaves, flowers, and fruits; conduction of water and minerals, and transportation of food to plant parts., Apical bud, , Leaf, Periole, , Clinging root, Epiphytic root, (Hanging root), , Internode, , Node, , Axillary bud, Stem, , Fig. 9.15 Epiphytic roots, , Fig. 9.17 Stem structure, , 101

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Modifications of stem : Stem develops some, modifications for additional or accessory, functions. To perform such function stem shows, different modifications :, a. Underground stem : In some herbaceous, plants stem develops below the soil surface, called as underground stem. Underground, stem remains dormant during unfavourable, condition and on the advent of favourable, condition produces aerial shoots. Underground, stem is known to store food, helps in perinnation, and vegetative propagation., , Use your brain power, , 2. Stem Tuber : Special underground branches, of stem at their tips become swollen due to, storage of food material which is mostly starch., Presence of distinct nodes but not internodes, classifies tuber as stem. At nodal part scale, leaves are present with axillary buds commonly, known as ‘eyes’. ‘Eyes’ can produce aerial, shoots under favourable conditions. Tubers are, porpogated vegetatively e.g. Potato (Solanum, tuberosum), Matalu (H elianthus tuberosus)., Tuber has two distinct ends viz. apical end, and basal end called as rose and heel end, respectively. The number of nodes and eyes is, more towards rose end., , Why underground stem is different from roots?, , 1. Rhizome : It is prostrate dorsiventrally, thickened and brownish in colour. It grows, either horizontally or obliquely beneath the soil., Rhizome shows nodes and internodes, bears, terminal and axillary buds at nodes. Terminal, bud under favourable conditions produces, aerial shoot which degenerates at the end of, favourable condition Growth of rhizome takes, place with lateral buds such growth is known, as sympodial growth. e.g. Ginger (Zingiber, officinale), Turmeric (Curcuma domestica),, Canna etc. In plants where rhizomes grows, obliquely, terminals bud brings about growth, of rhizomes. This is known as monopodial, growth. e.g. N ymphea, N elumbo (Lotus), Pteris, (Fern) etc., , Internode, , Fig. 9.19 Tuber of potato, , 3. Bulb : Bulb is an underground spherical, or pyriform stem. Stem is highly reduced and, discoid. It bears a whorl of fleshy leaves. The, scale leaves or fleshy leaves show concentric, arrangement over the stem. These store food, material. Some outer scale leaves become, thin and dry. The reduced stem produces, adventitious roots at its base. The bulb is of, different types Tunicated or layered bulb is, made up of fleshy leaves arranged in concentric, manner with outer dry scale leaf. e.g. Onion., In garlic the bulb is scaly or non-tunicatied., The fleshy scales are arranged in overlapping, pattern., , Scale leaf, Bud, , Node, Adventitious root, , Fig. 9.18 Rhizome of Ginger, , a. Scaly bulb e.g. Garlic b. Tunicate bulb e.g. Onion, , Fig. 9.20 Bulbs, , 102

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4. Corm : Corm is swollen underground, spherical or subspherical vertically growing, stem. It is condensed structure with circular, or ring like nodes. Presence of axillary buds, and scales is observed. Adventitious buds are, produced which help in vegetative propagation., Adventitious roots are produced at lower part, of stem e.g. Colocasia (Arbi), Amorphophallus, (Zamikand or Elephant foot) etc., , Presence of nodes with scale leaves and, axillary buds is observed. Eg. Cynodon (Lawn, grass) Centella (Hydrocotyl), Oxalis etc., Strawberry, New plantlet, , Underground, stem, , Old corm, Daughter, corm, Adventitious, roots, , Runner, , New root, , Soil surface, , Node, , Fig. 9.21 Corm, , b. Sub aerial stem : The stems are generally, weak or straggling stems growing over the, ground and need support for perpetuation., Sometimes these stems are found to grow, beneath the soil surface also. Thus they show, contact with both air and soil. Sub aerial stems, are meant for perennation and vegetative, propagation. Scale leaves and axillary buds are, present over stem surface. The later produces, aerial shoots., The different types of sub aerial, shoots are as follows:, 1. Trailer : The shoot spreads over the ground, without intervals. The branches are either flat, i.e. procumbent or partly vertical i.e. documbent, e.g. Euphorbia, tridax etc., , Ground, Trailer weak stem, , Main plant body, , Root, , Fig. 9.23 Runner, , 3. Stolons : The slender lateral branch arising, from the base of main axis is known as, stolon. In some plants it is above ground (wild, strawberry). Primarily stolon shows upward, growth in the form of ordinary branch, but, when it bends and touches the ground terminal, bud grows into new shoot and adventitious, roots e.g. Jasmine, Mentha etc., , Jasmine, , Crown, , Stolon, Daughter plant, , Fig. 9.24 Stolon, , 4. Sucker : It is non green runner like branch, of stem. It which develops from underground, base of roots. It grows horizontally below, soil and finally comes above the soil surface, to produce a new plant. Sucker can be termed, as underground runner eg. Chrysanthemum,, Banana etc., Main stem, , Fig. 9.22 Eu p horb ia trailer, , 2. Runner : They are special narrow, prostrate, or horizontal green branches which develop, at the base of erect shoots known as crown., Runners spread in all directions to produce new, crowns with bunch of adventitious roots., , 103, , Roots, Sucker, Tap root, , C hry santhem u m, , Fig. 9.25 Sucker

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5. Offset : These are one internode long, runners in rosette plants at ground or water, level. Offset helps in vegetative propagation, e.g. Water hyacinth or Jal kumbhi (Eichhornia), and Pistia., Leaves, , Lamina, , Offset, , Fig. 9.28 Phylloclade, , Swollen, petiole, , Roots, , Offset, , a. Pistia, , Spongy, stem, , Cactus, , 3. Cladodes : The branches of limited, growth i.e. one internode long and performing, photosynthetic function are called as cladodes., True leaves are reduced to spine or scales. E.g., Asparagus., , Root, pocket, , b. Eichhornia, , Fig. 9.26 Offset, c. Aerial modification : Stem or it's vegetative, part modify to carry out specialized functions., They develop various modifications for this, purpose. Such modified stems are called, as metamorphosed stems. The different, modifications can be discussed as under :, , 1. Thorn : It is modification of apical or, axillary bud. Thorn is hard pointed and mostly, straight structure (except Bougainvillea where, it is curved and useful for climbing) It provides, protection against browsing animals and also, helps in reducing transpiration. Apical bud, develops into thorn in Carrisa whereas axillary, bud develops into thorn in Duranta, Citrus,, Bougainvillea, etc., , Cladodes, , Scaly leaf, , Fig. 9.29 Cladodes, , Use your brain power, Why the stem has, photosynthesis in xerophytes?, , to, , performs, , 4. Cladophylls : These are leaf like structures, bore in the axil of scale leaf. It has floral bud, and scale leaf in the middle i.e. upper half is, leaf and lower half is stem. e.g. Ruscus., , Fig. 9.27 Thorn, 2. Phylloclade : Modification of stem into, leaf like photosynthetic organ is known as, phylloclade. Being stem it possesses nodes and, internodes. It is thick, fleshy and succulent,, contains mucilage for retaining water e.g., Opuntia, cylindrical in Casuarina and ribbon, like in Muehlenbeckia., , 104, , Fig. 9.30 Cladophylls

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Stem tendrils : Tendrils are thin, wiry, photosynthetic, leafless coiled structures. They give, additional support to developing plant. Tendrils have adhesive glands for fixation., Apical bud in V itis quadrangularis gets, modified in to tendril. The further growth, is carried out by axillary bud. This, branching pattern is termed dichotomous., , Normally floral buds are, destined to produced flowers., But in plants like Antigonon, they produce tendrils., , Extra axillary bud is the one, which grows outside the axil., This bud in cucurbita gets modified in to tendril., , 5. Bulbils : In plants like Agave, Dioscorea, etc. axillary bud becomes fleshy and rounded, due to storage of food called as bulbil. When, it falls off it produces new plant and help in, vegetative propagation., , Axillary tendril, in Passiflora, axillary, bud, gets modified, in tendril, , The nature of leaf base is varies in, different plants. It may be pulvinus (swollen),, sheathing or ligulate etc., In some plants leaves possess a pair of, lateral outgrowths called as stipules. The leaf, with stipule is said to be stipulate and without, stipule is exstipulate. Stipules are normally, green protective structure., Veinlet, , Apex, Margin, , Blade, , Vein, Base, , Fig. 9.31 Bulbils, , C. Leaf :, Leaves are the, most important, appendages as they carry out photosynthesis, and also help to remove excess amount of, water from plant body. Leaf develops from leaf, primordium. Leaf is dorsiventrally flattened, lateral appendage of stem. It is produced at, nodal region. Leaf is thin, expanded and green, due to presence of photosynthetic pigments. It, shows exogenous origin. Axil of leaf shows, presence of axillary bud. Leaf shows limited, growth, does not show apical bud or a growing, point., 1. Typical leaf structure : It shows presence, of three main parts Leaf base or Hypopodium,, Petiole or Mesopodium and Leaf lamina/, blade or epipodium., Leaf base : The point by which leaf remains, attached to stem is known as leaf base., , Petiole, Axial bud, Stipule, , Fig. 9.32 Structure of leaf, , Petiole or mesopodium : The part of leaf, which connect leaf lamina with the leaf base, is known as petiole of leaf. A leaf with petiole, is petiolate and a leaf without petiole is termed, as sessile leaf., Petiole helps lamina to get exposed to, light and also helps in conduction., Lamina or epipodium : Large expanded, flat, and green part of leaf. The lamina surface, plays important role in photosynthesis, gaseous, exchange and transpiration. The leaf is either, dorsiventral or isobilateral. Dorsiventral leaf is, common in Dicots and isobilateral in Monocots., , 105

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Centric or cylindrical leaves are those, in which both the surfaces of leaf cannot be, distinguished distinctly. Leaf lamina varies, greately in shpe, margin and apex., 2. Leaf venation : Arrangement of veins and, veinlets in leaf lamina is known as venation., Veins are responsible for conduction of water, and minerals as well as food. The structural, framework of the lamina is developed by veins., , b. Palmately compound : In which all the, leaflets are attached at tip of petiole., , Unifoliate, (Citrus), , Bifoilate, (Zorina), , Trifoliate, (Oxalis), , Internet my friend, Collect imformation of types of leaf venation., P, , R, , Quadrifoliate, (Marsilea), , Multifoliate, (Bombax), , Fig. 9.33 (b) Types of Compound leaf, , 3. Types of leaf : Based on incision of lamina, leaves are of two main types. i.e. simple and, compound. The leaf with entire lamina is called, simple leaf and leaf in which lamina is divided, into number of leaf lets called as compound, leaf., Compound leaf are of two types.., a. Pinnately compound : Leaflets are present, laterally on a common axis called rachis, which, represents the midrib of the leaf., , Paripinnate, (Cassia), , Imparipinnate, (Rosa), , Tripinnate, (Moringa), , 4. Modification of leaves : Apart from, photosynthesis leaf also performs transpiration, gaseous exchange and perception of light, for flowering. However leaves may undergo, modifications to perform several other, functions. As per the modification their are, different types of leaves shown below., a. Leaf spines: Sometimes entire leaf is, modified into spines (Opuntia) or margin of leaf, becomes spiny (Agave) or stipule modifies into, spine (Acacia) to check the rate of transpiration, or to protect plant from grazing. E.g. Ziz yphus, etc., , Bipinnate, (Caesalpinia), , Decompound, (Coriandrum), , Fig. 9.33 (a) Types of Compound leaf, , Fig. 9.34 Leaf Spines, , 106

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b. Leaf tendril: In some weak stems for, providing addtitional support; leaf, leaflet or, other part modifies to produce thin, green, wiry,, coiled structure called as leaf tendril. It helps in, climbing., , Fig. 9.37 Phyllode, , 5., Phyllotaxy : Arrangement of leaves, on the stem and branches in a specific manner, is known as phyllotaxy. It enable leaf to get, sufficient light., Whole leaf tendril, E.g. L athyrus, , Leaf tip tendril, E.g. Gloriosa, , Leaflet tendril, E.g. Pisum sativum, , Alternate, Single leaf from each, node E.g. Mango, , Whorled, Many leaves from each, node E.g. N erium, , Opposite decussate, A pair of leaf from each, node and the consecutive, pair at right angle E.g., Calotropis, , Opposite superposed, A pair of leaf from each, node and the consecutive, pair is arranged just, above. E.g. Jamun, , Stipular tendril, E.g. Smilax, , Fig. 9.35 Leaf tendrils, , c. Leaf hooks: In plants like Bignonia unguiscati (Cat’s nail) the terminal three leaflet get, modified into three stiff curve and pointed, hooks used to cling over bark of tree., , Fig. 9.38 Types of phyllotaxy, , Fig. 9.36 Leaf hooks, , d. Phyllode: When petiole of leaf becomes, flat, green and leaf like it is called as phyllode., In Acacia auriculof ormis the normal leaf is, bipinnately compound and falls off soon., The petiole modifies itself into phyllode. It is, xerophytic adaptation., , D. Inflorescence :, A specialised axis or branch over which, flowers are produced or borne in definite, manner is known inflorescence. Inflorescence, has two parts Penduncle and flowers. There, are basic types of inflorescence., All the flowers do not mature at same, time. Chances of pollination increase and large, number of flowers can be pollinated in single, visit also makes the plant attractive., , 107

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Types of inflorescence :, a. Racemose : Growth of peduncle is infinite, or unlimited. Apical bud is free for continuous, growth. Flowers are borne in acropetal, succession. (Mature flowers at the base) Order, of opening is centripetal., , Stigma, Carpel, or pistil, , Style, Ovary, , Anther, Filament, , Petal, Sepal, , Ovule, , Flower bud, , Thalamus, Pedicel, , Fig. 9.41 Typical Flower (Digrammatic), Mature, flower, , Flower with bilateral symmetry or, Clitoria is called zygomorphic flower e.g., Sweet pea and flower with radial symmetry is, called actinomorphic flower e.g. Sunflower., , Peduncle, , Fig. 9.39 Racemose, , Always Remember, , b. Cymose : Growth of peduncle is finite, limited. Apical meristem terminates into flower., Flowers are borne in basipetal succession., (Mature flowers at the apex) Order of opening, is centrifugal., , Terminologies related to flower :, 1. Complete : Presence of all four floral, whorls., 2. Incomplete : Absence of any one of the, floral whorl., 3. Perfect : Both androecium and gynoecium, are present, also called as hermophrodite, or bisexual flower., 4. Imperfect : Any one reproductive whorl, is present also called as monophrodite or, unisexual flower., 5. Unisexual : It can be either staminate, (male)/ pistillate (female) flower, 6. Neuter : When both reproductive whorls, are absent, it is said to be neuter flower, e.g. Ray floreti of sunflower., 7. Monoecious plant : Male and female, reproductive flowers are borne on same, plant. E.g. Maize., 8. Dioecious plant : Only one type of, unisexual flowers are present on plant e.g., Date palm., , Mature, flower, Flower bud, , Peduncle, , Fig. 9.40 Cymose, , E. Flower : Flower is highly modified and, condensed shoot meant for sexual reproduction., On the basis of position a flower can, be axillary or terminal. In a typical flower, the, thalamus (Consists of four compactly arranged, nodes and three highly condenseed internodes., From each node of thalamus, a circle or whorl, of modified leaves is produced., A flower may or may not show, presence of bract at base of pedicel or over the, pedicel, such a flower is said to be bracteate or, ebracteate respectively. A flower with pedicel, is said to be pedicellate flower and without, pedicel is called as sessile flower., , a. Insertion of floral whorls : The position and, arrangement of rest of the floral whorls with, respect to gynoecium on the thalamus is known, as insertion of floral whorls. In a typical flower, thalamus consist of four compactly arranged, nodes and three internods. Slope of thalamus, decides insertion of floral whorls., , 108

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Do you know ?, Mango is polygamous, plant and produces all, types of flowers, staminate,, bisexual and neuter., Hypogynous, , Epigynous, , Perigynous, , Fig. 9.42 Insertion of floral whorls, , a. Hypogyny : When the convex or conical, thalamus is present in flower, ovary occupies, the highest position while other floral parts are, below ovary. Ovary is said to be superior and, flower is called as hypogynous flower. E.g., Brinjal, Mustard, China rose etc. It is denoted, as G in floral formula., b. Perigyny : When cup shaped or saucer, shaped thalamus is present in a flower, ovary and, other floral parts occupy about same position., Such an ovary is said to be semi- superior or, semi-inferior. All floral whorls are at the rim of, thalamus. Flower is perigynous e.g. Rose, Pea,, Bean, etc. It is denoted as G - in floral formula., c. Epigyny : When thalamus completely, encloses ovary and may show fusion with wall;, the other floral parts occupy superior position, and ovary becomes inferior. Such flower is said, to be epigynous flower, e.g. Sunflower, Guava, etc. It is denoted as G - in floral formula., b. Floral parts and their structure : All floral, parts develop from thalamus from different, nodes. From each node of thalamus circle or, whorl of modified leaves is produced. Thalamus, is called as torus or receptacle. Thalamus is, green in colour hence it can perform the process, of photosynthesis., , 1. Calyx (K) : It is outermost floral whorl, and individual members are known as sepals., Sepals are usually green in colour and perform, photosynthesis. If all the sepals are united,, the condition is gamosepalous and if they are, free, the condition is called as polysepalous., Gamosepalous calyx is found in china rose and, polysepalous calyx is found in Brassica., The main function of sepals is to protect, inner floral parts in bud condition. Sometimes, sepals become brightly coloured (petaloid, sepals) and attract insects for pollination e.g., Canna, Mussaenda etc. Calyx i.e. Sepals, modify into hairy structures called as pappus., Such calyx helps in dispersal of seeds or fruits., E.g. Sonchus., 2. Corolla (C): It is second floral whorl, from outer side and variously coloured. The, individual member is called as petal. Petals may, be sweet to taste, posses scent, odour, aroma or, fragrance etc. The condition in which petals are, free is said to be polypetalous (e.g. Rose) and, if they are fused it is called as gamopetalous, (e.g. Datura). The main function of corolla is to, attract different agencies for pollination., Perianth (P) : Many times calyx and corolla, remain undifferentiated. Such member is, known as tepal. The whorl of tepals is known, as Perianth., , Do you know ?, Type of Calyx, Caducous, Deciduous, Persistent, , Nature of Sepals, , Example, , Sepals fall off as soon as the flower bud opens. e.g. Argemone (Poppy), Sepals survive till (withering of petals) fruit e.g. L otus, mustard, formation, Sepals remain even after fruit formation, e.g. Brinjal, Pea, etc., , 109

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Valvate : Margins of sepals or petals remain either in contact or, lie close to each other but do not overlap. e.g. Calyx of Datura,, Calotropis., Twisted : Margins of each sepal or petal is directed inwards, and is overlapped. While the other margin is directed outwards, and overlap the margin of adjacent. e.g. Corolla of China rose,, Cotton etc., Imbricate : One of the sepals or petals is internal and is, overlapped at both the margins. One is external i.e. completely, outside Rest of the members. Overlap and get overlapped. e.g., Cassia, Bauhinia, etc., Vexillary : Corolla is butterfly shaped and consists of five, petals. Outermost and largest is known as standard or vexillum,, two lateral petals are wings and two smaller fused forming boat, shaped structures keel. e.g Pisum sativum, Table 9.43 Arrangement of sepals, petals or tepals, If all the tepals are free the condition is, called as polyphyllous and if they are fused the, condition is called as gamophyllous. Sepaloid, perianth shows green tepals while petaloid, perianth brightly coloured tepals. E.g. L ily,, Amaranthus, Celosia, etc. It protects other floral, whorls. Petaloid tepal helps in pollination and, sepaloid tepals can perform photosynthesis., Aestivation : The mode of arrangement of, sepals, petals or tepals in a flower with respect, to the members of same whorl is known as, aestivation. (Refer table 9.42), Epicalyx : It is an additional whorl of sepal, like structures formed by bractiole which, occurs on the outside of calyx. These are 5-8 in, number. It is a characteristic feature of family., Malvaceae. They are protective in function., e.g. Ladies finger, 3. Androecium (A): It is third floral whorl from, outer side. Androecium is male reproductive, part of a flower. The individual member is, known as stamen. If all the stamens are free the, condition is polyandrous and if they are fused., (Cohesion = Fusion between members of a, similar whorl., Adhesion = Fusion between members of, dissimilar whorls), , Typical stamen shows three different parts :, 1. Anther : It is terminal in position. Anther, produces pollen grains. It is usually bilobed, bithecous,, tetralocular/tetra, sporangiate, structure. e.g. Datura. In some plants it, is monotheocus (single lobed). Bilocular, bisporangiate structure e.g. H ibiscus., 2. Filament : It is a stalk of stamen and bears, anther at its tip. It raises anther to a proper, height for easy dispersal of pollen grains., 3. Connective : It is in continuation with the, filament. It is similar to mid rib and connects, two anther lobes together and also with the, filament., Cohesion of stamens : When stamens are, united by filaments and anthers are free, the, condition is adelphy., , 110, , Syngenesious, , Monoadelphous, , Syngeny, , diadelphous Polyadelphous, , Fig. 9.44 Cohesion of Stamens

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Adhesion of stamens : When the stamens are, united to petals or tepals they are described as, epipetalous e.g. Datura, Lily etc., , Free central : Ovules are borne on central axis, which is not attached to ovary wall. e.g. Fig., , Syngeneious and Synandrous : When anthers, are united and filaments are free it is known, as syngeny. e.g. Sunflower, stamens are fused, by both filaments and anthers in synandrous, conditions e.g. Cucurbita., 4. Gynoecium (G): It is the female reproductive, part of flower and innermost in position. It is, also known as pistil. The individual member, of gynoecium is known as carpel. The number, of carpels may be one to many. If all the, carpels are fused the condition is described as, syncarpous and if they are free the condition, is described as apocarpous. The polycarpellary, gynoecium can be bicarpellary (two carpels, e.g. Datura) tricarpellary (three carpels e.g., Cucurbita), pentacarpellery (five carpels e.g., H ibiscus) and so on., A typical carpel consists of three parts, stigma, style and ovary. Stigma is a terminal, part of carpel which receives pollen grains, during pollination. It helps in germination, of pollen grain. Stigma shows variation in, structure to suit the pollinating agent. Style is, narrow thread like structure that connects ovary, with stigma. Ovary is basal swollen fertile part, of the carpel. Ovules are produced in ovary on, a soft fertile tissue called placenta., , Axile, , Marginal, , Basal, , Parietal, , Free central, , Fig. 9.45 Types of placentation, , F. Fruit : Angiosperms produce fruit, after fertilization from ovary. Sometimes, fruit is produced from ovary without, fertilization. Such types of fruits are called, as parthenocarpic fruits and phenomenon is, called as parthenocarpy. E.g Banana, Grapes,, etc. without or with one or more seeds. The fruit, which develops only from ovary is true fruit or, eucarp. e.g. Mango. The fruit which develops, from ovary and any other floral part is false, fruit of pseudocarp. e.g. Apple., , Placentation : The mode of arrangement, of ovules on the placenta within the ovary is, placentation., Types of Placentation :, Marginal : Ovules are placed on the fused, margins of unilocular ovary. e.g. Pea, Bean etc., Axile : Ovules are placed on the central axis, of a multilocular ovary. e.g. Chinarose, Cotton;, etc, Parietal : Ovules are placed on the inner wall of, unilocular ovary of multicarpellary syncarpus, gynoecium. e.g. Papaya, Cucumber,, Basal : Single ovule is present at the base of, unilocular inferior ovary. e.g. Sunflower, Rice,, Wheat., , 111, , Exocarp, Mesocarp, Endocarp, , Endocarp, (pit), , Fig. 9.46 Mango, , Fig. 9.47 Apple

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Observe and Discuss, Types of fruits, , True fruit has a wall (pericarp) and, seeds. Pericarp is further divided in outer, epicarp, middle mesocarp and inner endocarp., Fruits can develop from one ovary, of one flower. Such fruits are simple fruits., Simple fruits are further classified on the basis, of their pericarp. Those having thin pericarp, are dry fruits but those with thick pericarp are, fleshy fruits. In dry fruits the pericarp becomes, dry and thin. It breaks open (dehiscent) at, maturity. But in some others it does not, break open (indehiscent). Achene (Mirabilis),, caryopsis (Maize) and Cypsella (Sunflower), are indehiscent fruits. Capsule (Lady's finger), and legume (Pea) are dehiscent fruits. In fleshy, fruits berry (Tomato) has a very soft pericarp, but drupe (Coconut) has stony endocarp., Many ovaris of apocarpous gynoeciun, can form one fruit. Such fruits are aggregate, fruits. Aggregate fruits are a collection (Etario), of many varieties. Accordingly they can be, etario of achenes (Strawberry), etario berries, (Custard apple), etario of follicles (Calotropis),, etc., Many ovaries of many flowers but of, one inflorescence can form one fruit. Such fruits, are composite fruits. These fruits develop from, one inflorescence. The one which develops, from hypanthodium inflorescence is syconus, (fig). Sorosis (Pineapple) develops from Catkin, inflorescence., Families are group of plants having, very distinguished common characters., , G. Seed : Seed is a reproductive unit that, developed from fertilized mature ovule. The, seed is made up of seed coat and one or two, cotyledons. Outer most covering of a seed is, called seed coat, shows outer layers called, testa and inner tegmen. Hilum is a scar on, the seed coat through which seed attach to the, fruit. Embryo of a seed enclosed within seed, coat. Embryonal axis consists of radicle and, plumule. The part of embryonal axis between, cotyledon and plumule is epicotyl, while, the part between cotyledons and radicle is, hypocotyl. The nutritive tissue in a seed called, endosperm., 9.3, Study of some important families :, Fabaceae : Pea plant belongs to this family. The, plant is either tree shrub or herb. The root shows, root nodules. Pea is a erect climber. The leaves, are pinnately compound arranged in alternate, phyllotaxy. The inflorescence is racemose, type. Flowers are bisexual and zygomorphic., Calyx has five fused sepals (gamosepalous), arranged in imbricate aestivation. Corolla, has five free petals (polypetalous) arranged, vexillary aestivation. The petals are unequal, in size. The largest petal is vexillum, to small, petal are wings and to smallest petals are, keel. Androecium has ten stamens arranged, in diadelphous condition. Gynoecium is, monocarpellary. Unilocular ovary is superior, with many ovules on marginal placenta. Ovary, develops in legume type of fruit. Seeds are nonendospermic., , 112

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Floral formula : %, Floral diagram :, , Petal, , ↑, , K(5) C1 + 2 + (2) A(9) + 1 G1, , Tendrills, , Stigma, , Ovary, Style, Sepal L. S. of flower, Leaflets, Wing, , and actinomorphic. Calyx has five fused sepals, (gamosepalous) arranged in valvate aestivation., Corolla has five fused petals (gamopetalous), arranged valvate aestivation. Androecium, has five free epipetalous (adhesion) stamens., Gynoecium is bicarpellary, syncarpous., Bilocular ovary is superior with many, ovules arranged in axile placentation on, swollen placenta. Ovary develops in berry or, capsule type of fruit. Seeds are endospermic., ↑, Floral formula : ⊕, K(5) C(5) A5 G(2), Floral diagram :, , Flower, Foliaceous, stipule, , Standard, Keel, Corolla opened, , Habit sketch, Flower, , Fig. 9.48 Pea plant details, , Solanaceae : Plant is herb, shrub or small, tree. The root shows tap root system. The, stem is erect, woody and branched. It is, covered by hairy structures in some plants., In potato it is underground tuber. The leaves, are simple arranged in alternate phyllotaxy, with reticulate venation. The inflorescence is, Cymose type. Flowers are solitary, bisexual, , Activity :, , Fruit, , Fig. 9.49 D atu ra plant, , Study family Liliaceae, prepare a table of following characteristics., Character/Part, Description, Symmetry of flower, Bisexual/Unisexual, Calyx, Corolla, Androecium, Gynoecium, Aestivation, a. Calyx, b. Corolla, Placentation, Position of ovary, Type of fruit, , 113

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Exercise, 1. Choose correct option, A. Which one of the following will grow, better in moist and shady region?, a. Opuntia, b. Orchid, c. Mangroove, d. L otus, , 3. Write notes on, A. Fusiform root., B. Racemose inflorescence, C. Fasciculated tuberous roots, D. Region of cell maturation, E. Rhizome, F. Stolon, , B. A particular plant had a pair of leaves at, each node arranged in one plane. What is, the arrangement called?, a. Alternate phyllotaxy, b. Decussate phyllotaxy, c. Superposed phyllotaxy, d. Whorled phyllotaxy, C. In a particular flower the insertion of, floral whorls was in such a manner, so, the ovary was below other three whorls,, but its stigma was taller than other three, whorls. What will you call such flower?, a. Hypogynous, b. Perigynous, c. Inferior ovary, d. Half superior - half inferior, D. Beet and Arum both store food for, perennation. Are the examples for two, different types?, a. Beet is a stem but Arum is a root, b. Beet is a root but Arum is a stem, c. Beet is a stem but Arum is a leaf, d. Beet is a stem but Arum is an, inflorescence, , G. Leaf venation, H. Cymose inflorescence, I. Perianth, J. Vexillary aestivation, K. Axile placentation, 4. Identify the following figures and write, down the types of leaves arrangement, , 5. Students were on the excursion to a, botanical garden. They noted following, observation. Will you be able to help, them in understanding those conditions?, , 2. Answer the following questions, A. Two of the vegetables we consume are, nothing but leaf bases. Which are they?, B. Opuntia has spines but Carissa has thorns., What is the difference?, C. Teacher described H ibiscus as solitary, Cyme. What it means?, , 114, , A. A wiry outgrowth was seen on a plant, arising from in between the leaf and, stem., B. There was a green plant with flat stem,, but no leaves. The entire plant was, covered by soft spines., C. Many obliquelyx roots were given out, from the lower nodes, apparently for, extra support., D. Many plants in the marshy region had, upwardly growing roots. They could be, better seen during low tide.

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E. A plant had leaves with long leaf apex,, which was curling around a support., , 7. Observe the following figures and label the, different parts, , F. A plant was found growing on other, plant. Teacher said it is not a parasite. It, exhibited two types of roots., G. While having lunch onion slices were, served to them. Teacher asked which, part of the plant are you eating?, H. Students observed large leaves of coconut, and small leaves of Mimosa. Teacher, asked it what way they are similar?, , 8., , I. Teacher showed them Marigold flower, and said it is not one flower. What the, teacher meant?, J. Students cut open a Papaya fruit and, found all the seeds attached to the sides., Teacher inquired about the possible, placentation of Papaya ovary., 6. Match the following, 'Group A', , 1, , 'Group B', , A Marginal, , Differentiate with diagramatic, representation., A. Racemose and cymose infloresance, B. Reticulate and parallel venation, C. Tap root and Adventitious roots, , Practical / Project :, 1. Collect different leaves from nearby, region and observe variation in margin,, leaf base, apex etc., 2. Find out and make a note of economically, important plant from family Fabaceae,, Solanaceae and Liliaceae., 3. Collect different leaves from garden and, observe their veins and classify it., , 2, , B, , Basal, , 3, C, , Axile, , 4, , D Free central, , 5, , E, , Parietal, , 115

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10. Animal Tissue, Can you recall?, 1. What is tissue?, 2. Where is squamous epithelial tissue, located?, 3. Enlist functions of bone., Do you know ?, Number of cells in human body., As we know tissue is a group of cells, having same embryonic origin, structure and, function. Various tissues combine together in, an orderly manner to form large functional unit, called organs. These organs combine together, and form organ-system. The cells are of two, types, somatic cells and germ cells. The word, somatic is derived from the Greek word 'soma', means 'body'. All body cells of an organism, except sperm and ova are somatic cells. The, sperm and ova are germ cells. They belong to, reproductive system., Cells → Tissues → Organs → Organ systems →Body, , 10.1 Histology : The study of the structure, and arrangement of tissue is called histology., There are four types of tissues present in animals, namely epithelial, connective, muscular and, nervous. Let us study each type in details., , The cells of this tissue are compactly, arranged with little intercellular matrix. Cells, rest on non-cellular basement membrane., Cells are polygonal, cuboidal or, columnar in shape. Single nucleus is present, at the centre or at the base. This tissue is, avascular. It has good capacity of regeneration., Major function is protection and it also helps in, absorption, transport, filtration and secretion., Epithelial tissue is classified into two types :, Simple epithelium and Compound epithelium., Simple epithelium is made up of single layer of, cells. Compound epithelium is made up of two, or more layers of cells. Lowermost layer lies on, basement membrane., A. Simple epithelial tissue :, 1. Squamous epithelial tissue : Cells of this, tissue are flat, thin, polygonal with serrated, margin. Cells of this tissue fit together like, tiles of footpath. Hence it is called pavement, epithelium. Prominent spherical or oval nucleus, is present at the centre of the cell. Function :, Protection, absorption, transport, filtration,, secretion. It is found in blood vessels, alveoli,, coelom, etc., Apical surface, Nucleus, , Know the scientist, Marie Francois, Xavier Bichat (17711802), French anatomist, and pathologist discovered, tissue. He was known as, ‘Father of Histology’., , Basement, membrane, Basolateral surface, , Fig. 10.1 Squamous epithelial tissue, , Marie Francois Xavier, , 10.2, , Epithelial tissue (epi : above, thelium, : layer of cells), Epithelial tissue forms a covering on, inner and outer surface of body and organs., , 2. Cuboidal epithelial tissue : In this tissue,, the cells are cuboidal in shape with a spherical, nucleus at the centre. Function : Absorption,, secretion. It is found in lining of pancreatic duct,, salivary duct, proximal and distal convoluted, tubules of nephron., , 116

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Nucleus, Connective tissue, , Cytoplasm, Basement membrane, , Fig. 10.2 Cuboidal epithelial tissue, 3. Columnar epithelium : Columnar epithelial, cells are tall, pillar like. Inner ends of the cells, are narrow while free ends are broad and flat., Free surface shows large number of microvilli., Nucleus is oval and is present in the lower half, of the cell. Function : Secretion, absorption., It is found in inner lining of intestine, gall, bladder, gastric glands, intestinal glands, etc., , 5. Glandular epithelium : Here, the cells may, be columnar, cuboidal or pyramidal in shape., Nucleus is large and situated towards the base., Secretory granules are present in the cytoplasm., The glands may be unicellular (globlet, cells of intestine) or multicellular (salivary, gland) depending on the number of cells., Depending on mode of secretion, multicellular, glands can be classified as duct bearing, glands (exocrine glands) and ductless glands, (endocrine glands)., Microvilli, Mucus, Cytoplasm, Goblet cell, Nucleus, Cell membrane, Absorptive cell, Basement, membrane, , Microvilli, Non-, , Mucus in, goblet cell, , ciliated, Simple, columnar, epithelium, , Absorptive, cell, Basement, membrane, Connective tissue, , Fig. 10.3 Columnar epithelial tissue, 4. Ciliated epithelium : Cells of this tissue are, cuboidal or columnar. Free ends of cells are, broad while narrow ends rest on a basement, membrane. Free ends show hair like cilia., Nucleus is oval and placed at basal end of cell., Function : To create a movement of materials in, contact in a specific direction and thus able to, prevent entry of foreign particles in the trachea,, push the ovum through oviduct. It is found in, inner lining of buccal cavity of frog, nasal, cavity, trachea, oviduct of vertebrates, etc., Cilia, Cytoplasm, , Fig. 10.5 Glandular epithelial tissue, Exocrine glands pour their secretions, at a specific sites e.g. Salivary gland, sweat, glands etc. Endocrine glands release their, secretions directly into blood stream. e.g., thyroid gland, pituitary gland, etc. Function :, Secrete the musus that trap the dust particles,, lubricates the inner surface of respiratory and, digestive tracts, secretion of enzymes and, hormones., 6. Sensory epithelial tissue : It is composed of, modified form of columnar cells and elongated, neurosensory cells. Sensory hairs are present at, the free end of the cell. Function : It perceive, external as well as internal stimuli. These are, found in nose (Olfactory) Ear (Auditory hair, cells) Eye (photoreceptors)., Olfactory, bulb, , Olfactory tract, Mitral cell, , Cribriform, plate, , Axon, Supporting, cell, Receptor cell, , Epithelium, , Dendrite, , Nucleus, Basement, membrane, , Cilia, , Fig. 10.4 Ciliated epithelial tissue, , Fig. 10.6 Sensory epithelial tissue, , 117

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7. Germinal epithelial tissue : Cells of this, epithelium divide meiotically to produce, haploid gamets. Ex. : Lining of seminiferous, tubules, inner lining of ovary., , Use your brain power, When do the transitional cells change, their shape ?, , B. Compound epithelial tissue :, a. Stratified epithelium :, Nucleus is present in, stratum germinativum., Cells at free surface, become flat and lack, nucleus called stratum, corneum., Function : Protection, Ex. : Epidermis of skin,, oesophagus, cornea,, Fig. 10.7 Compound epithelial tissues, vagina, rectum., , b. Transitional epithelium:, Structure of transitional, epithelium is same like, stratified epithelium. The, cells can undergo a change, in their shape and structure, depending on degree of, stretch., Function : Distension of, organ, Ex. : Urinary bladder, , Cell junctions : The epithelial cells are connected to each other laterally as well as to the basement, membrane by junctional complexes called cell junctions., Gap Junctions, (GJs) :, This, intercellular, connection, allows, passage of ions and, small, molecules, between cells as, well as exchange of, chemical messages, between cells., , Tight junctions, (TJs):, These, junctions maintain, cell polarity, prevent, lateral diffusion of, proteins and ions., , Hemidesmosomes (HDs), : Allow the cells to strongly, adhere to the underlying, basement, membrane., These maintain tissue, homeostasis by signaling., , Desmosomes (Ds) :, These provide mechanical, strength to epithelial, tissue, cardiac muscles, and meninges., , Chart 10.8 Types of Cell junction :, , 118, , Adherens Junctions, (AJs) : It is, involved in various, signaling pathways, and transcriptional, regulations.

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Can you tell?, 1. Explain basic structure of epithelial tissue and mention its types., 2. Epithelial tissue has good capacity of, regenereation. Give reason., 3. Write a note on glandular epithelial, tissue., 4. How do cell junctions help in functioning, of epithelial tissue?, , Macrophage, , Matrix, , Collagen fibres, (white fibres), , Yellow, fibres, , Fibroblast, , 10.3 Connective tissue : It is most widely, spread tissue in the body. It binds, supports, and provides strength to other body tissues, and organs. It consists of a variety of cells, and fibres. These are embedded in the, abundant intercellular substance called matrix., Connective tissue protects the vital organs of, the body. It is highly vascular except cartilage., It acts as packing material and also helps in, healing process., Connective tissue is classified on the, basis of matrix present, as connective tissue, proper, supporting connective tissue and fluid, connective tissue. Connective tissue proper is, further classified as loose connective tissue (ex., areolar connective tissue and adipose tissue), and dense connective tissue (ex. ligament and, tendon). Supporting connective tissue also, called skeletal tissue includes cartilage and, bone. Fluid connective tissue includes blood, and lymph., , Mast cell, , Fig. 10.9 Areolar tissue, They produce fibres as well as, polysaccharides that form the ground, substance or matrix of the tissue. Mast cells are, oval cells that secrete heparin and histamine., Macrophages are amoeboid, phagocytic cells., Fat cells, also called adipocytes have eccentric, nucleus. These cells store fat. This tissue acts, as packing material, helps in healing process, and connects different organs or layers of, tissues. It is found under the skin, between, muscles, bones, around organs, blood vessels, and peritoneum., 2., Adipose tissue (adipo : fat) : In this, tissue large number of adipocytes are present., Cells are rounded or polygonal. Nucleus is, shifted to periphery because fats are stored in, the cell in the form of droplets. Matrix is less, and fibres and blood vessels are few in number., , A., Connective Tissue Proper, Loose connective tissue : Matrix of loose, connective tissue is semisolid, jelly like, viscous, matter made up of gelatin., 1., , Areolar tissue (Areola : air pockets):, Matrix of this tissue contains two types, of fibres namely white fibres and yellow fibres., White fibres are made up of collagen. They, give tensile strength to the tissue. Yellow fibres, are made up of elastin and are elastic in nature., The tissue also contains four different types, of cells; Fibroblast the large flat cells having, branching processes., , 119, , Empty, adipose, cell, , Nucleus, , Cytoplasm, Matrix, Fine white fibres, Fat globule, Blood vessel, Yellow fibre, Adipose cell, , Fig. 10.10 Adipose tissue

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There are two types of adipose tissue, : white adipose tissue appears opaque due to, presence of large number of adipocytes. It is, commonly seen in adults. Brown adipose tissue, is reddish brown in colour due to presence of, large number of blood vessels., Function : Adipose tissue is a good insulator,, acts as a shock absorber and a good source of, energy because it stores fat. The tissue is found, in sole and palm region as well as around, organs like kidney., Know your body, Achilles Tendon : Achilles Tendon connects, the calf muscles to heel bone. Pain at the, back of ankle or lower calf may signal a, problem with an Achilles Tendon. Athletes, who participate in track and field may face, Achilles tendon injury. Most tendon injuries, occur near joints such as the shoulder, elbow,, knee and ankle., B., , Dense Connective Tissue, In this tissue, fibres and fibroblasts are, compactly arranged. There are two types,, namely dense regular and dense irregular, tissue., In dense regular connective tissue,, collagen fibres are arranged in parallel manner., Two major examples of this tissue are tendons, and ligaments. Tendons connect skeletal, muscles to bones. To give tensile strength to the, tissue, tendons contain bundles of white fibres., E.g. Achielles tendon, Hamstring tendon., Flexer, muscle, , Extensor, muscle, , Ligaments are made up of elastic or, yellow fibres arranged in regular pattern. These, fibres make ligaments elastic. They are present, at joints. They prevent dislocation of bones., In dense irregular connective tissue fibres and, fibroblast are not arranged in orderly manner., This tissue is found in dermis of skin., C., , Supporting Connective Tissue, It is characterized by presence of hard, matrix. It is classified into two types cartilage, and bone., Cartilage : This is a pliable yet tough tissue., It forms endoskeleton of cartilagenous fishes, like shark. It is widely distributed in vertebrate, animals. In cartilage, abundant matrix is, delimited by a sheath of collagenous fibres called, perichondrium. Matrix is called chondrin. Just, below the perichondrium, immature cartilage, forming cells called chondroblast are present., Chondroblasts mature and get converted into, chondrocytes. Chondrocytes are seen scattered, in the matrix. Thay are enclosed in lacunae., Each lacuna contains 2-8 chondrocytes., Based upon the type of matrix, there are, four types of cartilage as explained below., Hyaline cartilage (Hyline : Glass like) : In, this type of cartilage, perichondrium is present., Matrix is bluish white and gel like., Very fine collagen fibres and, chondrocytes are present. Hyaline cartilage, is elastic and compressible in nature. It acts, as a good shock absorber as well as provide, flexibility. It reduces friction. It is found at the, ends of long bones, epiglottis, trachea, ribs,, larynx and hyoid., Perichondrium, , Epiphyseal, bone, , Chondroblast, Matrix, , Tendon, , Ligament, , Lacunae, Chondrocyte, , Fig. 10.11 Ligament, , Fig. 10.12 Hyline Cartilage, , 120

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Elastic cartilage : In elastic cartilage, perichondrium is present. Matrix contain, elastic fibres. Chondrocytes are few in number., It gives support and maintains shape of the, body part. It is found in ear lobe, tip of nose,, etc., Perichondrium, Matrix, Lacuna, Chondrocyte, Elastic fibre, , Fig. 10.13 Elastic cartilage, , Each lamella contains fluid filled, cavities called lacunae. Fine canals that, radiate from each lacuna are called canaliculi., Canaliculi of adjecent lamellae connect with, each other as they traverse through the matrix., In the lacunae osteoblasts, active bone cells, and osteocytes, the inactive bone cells and, osteoclasts are present. Mammalian bone, shows peculiar haversian system. Haversian, canal encloses an artery, vein and nerves., Observe figure 10.15 to understand haversian, system. According to presence of matrix there, are two types of bones present in human body., In spongy bones, haversian system is absent., Reticular matrix is arranged in the form of, trabeculae. It contains red bone marrow. In, compact bones, matrix shows haversian, system without any space between lamellae., , Fibrocartilage : Perichondrium is absent in, fibrocartilage. Matrix contains bundles of, collagen fibres and few chondrocytes, scattered, in fibres. Fibrocartilage is most rigid cartilage., It maintains position of vertebrae. Intervertebral, discs are made up of fibrocartilage. It is also, found at pubic symphysis., , Lacuna, , Canaliculi, Osteocyte, , Venule, Chondroblasts, , Arteriole, , Matrix, , Canaliculi, , Central canal, , Lacuna, White fibres, , Lamellae, , External, circumferential, lamellae, , Osteon, , Periosteum, , Fig. 10.14 White fibrous cartilage, Calcified cartilage : This type of cartilage, becomes rigid due to deposition of salts in the, matrix. This reduces flexibility of joints in old, age e.g. Head of long bones., Bone : Bone is characterised by hard matrix, called Ossein. Ossein is made up of mineral, salt hydroxy-apatite (Ca10(PO4)6(OH)2). Outer, tough membrane called periosteum encloses, the matrix. Blood vessels and nerves pierce, through periosteum. Matrix is arranged in the, form of concentric layers called lamellae., , Central canal, , Perforating, fibers, , Blood vessels, , 121, , Perforating, canals, , Trabeculae of, Central, canal spongy bone, , Fig. 10.15 Bone detailed structure

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Can you tell?, , Striations, , 1. Give reason., a. Bone is stronger than cartilage., b. As we grow old, cartilage becomes, rigid., 2. Explain, histological, structure, of, mammalian bone., , Nucleus, , D., , Fluid Connective tissue (Vascular), Blood and lymph are fluid connective, tissue present in the body of an animal. You, will study these tissues in details in chapter, 'Circulation' in class XII., , Z line, , Z line, , Sacromere, , Can you recall?, 1. How many skeletal muscles are present, in human body ?, 2. How can exercise improve your muscular system ?, , Sacromere, , 10.4, , Muscular tissue :, The cells of this tissue are elongated, and are called muscle fibres. Each muscle, fibre is covered by a membrane sarcolemma., Cytoplasm of muscle cell is called sarcoplasm., Large number of contractile fibrils called, myofibrils are present in sarcoplasm. One, or many nuclei are present in muscle cell, depending on the type. Myofibrils are made up, of proteins, actin and myosin. Muscle fibres, contract and decrease in length on stimulation., Hence, muscular tissue is known as contractile, tissue. It is vascular tissue and is innervated by, nerves too. Muscle cells contain large number, of mitochondria., A., Types of Muscular Tissue, 1., Skeletal muscles : These muscles are, found attached to bones. Skeletal muscles, consists of large number of fasciculi which, are wrapped by connective tissue sheath, called epimysium or fascia. Each individual, fasciculus is covered by perimysium. Each, fasiculus in turn consists of many muscle fibres, called myofibres., , 1. Sacromere is a, repeating unit of, contraction within, the myofibril, 2. The myofibril, can be seen to be, made up of repeating, units of overlaping, myofilaments, , Fig. 10.16 Muscular tissue, Each muscle fibre is a syncytial fibre, that contains several nuclei. The cell membrane, called sarcolemma delimits the cytoplasm, called sarcoplasm. Sarcoplasm contains large, number of parallely arranged myofibrils hence, nuclei get shifted to periphery. Each myofibril, is made up of repeated functional units called, sarcomeres. Each sarcomere has a dark band, called anisotropic or 'A' band in the centre. In, the centre of 'A' band is light area called 'H', zone or 'Hensen's Zone'. In the centre of 'H', zone there is 'M' line. 'A' bands are made up, of myosin as well as actin. On either side of, 'A' band are light bands called isotropic or 'I', bands that contain only actin. Myosin are thick, and dark coloured while actin filaments are, thin and light coloured. Adjacent light bands, are separated by 'Z' line (Z - Zwischenscheibe, line). Dark and light bands on neighbouring, myofibrils correspond with each other hence, the muscle gets striated appearance., , 122

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Skeletal muscles show quick and strong, voluntary contractions. They bring about, voluntary movements of the body. You will, study about working of skeletal muscles in the, chapter movement and locomotion., Red and white muscles : On the basis of, amount of a red pigment, skeletal muscles, are of two main types – Red and white., Red muscles contain very high amount of, myoglobin while white muscles contain very, low amount of this pigment., Myoglobin is an iron containing, red coloured pigment only in muscles. It, consists of one haeme and one polyepeptide, chain. It can carry one molecule of oxygen., Due to presence of myoglobin, the muscles, can obtain their oxygen from two sources,, myoglobin and haemoglobin., , 3., Cardiac Muscles : Muscles of this, tissue show characters of both striated and, non-striated fibres. Sarcolemma is not distinct., Hence uni-nucleate muscle fibres appear to, be multi-nucleate. Adjacent muscle fibres, join together to give branched appearance, to the tissue. Points of adhesion of muscle, fibres are formed by transverse thickenings of, sarcolemma called intercalated discs., Striations, , 2., Smooth or Non-striated muscles :, These muscles are present in the form of sheets, or layers. Each muscle cell is spindle shaped, or fusiform. The fibres are unbranched having, single nucleus at the centre. Sarcoplasm, contains myofibrils. Myofibrils are made up of, contractile proteins actin and myosin. Smooth, muscles contain less myosin and more actin, as compared to skeletal muscles. Striations, are absent. These muscles undergo slow and, sustained involuntary contractions. They are, innervated by autonomous nervous system., , Plasma membrane, Myofibrils, Nucleus, Sarcoplasm, , These are found in the walls of visceral, organs and blood vessels. Hence they are, also called as visceral muscles. They may be, arranged lengthwise (longitudenal muscles) or, around circumference (circular muscles) of any, organ., , Nucleus, , Juction between, adjacent cells, , Fig. 10.18 Cardiac muscles, These junctions at places allow cardiac, muscles to contract as a unit. i.e. It helps in, quick transfer of stimulus. The cardiac muscles, are striated involuntary muscles., Some mammalian cardiac muscles are, modified are capable of generating impulse on, their own. Hence mamalian heart is a myogenic, heart. In some animals, cardiac muscles need, neural stimulus to initiate the contraction. Such, a heart is called neurogenic heart. Cardiac, muscles form myocardium of the heart wall., Can you tell?, Compare and contrast between various types of muscles., , Fig. 10.17 Smooth muscle, , 123

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B., , Dendrites, Cell body, Dendron, Neuroplasm, Nucleolus, Nucleus, Axon, Nucleus of, Schwann, cell, Schwann cell, Node of Ranvier, , Impulse to CNS, , Nervous Tissue :, Nervous tissue is composed of nerve, cells or neurons and neuroglia. Neuron is, the structural and functional unit of nervous, system. Neuroglial cell are non-nervous, supporting cells that fill in the interneuronal, space. The neuroglial cells are capable of, regeneration and division but neurons are not, capable of regeneration because of lack of, centriole. Intercellular matrix is absent in the, neural tissue. Neuron is an impulse generating, and impulse conducting unit. They bring about, quick communication within the body. Neurons, change action potential of their membrane on, receiving any external stimulus. This property, of neuron is called excitability. They also carry, a wave of electric impulse from dendron to, axon, the processes of neuron. This is called, conductivity., A neuron is made up of cyton or cell, body. It contains granular cytoplasm called, neuroplasm and centrally placed nucleus., Neuroplasm contains mitochondria, Golgi, apparatus, RER and granules called Nissl’s, granules. They are made up of RNA. Cell body, gives out two types of processes namely dendron, and axon. Dendrons are short, branched,, processes. The fine branches of dendron are, called dendrites. They carry impulse towards, cyton., An axon is single, elongated, cylindrical, process. Axon is bounded by axolemma. The, protoplasm of the axon is axoplasm. It contains, large number of mitochondria and neurofibrils., Axon is enclosed in a fatty sheath called, myelin sheath. Outer covering of myelin sheath, is neurilemma. Myelin sheath and neurilemma, are parts of another cell called Schwann's cell., Schwann cell shows nucleus at periphery. The, myelin sheath is absent at intervals along the, axon and the place is called Node of Ranvier., The terminal arborization of an axon is called, telodendron., Based on their functions, Neurons are, classified into three types, , Neurilemma, , Telodendron, , Fig. 10.19 Structure of Multipolar Neuron, Afferent Neuron : It carries impulses from, sense organ to central nervous system (CNS)., Hence it is also called sensory neuron. It is, found in dorsal root of spinal cord., Efferent Neuron : It carries impulses from, CNS to effector organ. Hence it is also called, motor neuron. It is found in ventral root of, spinal cord., Interneuron or association neuron : These, are located between sensory and motor, neurons. These perform processing, integration, of sensory impulses and activate appropritate, motor neuron to generate motor impulse., Depending on the presence or absence, of myelin sheath, neurons are classified into, two types. i.e. myelinated and non-myelinated, nerve fibre., Myelinated or medullated nerve fibres, have a insulating fatty layer called myelin, sheath around the axon. This makes the fibre, appear white in colour. This sheath is secreted by, Schwann cells. The sheath is not continuous. It, is interrupted at nodes of Ranvier. Neurilemma, surrounds the axon., , 124

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The impulse is conducted at a faster, rate in such nerve fibres because it jumps from, one node to the next. Such transmission of, impulse is called saltatory conduction. Myelin, sheath prevents the loss of the impulse during, conduction. Cranial nerves of vertebrates are, myelinated. Schwann cell of a non-medullated, nerve fibre does not secrete myelin sheath., These fibres are grey in colour due to absence, of fatty layer. Conduction of impulse in a nonmyelinated fibre is slower as compared to, myelinated nerve fibre. Nerves of autonomous, nervous system are non-myelinated. Functional, contact between axonal ends and dendrites of, adjacent neurons is called a synapse. You will, learn about synapse in chapter control and, coordination, class-XII., , 1. Unipolar/Monopolar Neuron : It has a, single process originating from cyton. Both, axon and dendron arise from cyton at one, point. They conduct impulses to central, nervous system. Ex. Neurons of dorsal root, ganglion of spinal nerve., 2. Bipolar Neuron : It has two processes. A, single dendron and an axon are given off, from opposite poles of the cyton. They bring, about transmission of special senses like, sight, smell, taste, hearing etc. Ex. Neurons, of retina of eye, olfactory epithelium., 3. Multipolar Neuron : Cyton is star shaped, and gives out more than two processes., There is only one axon and remaining are, dendrons. Axon initiates from a funnel, shaped area called axon-hillock., , Internet my friend, Can you tell?, , Learn about transmission of impulse, from one neuron to another., , 1. Differentiate between medullated and, non medullated fibre., 2. Classify neuron on the basis of number, of processes given out from cyton with, examples., , a. Multipolar neuron, , Observe and Discuss, Explain the structure of nerve., A, , b. Bipolar neuron, Covering of a spinal nerve, , B, c. Unipolar neuron, , Axon, Myelin sheath, Endoneurium, Perineurium, Epineurium, , Blood, vessel, , Fig. 10.19 Nervous tissue, Based on the number of processes, given out from cyton, neurons are classified, in to three types., , 125, , Fasicle

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Exercise, 1. Choose correct option, A. The study of structure and arrangement, of tissue is called as _____________, a. anatomy, b. histology, c. microbiology d. morphology, B. ____________ is a gland which is both, exocrine and endocrine., a. Sebaceous b. Mammary, c. Pancreas, d. Pituitary, C. _____________ cell junction is mediated, by integrin., a. Gap, b. Hemidesmosomes, c. Desmosomes d. Adherens, D. The protein found in cartilage is _______., a. ossein, b. haemoglobin, c. chondrin, d. renin, E. Find the odd one out, a. Thyroid gland, b. Pituitary gland, c. Adrenal gland, d. Salivary gland, 2. Answer the following questions, A. Identify and name the type of tissues in, the following:, a. Inner lining of the intestine, b. Heart wall, c. Skin, d. Nerve cord, e. Inner lining of the buccal cavity, B. Why do animals in cold regions have a, layer of fat below their skin?, C. What enables the ear pinna to be folded, and twisted while the nose tip can’t be, twisted?, D. Sharad touched a hot plate by mistake, and took away his hand quickly. Can, you recognize the tissue and its type, responsible for it?, E. Priya got injured in an accident and hurt, her long bone and later on she was also, diagnosed with anaemia. What could be, the probable reason?, , F. Supriya stepped out into the bright street, from a cinema theatre. In response, her, eye pupil shrunk. Identify the muscle, responsible for the same., 3. Answer the following quetions, A. What is cell junction? Describe different, types of cell junctions., B. With help of neat labelled diagram,, describe the structure of areolar, connective tissue., C. Describe the structure of multipolar, neuron., D. Distinguish between smooth muscles, and skeletal muscles., 4. Complete the following table, Cell / Tissue / Muscles Functions, 1. Cardiac muscles, ---------2. ---------Connect skeletal, muscles to bones., 3. Chondroblast cells, ---------4. ---------Secrete heparin, and histamine, , 5. Match the following, 'A' Group, 1. Muscle, 2. Bone, 3. Nerve cell, 4. Cartilage, , 'B' Group, a. Perichondrium, b. Sarcolemma, c. Periosteum, d. Neurilemma, , Practical / Project :, , 126, , 1. To study the different tissues with, the help of permanent slides in your, college laboratory., 2. Collect the information about the, exercise to keep muscles healthy and, strong.

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11. Study of Animal Type - Cockroach, Can you recall?, 1. How many different types of animals are, present around us?, 2. Can a person complete detailed study of, each of those animals?, 3. Which phylum is most diverse and, populous?, 11.1, , Habit and habitat :, Cockroaches are omnipresent i.e., present everywhere, all over the world. It, prefers damp and moist places, crevices to live., It is omnivorous, nocturnal and cursorial., Periplaneta americana, Blatta orientalis and, Blatta germanica are the three common species, of cockroach found in India., 11.2 Systematic Position :, Kingdom : Animalia (Cell wall absent,, heterotrophic nutrition.), Phylym : Arthropoda (Jointed appendages are, present, segmented body, chitinous exoskeleton., Class : Insecta (Two pairs of wings and three, pairs of walking legs are present.), Genus : Periplaneta (Nocturnal, straight, wings.), Species : americana (Origin is in Continent of, America), , Exoskeleton : Body of cockroach is protected, by hard, waxy, tough, non-living exoskeleton., Exoskeleton is formed by a nitrogenous, polysaccharide-chitin that provides strength,, elasticity and surface area for attachment of, muscles. Each body segment of cockroach is, covered by four chitinous plates (sclerites), namely, dorsal tergum, ventral sternum and, two lateral pleurons., Filiform, antennae, Compound eye, Pronotum, Mesothrox, Prothoracic leg, Metathorax, , Head, Tegmina, Hind, wing, , Mesothoracic, leg, , Abdomen, Anal cerci, , Metathoracic leg, , Fig. 11.1 Dorsal view, Head, Antenna, Compound eye, Fore leg, , Prothorax, Mesothorax, Middle leg, , Wing, Abdomen, , Curiosity box:, 1. Why do insects need moulting?, 2. What is the difference between simple, and compound eyes?, , Anal cercus, , Hind leg, , Fig. 11.2 Ventral view, , 11.3 External morphology :, Shape and size : Cockroach has an elongated,, bilaterally symmetrical and dorso-ventrally, flattened body. They are triploblastic,, eucoelomate and truly segmented animals., Body cavity is called as haemocoel, filled with, haemolymph., Coloration : Cockroach is glistening brown or, red brown in colour., , Body Division : Body is divided into three, regions namely head, thorax and abdomen., Head is attached at right angles to thorax by a, thin, narrow, movable neck or cervix., Head : It is formed by the fusion of six, segments. It is triangular or ovate in shape. It, is highly mobile due to flexible neck. It bears, a pair of long antennae, a pair of compound, eyes and mouth parts adapted for chewing and, biting of food., , 127

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Ocellar spot, Compound eye, , Maxilla, Mandible, Labrum, , Labium, , Fig. 11.3 Head, 1. Antennae : Also called as feelers. There are, filamentous, long, segmented structures that, can be moved in all directions. They are lodged, in membranous pits called antennal sockets., They are tactile (touch) as well as olfactory, (smell) organs, useful in locating the food, material in the vicinity., 2. Fenestrae are also called as ocellar spots, situated at the base of each antenna and they, appear as white spots., 3. Compound eyes : They are paired, dark,, kidney shaped structures placed on lateral, sides of the head and are made up of large, number of ommatidia (singular ommatidium)., Ommatidia are structural and functional units, of compound eye, each forming an image of, very small part of visual field. Collectively,, compound eye produces a mosaic image., 4. Mouth parts : Cockroach has pre-oral cavity, in front of mouth in which foods is received., It is bounded by chewing and biting type of, mouth parts. These are movable, segmented, appendages which assist in ingestion of food., Mouth parts of cockroach comprise of...., i. Labrum (Upper lip) : It is single flap-like, movable part which covers the mouth from, upper side. It forms an anterior wall of pre-oral, cavity. It is useful in holding of the food during, feeding., , ii. Mandibles (True jaws) : These are two dark,, hard, chitinous structures with serrated median, margins. They are present on either side, behind, the labrum. They perform coordinated sidewise movements to cut and crush the food. This, movement is effected with the help of adductor, and abductor muscles, iii. Maxillae (Accessory jaws) : These are, also called as first pair of maxillae. These are, situated on the either side of mouth behind the, mandibles. Each maxilla consist of sclerites, like cardo, stipes, galea, lacinia and maxillary, palps. Maxillary palps act as tactile organs., The maxillae hold food, help the mandibles, for mastication. Maxillae are also used for, cleaning the antennae and front legs., iv. Labium (lower lip) : It is also called as, second maxilla which covers the pre-oral cavity, from ventral side and is firmly attached to the, posterior part of head. It has labial palps which, is three jointed and sensory in function. It is, useful in pushing the chewed food in the preoral cavity and also prevents the loss of food, falling from the mandibles during the chewing., v. Hypopharynx (Tongue) : In front of the, labium and between first maxillae, there is a, some what cylindrical single structure called, hypopharynx or lingua. A salivary duct opens, at the base of this structure. Lingua bears, comb-like plates called super-lingua on either, side. It is useful in the process of feeding and, mixing of saliva with food., , Grinding Labrum, region, Incising, Mandible region, , Mandible, , Hypopharynx, , Maxilla, , Labium, , Fig. 11.4 Mouth parts, , 128, , Maxilla

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Thorax : Thorax is three segmented. Anterior, segment is prothorax, middle mesothorax and, posterior metathorax. Thorax bears three pairs, of walking legs ventrally (one at each segment), and two pairs of wings dorsally (attached to, mesothoracic and metathoracic segment)., Legs : Three pairs of walking legs are present, on ventral side. Each leg has five podomeres, namely coxa, trochanter, femur, tibia and, tarsus. Tarsus is the last segment and is made up, of five movable segments or tarsomeres. Last, tarsomere bears a pair of claws and cushionlike arolium helpful in clinging., Trochanter, , Coxa, , Femur, , Laterally, tergum is jointed to sternum, by soft cuticle called pleura. The posterior, segments are telescoped in. Due to this, eighth, and ninth terga get overlapped by the seventh., The tenth tergum projects backward. It is, deeply notched. The tenth tergum also bears a, pair of small, many jointed anal cerci. In the, male, the abdomen is narrow and tapering than, that in female. In male, the ninth sternum also, bears a pair of short, unjointed anal style., 11.4 Body cavity : A body cavity or true, coelom is present around the viscera. Because, of the open type of circulation, the body cavity, is filled up with blood. Hence, it is called, haemocoel. In the haemocoel, fat bodies are, seen. It is in the form of loose, whitish mass, of tissue. The fat body is made up of large,, polygonal cells which contain fat globules,, proteins and sometimes glycogen., 11.5 Digestive system of cockroach :, Digestive system of cockroach consists, of mouth parts, alimentary canal and a pair of, salivary glands., Alimentary canal is a long (6-7 cm) tube, of different diameters and two openings., Alimentary canal is divisible into three, regions as Foregut (stomodaeum), Mid-gut, (mesenteron) and Hindgut (proctodaeum)., , Tibia, , Tarsus, , Fig. 11.5 Leg of cockroach, Wings : Two pairs of wings as forewings, and hindwings are present on dorsal side., Forewings are first pair of dark, opaque, thick,, leathery wings which are protective in function., Hindwings are thin, broad, membranous,, delicate and transparent. These are attached, to tergum of metathorax. These are helpful in, flight and hence are also called as true wings., Spiracles : These are a series of slit-like, openings on either side the body. In all, there, are ten pairs - two on thorax and eight on, abdomen. The spiracles let the air into and out, of the tubes called trachea., Abdomen : The abdomen is elongated and, made up of ten segments. Each segment has a, dorsal tergum and ventral sternum., , 129, , Pharynx, Salivary gland, Salivary reservoir, Oesophagus, Crop, Gizzard, Hepatic caeca, Mesenteron, or midgut, Malpighian, tubules, lleum, , Rectum, , Colon, , Fig. 11.6 Digestive system of Cockroach

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Mouth : Mouth / pre-oral chamber is a narrow, space bounded by mouth parts. Hypopharynx, is present at the centre of mouth. Salivary duct, opens at the base of hypopharynx. Mouth opens, into foregut., Fore-gut (Stomodaeum) :, Foregut, consists, of, pharynx,, oesophagus, crop and gizzard. Pharynx is very, short, narrow but muscular tube. It contains, taste sensillae. It leads to oesophagus., Oesophagus is slightly long and narrow, tube. It opens in crop. Crop is large, pearshaped sac like organ. It temporarily stores the, food and then sends it to gizzard., Gizzard (Proventriculus) is small,, spherical organ. Internally, it is provided with, a circlet of six chitinous teeth and backwardly, directed bristles. Teeth are responsible for, crushing the food. Bristles help in filtering the, food. Foregut ends with gizzard., , Longitudinal, groove, Circular, muscles, , Teeth, , Fig. 11.7 T. S. of Gizzard, , Hind-gut (Proctodaeum) : Hindgut consists, of ileum, colon and rectum. Ileum is short and, narrow part of hind-gut. Malpighian tubules, open in the anterior lumen of ileum, near the, junction of mid-gut with hind-gut. Posterior, region of ileum contains sphincter. Ileum, sends nitrogenous wastes and undigested food, towards colon., Colon is longer and wider part of hind-gut., It sends the waste material towards rectum., It reabsorbs water from wastes as per need., Rectum is oval or spindle-shaped, terminal, part of hind-gut. It contains six rectal pads, along internal surface for absorption of water., Rectum opens outside by anus. Anus is present, on ventral side of 10th segment. Anus is last/, posterior opening of digestive system. It gives, out undigested food., Salivary Glands : Cockroach has a pair of, salivary glands which secrete saliva. Each, gland consists of two glandular lobes and one, receptacle or reservoir. Glandular lobes consists, of many irregular-shaped and white lobules., These lobules secrete saliva. Each gland has, a salivary duct. Both ducts unite together to, form a common salivary duct. Receptacle of, each gland is thin-walled, elongated, sac-like, structure. Each receptacle has a duct. These, ducts unite to form common reservoir duct., Both common ducts i.e. common salivary duct, and common reservoir duct unite together to, form common efferent salivary duct. Efferent, salivary duct opens at the base of tongue or, hypopharynx., Hypopharynx, , Mid-gut (Mesenteron) : Midgut consists, of stomach and hepatic caecae. Stomach, (ventriculus) is straight, short and narrow. It is, lined by glandular epithelium. Which secretes, digestive enzymes. Hence, stomach is mainly, responsible for digestion and absorption., Hepatic caecae are thin, transparent, short,, blind (closed) and hollow tubules. Hepatic, caecae secrete digestive enzymes and thus help, in digestion of food., , 130, , Lobular, salivary, duct, , Common, salivary, duct, , Common efferent salivary, canal, Common, Reservoir or, reservor, receptacle, duct, Reservoir, duct, , Salivary duct, Glandular part, , Fig. 11.10 Salivary glands of Cockroach

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Food and digestion : Cockroach is omnivorous., It feeds upon plant and animal material. It has, chewing and biting type of mouth parts, that, chew the food and push it into alimentary, canal. As food passes through the alimentary, canal, it is digested and finally undigested food, is eliminated through anus., Do you know?, Cockroaches eat young cockroach., Such tendancy is called Cannibalism., 11.6 Circulatory system or blood vascular, system:, Cockroach has open type of circulatory, system that consists of colourless blood, (haemolymph), a dorsal blood vessel (heart, and dorsal aorta) and haemocoel., A. Haemolymph : Haemolymph of cockroach, is without any pigment; hence it is colourless., It consists of plasma and seven types of blood, cells / haemocytes. Plasma consists of water, with some dissolved organic and inorganic, solutes. It is rich in nutrients and nitrogenous, wests like uric acid., , Use your brain power, Why body cavity of cockroach is, called as haemocoel?, , B. Haemocoel : Body cavity (coelom) of, cockroach is divided into three sinuses due, to two diaphragms i.e. dorsal and ventral, diaphragm., Dorsal and ventral diaphragms are, thin fibromuscular septa (sing.—septum). It, remains attached to terga along lateral sides at, intermittent points., Dorsal diaphragm has 12 pairs (2, thoracic and 10 abdominal) of fan like alary, muscles. Alary muscles are triangular with, pointed end attached to terga at lateral side, and broad end lies between heart and dorsal, diaphragm. Ventral diaphragm is flat and, present just above the ventral nerve cord., Laterally, it is attached to sterna at intermittent, points., , Sinuses : Coelom of cockroach is gets divided, into three sinuses as pericardial, perivisceral, and perineural sinus. Pericardial sinus is, dorsal, very small and contains dorsal vessel., Perivisceral sinus is middle and largest. It, contains fat bodies and almost all major visceral, organs of alimentary canal and reproductive, system. Perineural sinus is ventral, small and, contains ventral nerve cord. It is continuous, into legs. All the three sinuses communicate, with each other through pores present between, two successive points of attachments of, diaphragms., Dorsal blood vessel : This is present in, pericardial sinus, just below the tergum. It is, divisible into posterior heart and anterior aorta, (dorsal aorta / cephalic vessel). Heart is about, 2.5cm long, narrow, muscular tube that is open, anteriorly and closed posteriorly. It starts from, 9th abdominal segment and extends anteriorly, upto 1st thoracic segment. It is divisible into, thirteen chambers. Ten chambers are in, abdominal region and three are in thoracic, region. Each chamber has a pair of vertical slit, like incurrent aperture / opening called ostium, (pl. - ostia). Ostia are present along lateral side, in posterior region of first 12 chambers., Each ostium has lip-like valves that, allow flow of blood from sinus to heart only., Heart is continued by a short, thin walled vessel, called as dorsal aorta. It lies in head region and, opens in the haemocoel., , 131, , Anterior aorta, , Alary muscles, , Chambers of heart, , Fig. 11.11 Circulatory System

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Blood circulation in cockroach :, Blood circulates between sinuses and, heart due to contraction and relaxation of heart, and alary muscles. Heart alternately contracts, (systole) and relaxes (diastole). After diastole,, there is a third phase in the heart cycle known, as diastasis. Heart remains in expanded state, during diastasis., During diastole, alary muscles contract,, making the dorsal diaphragm flat. As a result, blood passes from perivisceral to pericardial, sinus through fenestrae and finally to the heart, through ostia. During systole, contraction starts, at posterior end and wave of contraction passes, anteriorly. Due to this, blood is pushed towards, cephalic vessel i.e. dorsal aorta. During systole,, ostia remain closed with the help of valves. As, a result of systole, blood is flushed into head, region from where it goes to perivisceral and, perineural sinus., Alary muscles are relaxed during, systole. Due to this, dorsal diaphragm becomes, convex, reducing the volume of pericardial, sinus. This makes the blood to move from, pericardial sinus to perivisceral sinus through, fenestrae., 11.7 Respiratory system or tracheal, system :, Cockroach has an internal respiratory, system of air tubes called tracheal system,, by which air is brought into the body and is, in contact with every part of body. It allows, exchange of gases directly between the air and, tissues without the need of blood., Chitin of, body wall, , Chitinous lining, Epithelium, Lumen, , Spiracle, , Trachole, Small, fluid, tracheae, Tracheoles, , Tracheole cell, Muscle fibre, , Fig. 11.12 Respiratory System, , Spiracles : Spiracles are respiratory openings., They are paired, present on ventro-lateral side, of body, in pleural membrane. Cockroaches, have two pairs of thoracic and eight pairs of, abdominal spiracles. The spiracles open into a, series of air sacs from which the tubes called, trachea arise., Trachea : The trachea form a definite pattern of, branching tubes arranged transversely as well, as longitudinally. They are about 1mm thick, and have spiral or annular thickening of chitin., The inner lining of chitin prevents the trachea, from collapsing. Each trachea branches into, number of smaller tubes called tracheoles., Tracheole : These are fine intracellular tubes, that penetrate deep into tissues. They are thin, and not lined with chitin. They end blindly in, the cells. Each tracheole at the blind end is filled, with a watery fluid through which exchange, of gases takes place. The content of this fluid, keeps changing. At high muscular activity, a, part of fluid is drawn into the tissues to enable, more and rapid oxygen intake. The rhythmic, movements of thoracic and abdominal muscles, renew the air in the tracheal system. The body, fluid does not distribute the gases but simply, acts as a stationary medium for diffusion., 11.8, , Excretory System :, Malpighian tubules are main excretory, organs of cockroach. They are attached to, the alimentary canal between the midgut, and hindgut. They are thin, yellow coloured,, ectodermal thread-like structures hanging, freely in the haemocoel. They are about 150 in, number., Malpighian Tubule : Each Malpighian, tubule is lined with a single layer of glandular, epithelial cells having microvilli. Their distal, portion is secretory and proximal part is, absorptive in function. They extract water and, nitrogenous wastes from the haemocoel and, convert them into uric acid and pass them into, ileum. As the cockroach excretes uric acid, it is, said to be uricotelic. In addition, the fat bodies,, nephrocytes and uricose glands (in male, cockroach only) also help in excretion., , 132

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In cockroach, urate cells (nephrocytes), associated with fat bodies and cuticle are, also believed to be excretory in function. The, nephrocytes are cells present along with the, fat bodies or present along the heart and store, nitrogenous wastes. The excretory products, later are removed in the haemocoel. Some, nitrogenous wastes are deposited on the cuticle, and eliminated during moulting., Nervous system :, The nervous system of cockroach, consists of Central Nervous System (CNS),, Peripheral Nervous System (PNS), and, Autonomus Nervous System (ANS). Nervous, system of cockroach is ventral, solid and, ganglionated., A. Central Nervous System (CNS):, CNS consists of nerve ring and ventral, nerve cord. Nerve ring is made up of supraoesophageal ganglia, circum-oesophageal, connective and sub-oesophageal ganglion., A pair of supra-oesophageal / cerebral, ganglia is collectively known as brain. Brain, is present in head, above the oesophagus, and between antennal bases. Each cerebral, ganglion is formed by fusion of three small, ganglia- protocerebrum, deutocerebrum and, tritocerebrum., Sub-oesophageal ganglion is bilobed;, present below the oesophagus in head. It is also, formed by fusion of 3 pairs of ganglia., Cerebral ganglia are connected to suboesophageal ganglion by a pair of lateral nerves, called as circum-oesophageal connectives., Connectives arise from cerebral ganglia., Ventral nerve cord (VNC) : It arises, from sub-oesophageal ganglion. It is present, along mid-ventral position, in perineural sinus., It is double nerve cord and consists of nine, segmental, paired ganglia. First three pairs, of segmental ganglia are large and known as, thoracic ganglia. Six pairs of segmental ganglia, are in abdomen. Sixth abdominal ganglion, is largest and it is present in 7th abdominal, segment. There is no ganglion in 6th segment., , Brain or supra oesophageal, ganglion, Circumoesophageal, connective, Suboesophageal, ganglion, Prothoracic, ganglion, Ventral nerve cord, Mesothoracic, ganglion, Metathoracic, ganglion, , 11.9, , Optic nerve, Antennary nerve, Labrofrontal nerve, Mandibular nerve, Maxillary nerve, Labial nerve, Prothoracic nerves, Mesothoracic, nerves, Metathoracic, nerves, 1st abdominal, ganglion, Abdominal nerves, 6th abdomibal, gangliaon, , Fig. 11.13 Central Nervous System, B. Peripheral Nervous System (PNS):, Peripheral nervous system consists of, nerves arising from various ganglia of CNS., Six pairs of nerves arise from cerebral ganglia., They go to eyes, antennae and labrum. Nerves, arising from sub-oesophageal ganglion go, to mandibles, maxillae and labium. Nerves, arising from thoracic ganglia go to the wings,, legs and internal thoracic organs. Nerves from, abdominal ganglia go to the abdominal organs, of respective abdominal segments., C. Autonomous Nervous System (ANS):, It consists of four ganglia and a retrocerebral, complex. These ganglia are as follows., 1. Frontal ganglion : It is present above the, pharynx and in front of brain., 2. Hypocerebral ganglion : It is present on the, anterior region of oesophagus., 3. Ingluvial ganglion : It is present on crop. It, is also called as visceral ganglion., 4. Ventricular ganglion : It is present on, gizzard., Sense organs :, Collect the information and complete, the chart:, Sense Organ, Location, Function, 1. Antennae, 2. Eyes, 3. Maxillary palp, 4. Labial palp, 5. Anal Cerci, , 133

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Knowledge Enhancer : Compound eyes, are present in the cockroach, situated on the, dorsal surface of the head. Each eye consists, of about 2000 hexagonal ommatidia (singular, : Ommatidium). Each ommatidium is like, a simple eye, forming image independently,, hence with the help of several ommatidia, a, cockroach receives several images of an object., Compound eye gives mosaic or hazy vision,, but the animal is able to detect even a slightest, movement of the object. This kind of vision is, with more sensitivity but less resolution., 11.10 Reproduction system :, Cockroach is dioecious organism i.e., male and female individuals are separate., 1. Male Reproductive System : Male, reproductive system consists of primary and, secondary reproductive organs. Primary, sex organs (male gonads) are called testes, which are paired and located in the 4th to 6th, abdominal segments. They produce sperms, which are carried by vasa deferentia. It is a, pair of thin tubular structure arising from the, testes and opening into the ejaculatory duct, through seminal vesicle. They carry sperms to, the ejaculatory duct. Ejaculatory duct opens, into male gonopore situated ventral to anus., Mushroom shaped gland or Utricular, gland is accessory reproductive gland. It is, present in the 6th to 7th abdominal segments., Male gonapophyses or phallomere are, external genitalia of male. These are three, asymmetrical chitinous structures surrounding, the male gonophore., , The sperms produced by the testes are, stored in seminal vesicles and are glued together, in the form of bundles called spermatophores., These spermatophores are deposited in female, reproductive tract during copulation., 2. Female Reproductive System : Female, reproductive system consists of primary and, secondary reproductive organs. Primary, reproductive organs are ovaries. There is a pair, of large ovaries, lying laterally in the 2nd to 6th, abdominal segments. Each ovary is formed, of a group of 8 ovarian tubules or ovarioles,, containing a chain of developing ova., All ovarioles of an ovary open in lateral, oviduct of respective side. Both lateral oviducts, unite to form common oviduct or vagina., Common oviduct or vagina opens into the, genital chamber (bursa copulatrix), the female, organ of copulation., A sperm storing structure called, spermatheca is present in the 6th segment that, open into the genital chamber. Besides, paired, accessory glands-collaterial glands are also, present that open in genital chamber., Female gonapophyses consist of six, chitinous plates surrounding the genital pore., , Spermatheca, , Testis, , Gonapophyses, , Phallic gland, Small tubules, , Left, phallomere, Pseudopenis, Titillator, , Long tubules, Seminar vesicle, Vas deferens, Ejaculatory duct, Right phallomere, Ventral phallomere, Anal cercus, Caudal style, , Fig. 11.14 Male Reproductive System, , Ovary, Oviduct, Common, oviduct, or vagina, Collaterlal, glands, Genital, Vestibulum chamber, , Fig. 11.15 Female Reproductive System, Fertilization and formation of ootheca :, Male and female cockroaches come, together by their posterior ends and with the, help of phallomeres. The spermatophores are, transferred to the genital chamber of female, cockroach., , 134

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The sperms are released from, spermatophore and they reach the spermatheca., The eggs are discharged from both the ovaries, alternately into the common oviduct and, pass into the genital chamber where they, are fertilized by the sperms coming from the, spermatheca. The process of fertilization is, internal., Ootheca : The secretion of collaterial glands, forms a capsule around them is called as, ootheca or egg case. Ootheca is dark reddish, to blackish brown capsule about 8 mm long,, containing 14 to 16 fertilized eggs in two rows., Ootheca are dropped or glued to a suitable, surface like a crack or crevice of good humidity, near the food source. On an average, a female, produces 9 to 10 oothecae., Development of Eggs : The development of, Periplaneta americana is paurometabolous i.e., there is development through nymphal stage., Embryonic period varies as per temperature, and humidity. At 24oC, duration is about 58, days and at 30oC, the duration is about 32 days., Fertilized egg, , Nymph, , Adult, , The nymph looks like the adult but, far smaller and is sexually immature. After, sufficient growth, nymph undergoes moulting, and enters into next instar (a stage between two, successive moults)., American, , Oriental, , Smokey, brown, , German, , Cockroach may undergo moulting for, about 13 times before reaching the adult stage., The nymphal stages have wing pads but only, adult cockroaches have wings., 11.11 Interactions with mankind :, 1. Cockroach causes damage to the household, materials like clothes, shoes, paper etc. They, also eat and destroy the food stuff., 2. They contaminate food which gives typical, smell and make it unpalatable., 3. As they live in sewage pipes and gutter, holes, they carry with them harmful pathogens, causing diseases like cholera, diarrhoea,, tuberculosis, typhoid, etc., 4. Cockroach serves as a part of food chain, also. Many amphibians, birds, lizards and, rodents prey upon them making them a part of, food chain. They are eaten by certain groups of, people in South America, China and Myanmar., 5. Cockroach is used as experimental animal, in laboratories and for biological research, as, they can be obtained easily without causing, damage to ecological balance., Control Measures : As cockroach is, economically harmful organism it must be, controlled in an efficient way. Some of the, measures are as follows :, 1. Good Sanitation : Dark and humid places, of kitchen, cupboards, trolleys must be cleaned, regularly. Cracks and crevices and such areas, must be filled. There should not be any place in, a home, where accumulation of garbage may, take place., Cockroaches frequently enter home by, migrating up from sewer connections if the, drain trap is dry. So always keep the drain trap, filled with water., , Fig. 11.16 Cockroach Development stages, , 2. Chemical control : Organophosphates,, carbamates, pyrethroids and boric acid are, efficient poisons of cockroaches, various types, of their formulations are available in market,, under various brand names., , 135

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·, , Internet my friend, , Do you know ?, , Cockroaches are considered as bioindicators! Their presence indicate unhygienic, conditions., , Collect the information about, techniques and objectives of rearing the, cockroaches in countries like China and, make a powerpoint presentation including, video clips., , Interesting information :Different insects feed upon different types of food materials. Ex : Butterflies feed, upon nectar, mosquito (female) and bedbugs on human blood, mantis on other animals, etc., Depending upon nature of food and feeding habits, different insects have different, types of mouthparts. Collect images of different mouthparts and paste in appropriate, boxes., , Siphoning mouth parts, (Butterfly), , Sponging mouthpart, (Housefly), , Piercing and sucking, mouthpart, (female mosquito), , Piercing and sucking, (bed bug), , Chewing and biting, ( praying mantis ), , Chewing and lapping, (honey bee), , 136

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Exercise, 1. Choose correct option, A. Chemical nature of chitin is ............., a. protein., b. carbohydrate., c. lipid., d. glycoprotein., , G. Describe the, cockroach., , B. Cockroach has ................ type of, mouthparts., a. sponging, b. chewing and biting, c. piercing and Sucking, d. lapping, C. Spiracle is a part of .................... system, of cockroach., a. circulatory, b. respiration, c. reproductive, d. nervous, D. ................... is a part of digestive system., a. Trachea, b. Hypopharynx, c. Haemocyte d. Seminal vesicle, E. ..................... is also called as brain of, cockroach., a. Supra-oesophageal ganglion, b. Sub-oesophageal ganglion, c. Hypo-cerebral ganglion, d. Thoracic ganglion, digestive, , system, , of, , 3. Answer the following questions, A. How will you identify male or female, cockroach?, B. Write a note on : Gizzard of cockroach., C. Give the systematic position of cockroach., D. What would have happened if cockroach, did not had gizzard?, E. What is the functional difference between, eyes of cockroach and human being?, F. What is the functional difference between, respiratory systems of cockroach and, human being?, 4. Explain the following in short, A. What are anal cerci?, B. What is the ganglion?, C. What is the role of hypopharynx?, D. What is mesenteron?, E. Location of turgum., F. What is ootheca?, , 2. Answer the following questions, A. Describe the, cockroach., , cirulatory, , system, , G. How many chambers are present in heart, of cockroach?, , of, , B. Give an account on tracheal system of, cockroach?, C. Describe nervous system of cockroach., D. With help of neat labelled diagram,, describe female reproductive system of, cockroach., , Practical / Project :, Visit to nearest sericulture farm and, study the life cycle of silk worm., , E. With help of neat labelled diagram,, describe the digestive system of, cockroach., F. A student observed that the cockroaches, are killed for dissection by simply putting, them in soap water. He inquired whether, soap is so poisonous. Teacher said it is, due to its peculiar respiratory system., How?, , 137

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12. Photosynthesis, Can you recall?, 1. Why energy is essential in different life, processes?, 2. How do we get energy?, , Use your brain power, Justify: All life on earth is 'bottled solar energy'., , Photosynthesis is the only process on, earth by which solar energy is trapped by green, plants and converted into food. Photosynthesis, may be defined as synthesis of carbohydrates, ( glucose) f rom inorganic materials like CO2, and H 2 O w ith the help of solar energy trapped, by pigments like chlorophyll., 6CO2 + 12H2O, , Light, , Chloroplast, , Internal membrane, Plastoglobule, Intermembrane space, Ribosome, External membrane, Granum, Chloroplast, DNA, , C6H12O6 + 6O2 + 6H2O, , This process is unique to green plants, and is the final light energy trapping process, on which all life ultimately depends. It is one, of the most massive chemical processes going, on earth., Atmosphere contains only about 0.03, percent carbon dioxide by volume. This small, percentage represents 2200 billion tons of CO2, in the atmosphere. The oceans contain over, 50 times by amount of atmospheric CO2 in the, form of dissolved gas or carbonates. From these, two sources, about 70 billion tons of carbon is, fixed by the green plants annually., 12.1, , All the pigments chlorophylls, carotenes, and xanthophylls are located in the thylakoid, membranes. These pigments absorb light of, a specific spectrum in the visible region. The, pigments are fat soluble and located in the lipid, part of the membrane. With the help of certain, enzymes, they participate in the conversion, of solar energy into ATP and NADPH. The, enzymes of stroma utilize ATP and NADPH to, produce carbohydrates., , Chloroplasts :, These are mainly located in the, mesophyll cells of leaves. The CO2 reaches, them through the stomata and water reaches, them through veins. In higher plants, the, chloroplasts are discoid or lens-shaped. Each, chloroplast is bounded by double membrane., Inside the membranes is found a ground, substance, the stroma. Inside the stroma is, found a system of chlorophyll bearing doublemembrane sacs or lamellae. These are stacked, one above the other to form grana (singular,, granum). Individual sacs in each granum are, known as thylakoids., , Stroma, Thylakoid, Thylakoid, Lumen membrane, Lamella, Thylakoid, , Stroma lamellae, , Fig. 12.1 Chloroplasts, Two predominant types of chlorophylls :, Chlorophyll a and b differ in the, nature of groups. Chlorophyll a has a, methyl group (-CH3) while chlorophyll b, has an aldehyde group (-CHO). Chemically, chlorophyll molecule consists of two parts, head of tetrapyrrol the Porphyrin ring and a, long hydrocarbon tail called phytol attached, to the porphyrin group. Carotenoids are lipid, compound present universally in almost all the, higher plants and several micro-organisms., They are usually red, orange, yellow, brown,, and are associated with chlorophyll. They are, of two types - the carotenes and xanthophylls., The carotenes (C40H56) are orange red and, xanthophylls contain oxygen. The light energy, absorbed by the carotenoids is transferred to, chlorophyll a to be utilized in photosynthesis., , 138

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12.2, , Nature of Light :, Light is a form of energy. It travels, as stream of tiny particles called photons. A, photon contains a quantum of light. Light has, different wavelengths having different colors., One can see electromagnetic radiation with, wavelengths ranging from 390nm to 730nm., This part of the spectrum is called the Visible, light. It lies between wavelengths of ultraviolet, and infra-red., , Internet my friend, Collect information : Why does chlorophyll, appear red in reflected light and green in, transmitted light?, , Activity 1, Grind the spinach leaves in small, quantity of acetone / nail paint remover. Mix, the contents properly and filter with filter, paper in test-tube. Test-tube contains green, filtrate. Take the test-tube in dark-room, and put a flash of torch on it. Now, solution, appears red. Why does this occur? Which, phenomenon is this? Discuss this with your, physics, chemistry and biology teachers., , Activity 2, To separate the chloroplast pigments, by paper chromatography. Concentrate the, extracted chlorophyll solution by evaporation., Apply a drop of it at one end, 2cm away from, edge of a strip of chromatography paper and, allow it to dry thoroughly. Take a mixture of, petroleum ether and acetone in the ratio of 9 :, 1 at temperature of 40 to 600C. Hang the strip, in the jar with its loaded end dipping in the, solvent. Close the jar tightly and keep it for, an hour. The pigments separate into distinct, green and yellow bands of chlorophyll and, carotenoid respectively., , Fig. 12.2 Electromagentic spectrum of light, , Can you tell?, Tomatoes, carrots and chillies are red, in colour due to presence of pigments. Name, the pigment., All photosynthetic plants have these, pigments that absorb light between the red and, blue region of the spectrum. Carotenoids found, mainly in higher plants absorb primarily in the, violet to blue regions of the spectrum. They, not only absorb light energy and transfer it to, chlorophyll but also protect the chlorophyll, molecule from photo-oxidation., , Absorption of light, , Absorption and Action spectrum : All the, pigments of the chloroplast absorb light quanta, or photons and transfer the absorbed energy to, chlorophyll a. The amount of light absorbed at, each wavelength can be shown in the form of, a graph. It shows different curves at different, wavelengths. Such a curve which shows the, amount of light absorbed at each wavelength is, termed as Absorption spectrum., , 139, , Wavelength X axis, , Graph 12.3 Absorption spectrum

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The absorption spectrum of chlorophyll, a and b clearly shows that more light energy is, absorbed at blue, violet and red wavelengths, of the visible spectrum. The relative rate, of photosynthesis at different wavelengths, indicates close relationship with absorption, spectrum of chlorophyll a and b. This curve that, shows the rate of photosynthesis at different, wavelengths is called Action Spectrum., Action spectrum of photosynthesis, differs from the absorption spectrum. There, is quite a lot of photosynthetic activity even, in parts of the spectrum where chlorophyll, a absorb little light. This infers that the light, energy absorbed by other pigments (yellow, and orange carotenoids and also other forms of, chlorophyll) is transferred to chlorophyll a., , Light absorbed, , Rate of photosynthesis, Absorption, , C6H12O6 + 6H2O + 12S ↓, , 6CO2 + 12H2S, , This led Van Neil to postulate that in, green plants, water is utilized in place of H2S, and O2 is evolved in place of sulphur. Ruben (in, 1941) confirmed it in Chlorella. He used water, labeled with heavy oxygen (18O2) i.e. H218O., e-, , eeCHL, , CHL, , Original orbit, Photon, Ground state Excited state, , CHL+, , Ionized chlorophyll-a, , Fig. 12.5 Photoexitation of chlorophyll-a, , The oxygen evolved contain 18O2, thereby proving Van Neil’s hypothesis that, oxygen evolved in photosynthesis comes from, water. This leads to the currently accepted, general equation of photosynthesis Light, 6CO2 + 12H218O, , C6H12O6+ 6H2O + 6 18O2, , In 1937, R. Hill demonstrated that, isolated chloroplasts evolved oxygen when, they were illuminated in the presence of a, suitable electron acceptor such as f erricyanide., Ferricyanide is reduced to ferrocyanide by, photolysis of water. This is called Hill reaction., , 600, 700, 400, 500, Wavelength of light in nanometers (nm), , Graph 12.4 Action spectrum of, photosysnthesis, , Can you tell?, 1. What made Hill to perform his experiment?, 2. Distinguish between action spectrum and, absorption spectrum., 3. Draw well labeled diagram of chloroplast., , Think about it, , Large number of, gas bubbles are evolved during day time in a, pond of water., , Use your brain power, The photosysthetic lamellae taken, out from a chloroplast and suspended in a, nutrient medium in the presence of CO2 and, light. Will they synthesize sugar or not?, 12.3, , Mechanism of Photosynthesis :, In 1931, Van Neil proved that bacteria, used H2S and CO2 to synthesize carbohydrates, as follows :, , Thus Hill reaction proves that :, i. In photosynthesis, oxygen is released from, water., ii. Electrons for the reduction of CO2 are, obtained from water., According to Arnon, in this process, light energy is converted to chemical energy., This energy is stored in ATP and NADPH is, formed as hydrogen donor. This ATP formation, is known as photophosphorylation., , 140

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In modern concept, the process of, photosynthesis is an oxidation and reduction, process in which water is oxidized (to release, O2) and CO2 is reduced to form sugar. It, consists of two successive series of reactions., The first reaction requires light and is called, L ight or H ill reaction. Second reaction does not, require light and is called Dark or Blackman, reaction. Of the two reactions, the former is a, photochemical reaction, while the latter is a, biochemical reaction., Think about it, Does moon light support photosynthesis?, 12.4, , Light reaction :, In light reaction, solar energy is, trapped by chlorophyll and stored in the form, of chemical energy as ATP and in the form of, reducing power as NADPH2. Oxygen is evolved, in the light reaction by splitting of water., When a photon is absorbed by, chlorophyll molecule, an electron is boosted, to higher energy level. To boost an electron, a, photon must have a certain minimum quantity, of energy called quantum energy. A molecule, that has absorbed a photon is in energy rich, excited state. When the light source is turned, off, the high energy electrons return rapidly to, their normal low energy orbitals as the excited, molecule reverts to its original stable condition,, called the ground state., Reaction centre : The light absorbing pigments, are located in the thylakoid membranes. They, are arranged in clusters of chlorophyll and, accessory pigments along with special types, of chlorophyll molecules P680 and P700 (the, letter P stands for Pigment and 680 and 700, for the wavelengths of light at which these, molecules show maximum absorbance). P680, and P700 molecules form the Reaction centers, or Photocenters., The accessory pigments and other, chlorophyll molecule harvest solar energy, and pass it on the reaction centers. These are, called L ight harvesting or Antenna molecule., They function to absorb light energy, which, they transmit at a very high rate to the reaction, center where the photochemical act occurs., , Photosystems I and II : The thylakoid, membranes of chloroplasts have two kinds, of photosystems, each with its own set of, light harvesting chlorophyll and carotenoid, molecules. Chlorophyll and accessory pigments, help to capture light over larger area and, pass it on to the photocenters. Thus, a photon, absorbed anywhere in the harvesting zone, of a P680 center can pass it energy to the P680, molecule. The cluster of pigment molecules, which transfer their energy to P680 absorb at, or below the wavelength 680nm. Together, with P680 they form Photosystem- I I or PS- I I ., Likewise, P700 forms Photosystem- I or PS- I, along with pigment molecule which absorbs, light at or below 700nm., Photosystem II : This system brings about, photolysis of water and release of oxygen. In, this act, when PS-II absorbs light, electrons are, released and chlorophyll molecule is oxidized., The electrons emitted by P680 (PS-II) are, ultimately trapped by P700 (PS-I)., , Fig. 12.6 ATP synthesis through chemiosmosis, , The oxidized P680 regains its electrons, by the photolysis of water as follows:, 4H2O, , 4H+ + 4OH-, , 4OH-, , 4(OH) + 4e-, , 4OH, , 2H2O + O2, , 4H2O, , 2H2O + O2 ↑ + 4H+ + 4e-, , 141

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Oxygen is given out as byproduct by, the photosynthesizing plants. Protons (H+), accumulate inside the thylakoid resulting in a, Proton gradient., The energy released by the protons when, they defuse across the thylakoid membrane, into the stroma against the H+ concentration, gradient is used to produce ATP., Photosystem I : When light quanta are, absorbed by photosystem I (P700), energy rich, electrons are emitted from the reaction center., These flow down a chain of electron carriers, to NADP along with the proton generated by, splitting of water. This result in the formation, of NADPH., Hydrogen attached to NADPH is used, for reduction of CO2 in dark reaction. This is, also called Reducing pow er of the cell., , The, cyclic, electron-flow, is, accompanied by the photophosphorylation of, ADP to yield ATP. This is termed as Cyclic, photophosphorylation. Since this process, involves only pigment system I, photolysis of, water and consequent evolution of oxygen does, not takes place., ii., Non-cyclic photophosphorylation :, It involves both PS-I and PS-II, photosystems. In this case, electron transport, chain starts with the release of electrons from, PS-II. In this chain high energy electrons, released from PS-II do not return to PS-II but,, after passing through an electron transport, chain, reach PS-I, which in turn donates it, to reduce NADP+ to NADPH. The reduced, NADP+ (NADPH) is utilized for the reduction, of CO2 in the dark reaction., , 12.5, , Photophosphorylation :, Formation, of, ATP, in, the, chloroplasts in presence of light is called, photophosphorylation. It takes place in the two, forms., i. Cyclic photophosphorylation :, Illumination of photosystem-I causes, electrons to move continuously out of the, reaction center of photosystem-I and back to it., Fig. 12.8 Non-cyclic photophosphorylation, , FRS, Ferredoxin e, e, , ADP+Pi, , e-, , ATP, , Cytochrome b6, e- ADP+Pi, , e-, , ATP, , 2e-, , Cytochrome f, e-, , e-, , Plastocyanin, ePS I, , Light energy, , Fig. 12.7 Cyclic photophosphorylation, , Electron-deficient PS-II brings about, oxidation of water-molecule. Due to this,, protons, electrons and oxygen atom are, released. Electrons are taken up by PS-II itself, to return to reduced state, protons are accepted, by NADP+ where as oxygen is released., As in this process, high energy electrons, released from PS-II do not return to PS-II and, it is accompanied with ATP formation, this is, called N on- cyclic photophosphorylation., Thus, during the photochemical, reactions, photolysis of water takes place, O2 is, released and ATP and NADPH are synthesized., ATP and NADPH molecules function as, vehicles for transfer of energy of sunlight into, dark reaction leaving to carbon fixation. In this, reaction CO2 is reduced to carbohydrate., , 142

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The light reaction gives rise to, two important products : i. A reducing agent, NADPH and ii. An energy rich compound ATP., Both these are utilized in the dark phase of, photosynthesis., Dark reaction :, Carbon fixation occurs in the stroma by, a series of enzyme catalyzed steps. Molecules, of ATP and NADPH produced in the thylakoids, (light reaction) come in the stroma where, carbohydrates are synthesized., The path of carbon fixation in dark, reaction through intermediate compounds, leading to the formation of sugar and starch, was worked out by Calvin, Benson and their, co -workers. For this, Calvin was awarded, N obel Priz e in 1961., Path of carbon was studied with the help, of radioactive tracer technique using Chlorella,, a unicellular green alga and radioactive 14CO2., With the help of radioactive carbon, it becomes, possible to trace the intermediate steps of, fixation of 14CO2. The various steps in the dark, reactions (Calvin cycle / C-3 pathway, fig., 12.10) are as follows:, , Thylakoid, , ADP, , Carbon Dioxide, , NADP+, ATP, , Light, Reactions NADPH, , Granum, , 12.6, , 1. Carboxylation : CO2 reduction starts with, a 5-carbon sugar, ribulose-1,5-bisphosphate, (RuBP). It is a 5-carbon sugar (pentose) with, two phosphate groups attached to it., RuBP reacts with CO2 to produce a short, - lived 6-carbon intermediate in the presence of, an enzyme RuBP carboxylase or Rubisco and, immidiately splits into 3-carbon compound,, 3-phosphoglyceric acid (3-PGA). Rubisco is a, large protein molecule and comprises 16% of, the chloroplast proteins., 2. Glycolytic Reversal : Molecules of 3-PGA, form 1,3-diphosphoglyceric acid utilizing ATP, molecules. These are reduced to glyceraldehyde3-phosphate (3-PGAL) by NADPH supplied by, the light reactions of photosynthesis., For the Calvin cycle to run continuously,, , Light + Water, , Dark, Reactions, , Stroma, Oxygen, , Glucose, , Fig. 12.9 Relation between light, and dark reaction, , there must be sufficient amount of RuBP which, accepts CO2 and a regular supply of ATP, and NADPH. Out of each of 12 molecules, of 3-phosphoglyceraldehyde (3-PGAL), 2, molecules are used for synthesis of one glucose, molecule and remaining 10 molecules are used, for regeneration of 6 molecules of RuBP., 3. Regeneration of RuBP : Through a series of, complex reactions, 10 molecules of 3-PGAL are, used for regenration of six molecules of RuBP, at the cost of 6 ATP. For this purpose, six turns, of Calvin cycle are needed to be operated so, that a molecule of glucose can be synthesized., Plants form a variety of organic, compounds required for its structure and, function through these complex reactions., Thus, for every 6 molecules of CO2 and, Ribulose-1, 5-biphosphate used, 12 molecules, of 3-phosphoglyceraldehyde are produced. Out, of these 12 molecules, only two are utilized, for the formation of a molecule of glucose;, the other 10 molecules are converted into, ribulose-1, 5-biphosphate which combines with, fresh CO2., Thus, the Calvin cycle regenerates ADP, and NADP required for the light reaction., i. Light Reaction (in granum) :, 1. 24H2O, , 24OH- + 24H+, , 2. 24OH-, , 24OH + 24e-, , 3. 24e- + 24H+ + 12NADP+, 4. 18ADP + 18Pi, 5. 24OH, , 143, , 12NADPH, 18ATP, , 12H2O + 6O2 ↑

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CO2 (6 M), , (6 M, , (6 M, , ) AD, , ) ATP, , RUBISCO, ) (6 M, ), , 6 RuB, , P (5 C, , P, , CAR, , Unstable compound (6 M, 6 C), , BOX, , 6 RuMP (5 C, 6 M), , YLA, TIO, , RE, , N, , GE, , Ribose-5-phosphate (5 C, 4 M), , IO, N, , NE, , e, ulos, Xyl, , CT, DU, , ADP (12 M), 1, 3-diphosphoglycerate (12 M, 3 C), NADPH (12 M), , ), , C, te (5, , spha, , ho, -5-p, , RE, , Erythrose-4-phosphate (4 C), , N, , TIO, RA, , Sedoheptulose-7-phosphate (7 C, 4 M), , 3-phosphoglycerate (12 M) (3 C), ATP (12 M), , 3-phosphoglyceraldehyde, (12 M) (3 C), , NADP+ (12 M), , SYNTHESIS, , Dehydroxy Acetone Phosphate (3 C, 2 M), , Fructose-1, 6-diphosphate (1 M, 6 C), ADP, ATP, , Fructose-6-phosphate (1 M, 6 C), ADP, ATP, , Glucose-6-phosphate (1 M, 6 C), , Glucose (1 M, 6 C), Fig. 12.10 Schematic Presentation of C-3 Pathway / Calvin cycle, , 144

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ii. Dark reaction (in stroma) :, , O2, , (i + ii) 6CO2 + 24H2O, , Light, Chloroplast, , Chloroplast, , C6H12O6, 6CO2 + 18ATP + 12NADPH, + 6H2O + 18ADP + 18Pi + 12NADP+, C6H12O6 +, , 18H2O + 6O2 ↑, , Phosphoglycolate + PGA, , RuBP, PCR, cycle, , PGA, , Pi, ADP, , Glyoxylate, , ATP, Glycerate, , Can you tell?, , Photorespiration :, Photorespiration occurs under the, conditions like high temperature, bright light,, high oxygen and low CO2 concentration. It is a, wasteful process linked with C3-Cycle, where, instead of fixation of CO2 it is given out., It involves three organelles chloroplast, peroxisomes and mitochondria and occurs, in a series of cyclic reactions which is also, called PCO cycle. Enzyme Rubisco acts as, oxygenase at higher concentration of O2 and, photorespiration begins. When RuBP reacts, with O2 rather than CO2 to form a 3-carbon, compound (PGA) and 2-carbon compound, phosphologycolate. Later is converted to, glycolate which is shuttled out of the chloroplast, into the peroxisomes., In peroxisomes, enzyme glycolate, oxidase converts glycolate into glyoxylate,, which is converted into amino acid glycine, by transamination. In mitochondria, two, molecules of glycine are converted into serine, (amino acid) and CO2 is given out. Thus, it, looses 25% of photosynthetically fixed carbon., Serine is transported back to peroxisomes and, converted into glycerate. It is shuttled back to, chloroplast to undergo phosphorylation and, utilized in formation of 3-PGA, which get, utilized in C3 pathway., , Mitochondrion, , Peroxisome, , 1. How chlorophyll - a is excited? Show it, with a diagram., 2. Describe Calvin's cycle., 3. Draw a flowchart of non-cyclic, photophosphorylation., 12.7, , Glycerate, NAD+, NADH, Hydroxy pyruvate, , Glyoxylate, Glyoxylate + H2O2, , Serine, , Glycine, , Serine, , Glycine, NH3, CO2, , NADH, , NAD+, , Fig. 12.11 Photorespiration, , 12.8, , C4 pathway or Hatch-Slack pathway :, M. D. Hatch and C. R. Slack while, working on sugarcane found four carbon, compound (dicarboxylic acid) as the first stable, product of photosynthesis. It has been found, to occur in tropical and sub-tropical grasses, and some dicotyledons. Some of the important, plants are sugarcane, maize, Sorghum etc., The plants in which CO2 fixation takes, place by Calvin cycle are called C3 plants,, because first product of CO2 fixation is a, 3-carbon phosphoglyceric acid. But in HatchSlack pathway, first product of CO2 fixation is, a 4-carbon compound, oxaloacetic acid. Hence, such plants are called C4 plants., Anatomy of leaves of C4 plants is, different from leaves of C3 plants. C4 plants, show K ranz anatomy. In the leaves of such, plants, palisade tissue is absent. There is a, bundle sheath around the vascular bundles., The chloroplasts in the bundle - sheath cells, are large and without or less developed grana,, where as in the mesophyll cells the chloroplasts, are small but with well-developed grana., , 145

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Fig. 12.12 Kranz anatomy of C4 plant, CO2 taken from atmosphere is accepted, by a 3-carbon compound, phosphoenolpyruvic, acid in the chloroplasts of mesophyll cells,, leading to the formation of 4-C compound,, oxaloacetic acid with the help of enzyme pepco., It is converted to another 4-C compound, the, malic acid. It is transported to the chloroplasts, of bundle sheath cells. Here, malic acid (4-C) is, converted to pyruvic acid (3-C) with the release, of CO2 in the cytoplasm. Thus concentration of, CO2 increases in the bundle sheath cells., Chloroplasts of these cells contain, enzymes of Calvin cycle. Because of high, concentration of CO2, RuBP carboxylase, participates in Calvin cycle and not, photorespiration. Sugar formed in Calvin cycle, is transported into the phloem., , Pyruvic acid generated in the bundle, sheath cells re-enters mesophyll cells and, regenerates phosphoenolpyruvic acid by, consuming one ATP., Since this conversion results in the, formation of AMP (not ADP), two ATP are, required to regenerate ATP from AMP. Thus, C4 pathway needs 12 additional ATP. The C3, pathway requires 18 ATP for the synthesis of, one glucose molecule, whereas C4 pathway, requires 30 ATP., Thus, C4, plants, are, better, photosynthesizers, and, there, is, no, photorespiration in these plants., 12.9, , CAM-Crassulacean Acid Metabolism:, It is one more alternative pathway of, carbon fixation found in desert plants. It was first, reported in the family Crassulaceae, so called, as CAM (Crassulacean Acid Metabolism)., In CAM plants, stomata are scotoactive, i.e. active during night, so initial CO2 fixation, occurs in night., Thus C4 pathway fix CO2 at night and, reduce CO2 in day time via the C3 pathway by, using NADPH formed during the day. PEP, caboxylase and Rubisco are present in the, mesophyll cell (no K ranz anatomy)., Formation of malic acid during dark is, called acidification (phase I)., , Atmospheric CO2, Mesophyll cell, NADP+ NADPH, Malate, , AMP, , ATP, , PhosphoenolOxaloacetate, PEP, Malate, pyruvate (PEP), Pyruvatecarboxylase, dehydrogenase, phosphate dikinase, , Malic enzyme, , Pyruvate, , NADP+ NADPH + CO2, Bundle sheath cell, , Calvin cycle, , Fig. 12.13 C4 Pathway, , 146

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Malate is stored in vacuoles during, the night. Malate releases CO2 during the day, for C3 pathway within the same cell is called, deacidification (phase II)., Examples of CAM plants : K alanchoe, Opuntia,, Aloe etc., The Chemical reactions of the carbon, di-oxide fixation and its assimilation are similar, to that of C4 plants., C3 acid, CalvinBenson, cycle, , Stomata, closed, , CO2, Decarboxylation, , RUBISCO, , Starch, , Day, , Secondary, carboxylation, , C4 acid, , ATP, AMP, , PEP, , Pi, PEPC, , CO2, , HCO3-, , Primary, carboxylation, , Rate of photosynthesis, , Stomata, open, , In most of the plants, photosynthesis, is maximum in bright diffused sunlight. It, decreases in strong light and again slows down, in the light of very low intensity. It has also, been found that uninterrupted and continuous, photosynthesis for relatively long periods of, time may be sustained without any visible, damage to the plant., Carbon dioxide : The main source of CO2 in, land plants is the atmosphere, which contains, only 0.3% of the gas. Under normal conditions, of temperature and light, carbon dioxide acts, as a limiting factor in photosynthesis. An, increase in concentration of CO2 increases the, photosynthesis. The increase in CO2 to about, 1% is generally advantageous to most of the, plants. Higher concentration of the gas has an, inhibitory effect on photosynthesis., , C4 acid, Night, , Fig. 12.14 Crassulacean acid metabolism, Can you tell?, 1. C4 plants are more productive. Why?, 2. Xerophytic plants survive in high, temperature. How?, 3. Summarise the photosynthetic reaction., 4. Compare C4 plants and CAM plants., , Carbon dioxide concentration, , Graph. 12.15 Effect of CO2 concentration, , 12.10 Factors affecting Photosynthesis :, Like all other physiological processes,, photosynthesis is also influenced by a number, of factors., A. External Factors :, Light : It is an essential factor as it supplies, the energy necessary for photosynthesis., Both quality and intensity of light affect, photosynthesis. Highest rate of photosynthesis, takes place in the red rays and then come, the blue rays. In a forest canopy the rate of, photosynthesis decreases considerably in plants, growing under the it., , Temperature : Like all other physiological, processes, photosynthesis also needs a suitable, temperature. In the presence of plenty of light, and carbon dioxide, photosynthesis increases, with the rise of temperature till it becomes, maximum. After that there is a decrease or fall, in the rate of the process., The optimum temperature at which the, photosynthesis is maximum is 25 – 300C, though, in certain plants like Opuntia, photosynthesis, takes place at as high as 550C. This is known, as the maximum temperature. The temperature, at which the process just starts is the minimum, temperature., , 147

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Water : Being one of the raw material, water is, also necessary for the photosynthetic process., An increase in water content of the leaf results, in the corresponding increase in the rate of, photosynthesis. Thus the limiting effect of water, is not direct but indirect. It is mainly due to the, fact that it helps in maintaining the turgidity of, the assimilatory cells and the proper hydration, of their protoplasm., B. Internal Factors : Though the presence, of chlorophyll is essential for photosynthesis, but the rate of photosynthesis is proportional, to the quantity of chlorophyll present. It is, because of the fact that chlorophyll merely acts, as a biocatalyst and hence a small quantity is, quite enough to maintain the large bulk of the, reacting substances., The final product in the photosynthesis, reaction is sugar and its accumulation in the, cells slow down the process of photosynthesis., The thickness of cuticle and epidermis of the, leaf, the size and distribution of intercellular, spaces and the distribution of the stomata and, the development of chlorenchyma and other, tissues also affects the rate of photosynthesis., , Significance : This anabolic process uses, inoganic substances and produces food for, all life directly or indirectly. This process, transforms solar energy into chemical energy., The released by product O2 is necessary not, only for aerobic respiration in living organisms, but also used in forming protective ozone layer, around earth. This process is also helping us, in providing fossil fuels, coals, petroleum and, natural gas., , Rate of photosynthesis, , Blackman’s law of limiting factors :, The Blackman’s law of limiting factors, states that when a process is conditioned as to, its rapidity by a number of separate factors, the, rate of the process is controlld by the pace of, the “slowest factor”., , The slowest factor is that factor which is, present in the lowest or minimum concentration, in relation to others. The law of limiting factor, can be explained by taking two external factors, such as carbon dioxide and light. Suppose a, plant photosynthesizing at a fixed light intensity, sufficient to utilize 10mg of CO2 per hour only., On increasing the CO2 concentration,, the photosynthetic rate also goes on, increasing. Now, if the CO2 concentration is, further increased, no increase in the rate of, photosynthesis will be noted. Thus in this case, light becomes the limiting factor. Under such, circumstances, the rate of photosynthesis can be, increased only by increasing the light intensity., This evidently shows that the, photosynthetic rate responds to one factor alone, at a time and there would be a sharp break in the, curve and a plateau formed exactly at the point, where another factor becomes limiting. If any, one of the other factors which is kept constant, (say, light) is increased, the photosynthetic rate, increases again reaching and optimum where, again another factor become limiting., , Light intensity, , Graph. 12.16 Light intensity, and Photosynthesis, , 148

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Exercise, 1. Choose correct option, A. A cell that lacks chloroplast does not, a. evolve carbon dioxide, b. liberate oxygen, c. require water, d. utilize carbohydrates., B. Energy is transferred from the light, reaction step to the dark reaction step by, a. chlorophyll b. ADP, c. ATP, d. RuBP, C. Which one is wrong in photorespiration, a. It occurs in chloroplasts, b. It occurs in day time only, c. It is characteristic of C4-plants, c. It is characteristic of C3-plants, , G. C4 pathway is also called as, dicarboxylation pathway because, a. RuBP + CO2 in bundle sheath cells, b. PEPA + CO2 in mesophyll cells, c. both 'a' and 'b', d. It occurs in presence of intensive light, H. The head and tail of chlorophyll are, made up of, a. porphyrin and phytin respectively, b. pyrrole and tetrapyrrole respectively, c. prophyrin and phyrol respictively, d. tetrapyrole and pyrrole respectively, I., , D. Non-cyclic photophorylation differs, from cyclic photophosphorylation in that, former, a. involves only PS I, b. Include evolution of O2, c. involves formation of assimilatory, power, d. both 'b' and 'c', E. For fixation of 6 molecules of CO2 and, formation of one molecule of glucose in, Calvin cycle, requires, a. 3 ATP and 2 NADPH2, b. 18 ATP and 12 NADPH2, c. 30 ATP and 18 NADPH2, d. 6 ATP and 6 NADPH2, F. In maize and wheat the first stable, products formed in bundle sheath cells, respectively are, a. OAA and PEPA, b. OAA and OAA, c. OAA and 3PGA, d. 3PGA and OAA, , 149, , The net result of photo-oxidation of, water is release of, a. electron and proton, b. proton and oxygen, c. proton, electron and oxygen, d. electron and oxygen, , J. For fixing one molecule of CO2 in Calvin, cycle, are required, a. 3ATP + 1NADPH2, b. 3ATP + 2NADPH2, c. 2ATP + 3NADPH2, d. 3ATP + 3NADPH2, K. In presence of high concentration of, oxygen, RuBP carboxylase converts, RuBP carboxylase converts RuBP to, a. Malic acid and PEP, b. PGA and PEP, c. PGA and malic acid, d. PGA and phosphoglycolate, L. The sequential order in electron transport, from PSII to PSI of photosynthesis is, a. FeS, PQ, PC and Cytochrome, b. FeS, PQ, Cytochrome and PC, c. PQ, Cytochrome, PC and FeS, d. PC, Cytochrome, FeS, PQ

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2. Answer the following questions, A. Describe the light-dependent steps of, photosynthesis. How are they linked to, the dark reactions?, B. Distinguish between:, a. respiration, and photorespiration, b. absorption, spectrum and action spectrum c. cyclic, photophosphorylation and non-cyclic, photophosphorylation, C. What are the steps that are common to C3, and C4 photosynthesis?, D. Are the enzymes that catalyse the dark, reactions of carbon fixation located inside, the thylakoids or outside the thylakoids?, E. Calvin cycle consists of three phases,, what are they? Explain the significance, of each of them., F. Why are the plants that consume more, than the usual 18 ATP to produce 1, molecule of glucose favoured in tropical, regions?, G. What is the advantage of having, more than one pigment molecule in a, photocentre?, H. Why does chlorophyll appear green, in reflected light and red transmitted, light? Explain the significance of these, phenomena in terms of photosynthesis., I. Explain why photosynthesis is considered, the most important process in the, biosphere., J. Why is photolysis of water accompained, with non-cyclic photophosphorylation?, K. In C-4 plants, why is C-3 pathway, operated in bundle sheath cells only?, L. What would have happed if C-4 plants, did not have Kranz anatomy?, M. Why does RnBisCo carry out, preferentially, carboxylation, than, oxygenation in C4 plants?, N. What would have happened if plants did, not have accessoy pigments?, , O. How can you identify whether the plant is, C3 or C4? Explain / Justify., P. In C4 plants, bundle sheath cells carrying, out Calvin cycle are very few in number., Through also, C4 plants are highly, productive. Explain., Q. What is functional significance of Kranz, anatomy?, 3. Correct the pathway and name it, CO2, Mesophyll cell, , Bundle Sheath Cell, OAA, , Malic, Acid, , PEP, , CO2, , C3, pathway, , 4. Is there something wrong in following, schematic presentation? If yes, correct it so, that photosynthesis will be operated, Primary, acceptor, , Primary, acceptor, , Cytochrome, complex, , NADP reductase, , PS-I, ADP, , ATP, , H2O, , PS-II, NADP+, , NADPH, , 2H+ + 1/2 O2 ↑ + 2e, , Practical / Project :, 1. Draw schematic presentation of different, processes / cycles / reactions related to, photosynthesis., 2. Check the effects of different factors on, photosynthesis under the guidance of, teacher., , 150

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13. Respiration and Energy Transfer, Can you recall?, , Respiration is a catabolic process, wherein complex organic substrate is oxidized, to simple components to generate biological, energy. Cellular respiration occurs in two, different ways as anaerobic and aerobic, respiration., , 1. Which nutrients are used for energy, production?, 2. Which is most preferred nutrient among, carbohydrate, protein and fat for energy, production? Why?, 3. Why do organisms take up oxygen and, release carbondioxide?, 4. What is aerobic and anaerobic, respiration?, 5. Which steps are involved in aerobic, respiration?, , 13.2, , Always Remember, 1. Maintenance of life requires continuous, supply of energy., 2. Respiration fulfills the continuous need of, energy., 13.1, , Formation of ATP :, Formation of ATP is called as, phosphorylation. In nature, phosphorylation, occurs in three different ways as, photophosphorylation,, substratelevel, phosphorylation, and, oxidative, phosphorylation. You have already learnt the, photophosphorylation in the photosynthesis., Substrate-level phosphorylation is a, direct phosphorylation of ADP by transfer of a, phosphate group from any suitable substrate. It, occurs in cytoplasm of the cells and matrix of, mitochondria., Oxidative, phosphorylation, is, phosphorylation of ADP at the cost of energy, released during oxidation of substrates like, NADH+H+ and FADH2. This occurs on the, inner mitochondrial membrane only., When energy is required for any, metabolic process, ATP is hydrolysed. ATP, hydrolysis releases the energy which is used for, the metabolic activities., , Anaerobic respiration :, Anaerobic respiration is the cellular, respiration that does not involve the oxygen, at all. It is also called as fermentation. It is, completed through steps like glycolysis and, conversion of glycolytic product to any suitable, product like lactic acid, ethanol, etc., Glycolysis :, Glycolysis involves the breakdown, of glucose molecule into two pyruvic acid, molecules. Hence known as glycolysis. This is, a common step in anaerobic as well as aerobic, respiration. It occurs in cytoplasm of cell. It is, completed in two phases as preparatory phase, and pay-off phase., Overall process of glycolysis is, completed through ten steps. First five steps, constitute the preparatory phase through, which glucose is phosphorylated twice at the, cost of two ATP molecules and a molecule, of fructose 1, 6-bisphosphate is formed., This molecule is split to form a molecule of, glyceraldehyde 3-phosphate and a molecule, of dihydroxyacetone phosphate. Both of these, molecules are 3-carbon carbohydrates (trioses), and are isomers of each other. Dihydroxy, acetone phosphate is isomerised to second, molecule of glyceraldehyde-3-phosphate., Thus, two molecules of glyceraldehyde-3phosphate are formed and here, first phase i.e., preparatory phase of glycolysis ends., In the pay-off phase, both molecules, of glyceraldehyde-3-phosphate are converted, to two molecules of 1, 3-bisphoglycerate, by oxidation and phosphorylation. Here,, phosphorylation is brought about with the help, of inorganic phosphate and not ATP., , 151

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Glucose (6C, 1M), , , ATP, , Mg++, , Glycolysis is under tight control. Its rate, depends upon the requirement of ATP and, many other factors. Glycolytic rate control, is achieved by complex interplay between, ATP consumption, NADH2 regeneration and, regulation of various glycolytic enzymes like, hexokinase, PFK-1, pyruvate kinase, etc. Besides, it is also controlled by hormones like, glucagon, epinephrine and insulin., , Hexokinase, , ADP, , Glucose-6-phosphate (6C, 1M), Phosphohexose isomerase, , , , Fructose-6-phosphate (6C, 1M), Mg++, , , , ATP, , Phosphofructokinase, , ADP, , Use your brain power, , Fructose-1, 6-diphosphate (6C, 1M), Aldolase, , , , Triose phosphate isomerase, Glyceraldehyde-3-phosphate  Dihydroxy acetone phosphate, (3C,1M), , , , (3C,1M), Triose phosphate isomerase, , Glyceraldehyde-3-phosphate (3C, 2M),  2(H PO ), 3, 4, , ( Non-enzymatic, reaction), , 2(NAD+), Zn++, , 2(NADH+H+), , Triose phosphate, dehydrogenase, , 1,3-Bisphosphoglycerate (3C, 2M),  Mg++, , 2ADP, , Phosphoglycerate kinase, , 2ATP, , 3-Phosphoglycerate (3C, 2M), Phosphoglycerate mutase, , , , 2-Phosphoglycerate (3C, 2M), , , Mg++, , 2 H2O, , Enolase, , 2-Phosphoenolpyruvate (3C, 2M),  Mg++, , 2ADP, , Pyruvate kinase, , 2ATP, , Pyruvic acid, Overall reaction of glycolysis:, Glucose+2 ATP+2 iP + 4 ADP +2 NAD+, 2 Pyruvate+2ADP+4ATP+2NADH+H++2H2O, , Both, molecules, of, 1,, 3-bisphosphoglycerate are converted into two, molecules of pyruvic acid through series of, reactions accompanied with release of energy., This released energy is used to produce ATP (4, molecules) by substrate-level phosphorylation., , 152, , 1. What is role of Mg++, Zn++ in various steps, of glycolysis?, 2. Why some reactions of glycolysis are, reversible and some irreversible?, 3. Why is glycolysis considered as, biochemical proof of evolution?, 4. Why do athletes like sprinters have higher, proportion of white muscle fibers?, Do you know?, , 1. Glycolysis, is only source of energy production in, erythrocytes, renal medulla, brain and sperm., 2. Some plant tissues which are modified to, store starch (like potato) mainly depend upon, glycolysis for energy production., 3. In chapter 3, Biomolecules, you have read, about the oxygen storing and transporting, pigment myoglobin of skeletal muscles. Red, (dark) muscles are richer in myoglobin than, the white (pale) muscles. Therefore, red fibers, can utilize the oxygen stored in myoglobin to, continue energy production over prolonged, period by aerobic oxidation of glucose. This, enables them to perform sustained work over, a long period. On the contrary, white fibers, produce the energy needed for very fast and, severe work by glycolysis as sufficient oxygen, is not immediately available to them for such, work. But white muscles accumulate lactic, acid and get fatigued in a short time. Thus, athletes with a higher proportion of red fibers, in their muscles are physiologically better, adapted for sustained events like marathon or, swimming over long distances.

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C6H12O6, Glucose, , Glycolysis, , Glycolysis, , C6H12O6, Glucose, , 2CH3COCOOH + 2NADH+H+, Pyruvic acid, Lactic acid fermentation, , 2CH3CHOHCOOH + 2NAD+, Lactic acid, , 2CH3COCOOH, CO2 ↑ + 2CH3CHO + 2NADH+H+, Pyruvic acid, Acetaldehyde, Alcoholic fermentation, , In muscles, the NADH+H+ produced, during glycolysis is reoxidized to NAD+ by, donating one proton and two electrons to, pyruvic acid which yields lactic acid. Skeletal, muscles usually derive their energy by, anaerobic respiration. After vigorous exercise, lactic acid accumulates, leading to muscle, fatigue. During rest, however, the lactic acid is, reconverted to pyruvic acid and is channeled, back into the aerobic respiration pathway., In yeast, the pyruvate is decarboxylated, to acetaldehyde. The acetaldehyde is then, reduced by NADH+H+ to ethanol. Carbon, dioxide is also produced in this process., This type of anaerobic respiration is termed, alcoholic fermentation. Accumulation of, ethanol by fermentation in a culture of yeast, may stop further multiplication and lead to, the death of cells. In the presence of oxygen, however, yeast can respire aerobically., Aerobic Respiration :, Aerobic respiration involves molecular, oxygen as final electron acceptor which are, liberated during oxidation of glucose. Glucose, is completely oxidized in this process which, is operated through steps like glycolysis,, production of acetyl CoA (connecting link, reaction), Krebs cycle, electron transfer chain, reaction and terminal oxidation., First step of aerobic respiration i.e., glycolysis has been already studied in detail. In, case of aerobic respiration, glycolytic product, i.e. pyruvic acid is converted into actyl CoA., This process occurs in cytoplasm in case of, prokaryotes and in mitochondria in case of, eukaryotes. (For structure of mitochondria, refer, Chapter 5, Cell Sturcture and Organization), , 2C2H5OH, Ethanol, , Conversion of pyruvic acid to Acetyl CoA :, This is an oxidative decarboxylation, reaction. It is catalyzed by a multienzyme, complex - pyruvate dehydrogenase complex, (PDH). This enzyme is present in mitochondria, of eukaryotes and cytosol of prokaryotes., CoA-SH, , NAD+, , NADH+H+, , Acetyl CoA + CO2 ↑, Pyruvic acid, Pyruvate dehydrogenase, complex, , This reaction is called as 'connecting link', reaction between glycolysis and Krebs cycle., Do you know?, Pyruvate dehydrogenase complex, needs thiamin (vitamin B1) as a co-enzyme., It can not function in absence of vitamin, B1. Hence, thiamin deficiency causes, pyruvic acidosis and lactic acidosis, the life, threatening conditions., Hence balanced diet is very important, in maintenance of health., , 13.3, , Krebs Cycle ( TCA cycle/ Citric Acid Cycle):, Pyruvic Acid produced by glycolysis, undergoes aerobic oxidation in the, mitochondrial matrix through the TCA cycle., This cycle serves a common oxidative pathway, for carbohydrates fats and proteins. Moreover,, some intermediates of the TCA cycle are used, in synthesizing important biomolecules such as, glutamate and aspartate., Before participating in the TCA cycle, pyruvic acid enters the mitochondrion. Here it, is decarboxylated and the remaining 2-carbon, fragment is combined with a molecule of, coenzyme A to form acetyl-CoA., , 153

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These carriers and enzymes are, arranged on inner mitochondrial membrane, in the form of various complexes as complex, I, II, III, VI and V. NADH+H+ is oxidised, by NADH dehydrogenase (complex I) and, it's electrons are transferred to ubiquinone, (coenzyme Q CoQ) present on inner membrane, of mitochondria. Reduced ubiquinone is called, as ubiqunol. FADH2 is oxidised by complex II, (Succinate dehydrogenase) and these electrons, are also transferred to CoQ. During oxidation, of NADH+H+ and FADH2, electrons and, protons are released but only electrons are, carried forward whereas protons are released, into outer chamber of mitochondria., , Ubiquinol is oxidised by complex-III, (Cytochrome bc1, complex) and it's electrons, are transferred to cytochrome C. Cytochrome, C is a small, iron-containing protein, loosely, associated with inner membrane. It acts as, a mobile electron carrier, transferring the, electrons between complex III and IV., Cytochrome C is oxidised by complex, IV or cytochrome C oxidase consisting of, cytochrome a and a3. Electrons are transferred, by this complex to the molecular oxygen. This is, terminal oxidation. Reduced molecular oxygen, reacts with protons to form water molecule, called as metabolic water., Protons necessary for this are channeled, from outer chamber of mitochondria into inner, chamber by F0 part of oxysome (complex V), present in inner mitochondrial membrane. This, proton channeling by F0 is coupled to catalytic, site of F1 which catalyses the synthesis of, ATP from ADP and inorganic phosphate. This, is oxidative phosphorylation. As transfer of, protons is accompanied with synthesis of ATP,, this process is named as 'Chemiosmosis' by, Peter Mitchell., Oxidation of one NADH+H+ leads, to production of 3 ATP molecules where as, oxidation of FADH2 leads to production of 2, ATP molecules. However the number of ATP, produced depends upon the physiological, conditions and source of respiratory substrate., Internet my friend, , Production, Substrate level, Oxidative Phosphorylation, phosphorylation NADH+H+ FADH, Total, 2, , Glycolysis, 2, 4, 2 x 3 =6 ----6, 10, Pyruvate → AcetylCoA --------2 x 3 =6 ----6, 6, Krebs cycle, ----1x2=2, 6 x 3=18 2 x 2 = 4, 22, 24, Total, 2, [6], 30 + 4 = [34], [40], Table 13.3 Balance sheet for ATP by aerobic oxidation of 1 glucose molecule, , 155, , Net benefit, , Step of Respiration, , Consumption, , Fig. 13.2 Electron Transport system (ETS), , Total, , What is effect of carbon monoxide, poisoning on cytochromes?, , 8, 6, 24, 38

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Cytoplasm, Matrix, , Glucose, Glycolysis, , Pyruvic acid, , Pyruvic acid, , Krebs, cycle, , Amino acids, Fatty acids, , CO2, O- - +2H+ H2O, FADH, NADH+H, 2, ADP+iP, + e, H, ATP, , , , Acetyl CoA, , +, , Outer chamber, , H+, , H+, , Fig. 13.4 Summary of Aerobic Respiration, Significance of ETS :, • The electron transport system (ETS) or, terminal oxidation generates major amount, of energy in the form of ATP molecules,, 34 ATP molecules out of total 38 ATP, molecules are produced through ETS., • It regenerates oxidized coenzymes such as, NAD+ and FAD+ from their reduced forms, (NADH+H+ and FADH2) for recycling., • It also provides water molecules necessary, for Krebs cycle., • It releases energy in a stepwise manner to, prevent damage of cells., Always Remember, Not only glucose but amino acids, from protein metabolism and fatty acids from, lipid metabolism also participate in Kreb's, cycle through acetyl CoA., Try this, Aerobic, respiration, can, be, demonstrated by two simple experiments., A., A pinch of dry bakers yeast suspended, in water or a few ml of yeast suspension used in, a bakery is added to about 10ml of 10 percent, glucose solution in a test tube (Tube A)., , The surface of the liquid is carefully, covered with oil to prevent contact with air., The test tube is closed tightly with rubber, stopper. One end of a short bent glass tube is, inserted through it to reach the air inside the, tube. Other end of the glass tube is connected, by a polyethylene or rubber tubing to another, bent glass tube fitted into a stopper. The open, end of the glass tube (delivery tube) is dipped, into lime water containing in a test tube (Tube, B). Stoppers of both the tubes are fitted tightly, to prevent leakage of gases. First test tube is, placed in warm water (370C-380C) in a beaker., Lime water gradually turns milky, indicating, the evolution of carbon dioxide from the yeast, preparation., Level of the lime water in the delivery, tube does not rise, showing that there is no, decline in volume of gas in test tube A and, consequently no utilization of oxygen by yeast., Preparation is stored for a day or two. When, you open the stopper of tube A. You will notice, a smell of alcohol indicating the formation of, ethanol. From this activity it may be inferred, that yeast respires anaerobically to ferment, glucose to ethanol and carbon dioxide., , 156

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B., Seed coats of a few germinating seeds, (peas, beans or gram) are removed. Seeds, are then put in a test tube filled with mercury., After closing the test tube with the thumb, it is, vertically inverted in a trough of mercury and, the thumb is carefully removed. Being lighter, than mercury, the seeds rise to the closed upper, end of the test tube. No gas is seen at first in, the test tube. As germination proceeds, a gas, begins to collect at the top of the mercury in the, test tube. On introducing a pellet of potassium, hydroxide into the tube, it rises to the top and, absorbs the gas. The mercury again fills the, tube. The potassium hydroxide reacts with, carbon dioxide gas to produce potassium, carbonate and water., , Use your brain power, Do the plants breath like animals? If, yes, how and why?, The gas therefore disappears. Evidently, germinating seeds produce carbon dioxide by, anaerobic respiration in the absence of oxygen, in the mercury column., 13.4, , Utility of stepwise oxidation :, You have noted that both anaerobic and, aerobic respiration are conducted in many steps., You may wonder what could be the utility of a, metabolic pathway with so many steps? Such, stepwise metabolism serves several purposes., i. A stepwise release of the chemical bond energy, facilitates the utilization of a relatively higher, proportion of that energy in ATP synthesis., ii. Activities of enzymes for the different, steps may be enhanced or inhibited by, specific compounds. This provides a means, of controlling the rate of the pathway and the, energy output according to need of the cell., iii. The same pathway may be utilized for, forming intermediates used in the synthesis of, other biomolecules like amino acids., , Always Remember, Removal of Hydrogen from respiratory, materials is the primary process in respiration, : The fact that during respiration oxygen, is taken in and carbon dioxide is given out, may give a false impression that respiratory, materials directly unite with oxygen. It must, be remembered that oxygen does not play such, a primary role in the process of respiration., The primary process in respiration consists, in removal of hydrogen from the respiratory, materials. The reactions in which hydrogen, is removed are catalyzed by enzymes called, dehydrogenases free hydrogen cannot exists in, the cell. As soon as it is removed from respiratory, material it is picked up by substances known as, acceptors. In aerobic respiration this hydrogen, is ultimately handed over to oxygen. These two, combine with each other and form water., Think and Compare, Comparison of overall equations of, photosynthesis and respiration show that to, some extent, two process are reverse of each, other. Photosynthesis involves reduction of CO2, and respiration involves oxidation of glucose., Respiratory Quotient :, Ratio of volume of CO2 released to the, volume of O2 consumed in respiration is called, the respiratory quotient (RQ) or respiratory, ratio. It depends on the type of respiratory, substrate., When carbohydrates are used as, respiratory substrate and are completely, oxidized, the RQ is 1, because volume of CO2, evolved is equal to volume of O2 consumed, as, shown in the equation., When fats or proteins are used as a, substrate, the RQ is less than 1, as volume of, CO2 evolved is always less than volume of O2, consumed., Mostly for fats, RQ is about 0.7 and for, proteins it is about 0.9, , 157

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In case of anaerobic respiration RQ, is always infinity as CO2 is evolved without, taking O2., Significance of Respiration, 1. Respiration provides energy for biosynthesis, of cellular materials such as carbohydrates,, proteins, fats, lipids, vitamins, pigments, etc., 2. It is also a source of energy for cell division,, growth, repairs and replacement of worn, out parts, movements, locomotion etc., 3. Various intermediates of Krebs cycle are, used as building blocks for synthesis of, other complex compounds., , 4. Coupled with photosynthesis, it helps to, maintain the balance between CO2 and O2, in the atmosphere., 5. Anaerobic respiration (fermentation) is, used in various industries such as diaries,, bakeries, distilleries, leather industries,, paper industries etc. It is used in the, commercial production of alcohol, organic, acids, vitamins, antibiotics etc., 6. Energy of respiration is also used to convert, insoluble substances into soluble form., , Internet my friend, Calculate the RQ for different respiratory substrates using appropriate formula., , 158

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Exercise, 1. Choose correct option, A. The reactions of the TCA cycle occur in, a. ribosomes, b. grana, c. mitochondria, d. endoplasmic reticulum, B. In eucaryotes the complete oxidation of, a molecule of glucose results in the net, gain of, a. 2 molecules of ATP, b. 36 molecules of ATP, c. 4 molecules of ATP, d. 38 molecules of ATP, C. The intermediate between glycolysis, and TCA cycle is :, a. 2 molecule of ATP, b. 36 molecule of ATP, c. 4 molecule of ATP, d. 38 molecule of ATP, D. Which step of Kreb's cycle operates, substrate-level phosphorylation?, a. α-ketoglutarate → succinyl CoA., b. Succinyl CoA → succinate, c. Succinate → fumarate, d. Fumarate → malate, , 3. Answer the following questions, A. When and where does anaerobic, respiration occur in man and yeast?, B. Why is less energy produced during, anaerobic respiration than in aerobic, respiration?, C. Where is the respiration electron, transport system located in a cell?, D. Which compound is the terminal, electron acceptor in aerobic respiration?, E. What is RQ.? What is its value for fats?, F. What are respiratory substrates? Name, the most common respiratory substrate., G. Write explanatory notes on :, i. Glycolysis, ii. Fermentation by yeast, iii. Electron transport chain, H. How are glycolysis, TCA cycle and, electron transport chain linked? Explain., I. How would you demonstrate that, yeast can respire both aerobically and, anaerobically?, J. What is the advantage of step wise, energy release in respiration?, , 2. Fill in the blanks with suitable words, A. Acetyl CoA is formed from ................., and co-enzyme A., B. In the prokaryotes ................. molecules, of ATP are formed per molecule of, glucose oxidised., C. Glycolysis takes place in ................., D. F1- F0 particles participate in the, synthesis of ................., E. During glycolysis .................. molecules, of NADH+H+ are formed., , 159, , K. Explain ETS., L. Discuss. "The respiratory pathway is an, amphibolic pathway"., M. Why is Krebs cycle reffered as, amphibolic pathway?, N. Which of the following step of aerobic, respiration would be omitted when fatty, acids are used as respiratory substrate?, a. Glycolysis, b. Krebs cycle, c. Electron transfer chain reaction, d. Terminal oxidation.

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14. Human Nutrition, Can you recall?, , Label the diagram, , 1. What is nutrition?, 2. Enlist life processes that provide us, energy to perform different activities., Nutrition is the sum of the processes by, which an organism consumes and utilises food, substances. WHO (World Health Organisation), defines nutrition as the intake of food,, considered in relation to the body's dietary, needs. The dietary needs of a healthy human, being include carbohydrates, proteins, fats,, vitamins, minerals, water and fibres in adequate, amounts. The term nutrition includes the, processes like ingestion, digestion, absorption,, assimilation and egestion. Food provides, energy and organic material for growth and, tissue repair. Vitamins and minerals are also, required in small quantities for nutrition. The, food that is consumed needs to be processed, before it is utilised., Think about it, Our diet includes all necessary, nutrients. Still we need to digest it. Why is it, so?, Digestion is defined as the process by, which the complex, non-diffusible and nonabsorbable food substances are converted into, simple, diffusible and assimilable substances., 14.1, , Human Digestive System : Digestive, , system of man consists of alimentary canal, and associated digestive glands., Alimentary canal : It is a long tubular structure, starting from mouth and ending with anus., It is about 8-10 meters long and consists of, following organs :, Mouth : Also called as oral or buccal cavity, , is bounded by fleshy lips. It’s side walls are, formed of cheeks, roof is formed by palate, and floor by tongue. It is internally lined by a, mucous membrane. Salivary glands open into, the buccal cavity., Teeth : 32 teeth are present in the buccal cavity, of an adult human being. Human dentition, is described as thecodont, diphyodont and, heterodont. It is called thecodont type because, each tooth is fixed in a separate socket present, in jaw bones by gomphosis type of joint. In, our life time, we get only two sets of teeth,, milk teeth and permanent teeth. This is called, diphyodont dentition. We have four different, type of teeth hence we are heterodont. Types, of teeth are incisors (I) canines (C) premolars, (PM) and molar (M). Each half of each jaw has, two incisors, one canine, two premolars and, three molars., Thus, dental formula of adult human, can be represented as., , 161

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The study of teeth with respect to their, number, arrangement, development etc is, known as dentition., , 2,1,2,3, 3, I 2 , C 1 , PM 2 , M, =, 2,1,2,3, 3, 2, 1, 2, i.e. 8 × 2=16 teeth in each jaw. =32 teeths, , Tongue : It is a muscular, fleshy organ and, roughly triangular in shape. It lies along the, floor of the buccal cavity. The upper surface of, the tongue bears numerous projections called, papillae. Some papillae bear sensory receptors, called taste buds., , Enamel, Dentin, , Crown, , Pulp, Gums, Bone, , Root, , Do you know ?, , Root canal, , 1. Who controls the deglutition?, 2. Is deglutition voluntary or involuntary?, , Nerves and, blood vessels, , Pharynx : The buccal cavity leads to a short, pharynx. Pharynx is a common passage for, food and air. The upper region of pharynx is, called trachea. The pharynx opens into trachea, through an opening called glottis. The glottis is, guarded by a cartilaginous flap called epiglottis., The epiglottis closes during the swallowing, (deglutition) action and prevents entry of food, into the trachea. The lower region of pharynx, is called oropharynx. Oropharynx opens into, oesophagus through gullet., , Fig. 14.1 Tooth Anatomy, Find out, 1. What will be the dental formula of a three, years old child?, 2. What is dental caries and dental plaque?, How can one avoid it ?, Internet my friend, 1. Find out the role of orthodontist and, dental technician., 2. What is root canal treatment?, A tooth consists of the portion that, projects above the gum called crown and the, root that is made up of two or three projections, which are embeded in gum. A short neck, connects the crown with the root. The crown is, covered by the hardest substance of the body, called enamel. Enamel is made up of calcium, phosphate and calcium carbonate. Basic shape, of tooth is derived from dentin, a calcified, connective tissue. The dentin encloses a cavity, called pulp cavity. It is filled with connective, tissue pulp. Pulp cavity contains blood vessels, and nerves. Pulp cavity has extension in the, root of the tooth called root canal. The dentin, of the root of tooth is covered by cementum, a, bone like substance that attaches the root to the, surrounding socket in the gum., , Oesophagus : The oesophagus is a thin,, muscular tube. It lies behind the trachea., This ≈25cm long tube passes through the, neck, central aspect of rib cage, pierces the, diaphragm and joins the stomach. It is lined by, mucus cells. Mucus lubricates the passageway, of food. Histologically, oesophagus is made, up of longitudinal and circular muscles. The, rhythmic wave of contraction and relaxation of, these muscles is called peristalsis that helps in, passage of food through oesophagus., Stomach : The stomach is located in the, upper left portion of the abdominal cavity. It, is a muscular sac-like 'J' shaped organ, around, 25 to 30cm in length. It is divided into upper, cardiac region and lower pyloric region., , 162

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Gastroesophageal, junction, , Jejunum : It is about 2.5 meters long, coiled, middle portion of small intestine. It is narrower, than the duodenum., Ileum : It is about 3.5 meters long. It is highly, coiled and little broader than jejunum. The, ileum opens into the caecum of large intestine, at ileocaecal junction., , Oesophagus, Fundus, , Cardia, Lesser curvature, Body, , Duodenum, , Greater curvature, , Pylorus, , Fig. 14.2 Stomach, Cardia or Cardiac : It is first part in which, oesophagus opens. The cardia surrounds the, band of circular muscles present at the junction, of oesophagus and stomach called cardiac, sphincter. The cardiac sphincter prevents back, flow or regurgitation of food from stomach to, oesophagus., Fundus : It is the dome shaped region above, and left of cardia., Body : It forms the large central portion of, stomach that stores the food., Pylorus : It is a narrow posterior region of, stomach. It opens into duodenum, the initial, part of small intestine. This opening is guarded, by a set of sphincter muscles called pyloric, sphincter. It regulates the flow of food from, stomach to small intestine., The stomach temporarily stores the, food and gives the feeling of satiety. It churns, the food and helps in mixing the food with, gastric juice., Small Intestine : In human, it is about 6 meters, long and 2.5 cms broad tube coiled within, abdominal cavity. The coils are held together, by mesenteries, supporting the blood vessels,, lymph vessels and nerves. It is divided into, three parts., Duodenum : It is about 26 cm long ‘U’ shaped, structure. The duodenum turns towards left side, of abdominal cavity below the stomach., , Large Intestine : Ileum opens into large, intestine. It is 1.5 meters in length. It is wider, in diameter and shorter than small intestine. It, consists of caecum, colon and rectum., Caecum : Caecum is a small, blind sac present, at the junction of ileum and colon. It is 6cm, in length. It hosts some symbiotic microorganisms. An elongated worm like vermiform, appendix arises from the caecum. Appendix is, vestigial organ in human beings and functional, in herbivorous animals for the digestion of, cellulose., Colon : Caecum opens into colon. Colon is, tube like-organ consist of three parts, ascending, colon, transverse colon and descending colon., The colon is internally lined by mucosal cells., Rectum : It is posterior region of large, intestine. It temporarily stores the undigested, waste material called faeces till it is egested, out through anus., Anus : Anus is the terminal opening of, alimentary canal. It is guarded by sphincter., It expels faecal matter by a process called, egestion or defaecation., 14.2, , Histological structure of alimentary, Find out, , 1. What is heart burn? Why do we take, antacids to control it?, 2. You must have heard of appendicitis. It, is inflammation of appendix. Find more, information about this disorder., , Activity :, Make a model of human digestive, system in a group., , 163

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canal :, The entire gastrointestinal tract is lined, by four basic layers from inside to outside, namely, mucosa, submucosa, muscularis, and serosa. These layers show modification, depending on the location and function of the, organ concerned., Circular muscle layer, , Mucosa of small intestine forms finger, like foldings called villi. The intestinal villi are, lined by brush border or epithelial cells having, microvilli at the free surface. Villi are supplied, with a network of capillaries and lymph vessels, called lacteals. Mucosa forms crypts in between, the bases of villi in intestine called crypts of, Lieberkuhn. These are intestinal glands., 12.3, , Glandular, epithelium of, mucosa, , Serosa, , Longitudinal, muscle layer, , Blood vessel, Submucosa, , Fig. 14.3 Histology of alimentary, canal, Serosa : It is the outermost layer. It is made, up of a layer of squamous epithelium called, mesothelium and inner layer of connective, tissue., Muscularis : This layer is formed of smooth, muscles. These muscles are usually arranged in, three concentric layers. Outermost layer shows, longitudinal muscles, middle circular muscles, and inner oblique muscles. This layer is wider, in stomach and comparatively thin in intestinal, region. The layer of oblique muscles is absent, in the intestine., Submucosa : It is formed of loose connective, tissue containing blood vessels, lymph vessels, and nerves. Duodenal submucosa shows, presence of glands., Mucosa : The lumen of the alimentary canal, is lined by mucosa. Throughout the length of, alimentary canal, the mucosa layer shows, presence of goblet cells that secrete mucus. This, lubricates the lumen of alimentary canal. This, layer shows modification in different regions, of alimentary canal. In stomach, it is thrown, into irregular folds called rugae. In stomach, mucosa layer forms gastric glands that secrete, gastric juice., , Digestive Glands :, The digestive glands associated with, the alimentary canal include the salivary, glands, liver and pancreas., Salivary glands : There are three pairs of, salivary glands which open in buccal cavity., Parotid glands are present in front of the ear., The submandibular glands are present below, the lower jaw. The glands present below the, tongue are called sublingual. Salivary glands, are made up of two types of cells. Serous, cells secrete a fluid containing digestive, enzyme called salivary amylase. Mucous cells, produce mucus that lubricates food and helps, swallowing., Liver : This dark reddish-brown coloured gland, is present just below the diaphragm. It occupies, the right upper portion of the abdominal cavity., It is the largest gland of the body. It weighs, about 1.2 to 1.5 kg in an adult human being., Each lobe of this bilobed gland is covered by, thin covering called Glisson's capsule. This, capsule is made up of connective tissue. Each, lobe is divided into several structural and, functional units of liver called hepatic lobules., Each hepatic lobule is polygonal in shape. At, the junction of adjacent lobules a triangular, portal area is present. In this portal area a, branch of each of hepatic artery, hepatic portal, vein and bile duct is present., A lobule consist of cords of hepatic, cells which are arranged around a central vein., In between the cords of hepatic cells, spaces, called sinusoids are present through which the, blood flows. In the sinusoids, phagocytic cells, called Kupffer cells are present., , 164

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These cells destroy toxic substances,, dead and worn-out blood cells and, microorganisms. Hepatic cells produce bile, juice. It is collected and carried through bile, duct and stored in sac like gall bladder. The duct, of the gall bladder and hepatic duct together, form common bile duct. Liver is a vital organ., Bile juice secreted by liver emulsifies fats and, makes food alkaline., Liver stores excess of glucose in the, form of glycogen. Deamination of excess amino, acids to ammonia and its further conversion to, urea takes place in liver. It is also involved in, synthesis of vitamins A, D, K and B12. Liver, also produces blood proteins like prothrombin, and fibrinogen. During early development,, liver acts as haemopoietic organ. Kupffer cells, help in detoxification process and destruction, of old RBCs., Bile ducts, , Liver, Gall bladder, , Hepatic duct, Cystic duct, , Interlobular ducts, , Capillary, network, alpha cell, beta cell, Islet of Langerhans, , delta cell, Central duct, , Fig. 14.4 Histological structure of Pancreas, Endocrine part of pancreas is made up, of groups of cells called islets of Langerhans, present between the acini. Islets contain, three types of cells. α-cells secrete glucagon,, β-cells secrete insulin and somatostatin, hormone is secreted by δ-cells. Glucagon and, insulin together control the blood-sugar level., Somatostatin hormone inhibits glucagon and, insulin secretion., , Common, hepatic duct, , Use your brain power, 1. Draw a neat labelled diagram of human, alimentary canal and associated glands, in situ., 2. Write a note or human dentition., 3. Liver is a vital organ. Justify., 4. Muscularis layer in stomach is thicker, than that in intestine. Why is it so?, , Pancreatic, duct, Pancreas, Common, bile duct, , Duodenum, , Acinar cells, , Hepatopancreatic, sphincter, , 12.4, , Fig. 14.3 Liver and Pancreas, Pancreas : Pancreas is a leaf shaped heterocrine, gland present in the gap formed by bend of, duodenum under the stomach. Exocrine part, of pancreas is made up of acini. Acinar cells, secrete alkaline pancreatic juice that contains, various digestive enzymes. Pancreatic juice is, collected and carried to duodenum by pancreatic, duct. The common bile duct joins pancreatic, duct to form hepato-pancreatic duct. It opens, into duodenum. Opening of hepato-pancreatic, duct is guarded by sphincter of Oddi., , Physiology of digestion :, We are already aware that food we, consume needs to be processed in order to utilise, it completely. Physiology of digestion includes, various processes involved in simplification of, food. Digestion process is carried out by both, mechanical as well as biochemical methods., Mechanical digestion includes various, movements of alimentary canal that help, chemical digestion. Mastication or chewing, of food by teeth, churning in stomach and, peristaltic movements of gastrointestinal tract, bring about mechanical digestion in human, body., , 165

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Chemical digestion is a series of, catabolic (breaking down) reactions that, hydrolyse the food. Let us now study the process, of digestion from the point where it enters the, body i.e. mouth., Digestion in the buccal cavity : Both, mechanical and chemical digestion processes, take place in mouth. Mastication or chewing, of food takes place with the help of teeth and, tongue. Teeth crush and grind the food. Tongue, manipulates the food. Crushing of food becomes, easier when it gets moistened by saliva. Mucus, in the saliva lubricates the food as well as it, helps in binding the food particles into a mass, of food called bolus. The bolus is swallowed, by deglutition. The tongue presses against, the palate and pushes the bolus into pharynx., Bolus further passes to the oesophagus., The saliva contains 98% water and 2%, other constituents like electrolytes (sodium,, potassium, calcium, chloride, bicarbonates),, digestive enzyme salivary amylase. The only, chemical digestion that takes place in mouth is, by the action of salivary amylase. It helps in, conversion of starch into maltose. About 30%, starch gets converted to maltose in mouth., Salivary amylase, Starch, Maltose, (Polysaccharide), pH 6.8, (Disaccharide), , Digestion in the stomach : Both mechanical, and chemical digestion takes place, in stomach. The stomach stores the food for, 4-5 hours. The physical digestion happens, by churning of food. Thick muscular wall of, stomach helps churning process. Churning, further breaks down the food particles and also, helps in thorough mixing of gastric juice with, food., The mucosa layer of stomach has, gastric gland. Each gastric glands has three, major types of cells namely, mucus cells, peptic, or chief cells and parietal or oxyntic cells., Mucus cells secrete mucus. Peptic cells secrete, proenzyme pepsinogen. Parietal cells secrete, HCl and intrinsic factor which is essential for, absorption of vitamin B12. Thus, gastric juice, contains mucus, inactive enzyme pepsinogen,, HCl and intrinsic factor. In infants, stomach, also secretes rennin. Mucus protects the inner, lining of stomach from HCl present in gastric, juice., HCl in gastric juice makes the food, acidic and stops the action of salivary amylase., It kills the germs that might be present in the, food. Pepsinogen gets converted into active, enzyme pepsin in the acidic medium provided, by HCl. In presence of pepsin, proteins in the, food get converted into simpler forms like, peptones and proteoses., , Saliva also contains lysozyme. It acts as, an antibacterial agent that prevents infections., The bolus further passes down through, the oesophagus by peristalsis. Sometimes, regurgitation or vomiting takes place due to, reverse spasmodic peristalsis. Food from the, oesophagus enters the stomach. The gastrooesophageal sphincter controls the passage of, food into the stomach., , HCl, Pepsinogen, Pepsin, (Inactive enzyme) pH (1.8) (Active enzyme), , Proteins, , Pepsin, Acidic medium, , Peptones + Proteoses, , Always Remember, Food remains for a very short time in mouth but action of salivary amylase continues, for further 15 to 30 minutes till gastric juice mixes with food in the stomach. Why do you think, it stops after the food gets mixed with gastric juice?, , 166

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Rennin found in gastric juice of infants, acts on casein, a protein present in milk. It, brings about curdling of milk proteins with the, help of calcium. The coagulated milk protein, is further digested with the help of pepsin., Rennin is absent in adults. At the end of gastric, digestion, food is converted to a semifluid, acidic mass of partially digested food is called, chyme., The chyme from stomach is pushed in, the small intestine through pyloric sphincter for, further digestion., , Both pancreatic and intestinal lipases, initially convert fats into fatty acid and, diglycerides., Diglycerides are further converted to, monoglycerides by removal of fatty acid from, glycerol. The mucus and bicarbonates present, in pancreatic juice protect the intestinal mucosa, and provide alkaline medium for enzymatic, action. Sub-mucosal Brunner's glands help in, the action of goblet cells. Most of the digestion, gets over in small intestine. Let us study the, action of pancreatic and intestinal secretion in, sequential manner., , Internet my friend, Think about it, , 1. What is lactose intolerence?, 2. How are bile pigments formed?, , How can I keep my pancreas healthy?, Can a person live without pancreas?, , Digestion in the small intestine : In the, small intestine, intestinal juice, bile juice, and pancreatic juice are mixed with food., Peristaltic movements of muscularis layer help, in proper mixing of digestive juices with chyme., Bile juice and pancreatic juice are poured in, duodenum through hepato-pancreatic duct., Bile juice is dark green coloured fluid, that contains bile pigments (bilirubin and, biliverdin), bile salts (Na- glycocholate and Nataurocholate), cholesterol and phospholipid., Bile does not contain any digestive enzyme., Bile salts neutralise the acidity of chyme and, make it alkaline. It brings about emulsification, of fats. It also activates lipid digesting enzymes, or lipases. Bile pigments impart colour to faecal, matter., Pancreatic juice secreted by pancreas, contains pancreatic amylases, lipases, and inactive enzymes trypsinogen and, chymotrypsinogen. Pancreatic juice also, contains nucleases- the enzymes that digests, nucleic acids. The intestinal mucosa secretes, digestive enzymes. The goblet cells of, mucosa produce mucus. Mucus plus intestinal, enzymes together constitute intestinal juice or, succus entericus. The intestinal juice contains, various enzymes like dipeptidases, lipases,, disaccharidases etc., , Do you know ?, Why do we feel hungry? Ghrelin is, a hormone that is produced mainly by the, stomach and small intestine, pancreas and, brain. It is known as the 'hunger hormone', because it stimulates appetite, increases food, intake and promotes fat storage., Action of pancreatic juice :, Pancreatic amylase acts on glycogen and starch, and convert those to disaccharides. Lipases, hydrolyse fat molecules into fatty acids and, monoglycerides. Inactive trypsinogen present, in pancreatic juice is converted to its active, form, trypsin. This conversion is brought about, by enterokinase present in intestinal juice., Trypsin converts proteins as well as proteoses, and peptones to polypeptides. It also converts, chymotrypsinogen to active chymotrypsin., Chymotrypsin converts polypeptides to, dipeptides., , 167, , Do it yourself, You have studied the representation, of enzymatic actions in the form of reactions., Write the reactions of pancreatic enzymes.

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Nucleases present in pancreatic juice, help in digestion of nucleic acids to pentose, sugar and nitrogenous base., Nucleases, , Nucleic acids, Nucleotides, Nucleosides, , Nucleotides, , Nucleotidases, , Nucleosides + phosphate, , Nucleosidases, , Sugar + base, , Action of intestinal juice :, , Do it yourself, Observe the following reactions and, explain in words., , Maltose, Sucrose, Lactose, , Dipeptides, , Emulsified fats, , Maltase, , glucose, , Sucrase, , glucose + fructose, , Lactase, , glucose + galactose, , Dipeptidase, , Lipase, , Amino acids, , Protein digestion in large intestine ends, up into production of substances like indole,, skatole and H2S. These are the reason for the, odour of faeces. These bacteria synthesise, several vitamins like B vitamins and vitamin, K., It is essential that the digestive enzymes, and juices are produced in sequential manner, and at a proper time. These secretions are, under neurohormonal control. Sight, smell and, even thought of food trigger saliva secretion., Tenth cranial nerve stimulates secretion of, gastric juice in stomach. Even the hormone, gastrin brings about the same effect. You, must have experienced hunger pangs at your, regular meal times. Can you now reason out, why it happens? Intestinal mucosa produces, hormones like secretin, cholecystokinin (CCK), and gastric inhibiting peptide (GIP). Secretin, inhibits secretion of gastric juice. It stimulates, secretion of bile juice from liver, pancreatic, juice and intestinal juice. CCK brings about, similar action and induces satiety that is feeling, of fullness or satisfaction. GIP also inhibits, gastric secretion., Do you know ?, , fatty acids + monoglycerides, , Conversion of proteins into amino, acids, fats to fatty acids and monoglycerides,, nucleic acids to sugar and nitrogenous base, and carbohydrates to monosaccharides marks, the end of digestion of food. Food is now, called chyle. Chyle is an alkaline slurry which, contains various nutrients ready for absorption., The nutrients are absorbed and undigested, remains are transported to large intestine., Remember, mucosa of large intestine, produces mucus but no enzymes. Some, carbohydrates and proteins do enter the large, intestine. These are digested by the action, of bacteria that live in the large intestine., Carbohydrates are fermented by bacterial, action and hydrogen, carbon dioxide and, methane gas are produced in colon., , 168, , Pancreatitis is inflammation of the, pancreas. It may occur due to alcoholism and, chronic gallstones. Other reasons include high, levels of calcium, fats in blood. However, in, 70% of people with pancreatitis, main reason, is alcoholism., , Use your brain power, 1. Make a flow chart for digestion of, carbohydrate., 2. What is a proenzyme? Enlist various proenzymes involved in process of digestion, and state their function., 3. Differentiate between chyme and chyle., 4. Digestion of fats take place only after the, food reaches small intestine. Give reason.

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Observe and Discuss Action of digestive juice in your group., , Fig. 14.5 Regulation of gastric function, 14.5 Absorption, assimilation and egestion:, The passage of end products of digestion, through the mucosal lining of alimentary canal, into blood and lymph is called absorption., Absorption takes place by various ways like, simple diffusion, osmosis, facilitated transport, and active transport. About 90% of absorption, takes place in the small intestine and the rest in, mouth, stomach and large intestine., Mouth: Absorption, Stomach: Gastric, takes place through mucosa is impermeable, mucosa of mouth to most substances, and lower side of hence nutrients reach, tongue into the blood, unabsorbed till, capillaries. e.g., small intestine., Some, drugs, Little water,, like, certain, electrolytes,, painkillers., alcohol and, Small Intestine:, drugs like aspirin, Glucose, fructose,, get absorbed in, galactose, amino, stomach., acids,, minerals, Large, and water soluble, intestine:, vitamins, are, absorbed in blood Absorption of water,, capillaries in villi. electrolytes like sodium, Lipids and fat soluble and chloride, drugs and, vitamins (A, D, E,, some vitamins takes, K) are absorbed in, place., lacteals., , Absorption of part of glucose, amino, acids and some electrolytes like chloride ions, are absorbed by simple diffusion depending on, concentration gradient., Some amino acids as well as substances, like fructose are absorbed by facilitated, transport. In this method, carrier ions like Na+, bring about absorption. Some ions are absorbed, against concentration gradient. It requires, energy. This type of absorption of mineral, like sodium is called active transport. Water is, absorbed along the concentration gradient., Monoglycerides and fatty acids can, not be absorbed in blood. These dissolve in, the centre of spherical aggregates formed by, bile salts called micelles. Micelles enter into, intestinal villi. Here, they are reformed into, chylomicrons. Chylomicrons are small protein, coated fat globules. They are transported into, lymph vessels called lacteals. From here, they, are transported to blood stream., Observe the adjacent chart to find, out absorption in various parts of alimentary, canal., Assimilation : The absorbed food material, finally reaches the tissue and becomes a part of, protoplasm. This is called as assimilation., , Absorption of nutrients in alimentary canal, , 169

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Egestion : Undigested waste is converted to, faeces in colon and reaches rectum. Faeces, contain water, inorganic salts, sloughed of, mucosal cells, bacteria and undigested food., Distension of rectum stimulates pressure, sensitive receptors that initiate a neural reflex, for defecation or egestion. It is a voluntary, process that takes place through anal opening, guarded by sphincter muscles., Can you recall?, 1. What is balanced diet?, 2. Explain the terms undernourished,, overnourished and malnourished in, details., , Do you know ?, Now a days we talk about calories, of food we consume. What is this calorie?, The amount of heat liberated by complete, combustion of 1g food in a bomb calorimeter, is termed as gross calorific (gross energy), value. In animals, the energy content of, food is expressed in terms of heat energy., The actual energy produced by 1g food is its, physiological value., Actual energy produced by 1 gm of food., S r . Food, No. Component, , Physiological, value, (Kcal/g), , 1., 2., 3, , 9.0, 4.0, 4.0, , 14.6, , Gross, calorific, value, (Kcal/g), Fats, 9.45, Proteins, 5.65, Carbohydrates 4.1, , Nutritional disorders and disorders, of digestive system :, Nutrition related disorders can be, categorised based on the food that an individual, consumes and conditions that develop due, to malfunctioning of the organ/s or glands, associated with digestive system., , You are already aware that little, extra or less of nutrition can lead to dietary, disorder. Inadequate intake of proteins causes, Protein Energy Malnutrition (PEM). It can be, associated with inadequacy of vitamins and, minerals in diet. PEM can cause diseases like, Kwashiorkar and Marasmus., Kwashiorkar : This protein deficiency, disorder is found generally in children between, one to three years of age. Children suffering, from Kwashiorkar are underweight and show, stunted growth, poor brain developement, loss, of appetite, anaemia, protruding belly, slender, legs, bulging eye, oedema of lower legs and, face, change in skin and hair colour., Marasmus : It is a prolonged protein energy, malnutrition (PEM) found in infants under one, year of age. In this disease, protein deficiency, is coupled with lower total food calorific value., Inadequate diet impairs physical growth and, retards mental development, subcutaneous, fat disappears, ribs become prominent,, limbs become thin, skin becomes dry, thin, and wrinkled, loss of weight, digestion and, absorption of food stops due to atrophy of, digestive glands. There is no oedema., Major cause of these disorders is, unavailability of nutritious food. Poverty,, large family size, ill spacing of children, early, termination of breast feeding and overdiluted, milk are a few causes. Because of malnutrition,, infectious diseases become opportunistic and it, worsens the condition. Proper diet can help in, reversal of symptoms., Indigestion : Overeating, inadequate enzyme, secretion, spicy food, anxiety can cause, discomfort and various symptoms. It is called, indigestion. Improperly digested food or, food poisoning also can cause indigestion. It, leads to loss of appetite, acidity (acid reflux),, heart burn, regurgitation, dyspepsia (upper, abdominal pain), stomach pain., Avoiding eating large meal, lying down, after meal, spicy, oily, junk food, smoking,, alcohol are the preventive measures for, indigestion., , 170

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Constipation : When frequency of defaecation, is reduced to less than once per week the, condition is called constipation. Difficulty, in defaecation may result in abdominal pain, distortion, rarely perforation. The causes are,, affected colonic mobility due to neurological, dysfunction like spinal cord injury, low fibre, diet, inadequate fluid intake and inactivity., Roughage, sufficient fluids in diet, exercise can, help improve the conditions., Diarrhoea : Passing loose watery stools more, than three times a day is called diarrhoea., Diarrhoea can lead to dehydration. The other, symptoms are blood in stool, nausea, bloating,, fever depending on cause and severity of the, disorder. The causes of diarrhoea are infection, through food and water or disorders like ulcer,, colitis, inflammation of intestine or irritable, bowel syndrome., Jaundice : We all associate jaundice with, yellowness of conjunctiva of eyes and skin, and whitish stool. These are the symptoms, of condition called jaundice. It is a sign of, abnormal bilirubin metabolism and excretion., Jaundice develops if excessive break down of, red blood cells takes place along with increased, bilirubin level than the liver can handle or there, is obstruction in the flow of bile from liver to, duodenum. Bilirubin produced from breakdown, of haemoglobin is either water soluble or fat, soluble. Fat soluble bilirubin is toxic to brain, cells. Hence serum bilirubin values have great, diagnostic importance. There is no specific, treatment to jaundice. Supportive care, proper, rest are the treatments given to the patient., Vomiting : In this condition, the stomach, contents are thrown out of the mouth due to, reverse peristaltic movements of gastric wall., It is controlled by non-vital vomiting centre, of medulla. It is typically associated with, nauseatic feeling., , Find out, 1. Find out the status of malnutrition among, children in Maharashtra and efforts, taken by the government to overcome, the situation. Search for various NGOs, working in this field., 2. Are jaundice and hepatitis same disorders?, , Do you know ?, Alcoholism causes different disorders, of liver like steatosis (fatty liver), alcoholic, hepatitis, fibrosis and cirrhosis., Collect more information on these, disorders and try to increase awareness, against alcoholism in society., Collect information about NGOs, working against alcoholism., Know the scientists, Kamala, Sohonie was the, first Indian woman, to receive Ph.D. in, science discipline., She worked under, the guidence of Dr., Robert Hill and discovered 'Cytochrome, C', the electron carrier Dr Kamala Sohonie, (1912 - 1998), in mitochondria from, potato., Dr. Sohonie also worked on nutritional aspects of legumes, milk and neera., Her contribution was significant in terms of, India's fight against malnutrition. She had, designed a protocol for Aarey dairy to avoid, curdling of milk., , Internet my friend, Collect the different videos of functioning of digestive system., , 171

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Exercise, 1. Choose correct option, A. Acinar cells are present in ..........., a. liver, b. pancreas, c. gastric glands d. intestinal glands, B. Which type of teeth are maximum in, number in human buccal cavity?, a. Incisors, b. Canines, c. Premolars, d. Molars, C. Select odd one out on the basis of, digestive functions of tongue., a. Taste, b. Swallowing, c. Talking d. Mixing of saliva in food, , C. Explain heterocrine nature of pancreas, with the help of histological structure., 4. Write short note on, A. Position and function of salivary glands., B. Jaundice, 5. Observe the diagram. This is histological, structure of stomach. Identify and, comment on significance of the layer, marked by arrow, , D. Complete the analogy:, Ptyalin: Amylase, : : Pepsin :, ................. ., a. Lipase, b. Galactose, c. Proenzyme, d. Protease, 2. Answer the following questions, A. For the school athletic meet, Shriya was, advised to consume either Glucon-D or, fruit juice but no sugarcane juice. Why it, must be so?, B. Alcoholic people may suffer from liver, disorder. Do you agree? Explain your, answer., C. Digestive action of pepsin comes to a, stop when food reaches small intestine., Justify., D. Small intestine is very long and coiled., Even if we jump and run, why it does not, get twisted? What can happen if it gets, twisted?, , 6. Find out pH maxima for salivary, amylase, trypsin, nucleotidase and pepsin, and place on the given pH scale, 1 2 3 4 5 6 7 8 9 10 11 12 13 14, , 7. Write the name of a protein deficiency, disorder and write symptoms of it, 8. Observe the diagram given below label, the A, B, C, D, E and write the function, of A, C in detail., A, , 3. Write down the explanation, A. Digestive enzymes are secreted at, appropriate time in our body. How does, it happen?, B. Explain the structure of tooth. Explain, why human dentition is considered as, thecodont, diphydont and heterodont., , 172, , B, , C, E, D

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15. Excretion and Osmoregulation, Can you recall?, , Have you ever observed ?, 1. When does urine appear deeply coloured?, 2. If we consume onion and garlic, we get, bad breath. Why?, , 1. Why are various waste products produced, in the body of an organism ?, 2. How are these wastes eliminated ?, Array of chemical processes occur, in the body of an organism. Sum total of these, processes is called 'metabolism'. Metabolism, involves catabolic (breaking down) and, anabolic (building up) processes. Metabolism, produces a variety of by-products, some of, which need to be eliminated. Such byproducts, are called metabolic 'waste products'., Metabolic waste products might be, fluid, gaseous, organic or inorganic. Depending, on the type, they are eliminated through various, organs of the body of an organism., 15.1, , Excretion and excretory products :, Elimination of metabolic waste, products from the body is called excretion., Unlike digestive wastes, which are primarily, composed of unabsorbed or undigested, substances that have never entered the cells,, metabolic wastes are produced inside body, cells., Let us try to enlist various excretory, waste products produced in human body;, Fluids such as water, gaseous wastes like CO2,, nitrogenous wastes like ammonia, urea and, uric acid, creatinine, mineral, salts of sodium,, potassium, calcium, etc. which if, are present, in body in excess are excreted through urine,, faeces and sweat. Pigments formed due to, breakdown of haemoglobin are like bilirubin, (excreted through faeces) and urochrome, (eliminated through urine). Also, the pigments, present in foodstuff like beet root consumed by, organism, excess of vitamins, hormones and, drugs taken are eliminated. Spices we consume, contain volatile substances that are excreted, through lungs., , Think about it, 1. Do organisms differ in type of metabolic, wastes they produce?, 2. Do environment or evolution have any, effect on type of waste produced by an, organism?, 3. How do thermoregulation and food habits, affect waste production ?, Body of an organism can store excess, carbohydrates and fats but is unable to store, excess amino acids. Hence, excess amino acids, are essentially broken down by a process called, as deamination. In this process, amino group is, separated from the amino acid and ammonia is, formed. Toxic ammonia is either excreted as it, is or further converted to less toxic forms like, urea or uric acid before excretion., There is no clear correlation between, the phylogenetic relationship of organisms and, their major excretory products, but it's habitat, has. e.g. Tadpole of frog excretes ammonia, and adult frogs mostly are ureotelic. Some, terrestrial turtles excrete uric acid whereas, others excrete urea or ammonia., Animals can be broadly classified, into three types based on nitrogenous wastes, they produce : Ammonia is the basic product, of deamination process. But it is highly toxic., Hence, it is to be diluted immediately. If there, is no or limited access to water, need for, conversion of ammonia becomes necessary., Thus, availability of water plays key role in, deciding mode of excretion of an organism., These are of mainly three types :, , 174

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Think about it, Endotherms consume more food in order to meet energy requirements. Also, carnivorous, diet contains more proteins than herbivorous. Does it affect excretion of nitrogenous waste ?, Ammonotelism : Elimination of nitrogenous, wastes in the form of ammonia is called as, ammonotelism. It is basic in nature. Hence, it, would disturb pH of body, if retained. Slight, increase in pH would disturb all enzymecatalyzed reactions in body and would also, make the plasma membrane unstable. It, is readily soluble in water and needs large, quantity of water to dilute and reduce, the toxicity. However, it is energy saving, mechanism of excretion. Hence all animals, that have plenty of water available for dilution, of ammonia, excrete nitrogenous wastes in the, form of ammonia. Such animals are called, ammonotelic. 1 gm ammonia needs about 300, – 500 ml of water for elimination., Ammonotelism is found in aquatic, invertebrates, bony fishes, and aquatic / larval, amphibians. Animals without excretory system, are also ammonotelic. e. g. Protozoa, Ammonotelic animals excrete ammonia, through general body surface (skin), gills and, kidneys., , ornithine / urea cycle (Krebs and Hanseleit,, 1932). 3 ATP molecules are used to produce, one molecule of urea., Sharks retain more urea in their body, fluid (blood) to make their blood isotonic to, surrounding marine water. This helps them to, prevent possible loss of water by exosmosis., Uricotelism (C5H4O3N4) : Elimination of, nitrogenous wastes in the form of uric acid is, called as uricotelism. Uric acid is least toxic., Hence, it can be retained in the body for some, time in concentrated form. It is least soluble in, water. Hence minimum (about 5—10 ml for, 1 gm) or no need of water for its elimination., Hence, animals those need to conserve more, water follow uricotelism. Ammonia is converted, into uric acid by ‘inosinic acid pathway’ in, the liver of birds. Birds, some insects, many, reptiles, land snails, are uricotelic; because, they need to conserve the water. However, they, have to spend more energy., , Ureotelism : Elimination of nitrogenous, wastes in the form of urea (H2N-CO-NH2) is, called as ureotelism. Urea is less toxic and, less water-soluble than ammonia. Hence it can, be concentrated to some extent in body. Due, to this, it requires less water for elimination., (Compared to ammonia, about 100 time less, water in human, several hundred times in camel,, kangaroo rat and shark). As it is less toxic and, less water soluble; hence, ureotelism is suitable, for animals those need conservation of water to, some extent. Hence it is common in terrestrial, animals, as they have to conserve H2O. It takes, about 50 ml H2O for removal of 1 gm NH2 in, form of urea. Mammals, cartilaginous fishes, (sharks and rays), many aquatic reptiles, most, of the adult amphibians, etc. are ureotelic. They, convert ammonia to urea in liver by operating, , 175, , Use your brain power, Why ammonia is highly toxic?, Always Remember, Animals like spiders, scorpions and, penguins excrete guanine. This mode of, excretion is called guanotelism., , Find out, You will study about a type of, arthritis called gouty arthritis caused due to, accumulation of uric acid in joints. Where, does uric acid comes from in case of ureotelic, human beings?

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Observe and Discuss, These are blood reports of patients undergoing investigations for kidney function. What, is creatinine ? What is your observation and opinion about the findings ? Why is it used as an, index of kidney function?, Report B, PERFECT PATHOLOGY, , Reg. No. :- _______, , Dr. _________________________ Date :- _________, , Report A, PERFECT PATHOLOGY, , Patient name :-________________, , Reg. No. :- _______, , Dr. ______________________, , Age :-_______, , M/F, , Date :-, , Reference :- Dr.________________, , Patient name :-__________________ Age :-____ M/F, Reference :- Dr.________________, Examination of Blood, , Examination of Blood, Test, , Result, , Normal values, , Fasting blood sugar, , 185, , 70 - 110 ml/dl, , Test, , Result, , Normal values, , Creatinine, , 1.92, , Male : 0.6 to 1.4 mg/dl., , Test, , Female : 0.6 to 1.2 mg/dl., , Sugar, , Chemical Examination of Urine, , Plasma creatinine is produced from catabolism of, creatinine phosphate during skeletal muscle contraction. It, provides ready source of high energy phosphate. Normally, blood creatinine levels remain steady because the rate of, production matches it's excretion in urine. Hence, level above, normal is an indication of poor renal function., Excretory organs play an important role in maintenence, of constant internal environment of the body called homeostasis., It requires osmoregulation, the process of controling solute, concentrations and water balance. It can be rightly said that, composition of blood (and internal environment) is determined, not by what mouth ingests but by what excretory organs retain., Marine birds like Albatross spend their life on the sea., That means water, they drink is salty ! How do they manage, osmoregulation then?, They have special glands called salt glands near nostrils., These are capable of secreting salts by active transport and help, to manage osmotic balance. Many marine organisms like sea, turtles and marine iguanas also have such salt excreting glands., Animals can either be isoosmotic to the surrounding, (osmoconformers) or control internal environment independent, of external environment (osmoregulators). Marine organisms, mostly are osmocomformers because their body fluids and, external environment are isoosmotic in nature., Fresh water forms and terrestrial organisms are, osmoregulators., , 176, , Result, , Normal values, , Present ++, , Absent, , Think about it, During summer, we tend, to produce less urine, why is it, so ?, , Use your brain power, What would happen if, human being has no option but, to drink sea water ?, Think about it, Like ectothermic and, endothermic animals, do, organisms differ in the way, they maintain salt balance ?, , Find out, How do freshwater, fishes and marine fishes carry, out osmoregulation ?

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Whether conformers or regulators, most, organisms can tolerate only narrow range of, salt concentrations. Such organisms are called, stenohaline organisms. (steno : narrow), Those who are capable of handling, wide changes in salinity are called euryhaline, organisms ex. barnacles, clams etc., Unicellular forms have contractile, vacuoles which collect and discharge waste, products outside the cell. Excretion in sponges, takes place by diffusion of waste material in, water which is discharged through osculum., True organs of excretion are found in, those animals that show bilateral symmetry., Most common type is simple or branching, tube that opens to exterior through pores called, nephridiopores., , Metanephridia : These are unbranched coiled, tubes that connect to body cavity through funnel, like structures called nephrostomes. Body fluid, enters the nephridium through nephrostome, and gets discharged through nephridiopore. eg., Earthworms., In most of the insects, excretion takes, place by set of blind ended tubules called, malpighian tubules. Crustaceans have green, glands as excretory organs. Members of phylum, Echinodermata do not have any specialised, excretory organs. Waste materials directly, diffuse into water or are excreted through tube, feet. Mammalian kidneys are a collection of, functional units called nephrons, which are, well designed to extract metabolic waste., , Two major types of nephridia :, Protonephridia : These are network of dead, end tubes called flame cells. These are found, mostly in animals that lack true body cavity e.g., Platyhelminthes. Protonephridia are also found, in rotifers, some annelids and Amphioxus., , Abdomen, , Midgut, Malpighian, tubules, Hindgut, Rectum, Abdomen, , Dry waste, with uric acid, , Fig. 15.3 Insects excretion, , Fig. 15.2 Excretory system in platyhelminthes, , 177

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Make a table, , Use your brain power, , 1. The details of modes of excretion of nitrogenous wastes., 2. The excretory organs found in various animal phyla., 15.2, , Excretory system in human being :, , Creatinine is considered, as index of Kidney function., Give reason., , Observe and complete, Label the adjacent diagram and complete, following paragraphs., Kidney : A pair of, shaped kidneys are, present on either side of, from 12th thoracic, to 3rd Lumbar vertebra. Kidneys are present behind ................ Hence are called Retroperitoneal., Dimensions of each kidney are 10 x ........ x ........., cms. Average weight is ............ g in males and, 135 g in ............... Outer surface is ............. and, inner is concave. Notch on the inner concave surface is called, Renal artery enters and renal, vein as well as ureter leave the kidney through hilus. Each kidney has almost 1 million functional, units called ..............., Ureters : A pair of ureters arise from .........of, each kidney. Each ureter is a long muscular tube 2530 cm. in length. Ureters open into ................ by separate openings, which are not guarded by valves. They, pass obliquely through the wall of urinary bladder., This helps in prevention of ............ of urine due to, compression of ureters while bladder is filled., , Fig. 15.4 Excretory system, , Urinary bladder : It is a median ............... sac. A, hollow muscular organ, the bladder is situated in pelvic, cavity posterior to public symphysis. At the base of the, ............. there is a small inverted triangular area called, Trigone. At the apex of this triangle is opening of urethra. At the two points of the base of the triangle are, openings of ureters. Urinary bladder is covered externally by peritoneum. Inner to peritoneum is muscular, layer. It is formed by detrusor muscles which consist of, three layers of smooth muscles. Longitudenal -circular-longitudenal respectively. Innermost layer is made, up of transitional.............. It helps bladder to stretch., , 178, , Urethra : It is a ......... structure arising from urinary bladder and opening to the exterior, of the body. There are .........., urethral sphincters between urinary bladder and urethra., a. Internal sphincter : Made up, of ............ muscles, involuntary, in nature., b. External sphincter : Made up, of ............. muscles, voluntary, in nature., If this valve is not functioning, properly during inflammation, of bladder, it can lead to kidney, infection.

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Kidneys bring about separation and, elimination of nitrogenous waste, excess water and toxic substances from the body. They, maintain homeostasis by way of their role in, osmoregulation and regulation of pH of body, fluids. They produce calcitriol and renin., Erythropoietin secreted by kidneys is essential, for production of RBCs. Ureters transport urine, from renal pelvis to urinary bladder. Urinary, bladder is a temporary storage organ for urine., It helps to expel urine (micturition). Urethra is, a passage way for discharging urine from body., In males, it acts as urinogenital organ., Do you know ?, Micturition : Average capacity of urinary, bladder is 700 ml. When urinary bladder, is almost half filled, stretch receptors in, urinary bladder transmit impulses to spinal, cord. This initiates conscious desire to expel, urine. Micturition reflex center of spinal, cord transmit impulses to the wall of urinary, bladder and internal urethral sphincter., Bladder muscles contract and muscles of, internal, urethral sphincter relax. Then, external sphincter receives impulses from, conscious centre of brain and relaxes. This, leads to expellation/ elimination of urine, from bladder., , Each kidney is covered by 3 layers, of tissue. Outermost Renal fascia is made up, of thin layer of fibrous connective tissue. It, anchors the kidney to abdominal wall as well, as surrounding tissue., Middle layer is a mass of fatty tissue, called adipose capsule. Protects kidneys by, shock absorption. Innermost layer, renal, capsule is a smooth transparent fibrous, membrane that is continuous with outer layer, of ureters. It acts as a barrier against spread of, infections in kidney. L.S. of kidney shows two, distinct regions within capsule., Histologically, kidney is divisible, into two regions as renal cortex and renal, medulla. Renal cortex is outer / peripheral, red, coloured and granular region. Cortex contains, Malpighian bodies, convoluted tubules and, blood vessels. Medulla is inner region of kidney, with pale red colour and striated appearance., Medulla mainly consists of Loops of Henle, and collecting ducts. All these are arranged in, conical manner to form renal pyramids. Cortex, extends in medulla as columns of Bertini /, renal columns between pyramids. Narrow tip, of pyramid is called as renal papilla., Minor calyx, , Renal papilla, of pyramid, , Major calyx, , Renal cortex, Renal, medula, , Internet my friend, Find out what is floating kidney?, Can you recall?, Observe the figure carefully and label, various regions of L.S. of kidney., , Renal, column, , Renal, pelvis, , Always Remember, , Renal, pyramid, , Ureter, , Infants up to 2 years of age show lack, of voluntary control over micturition. This, is because neurons to the external sphincter, muscles are not developed., , Fig. 15.5 L. S. of Kidney, , 179

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There are several pyramids. Renal, papilla open into minor calyx. Minor calyces, merge together to form major calyces and, major calyces unite together to form renal, pelvis. Renal pelvis (renal sinus) is funnelshaped area in the region of medulla of kidney., Renal pelvis continues as ureter which leaves, kidney through hilus., , Proximal convoluted, tubule, Juxtaglomerular, apparatus, Afferent, arteriole, Podocyte, , Do you know ?, , Glomerulus, , Nephrology is branch of biology that, deals with structure, function and disorders, of male and female urinary system., , Glomerular capsule, , Nephron : Nephrons are structural and, functional units of kidney. Each nephron, consists of about 4 - 6 cm long thin-walled, tube- ‘renal tubule’ and a bunch of capillaries‘glomerulus’. Wall of renal tubule is made up of, single layer of epithelial cells. Its proximal end, is wide, blind, cup-like, called as Bowman’s, capsule. Distal end is open. It is divisible into, Bowman’s capsule, neck, proximal convoluted, tubule (PCT), Loop of Henle (LoH), distal, convoluted tubule (DCT) and collecting tubule, (CT)., Glomerulus is present in the cuplike cavity of Bowman’s capsule and both, are collectively known as renal corpuscle or, Malpighian body., Each Malpighian body is about 200µm, in diameter and consists of a Bowman’s capsule, and glomerulus., Glomerulus : Glomerulus is a bunch of fine, blood capillaries lying in the cup of Bowman’s, capsule. A small terminal branch of renal, artery called as afferent arteriole enters the cup, cavity and undergoes extensive fine branching, to form network of several capillaries. This, bunch is called as glomerulus. Capillary wall, is fenestrated. All capillaries reunite and form, an efferent arteriole that leaves the cup cavity., Diameter of afferent is greater than efferent, arteriole to create a high hydrostatic pressure, in glomerulus. It is important for ultrafiltration., , Afferent, arteriole, , Efferent, arteriole, , Glomerulus, , Podocyte, showing feet, and slit pores, in between, , Blood pressure, 75 mm. Hg, Efferent, arteriole, Capillary, showing pores, Basement, membrane, Visceral wall, Parietal wall, Capsular space, PCT cell, , Colloidal, osmotic, pressure, 30 mm Hg., Capsular, hydrostatic, pressure 15, mm Hg., , Distal, convoluted, tubule, , Basal channel, Intercellular space, Microvillus, , Fig. 15.6 Bowman's capsule and glomerulus, Bowman's capsule : It is a cup-like structure, having double wall. Both walls are composed, of squamous epithelium. Outer wall is called, as parietal and inner wall is called as visceral, wall. There is a space called as capsular space, / urinary space in between two walls. Visceral, wall consists of special type of squamous cells, called podocytes having a foot-like pedicel., These podocytes are in close contact with the, walls of capillaries of glomerulus., There are small slits called as filtration, slits in between adjacent podocytes. Parietal, wall is thin consisting of simple squamous, epithelium. It continues into neck., The wall of neck is made up of ciliated, epithelium. Lumen of neck is called urinary, pole. Neck leads to proximal convoluted tubule., , 180

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Proximal Convoluted Tubule : This is highly, coiled part of nephron. It is lined by cuboidal, cells with brush border (microvilli) and, surrounded by peritubular capillaries. It is place, of selective reabsorption. Due to convolutions, (coiling), filtrate flows slowly and remains in, the PCT for longer duration. This ensures the, reabsorption of maximum amount of useful, molecules., Loop of Henle : This is ‘U’ shaped tube, consisting of descending and ascending limb., Descending limb is thin walled and permeable, to water. It is lined with simple squamous, epithelium. Ascending limb is thick walled and, impermeable to water. It is lined with simple, cuboidal epithelium. LoH is surrounded by, capillaries called vasa recta. Its function is to, operate counter current system - a mechanism, for osmoregulation. Regulation of salt and water, balance in body is called as osmoregulation., Ascending limb of Henle’s loop leads to DCT., Distal convoluted tubule: This is another, coiled part of nephron. Its wall consists of, simple cuboidal epithelium., DCT performs tubular secretion /, augmentation / active secretion in which, wastes, are taken up from surrounding capillaries and, secreted into passing urine., Blood Supply to, Kidney, , DCT helps in water reabsorption and, regulation of pH of body fluids., Collecting tubule: This is a short, straight part, of DCT. Collecting tubule reabsorbs water and, secretes protons. Collecting tubule opens to, collecting duct., There are two types of nephrons in, human kidney. Cortical nephrons with shorter, loop of Henle which extend very little in, medulla. Most of the nephrons are cortical, nephrons. Few nephrons have longer loop of, Henle that runs deep into medulla. These are, called Juxtamedullary nephrons., A small branch of efferent arteriole, forms peritubular capillary network around, DCT, PCT and Henle’s loop of cortical nephrons, also forms loop-shaped vasa recta around, Henle’s loop of juxtamedullary nephrons., Nephrons are responsible for elimination, of waste and osmoregulation. Hence are richly, supplied with blood. About one fourth of, cardiac output is supplied to kidneys!, Efferent arteriole, Afferent, arteriole, Distal, convoluted, tubule, Proximal, convoluted, tubule, , Renal artery, Renal arteriole, , from renal, artery, To renal vein, , Afferent arteriole, , Peritubular, capillaries, , Glomerular capillary, Efferent arteriole, Peritubular capillaries, network, , Glomerular, Glomerulus (Bowman), capsule, , Ascending, limb, Loop of, Descending, Henle, limb, , Collecting, duct, Calyx, , Renal veinule, , Fig. 15.7 Nephron and peritubular, capillaries network, , Renal vein, , 181

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Juxta Glomerular Apparatus :, Some smooth muscle cells of the wall, of afferent arteriole are modified in such a way, that their sarcoplasm is granular. These cells are, called ‘juxtaglomerular (JG) cells., In each nephron, beginning part of DCT, makes contact with the afferent arteriole of same, nephron. Cells in the wall of DCT in this region, are packed more densely than those in other, region of DCT. This is called macula densa., Macula densa and the JG cells together form, Juxta Glomerular Apparatus (JGA) that plays, important role in blood pressure regulation, within kidney., Can you tell?, 1. Why are kidneys called 'retroperitoneal'?, 2. Why urinary tract infections are more, common in females than males?, 3. What is nephron? Which are it's main, parts? Why are they important?, Think about it, How much blood is supplied to kidney?, , 17.3, , Urine formation :, Process of urine formation is completed, in three successive steps as- Ultrafiltration /, Glomerular filtration, Selective reabsorption,, Tubular secretion / Augmentation., a. Ultrafiltration / Glomerular filtration :, Diameter of afferent arteriole is greater, than efferent arteriole. Diameter of capillaries, is still smaller than both arterioles. Due to such, difference in diameter, blood flows with greater, pressure through glomerulus. This is called as, glomerular hydrostatic pressure (GHP) and, normally, it is about 55 mm Hg., This pressure is opposed by osmotic, pressure of blood (normally, about 30 mm Hg), and capsular pressure (normally, about 15 mm, Hg). Hence net / effective filtration pressure, (EFP) is 10 mm Hg., Walls of capillaries are extremely thin., Under the effect of high pressure, walls become, permeable to major components of blood, (except blood cells and macromolecules like, protein). Thus plasma except proteins oozes out, through wall of capillaries. About 600 ml blood, passes through each kidney per minute., , ., . . EFP = Hydrostatic pressure in glomerulus - (Osmotic pressure of blood + filtrate hydrostatic pressure), 10 mmHg = 55 - (30 +15), Glomerular filtration, , Tubular reabsorption, , Tubular secretion, , The movement of substances from the, blood within the glomerulus into the, capsular space., , The movement of substances from, the tubular fluid back into the blood., , The movement of substances from, the blood into the tubular fluid., , Peritubular capillaries, , Efferent, arteriole, , Nephron loop, , Afferent, arteriole, PCT, Glomerulus, Glomerular capsule, , DCT, , Collecting, tubule, , Ascending limb, , Capsular space, , Desending limb, Collecting duct, Vasa recta, , Fig. 17.8 Process of urine formation, , 182

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Proximal convoluted tubule, , Distal convoluted tubule, , Renal, tubule, , Collecting system, Collecting duct, , Efferent arteriole, Afferent arteriole, Ascending limb, of loop ends, , Glomerular, capsule, Capsular space, Glomerulus, Renal corpuscle, Descending limb, of loop begins, Nephron loop, Thin, limb, , Papillary duct, , Ascending limb, , Descending limb, , Thick, limb, , Fig. 15.9 Reabsorption, The blood (plasma) flowing through, kidney (glomeruli) is filtered as glomerular, filtrate - at a rate of 125 ml / min. (180 L/d)., Glomerular filtrate / deproteinized, plasma/primary urine is alkaline, contains, urea, amino acids, glucose, pigments, and, inorganic ions., Glomerular filtrate passes through, filtration slits into capsular space and then, reaches the proximal convoluted tubule., b. Selective reabsorption :, PCT is place of reabsorption. It is, highly coiled so that glomerular filtrate, passes through it very slowly. Columnar cells, of PCT are provided with microvilli due to, which absorptive area increases enormously., This makes the process of reabsorption very, effective., These cells perform active (ATP, mediated) and passive (simple diffusion), reabsorption., Substances, with, considerable, importance (high threshold) like - glucose,, amino acids, Vit.C, Ca++, K+, Na+, Cl¯ are, absorbed actively, against concentration, gradient. Low threshold substances like water,, sulphates, nitrates, etc. are absorbed passively., In this way, about 99% of glomerular filtrate is, reabsorbed in PCT and DCT., , Do this, Check blood reports of patients and, comment about possibility of glucosuria., c. Tubular secretion / Augmentation :, Finally filtrate reaches the distal, convoluted tubule via loop of Henle., Peritubular capillaries surround DCT. Cells of, distal convoluted tubule and collecting tubule, actively absorb the wastes like creatinine and, ions like K+, H+ from peritubular capillaries, and secrete into lumen of DCT and CT, thereby, augmenting the concentration of urine and, changing its pH from alkaline to acidic., Secretion of H+ ions in DCT and CT is, an important homeostatic mechanism for pH, regulation of blood. This process is called as, tubular secretion or augmentation., Tubular secretion is only mode of excretion in, marine bony fishes and desert amphibians., 15.4, , Concentration of urine :, Under the conditions like low water, intake or high water loss due to sweating,, human can produce concentrated urine. It can, be almost four times concentrated i.e. 1200, mOsm/L than the blood (300 mOsm/L). For this, purpose, a mechanism called countercurrent, mechanism is operated in human kidneys., , 183

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Afferent, arteriole, , Bowman's capsule, Glomerulus, , ↑, , NaCl, , ↑, , ↑, , H2O, , Efferent, arteriole, , ↑, , Cortex, , ↑, , ↑, ↑, , H 2O, , Outer, medulla, , NaCl, , ↑, , H2O, , ↑, , ↑, , 1200, , Vasa recta, , NaCl, , ↑, , ↑, , H2O, , H2O, , ↑, , ↑, , H2O, , ↑, , ↑ ↑ ↑, , ↑, , ↑, , NaCl, , ↑, , NaCl, , NaCl, NaCl, , NaCl, , ↑, ↑, , NaCl, , ↑ ↑ ↑ ↑ ↑, , ↑, , ↑, , ↑, , 900, mOsmolL-1, 1200, mOsmolL-1, , NaCl, , ↑, , 600, mOsmolL-1, , ↑, , ↑, , 300, mOsmolL-1, , Urea, H2O, , Inner, medulla, , Nephron, , Fig. 15.10 Concentration of urine, Limbs of Henle’s loop of juxtamedullary, nephrons and vasa recta operate countercurrent, mechanism as followsThis mechanism involves the passage, of fluid from descending to ascending limb of, Henle’s loop. Flow of tubular fluid is in opposite, direction through both limbs; hence the namecounter (opposite) current (flow). In case of, vasa recate, blood flows from ascending to, descending parts of itself., Wall of descending limb is thin and, permeable to water where as that of ascending, limb is thick and impermeable to water. In the, region of descending limb, water diffuses from, tubular fluid into tissue fluid due to which,, tubular fluid becomes concentrated. Ascending, limb of Henle’s loop is thick walled and its, cells can reabsorb Na+ and Cl¯ from tubular, fluid and release into tissue fluid., Due to this, tissue fluid around, descending limb becomes concentrated. This, makes the more water to move out from, descending limb into tissue fluid by osmosis., Thus, as tubular fluid passes down through, descending limb, its osmolarity (concentration), increases gradually due to water loss and on, the other hand, progressively decreases due, to Na+ & Cl¯ secretion as it flows up through, ascending limb., Besides, whenever water retention is, necessary, pituitary secretes ADH., , ADH makes the cells in the wall of, collecting ducts permeable to water. Due to, this, water moves from tubular fluid into tissue, fluid, making the urine concentrated., Cells in the wall of deep medullar part, of collecting ducts are permeable to urea., As concentrated urine flows through it, urea, diffuses from urine into tissue fluid and from, tissue fluid into the tubular fluid flowing through, thin ascending limb of Henle’s loop. This urea, cannot pass out from tubular fluid while flowing, through thick segment of ascending limb, DCT, and cortical portion of collecting duct due to, impermeability for it in these regions. However,, while flowing through collecting duct, water, reabsorption is operated under the influence of, ADH. Due to this, urea concentration increases, in tubular fluid and same urea again diffuses, into tissue fluid in deep medullar region. Thus,, same urea is transferred between segments of, renal tubule and tissue fluid of inner medulla., This is called urea recycling; operated for more, and more water reabsorption from tubular, fluid and thereby excreting small volumes of, concentrated urine., Osmotic gradient is essential in the, renal medulla for water reabsorption by, countercurrent multiplier system. This osmotic, gradient is maintained by vasa recta by, operating countercurrent exchange system., Vasa recta also have descending and ascending, limbs. Blood that enters the descending limb of, the vasa recta has normal osmolarity of about, 300 mOsm/L. As it flows down in the region, of renal medulla where tissue fluid becomes, increasingly concentrated, Na+, Cl¯ and urea, molecules diffuse from tissue fluid into blood, and water diffuse from blood into tissue fluid., Due to this, blood becomes more concentrated, which now flows through ascending part of, vasa recta. This part runs through such region of, medulla where tissue fluid is less concentrated., Due to this, Na+, Cl¯ and urea molecules, diffuse from blood to tissue fluid and water, from tissue fluid to blood. This mechanism, helps to maintain the osmotic gradient., , 184

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So as to reabsorb water to maximum, capacity, loops of Henle are longer in desert, mammals like camel. Due to this, camel, excretes concentrated urine., Can you tell?, 1. Explain the process of urine formation in, details., 2. How does counter current mechanism, help concentration of urine?, , Use your brain power, In which regions of nephron the, filtrate will be isotonic to blood?, Try this, Read the given urine report and, prepare a note on composition of normal, urine., Report A, PERFECT PATHOLOGY Reg. No. :-_______, Dr. _____________________, Date :-________, Patient name :-_______________Age :-_____ M/F, Reference :- Dr.________________, URINE ROUTINE, Quantity, Colour, Appearence, Deposits, Reaction, Specific gravity, Albumin, Sugar, Ketone bodies, Bile salts, Bile pigments, , Pale yellow, clear, Absent, Acidic, 1.02, Absent, Absent, Absent, Absent, Absent, , Occult blood, , Negative, , Casts, , Absent, , Think and appreciate, How do kidneys bring about, homeostasis? Is there any role of, neuroendocrine system in it ?, , 15.5 Composition of Urine :, Normal urine is pale yellow coloured, transparent liquid. This colour is due to pigment, urochrome. Composition of urine depends upon, food and fluid consumed by the individual., Well yes; let us find out how : There, are two ways. One by regulating water, reabsorption through ADH and other by, electrolyte reabsorpion though RAAS., Hypothalamus in midbrain has special, receptors called osmoreceptors. They can detect, change in osmolarity (measure of total number, of dissolved particles per litre of solution) of, blood., If osmolarity of blood increases due, to any reason such as after eating namkeen or, due to sweating, in other words, due to water, loss from the body, osmoreceptors trigger, release of Antidiuretic hormone (ADH) from, neurohypophysis. (posterior pituitary). ADH, stimulates reabsorption of water from last part, of DCT and entire collecting duct by increasing, the permeability of cells. This leads to reduction, in urine volume and decrease in osmolarity of, blood. Once the osmolarity of blood comes to, normal, activity of osmoreceptor cells decreases, leading to decrease in ADH secretion. This is, called negative feedback., Think, What would happen if ADH secretion, decreases due to any reason ?, In case of haemorrhage or severe, dehydration too, osmoreceptors stimulate ADH, secretion. ADH is important in regulating water, balance through kidneys., In absence of ADH, diuresis (dilution of, urine) takes place and person tends to excrete, large amount of dilute urine. This condition, called as diabetes insipidus., Another regulatory mechanism is RAAS, (Renin Angiotensin Aldosterone system) by, Juxta Glomerular Apparatus (JGA)., , 185

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Whenever blood supply (due to change, in blood pressure or blood volume) to afferent, arteriole decreases (e.g. low BP/dehydration),, JGA cells release Renin. Renin converts, angiotensinogen secreted by hepatocytes in, liver to Angiotensin I. Angiotensin converting, enzyme further modifies Angiotensin I to, Angiotensin II, the active form of hormone., Angiotensin II has triple function, 1. It constricts arterioles in kidney thereby, reducing blood flow and increasing blood, pressure., 2. Stimulates PCT cells to enhance, reabsorption of Na+, Cl- and water., 3. It stimulates adrenal cortex to release, another hormone called aldosterone that, stimulates DCT and collecting ducts to, reabsorb more Na+ and water, thereby, increasing blood volume and pressure., , Kidneys participate in synthesis of, calcitriol, the active form of Vitamin D which, is needed for absorption of dietary calcium., Deficiency of calcitriol can lead to brittle, bones., Something Interesting :, Vampire bat from south America is, a nocturnal sanguivorous mammal. It feeds, on blood of large birds and mammals. It has, to fly long distances to locate suitable prey., Once found, it can even consume blood to, an extent of more than half it's body mass., In such a case, the body of bat becomes too, heavy to fly. To compensate for this, while, the bat is feeding, it's kidneys excrete large, amount of dilute urine (upto 24% of it's body, mass). Now bat can fly back to the cave/tree, where it can spend the day., During day time, it cannot go to, drink water. At the same time diet being high, on proteins, large amount of nitrogenous, waste is produced. Instead of diluting waste,, kidneys resort to concentrating urine in order, to conserve water. This capacity to rapidly, change the osmolarity of urine is a classic, example of adaptation., , Use your brain power, Can we use this knowledge in, treatment of high blood pressure? Why high, BP medicines are many a times diuretics?, Would only ADH or only RAAS be, sufficient for homeostasis?, Both ADH and RAAS are essential., Only ADH can lower blood-Na+ concentration, by way of water reabsorption in DCT and, collecting duct, whereas RAAS stimulates Na+, reabsorption, thus maintains osmolarity of, body fluid., Action of ADH and RAAS leads to, increase in blood volume and osmolarity. A, large increase in blood volume and pressure, stimulates atrial wall to produce atrial, natriuretic peptide (ANP). ANP inhibits Na+, and Cl- reabsorption from collecting ducts, inhibits release of renin, reduces aldosterone, and ADH release too. This leads to a condition, called Natriuresis (increased excretion of Na+, in urine) and diuresis., Can you tell?, How do skin and lungs help in excretion ?, , 15.6, , Role of other organs in excretion :, , Skin :, Skin of many organisms is thin and, permeable. It helps in diffusion of waste, products like ammonia. Human skin is thick and, impermeable. It shows presence of two types, of glands namely, sweat glands and sebaceous, glands. Sweat glands are distributed all over, the skin. They are abundant in palm and facial, regions., , 186

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15.7, Pores, , Hair, , Epidermis, , Oil gland, (sebaceous, gland), , Dermis, , Hair-erector, muscle, , Sweat, gland, , Blood, vessels, , Subcutaneous, fatty tissue, , Fig. 15.11 L. S. of Skin, These simple, unbranched, coiled,, tubular, glands open on the surface of skin, through an opening called sweat pore. Sweat, is primarily produced for thermoregulation but, it also excretes substances like water, NaCl,, lactic acid and urea., Sebaceous glands :, They are present at the neck of hair, follicles. They secrete oily substance called, sebum. It forms a lubricating layer on skin, making it softer. It protects skin from infection, and injury., Lungs :, Lungs are the respiratory organs., They help in excretion of volatile substances, like CO2 and water vapour produced during, cellular respiration. They also excrete volatile, substances present in spices and other food, stuff., Can you tell?, 1. What is the composition of sweat?, 2. When does kidney produce renin? Where, is it produced in kidney?, 3. Explain role of lungs and skin in excretion., 4. Explain how electrolyte balance of blood, plasma maintained., 5. Refer to blood report A and B what is the, significance of values of albumin, blood, cells, casts etc?, , Disorders and diseases :, Excessive, albumin, in, urine, (albuminuria) indicates injury to endothelialcapsular membrane as a result of increased, blood pressure, injury or irritation of kidney, cells by substances such as toxins or heavy, metals. Presence of excessive quantities of, ketone bodies in urine may be caused due, to diabetes mellitus, starvation or too little, carbohydrates in diet., Presence of leucocytes in urine indicate, possibility of infection of kidney or other, urinary organs., 1. Kidney stones :, These are also called renal calculi They may be formed in any portion of urinary, tract-from kidney tubules to external opening., Depending on composition they are, classified into :, Calcium stones : Usually are calcium oxalate, stones or calcium phosphate ones., Struvite stones : These are formed in response, to bacterial infection caused by urea splitting, bacteria. These grow quickly and become quite, large., Uric acid stones : In people who don't drink, enough water or consume high protein diet can, suffer from this type of stones., Cystine stones : It is a genetic disorder that, causes kidney to excrete too much of certain, amino acid., Symptoms : Intermittent pain below rib cage in, back and side ways. Hazy, brownish/reddish/, pinkish urine. Frequent urge to pass urine. Pain, during micturition., Diagnosis : Uric acid content of blood, colour of, urine, kidney X-ray, sonography of kidney are, different diagnostic tests prescribed depending, on symptoms., 2. Uremia :, Blood normally contains 0.01 to 0.03%, urea; but if it rises above 0.05%, it is called, uremia. It is harmful and may lead to kidney, failure., , 187

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3. Nephritis : It is inflammation of kidenys characterised by proteinuria caused due to increased, permeability of glomerular capsular membrane, permitting large amounts of proteins to, escape from blood to urine. This lead to change in blood colloidal osmotic pressure, leading, to movement of fluid from blood to interstitial spaces. It is reflected as edema., 4. Renal Failure : It is decrease or cessation of glomerular filtration, is classified into two types., a. Acute Renal failure (ARF) : ARF is sudden worsening of renal function that most commonly, happens after severe bleeding. There is decrease in urine output (oligouria-scanty urine) (less, than 400 ml/day or less than 0.5 ml/kg/h in children). Other causes of ARF may include acute, obstruction of both ureters or nephrotoxic drugs. ARF can be detected biochemically by elevated, serum creatinine level., Venous pressure monitor, , b. Chronic kidney disease (CKD) : It, is progressive and generally irreversible, decline in glomerular filtration rate, (GFR). It may be caused due to chronic, glomerulonephritis. It can be detected Fresh dialysate, by reduced kidney size and possibility of, Dialyser, anaemia., Haemodialysis :, When renal function falls below 5 to, 7%, accumulation of harmful substances in, blood begins. In such a condition, the person, has to go for artificial means of filtration, of blood. You have already studied about, haemodialysis wherein dialysis machine is, used to filter blood. In haemodialysis, blood, is filtered outside the body using dialysis, unit. In this procedure, patients’ blood is, removed; generally from radial artery. It is, passed through a cellophane tube that acts, as a semipermeable membrane. The tube, is immersed in a fluid called dialysate., Dialysate is isosmotic to normal blood, plasma. Hence only excess salts if present, in plasma pass through the cellophane tube, into the dialysate., Waste substances being absent in, the dialysate, move from blood into the, dialyzing fluid. Filtered blood is returned, to vein. In this process it is essential that, anticoagulant like heparin is added to the, blood while it passing through the tube, and before resending it into the circulation,, adequate amount of anti-heparin is mixed., The blood has to move slowly through the, tube and hence the process is slow., , Air trap and air detector, Clean blood, , Patient, , Used Dialysate, Dialyser inflow, pressure monitor, Heparin pump (to, prevent clotting), Blood pump, , Arterial, pressure, monitor, , Removed, blood for, cleaning, , Fig. 15.12 Haemodialysis, Dialysate bag, , Peritoneal, space, Catheter, Peritoneum, Dialysate, with waste, products, drained, from, peritoneal, space, Drainage bag, , Fig. 15.13 Peritoneal dialysis, , 188

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5. Kidney transplant :, It is organ transplant of a healthy, kidney into a patient with end stage renal, disease. Kidney transplantation is classified, as cadaveric (deceased donor) or living, donor kidney transplant. Living donor kidney, transplant are further classified as genetically, related (living-related) or non-related (living, non-related) transplants., , Always Remember, Dialysis is regarded as a 'holding, measure' until a renal transplant can, be performed or sometimes as the only, supportive measure in those for whom a, transplant would be inappropriate., Peritoneal dialysis :, In this method, the dialyzing fluid is, introduced in abdominal cavity or peritoneal, cavity. The peritoneal membrane acts as, semipermeable dialyzing membrane., Toxic wastes and extra solutes pass, into the fluid. This fluid is drained out after, prescribed period of time. Peritoneal dialysis, can be repeated as per the need of the patient., It can be carried out at home at work or, while travelling. But it is not as efficient as, haemodialysis., Kidneys are associated with secretion, of erythropoietin, renin and calcitriol which is, not possible using dialysis machine., , 189, , Use your brain power, If a person is undergoing kidney, transplant,, immunosuppresants, are, administered. Justify., Internet my friend, 1. Treatments other than surgical removal of, kidney stone like Lithotripsy. (Breaking, down of kidney stones using shock, waves)., 2. Dietary restrictions suggested for kidney, patients.

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Exercise, 1. Choose correct option, A. Which one of the following organisms, would spend maximum energy in, production of nitrogenous waste?, a. Polar bear b. Flamingo, c. Frog, d. Shark, B. In human beings, uric acid is formed due, to metabolism of __________., a. amino acids, b. fatty acids, c. creatinine, d. nucleic acids, , I. Tubular secretion does not take place in, ________., a. DCT, b. PCT, d. collecting duct, d. Henle's loop, J. The minor calyx ____________., a. collects urine, b. connects pelvis to ureter, c. is present in the cortex, d. receives column of Bertini, , C. Visceral layer : Podocytes :: PCT :, _______, a. Cilliated cells, b. Squamous cells, c. Columnar cells, d. Cells with brush border, , K. Which one of the followings is not a part, of human kidney?, a. Malpighian body, b. Malpighian tubule, c. Glomerulus, d. Loop of Henle, , D. Deproteinised plasma is found in, __________., a. Bowman's capsule, b. Descending limb, c. Glomerular capillaries, d. Ascending limb, , L. The yellow colour of the urine is due to, presence of ___________, a. uric acid, b. cholesterol, c. urochrome, d. urea, , E. Specific gravity of urine would _______, if level of ADH increases., a. remain unaffected b. increases, c. decreases, d. stabilise, , N. In reptiles, uric acid is stored in _____, a. cloaca, b. fat bodies, c. liver, d. anus, O. The part of nephron which absorbs, glucose and amino acid is______, a. collecting tubule, b. proximal tubule, c. Henle's loop, d. DCT, , F. What is micturition?, a. Urination, b. Urine formation, c. Uremia, c. Urolithiasis, G. Which one of the following organisms, excrete waste through nephridia?, a. Cockroach b. Earthworm, c. Crab, d. Liver Fluke, H. Person suffering from kidney stone is, advised not to have tomatoes as it has, _______., a. seeds, b. lycopene, c. oxalic acid, d. sour taste, , 190, , M. Hypotonic filtrate is formed in _______, a. PCT b. DCT c. LoH d. CT, , P. Bowman's capsule is located in kidney, in the ________, a. cortex, b. medulla, c. pelvis, d. pyramids, Q. The snakes living in desert are, mainly__________, a. aminotelic, b. ureotelic, c. ammonotelic, d. uricotelic

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R. Urea is a product of breakdown of, ___________, a. fatty acids b. amino acids, c. glucose, d. fats, S. Volume of the urine is regulated, by__________, a. aldosterone b. ADH, c. both a and b d. none, 2. Answer the following questions, A. Doctors say Mr. Shaikh is suffering from, urolithiasis. How it could be explained, in simple words?, B. Anitaji needs to micturate several, times and feels very thirsty. This is an, indication of change in permeability of, certain part of nephron. Which is this, part?, C. Effective filtration pressure was, calculated to be 20 mm Hg; where, glomerular hydrostatic pressure was, 70 mm of Hg. Which other pressure is, affecting the filtration process? How, much is it?, , A, , D., E., F., G., , Name any one guanotelic organism., Why are kidneys called 'retroperitoneal'?, State role of liver in urea production., Why do we get bad breath after eating, garlic or raw onion?, , 3. Answer the following questions, A. John has two options as treatment for, his renal problem : Dialysis or kidney, transplants. Which option should he, choose? Why?, B. Amphibian tadpole can afford to be, ammonotelic. Justify., C. Birds are uricotelic in nature. Give, reason., 4. Write the explanation in your word, A. Nitya has been admitted to hospital after, heavy blood loss. Till proper treatment, could be given; how did Nitya's body, must have tackled the situation?, 5. Complete the diagram / chart with correct, labels / information. Write the conceptual, details regarding it, , RETURN TO HOMEOSTASIS, Restoration of normal, blood pressure, INPUT, , Increases glomerular, blood flow and pressure, , Decreased arterial, pressure in kidney, , Stimulates juxtaglomerular, apparatus to send a signal, to afferent arterioles, , Stimulates juxtaglomerular, apparatus to secrete renin, into the blood, , OUTPUT, , Increases blood, volume and blood, Na+ level, , ___________, , __________, , Vasodilation of, efferent arterioles, , Angiotensin I is converted, into angiotensin II, ___________, , 191, , Stimulates, juxtaglomerular, apparatus to secrete, renin into the blood

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C, B, , D, INPUT, , INPUT, , Low water concentration in, blood detected by osmoreceptors in hypothalamus, Stimulates release of, hypothalamic ADH by, posterior pituitary, , Na+ transported from, proximal convoluted, tubules into blood, , Causes higher osmotic, pressure in peritubular, blood than in filtrate, , ______________, , RETURN TO HOMEOSTASIS, , High water concentration in blood, , Facultative water, reabsorption, OUTPUT, , Inhibits, secretion, of _____, , Restoration of normal water concentration in blood, , High water, concentration in, blood, , E, 6. Prove that mammalian urine contains, urea., Practical / Project :, Visit to a nearby hospital or, pathological laboratory and collect detailed, information about different blood and urine, tests., , 192

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16. Skeleton and Movements, Can you recall?, 1., 2., 3., 4., 5., 6., , Which are different types of muscular tissues ?, Name the type of muscles which bring about running and speaking., Name the muscles which do not contract as per of our will., Which types of muscles show rhythmic contractions?, Which type of muscle is present in the diaphragm of the respiratory system ?, Name the part of human skeleton situated along the vertical axis., , Organism exhibit varieties of the, movements. Movements vary from streaming of, protoplasm to peristalsis to walking or running, etc. A movement may or may not end up into, locomotion or displacement of organism., 16.1 Movements and locomotion :, Movements : Movements may be internal or, external. Which of the above mentioned the, movements are internal? Which are external?, Can you add few more examples! Movements, may be voluntary or involuntary. Three type, of muscles bring about these movements in, human beings., a. Smooth muscles bring about involuntary, movements like peristaltic movements, in the alimentary canal, constriction and, dilation of blood vessels, etc., b. Contraction and relaxation of the heart is, controlled by cardiac muscles., c. Voluntary movements of limbs, head, trunk,, eyes, etc. are controlled by striated muscles., Locomotion : The change in locus of whole, body of living organism from one place to, another place is called locomotion. Locomotion, is for search of food, shelter, mate, breeding, ground and escape from enemy. There are four, basic types of locomotory movements found, throughout the animal kingdom., 1. Amoeboid movement : performed by, pseudopodia e.g. leucocytes., 2. Ciliary movement : performed by cilia, e.g. ciliated epithelium. In Paramecium,, cilia help in passage of food through, cytopharynx., , 3. Whorling movement : performed by, flagella e.g. Sperms., Always Remember, There are about 640 muscles in, human body. Out of these 634 are paired and, 6 muscles are unpaired., 1. Think about it, 1. Why do we shiver during winter ?, 2. Why do muscles show spasm after, rigourous contraction?, 3. Did you ever feel tickling in muscles?, 4. Muscular movement : Performed by, muscles, with the help of bones and joints., Remember : All locomotions are movements, but all movements are not locomotion., Skeletal muscles are attached to the, bones by tendons and help in the movement, of the parts of skeleton. Tendons are inelastic, thick band of collagen fibers. Movement and, locomotion is the combined action of bones,, joints and skeletal muscles., 16.2, , Location and structure of skeletal, muscles :, Major part of the muscle which moves, a bone usually do not lie on the same bone but, is located on the bone atop. e.g. Biceps and, triceps that move forearm are located in the, upper arm. At any joint, two types of bones are, present i.e. stationary and movable., , 193

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On the basis of movement, striated muscles are of three types, Agonists : (Prime, movers) Bring initial movement of, part e.g. Biceps, , Antagonists : Bring, the action opposite to that of prime, movers e.g. Triceps, , Synergists : Assist, prime movers e.g., Brachialis assist, Biceps, , Chart 16.1 Types of Skeletal Muscles, , The end of muscle attached to stationary, bone is called origin while the opposite end, attached to movable bone is called insertion., The middle thick part of muscle is called belly., All the fibres in a muscle do not extend from, end to end and there is a maximum number in, the middle. Thus, large muscles are most often, fusiform in shape., 16.3, , Working of Skeletal Muscles :, Generally muscles work in pairs and, produce opposite action e.g. Biceps (flexors), bring flexion (folding) and triceps (extensors), bring extension of elbow joint. The muscles, which bring opposite action are called, antagonistic. If one member of a pair is capable, of bending the joint by pulling of bones, the, other member is capable of straightening the, same joint also by pulling. e.g. Triceps and, Biceps of upper arm are antagonistic to each, other., In antagonistic pair of muscles, one, member is much stronger than the other. e.g., The biceps is stronger than the triceps., The fundamental characteristic of, muscle is contraction. Therefore, muscle can, only pull and not push the bone., , 1., , Some important antagonistic muscles, 1. Flexor and Extensor: Flexor muscle on, contraction results in bending or flexion of, a joint e.g. Biceps. Extensor on contraction, results in straightening or extension of a, joint e.g. Triceps., 2. Abductor and Adductor : Abductor muscle, moves body part away from the body axis, e.g. Deltoid muscle of shoulder moves, the arm away from the body. Adductor, moves body part towards the body axis e.g., Latissimus dorsi of shoulder moves the arm, near to the body., 3. Pronator and Supinator : Pronator turns, the palm downward. Supinator to turns the, palm upward., 4. Levator and Depressor : Levator raises a, body part. Depressor lowers the body part, 5. Protractor and Retractor : Protractor, move forward. Retractor move backward., 6. Sphincters : Circular muscles present in, inner wall of anus, stomach, etc. for closure, and opening., Can you tell?, 1. Why are movement and locomotion, necessary among animals?, 2. Differentiate between :, a. Flexor and extensor muscles, b. Pronator and Supinator., 3. What are antagonistic muscles? Explain, with example., , Can you recall?, , Comment on contraction of skeletal, muscles (Hint : Refer chapter on Animal, Tissues), , 194

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You are aware that both flexion and, extension take place by contraction of skeletal, muscles. Do you know, how do these muscles, contract and bring about movement and, locomotion? Striated muscles are specifically, designed to bring about vigorous contractions., Refer to ultra-microscopic structure of, skeletal muscle you have studied in animal, tissues. The contractile unit of muscles is called, sarcomere which contains contractile proteins, actin and myosin., Structure of myosin and actin filaments :, Myosin filament :, Each myosin filament is a polymerized, protein. Many monomeric proteins called, meromyosins constitute one thick filament., Myosin molecule consists of two heavy chains, (heavy meromyosin/HMM) coiled around each, other forming double helix. One end of each, of these chains is projected outwardly. It is, known as cross bridge. This end is folded into a, globular protein mass called myosin head., Two light chains are associated, with each head (Total 4 light chains/light, meromyosin/LMM). Myosin head has, a, special ATPase activity. It can split ATP to, produce energy. Myosin contributes 55% of, muscle proteins., Tail, , Heads, , Tropomyosin, , Actin, , Fig. 16.3 Actin filament, i. F actin : It forms the backbone of actin, filament. It is double stranded protein. Each, strand is composed of polymerized G actin, molecules. One ADP molecule is attached, to each G actin molecule., ii. Tropomyosin : The actin filament contains, two additional protein strands that are, polymers of tropomyosin molecules. Each, strand is loosely attached to an F actin. In, the resting stage, tropomyosin physically, covers the active binding sites for myosin, of the actin strand., iii. Troponin : It is a complex of three, globular proteins, which are attached, approximately 2/3 rd distance along each, tropomyosin molecule. It has affinity for, actin, tropomyosin and calcium ions. The, troponin complex is believed to attach the, tropomyosin to the actin. The strong affinity, of troponin for calcium ions is believed to, initiate the contraction process., 16.4, , Myosin tails are arranged to point toward, the centre of the sacromere, and the heads, point to the sides of the myofilament band., , Myosin head, , Fig. 16.2 Myosin filament, Actin filament :, It is also a complex type of contractile, protein. It consists of three different components., , Troponin, , Mechanism of muscle contraction :, Sliding filament theory was putforth by, H.E. Huxley and A.F. Huxley. It is also called, walk along theory or Ratchet theory., According to this theory, interaction, between actin and myosin is the basic cause, of muscular contraction. Actin filaments are, interdigitated with myosin filaments. (like the, crossing of fingers of two hands), The head of the myosin is joined to, the actin backbone by a cross bridge forming, a hinge joint. From this joint, head can not, tilt in forward and backward directions. This, movement is an active process which requires, use of ATP., , 195

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Myosin head contains ATPase activity., It can derive energy by the breakdown of ATP, molecule. This energy can be used for the, movement of myosin heads., During contraction process, the myosin, heads gets attached to the active site of actin, filaments and pull them inwardly, so that actin, filaments slide over the myosin filaments. This, results in the contraction of muscle fibre., ADP, P1, , , , ATP, hydrolysis, , ADP, , ADP, P1, , , , , , ATP, , ATP, , , , Fig. 16.4 Cyclic events in, muscle Contraction, Impulse from, motor nerve, , Action potential, develops in T, tubule, T tubule releases Ca++, ions in sarcoplasm, A conformation change, in troponin - tropomyosin complex, , Actin filament slide, over myosin and, contraction occurs, , 16.5, , Physiology of muscle relaxation :, When the muscle is relaxed, the active, sites remain covered with tropomyosin and, troponin complex. Due to this, myosin cannot, interact with active site of actin and therefore, contraction cannot occur. When an action, potential (impulse) comes to muscle through, motor end plate, it spreads throughout the, sarcolemma of the myofibril. The transverse, tubules of sarcoplasmic reticulum releases, large number of calcium ions into sarcoplasm., These calcium ions interact with, troponin molecules. This interaction inactivates, troponin-tropomyosin complex. This leads to, change in the structure of tropomyosin., As a result, it gets detached from the, active site of actin (F actin) filament. Thus, active site becomes uncovered. Now head of, the myosin cleaves the ATP and derives energy., Using this energy, myosin gets attached, to the uncovered active site of actin and results, in the formation of actomyosin complex., The myosin heads are now tilted, backwards and pull the attached actin filament, inwardly. This results in contraction of the, muscle fibres., Sarcomere, thick filament, (myosin filament), , Myosin head tilts and, pull actin filaments, towards them, , Relaxation, , Myosin head gets, attached to active, sites of actin, forming, acto myosin complex, Myosin head, breaks up ATP to, derive energy, , thin filament, (actin filament), , Contraction, , Fig. 16.6 Relaxation and contraction, of muscle, , Active sites of actin filaments, become uncovered, , Internet my friend, Collect information about 'T' tubules, of sarcoplasmic recticulum., , Chart 16.5 Mechanism of Muscle, Contraction, , 196

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16.6, , Relaxation of muscle fibres :, During relaxation all the events, occur in reverse direction. When stimulation, is terminated, actomyosin complex is broken, down and myosin head gets detached from, actin filaments. This process involves use of, ATP. At the same time calcium ions return, back. This is also an active process that uses, energy. Due to disappearance of calcium, ions, troponin – tropomyosin complex is, restored again. This complex covers the, active sites of actin filament. Due to this the, interaction between actin and myosin ceases, to occur and the actin filaments return, back to their original position. This results, in muscular relaxation. Like contraction,, relaxation is also an active process., Always Remember, Oxygen debt is used in oxidizing, the accumulated lactic acid aerobically, and in restoring the depleted creatine, phosphate and ATP., Rigor Mortis : Usually, some hours, after the death of an individual, its muscles, are stiffened. This muscular stiffening,, after death is rigor mortis. It helps in, fixation of hours of death after a murder., After death, the fresh supply of ATP to, muscles becomes impossible. Therefore, once the local store of ATP is finished, the, detachment of myosin from actin cannot, take place. This results in permanent state, of contraction of the muscle., Can you tell?, 1. Why are muscle rich in creatine, phosphate?, 2. What do you understand by muscle, twitch?, 3. Explain mechanism of muscle, contraction and relaxation., 4. Explain the chemical changes taking, place in muscle contraction., , 16.7, , Properties of Muscles on Electrical, Stimulation:, , A. Single muscle twitch : A muscle contraction, initiated by a single brief-stimulation is called, a single muscle twitch. It occurs in 3 stages : a, latent period of no contraction, a contraction, period and a relaxation period., B. Summation : If the muscle is stimulated before, the end of the twitch, it generates greater, tension i.e., summation or addition of effect, takes place. Repeated stimuli will produce, increasing strength of contraction (stair case, phenomenon)., C. Tetanus : If stimulation is very rapid and, frequent the muscle does not have time to, relax. It remains in a state of contraction called, tetanus., D. Refractory period : Immediately after one, stimulus, the muscle fibre cannot respond to, another stimulus. This resting or refractory, period is about 0.02 seconds., E. Threshold stimulus : For a muscle fibre, to contract, a certain minimum strength or, intensity of stimulus is required. This is called, threshold stimulus., F. All or none principle : A stimulus below, threshold will not result in contraction. A, threshold stimulus will result in contraction., This contraction leads to maximum force., Higher stimulus will not increase force of, contraction i.e. a muscle fibre contracts either, fully or not at all. This is 'all or none' principle., All types of muscle fibres and nerve fibres, obey this law., G. Oxygen debt : During strenuous exercise,, muscle’s oxygen supply rapidly becomes, insufficient, to, maintain, oxidative, phosphorylation of respiratory substrate. At, this stage, muscles contract anaerobically and, accumulate lactic acid produced by anaerobic, glycolysis. Lactic acid produces less ATP and, is toxic. It causes tiredness, pain and muscle, cramps. During recovery, oxygen consumption, of the muscle far exceeds than that in the resting, state. This extra oxygen consumed during, recovery is called oxygen debt of the muscle., , 197

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Use your brain power, , Do you remember?, 1. What are the components of our skeletal system ?, 2. What type of bones are present in our body?, 3. How do bones help us in various ways ?, , Can you compare bone,, muscle and joint which help in, locomotion with any of simple, machines you have studied earlier ?, , We can compare this unit with lever. Where joint acts as fulcrum, respective muscle, generates the force required to move the bone associated with joint., , F, R, , E, , E, , E, , F, R, , R, , F, Class I lever : The joint, between the first vertebra, and occipital condyle of skull, is an example of first class, lever. The force is directed, towards the joints (fulcrum);, contraction of back muscle, provides force while the part, of head that is raised acts as, resistance., Resistance (R), , Fulcrum (F), , Class II lever : Human body, raised on toes is an example, of second class lever. Toe, acts as fulcrum, contracting, calf muscles provides the, force while raised body acts, as resistance., , F, , E, , R, , Class III lever : Flexion of, forearm at elbow exhibit, lever of class III. Elbow joint, acts as fulcrum and Radius, and ulna provides resistance., Contracting biceps muscle, provides force for the, movement., R, , E, , F, , Effort (E), , 16.8, , Skeletal System :, Multicellular animals need support to, maintain body structure. Various groups of, organisms show various supportive structures;, either inside or outside the body or both inside, as well as outside. You have studied that these, skeletal structures are called exoskeleton., When present on outer surface of the body and, endoskeleton when they are present inside the, body., Bones and cartilage form major, endoskeletal, components., Exoskeletal, components change from lower to higher, groups of animals. These include chitinous, structures, nails, horns, hooves, scales, hair,, etc; you may add to the list., , Do any of these exoskeletal structures, help in movement and locomotion? How do, scales and plates of a snake help in movement, and locomotion? Are scales of a fish and that, of a snake similar? Find out more information, about exoskeletal structures and their role in, movement and locomotion., Can you imagine life without skeletal, system? Our skeletal system is made up of, cartilage and bone; which together form the, framework of the body. Cartilage is slightly, pliable while bones have hard matrix., , 198

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Bones form the framework of our, body and thus provide shape which give, us our identity. They protect delicate, organs thus help in smooth functioning, of body. Joints between bones help, in movement and locomotion. Bones, provide firm surface for attachment of, muscles. They are reservoirs of calcium, and one important site for haemopoiesis., Endoskeleton of an adult human, consists of 206 bones which can be, grouped into two principle divisions;, axial and appendicular skeleton., Bones of axial skeleton lie along, the longitudinal axis of human body., Bones of appendicular skeleton include, bones of fore limb, hind limb and girdles., Girdles are the bones that connect the, limbs to the axial skeleton., , Identify and label, Identify the different bones., , Fig. 16.7 Human Skeleton, , Use your brain power, 16.9, , Why are long bones slightly bent and not straight ?, , Group of skeleton :, , A. Axial Skeleton :, Skull :, Made up of 22 bones, skull is, located at superior end of vertebral, column. It consists of two main sets of, bones, cranium or brain box and facial, bones. Bones are joined by fixed or, immovable joints except for lower jaw., Cranium :, It is made up of four median, and two paired bones., F rontal bon e : Median bone (Unpaired), forms forehead, roof of orbit (eye, socket) and most of the anterior part, of cranium. It is connected to two, parietals, sphenoid and ethmoid bone., Parietal bo nes : Paired bones, form, roof of the cranium and greater portion, of sides of the cranium., , Fontal bone, Sphenoid bone, , Parietal bone, Temporal, bone, , Nasal bone, Ethmoid bone, Lacrimal bone, , Occipital, bone, , Zygomatic bone, Maxilla, Mandible, , Mastoid process, , Fig. 16.8 Lateral view of skull, Maxilla, Palatine, , Zygomatic, Sphenoid, , Condyle, , Vomer, , Parietal, , Temporal, , Fpramen, magnum, , Occipital, , Fig. 16.9 Ventral view of skull, , 199

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T em por al bon es : Paired bones situated laterally just above the ear, on either side. Each temporal bone gives out zygomatic process that, joins zygomatic bone to form zygomatic arch. Just at the base of, zygomatic process is mandibular fossa, a depression for madibles, (lower jaw bone) that forms only movable joint of skull. This bone, harbours ear canal that directs sound waves into the ear., Processes of temporal bones provide points for attachment, for various muscles of neck and tongue., O ccipi tal bon e : Present at the back of the head, this single bone, forms posterior part and most of the base of cranium. Inferior, part of this bone shows ‘Foramen magnum’ the opening through, which medulla oblongata connects with spinal cord. On either, side of foramen magnum are two prominent protuberances called, ‘Occipital condyles’. These fit into the corresponding depressions, present in 1st vertebra., , Axial skeleton :, , Skull, Cranium, Face, , 8, 14, , Hyoid, , 1, , Ear ossicles, , 6, , Vertebral, column, , 26, , Thorax, Sternum, Ribs, , 1, 24, -------------Subtotal : 80, -------------------------------Appendicular skeleton, --------------------------------, , S p henoid bon e : Median bone present at the base of the skull that Pectoral Girdle, articulates with all other cranial bones and holds them together., Clavicle, This butterfly shaped bone has a saddle shaped region called sella, Scapula, turcica. In this hypophyseal fossa, the pituitary gland is lodged., Upper Limbs, Refer : Read about sella turcica in chapter hormonal co-ordination., Ethm oid bon e : This median bone is spongy in appearance. It, is located anterior to sphenoid and posterior to nasal bones. It, contributes to formation of nasal septum and is major supporting, structure of nasal cavity., In this chapter you are going to learn about sutures, a type, of immovable joints. In skull there are many sutures present; four, prominent ones are;, 1. Coronal suture : Joins frontal bone with parietals., 2. Sagittal suture : Joins two parietal bones., 3. Lambdiodal suture : Joins two parietal bones with occipital, bone., 4. Lateral/squamous sutures : Joins parietal and temporal bones on, lateral side., , Identify and label, Name A, B, C and D, from the given figure and, discuss in group., , A, , B, , C, , 200, , D, , Humerus, Radius, Ulna, Carpals, Metacarpals, Phalanges, , 2, 2, 2, 2, 2, 16, 10, 28, , Pelvic Girdle, Hip bone, , 2, , Lower Limbs, Femur, Patella, Tibia, Fibula, Tarsals, Metatarsals, , 2, 2, 2, 2, 14, 10, , Phalanges, , 28, -------------Subtotal : 126, -------------Total : 206, , Table 16.10 Details, of Human Skeleton

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Do you know ?, , If there is a newborn in the family, you are told not to touch the head, as it is still soft. Have you seen it? Why is it so? There are six soft spots called fontanelles in, cranial bones. Eventually they get ossified at the age of two. Fontanelles provide some flexibility, to skull during birth and also for rapid growth of brain during infancy., Facial Bones : Fourteen facial bones give, characteristic shape to face. Growth of face, stops of the age of 16. Facial bones are as, under :, N asal s : Paired bones form bridge of nose., M axil l ae : Upper jaw bones, paired bones that, join with all facial bones except mandible., Upper row of teeth are lodged in these., Pal atines : Paired bones, form roof of buccal, cavity or floor of nasal cavity., Z y gom atic bon es : Commonly called cheek, bones. You have read about zygomatic arch, earlier in this chapter., L acrim al bon es : Smallest of the facial bones., These bones form medial wall of each orbit., They have lacrimal fossa that houses lacrimal, sacs. These sacs gather tears and send them to, nasal cavity., I nf erior nasal conchae : They form part of, lateral wall of nasal cavity. These help swirl, and filter air before it passes to lungs., V om er : Median, roughly triangular bone that, forms inferior portion of nasal septum., M andi bl e : Median bone that forms lower, jaw. Largest and strongest facial bone. Only, movable bone of skull. It has curved horizontal, body and two perpendicular branches i.e. rami., These help in attachment of muscles. It has, lower row of teeth lodged in it., Hyoid bone : It is a ‘U’ shaped bone that, does not articulate with any other bone. It is, suspended from temporal bone by lingaments, and muscles. It is located between mandible, and larynx. It has horizontal body and paired, projections called horns. It provides site for, attachment of some tongue muscles and, muscles of neck and pharynx., , 201, , Sphenoid, bone, , Frontal, bone, , Nasal bone, Ethmoid bone, , Temporal, bone, Sphenoid, bone, Inferior, bone, , Parietal bone, , Lacrimal bone, Maxilla, , Mandible, , Zygomatic, bone, Vomer, , Fig. 16.11 Anterior view of skull, Internet my friend, Cleft palate and cleft lip., Greater horns, (greater cornua), Lesser horns, (lesser cornua), , body, , Thyroid, cartilage, Trachea, , Fig. 16.12 Hyoid bone, Can you tell?, 1. Give schematic plan of human skeleton., 2. Enlist the bones of cranium., 3. Write a note on structure and function of, skull.

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Something interesting : If Police suspect strangulation, they carefully inspect hyoid bone, and cartilage of larynx. These get fractured during strangulation. Various such investigations, are done in case of suspicious death of an individual where ossification of sutures in skull, width, of pelvic girdle, etc. are examined to find out approximate age of victim or gender of victim, etc., You may find out information about forensic science., Try this, , Internet my friend, , Feel your spine (vertebral column). Is, it straight or curved?, , Find out information about sinuses, present in skull, functions of skull and disorder, 'sinusitis'., Can you Tell?, Why skull is important for us? Enlist, few reasons., Ear ossicles : Three tiny bones namely malleus,, incus and stapes, together called ‘ear ossicles’, are present in each middle ear., Incus articulation, , Malleus articulation, Head of malleus, Short limb, , Neck of, malleus, , Lateral, process, , Body, of incus, Anterior process, Long limb, Handle of malleus, , There are four curvatures in human spine,, cervical and lumbar curves are secondary and, convex whereas thoracic and sacral curvatures, are primary and concave. Curvatures help in, balancing in upright position, absorb shocks, while walking and also protect vertebrae from, fracture., You will study about intervertebral, discs in this chapter. Find information about, slipped disc., There are five types of vertebrae in, human spine namely, 7 cervical (neck), 12, Thoracic (chest), 5 lumbar (abdominal), 5, sacral (hip region, fused in adults forming, 1 sacrum) and 4 coccygeal (fused to form, vestigial tail bone called coccyx)., Though vertebrae vary in size, shape or, processes, they exhibit similar basic plan., 7 Curvical, vertebrae, , Incus, , Base of stapes, , Malleus, Posterior limb, , Thoracic curve, (primary), , Anterior limb, Stapes, , Cervical curve, (secondary), , Head of stapes, , 12 Thoracic, vertebrae, , Fig. 16.13 Ear ossicles, , Intervertebral, discs, , Vertebral Column :, Human backbone or vertebral column, is made up of a chain of irregular bones called, vertebrae. It consists of 33 vertebrae during, childhood. In adults, five sacral vertebrae, fuse to form one sacrum and four coccygeal, vertebrae fuse to form single coccyx, thus total, number of bones are 26., , 202, , 5 Lumbar, vertebrae, , Sacrum, , Lumbar curve, (secondary), Intervertebral, foramina, Sacral curve, (primary), , Coccyx, , Fig. 16.14 Vertebral column lateral view

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Typical Vertebra :, Each vertebra has prominent central, body called centrum. Centra of, human, vertebrae are flat in anterio-posterior aspect., Hence human vertebrae are amphiplatyan., From either side of centrum are given out two, short, thick processes which unite to form an, arch like structure called neural arch, posterior, to centrum. Neural arch forms vertebral, foramen which surrounds the spinal cord., Vertebral foramina of all vertebrae form a, continuous 'neural canal'. Spinal cord along, with blood vessels and protective fatty covering, passes through neural canal., Point where two processes of centrum, meet, neural arch is drawn into a spinous, process called neural spine. From the base of, neural arch, two articulating processes called, zygapophyses are given out on either side. The, anterior are called superior and posterior called, inferior zygapophyses. In a stack of vertebrae,, inferior zygaphyses of one vertebra articulates, with superior zygapophyses of next vertebra., This allows slight movement of vertebrae, without allowing them to slip off. At the junction, of zygapophyses, a small opening is formed, on either side of vertebra called intervertebral, foramen that allows passage of spinal nerve., From the base of neural arch, lateral processes, are given out called transverse processes., Neural arch, neural spine and transverse, processes are meant for attachment of muscles., Let us now study modifications seen, in vertebrae in different regions of vertebral, column., A tl as v ertebr a : This is a ring like 1st cervical, vertebra. It consists of anterior and posterior, arches. It does not have centrum and spinous, process. Transverse processes and transverse, foramina are large. Vertebral foramen is, large and divided into two parts by transverse, ligament. Spinal cord passes through anterior, compartment. Anterior zygapophyses, are, replaced by facets for attachment with occipital, condyle of skull that forms ‘Yes Joint’., , Spinous process (spine), Transverse process, , Lamina, , Neural arch, Pedicle, Vertebral foramen, (neural canal), Posterior (end) view, Cemtrum (body), Pedicle Lamina, Superior articular, process, , Centrum (body), Lateral view, , Spinous process, (spine), Transverse process, Inferior articular process, , Fig. 16.15 Basic plan of vertebra, Facet for articulation with, odontoid process of axis, , Anterior arch, , Anterior, portion, Facet for, articulation, with occipital, condyle, , Foramen, for vertebral, artery, , Posterior portion, , Posterior tubercle, representing spine, , Fig. 16.16 Atlas vertebra, A xis v ertebr a : This is the second cervical, vertebra. Centrum of this vertebra gives out, tooth-like ‘Odontoid Process’. This process fits, into the anterior portion of vertebral foramen of, Atlas vertebra forming pivot joint, also called, ‘No joint’., Odontoid, process, Facet for, transverse, ligament, , Pedicle, , Foramen, for vertebral, artery, , 203, , Facet, for Atlas, , Transverse, process, Body, Lamina, Spinous process, , Fig. 16.17 Axis vertebra

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7, , Typical cervical vertebrae : Vertebrae number, 3 to 6 are called typical cervical vertebrae. They, show short centrum and bifid spinous process., Transverse processes of these vertebrae are, reduced; each having large vertebrarterial canal, at it’s base for passage of vertebral artery., cerv ical v ertebr a ( V ertebr a pr om inens) :, It is the largest cervical vertebra where neural, spine straight., th, , T horacic v erteb ra : These are twelve in number, and found in chest region. Centrum of thoracic, vertebrae is heart shaped and all processes are, well developed. Except for vertebrae number, 11, 12; transeverse process of other thoracic, vertebrae show facets for attachment with ribs., Spine (spinous process), Lamina, Transverse process, , S acru m : Sacrum is a triangular bone formed, by fusion of five sacral vertebrae. It is located in, pelvic cavity between two hip bones. Anterior, end of sacrum is broad and posterior end is, narrow. Vertebral foramina that are formed, by fusion of vertebrae can be seen. Reduced, neural spines can be observed projecting from, dorsal aspect of sacrum. It gives strength to, pelvic girdle., C occy x : Coccyx is formed by fusion of four, coccygeal vertebrae. It is reduced and does, not show vertebral foramina and spinous, processes. Transverse processes of coccygeal, vertebrae are reduced. It is a triangular bone., , Pedicel, Facet for head of rib, Heart- shaped centrum, , Surface for, articulation, with the, left ilium, , S2, S3, S4, S5, , Coccyx, , C1, C2, C3, C4, , Fig. 16.20 Sacrum and Coccyx, , Fig. 16.18 Thoracic vertebra, L u m bar v ertebr a : There are five lumbar, vertebrae. These are well developed vertebrae, that exhibit all characters of a typical vertebra., Centrum is kidney shaped., , Thoracic cage : It consists of twelve thoracic, vertebrae; which are already discussed; twelve, pairs of ribs and breast bone, the sternum., Sternum, Manubrium, Body, , Rib, , Body, , Spinous, process, , Articular, process for L5, , S1, , Foramina, for passage, of nerves, , Facet for tubercle of rib, Vertebral foramen, , Superior, articular, process, , Promontory, , Articulating, surface for, intervertebral, disc(body), , Pedicle, , Lamina, , Xiphoid, process, , Vertebral, foramen, Transverse, process, , Vertebral column, , Fig. 16.19 Lumbar vertebra, , Fig. 16.21 Thoracic cage, , Can you tell?, 1. Explain the structure of a typical vertebra., 2. How will you identify a thoracic vertebra?, 3. Write a note on curvatures of vertebral column and mention their importance., , 204

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Sternum : It is a flat, narrow bone, around 15, cms in length. It is placed medially in anterior, thoracic wall (chest region). It consists of three, distinct parts-manubrium, body and xiphoid, processes., Manubrium shows two notches on, anterio-lateral side for attachment with clavicle, of each side. It also shows two notches on each, of the lateral side for attachment of first two, pairs of ribs., Body of sternum is a flat bone that, shows five notches on lateral aspect which, are meant for direct or indirect attachment of, ribs. Ribs are attached to sternum by means, of cartilaginous extensions called coastal, cartilages., Xiphoid process is lowermost part of, sternum which is cartilaginous initially and, gets ossified in adults. It provides space for, attachment of diaphragm and abdominal, muscles., Suprasternal or, jugular notch, , On the ventral side, the ribs may or may, not attach to the sternum. Depending on their, attachment, ribs are classified into three types., i. T ru e ribs : First seven pairs of ribs are, attached directly to the sternum by means, of their coastal cartilages., ii. F al se ribs : Coastal cartilages of ribs no., 8, 9 and 10 are attached to rib number 7 on, either side and not directly to the sternum., Hence these are called false ribs., iii. F l oating ribs : Last two pairs of ribs have, no ventral connection. Hence are called, floating ribs., Space between ribs is called intercoastal, space. Ribs provide space for attachment of, intercoastal muscles., , Costal, groove, , Clavicular, notch, , Inferior border, , Sternal, angle, Body, Xiphoid, process, , Neck, , Head, articulates with, vertebral, bodies, , Facet articulates, with transverse, process of vertebra, , Shaft, , Manubrium, , Ribs, , Tubercle, , Angle, , Depression for, costal cartilage, , Fig. 16.23 Rib, Something interesting :, Approximately 8 % of humans have, an extra pair of ribs attached to the lumbar, vertebra. Such a rib is found in some types, of gorillas. Hence 13th pair of ribs is called, gorilla rib., , Fig. 16.22 Sternum, Rib : A rib is a 'C' shaped bone that is attached, to respective thoracic vertebrae on dorsal, side. Twelve pairs of ribs are attached to, twelve thoracic vertebrae. For this attachment,, posterior ends of ribs have two protuberances, namely the head and tubercle. The head of, rib attaches to facet formed by demifacets, of adjacent thoracic vertebrae at the base, of transverse processes. Tip of transverse, processes of these vertebrae also have facets, for attachment of ribs where tubercles of ribs, are attached., , B., Appendicular skeleton : As mentioned, earlier in this chapter, appendicular skeleton, consists of bones of limbs and girdles., Pectoral girdle : Also called shoulder girdle, it, attaches forelimb skeleton with axial skeleton., There are two pectoral girdles, each consists of, a shoulder blade or scapula and collar bone or, clavicle., , 205

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Clavicle, Acromion, Caracoid, process, Glenoid, cavity, , Scapula, , Humerus, , Body, , Humerus : This is the bone of upper arm. It, has hemispherical head at it's proximal end., On either side of head of humerus are, present a pair of projections termed greater and, lesser tubercles. There is a deep groove between, the tubercles called bicipital groove where a, tendon of biceps muscle is attached., Shaft of humerus shows deltoid, tuberosity. Distal end of humerus shows pulley, like part called trochlea that articulates with, ulna., , Fig. 16.24 Pectoral girdle, , Scapula : It is a large, flat, triangular bone that, occupies posterior chest wall extending from, second to seventh ribs. It is attached to axial, skeleton by muscles and tendons., At it’s lateral angle, scapula bears a, concave socket called glenoid cavity. Head, of humerus (the upper arm bone) fits into, the glenoid cavity. Two processes arise from, scapula, a beak like coracoid process that, projects from lateral angle of scapula and, acromion process, easily felt as high point of, shoulder. Both are meant for attachment of, muscles., Bones of forelimb : It consists of humerus,, radius and ulna (together forming forearm, bones), Bones of wrist -the carpals, bones of, palm-the metacarpals and bones of digitsphalanges together making to 30 bones., , Can you recall?, , How does humerus form ball and, socket joint? Where is it located ?, , Head, , Bicipital, groove, , Clavicle : It is ‘s’ shaped slender bone. One end, of clavicle is attached to acromion process of, scapula. The other rounded end called sternal, end attaches to manubrium of sternum. This, connects upper arm skeleton to axial skeleton., , 1., , Lesser, tubercle, , Greator, tubercle, , Right humerous, anterior aspect, Radial, fossa, lateral, epicondyle, , Coronoid, fossa, Medial, epicondyle, Trochlea, , Capitalum, , Fig. 16.25 Humerus, Radius and Ulna : Radius is located laterally, on thumb side of the forearm. Proximal end of, radius has disc like head that articulates with, humerus bone. The shaft of radius widens, distally to form styloid process., Ulna is located medially on little finger, side of forearm. At the proximal end of ulna, there is a prominent process called 'Olecranon, process’ that forms elbow joint with humerus, bone. On the lateral side, near the upper end of, ulna is present the radial notch into which the, side of head of radius is fixed., Radius and ulna articulate with each, other at upper and lower extremities by superior, and inferior radio-ulnar joints. In between the, shaft of two bones, interosseous membrane is, present., , 206

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Olecranon, Head, , The two pubis bones are joined medially, by cartilaginous joint called pubic symphysis., Pubis and ischium together form a ring of bone, that encloses a space called obturator foramen., , Coronoid, process, , Radius and ulna, anterior aspect, Radius, Styloid, process of, radius, , Sacrum, Ulna, , Acetabulum, , Styloid process, of ulna, , Superior, ramus, of pelvis, , Fig. 16.26 Radius and Ulna, Carpals : These are bones of wrist, arranged in, two rows of four each., Metacarpals : Five elongated metacarpals, form bones of palm. Their proximal ends join, with carpals and distal ends form knuckles., Phalanges : These are bones of fingers and, thumb. Four fingers have three phalanges each, and thumb has two; thus making it fourteen, phalanges in each hand., , Obturator, foramen, inferior ramus of pelvis, , Fig. 16.28 Pelvic girdle, Bones of lower limb :, Femur : The thigh bone is the longest a bone in, the body. The head is joined to shaft at an angle, by a short neck. It forms ball and socket joint, with acetabulum cavity of coxal bone., The lower one third region of shaft, is triangular flattened area called popliteal, surface. Distal end has two condyles that, articulate with tibia and fibula., Greater trochanter, , Carpals, , Head, Neck, , Metacarpals, , Lesser, trochanter, , Phalanx 1, Phalanx 2, , Shaft, , Phalanx 3, , Fig. 16.27 Carpals, Metacarpals, and Phalanges, , Lateral, condyle, , Pelvic girdle : Pelvic or hip girdle connects, hind limb skeleton with axial skeleton. It is, made up of two hip bones called coxal bones., They unite posteriorly with sacrum. Each large, irregularly shaped bone, the coxal bone is made, up of three parts, ilium, ischium and pubis. At, the point of fusion of three bones, a cavity, called acetabulum is present that forms ball and, socket joint with thigh bone., , Medial, condyle, , Fig. 16.29 Femur, Patella : Also called knee cap is a sesamoid, bone. It is a flat rounded bone with a pointed, lower end., , 207, , Base, Apex, , Fig. 16.30 Patella

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Tibia and fibula : These are the two long bones, of shank or lower le.g. The two are connected, to each other at the extremities. In between the, two bones interosseous membrane is present., , Phalanges : These are the bones of the toes., Except the big toe which has two phalanges,, rest four toes have three phalanges each., Can you tell?, , Medial condyle, Lateral condyle, , 1. Differentiate between skeleton of palm, and foot., 2. Explain the longest bone in human body., , Facet for, head of fibula, Fibula, Tibia, , Do you remember?, , Lateral, malleolus, , 1. What are joints? What are their types?, 2. What types of joint is present at knee?, , Medial, malleolus, , Imagine, , Fig. 16.31 Tibia and Fibula, , If your elbow joint would be a fixed, type of joint and joint between teeth and gum, would be freely movable., , Tibia : It is much thicker and stronger than, fibula. It’s broad and expanded upper end, articulates with femur. Lower end articulates, with talus, a tarsal bone., Fibula : It is a long slender bone on lateral side, of tibia., Tarsals : These are the bones of ankle. Seven, tarsals are arranged in three row, two proximal,, one intermediate and four distal., , 16.10 Types of joints :, You have studied about joints in, previous standard. Without joints, various, movements of the body wouldn’t be possible., A point where two or more bones get, articulated is called joint or articulation or, arthrosis. Study of joints is called arthrology., Though bones are rigid, the ligaments, Calcaneum, that cover the bones, forming a joint render, (heel bone), Talus, slight flexibility to the bones., Tarsals, Joints are classified based on degree of, flexibility or movement they permit into three, Metatarsals, types namely, fibrous joints, which are also, Base, known as synarthroses or immovable joints,, Shaft, Phalanx 1, cartilagenous or slightly movable joints also, Head, Phalanx 2, called amphiarthroses and lastly synovial or, Phalanx 1, Phalanx 3, freely movable or diarthroses type of joints., Phalanx 2, Big toe, Degree of movement of joints in various, parts, of, your body is so apt! We must always, Fig. 16.32 Tarsals, Metatarsals and phalanges, appreciate the design of our body., , Metatarsals : Five metatarsal bones support the, sole region of the foot. Proximally they attach, with distal row of tarsals. Distally metatarsals, articulate with phalanges., , Synarthroses : In this joint, the articulating, bones are held together by means of fibrous, connective tissue. Bones do not exhibit, movement. Hence it is immovable or fixed type, of joint., , 208

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Fibrous tissue, , Bone, , Type of suture, Butt joint, , Character, Square edged, , Scarf joint, , Tapering, , Lap joint, , Over lapping, , Serrate joint, , Irregular/Inter, locking, , Diagram, , Example, Two nasal, bones, Various skull, bones, Temporal and, parietal bone, Various skull, bones, , Table 16.34 Types of Sutures, Fig. 16.33 Structure of Sutures, Fibrous joints are further classified into, sutures, syndesmoses and gomphoses., Sutures : It is composed of thin layer of a, dense fibrous connective tissue. Sutures are, places of growth. They remain open till growth, is complete. On completion of growth they tend, to ossify. Sutures may permit some moulding, during childhood. Sutures are further classified, into different types as shown in Table 16.34., Syndesmoses : It is present where there is, greater distance between articulating bones., At such locations, fibrous connective tissue, is arranged as a sheet or bundle. e.g. Distal, tibiofibular ligament, inter osseous membrane, between tibia and fibula and that between, radius and ulna., Tibia, Fibula, , Interosseous, ligament, , Socket, Gomphosis, , Root of, tooth, , Periodontal, ligament, , Fig. 16.36 Gomphoses, A. Cartilagenous or slightly movable joints :, These are also called as amphiarthroses., These joints are neither fixed nor freely, movable. Articulating bones are held together, by hyaline or fibrocartilages. They are further, classified as, a. Synchondroses : The two bones are, held together by hyaline cartilage. They, are meant for growth. On completion of, growth, the joint gets ossified. Example:, Epiphyseal plate found between epiphysis, and diaphysis of a long bone, Rib – Sternum, junction., Epiphyseal plates, , Ulna, , Epiphysis, , Radius, Epiphysis, , Fig. 16.35 Syndesmoses, Gomphoses : In this type of joint a cone shaped, bone fits into a socket provided by other bone., e.g. Tooth and jow bones., , 209, , Diaphysis, , Fig. 16.37 Synchondroses

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b. Symphysis : In this type of joint, broad flat, disc of fibrocartilage connects two bones., These occur in midline of the body. One, example of this type of joint is intervertebral, discs. Can you write another example?, B. Synovial joints or freely movable joints :, They are also called as diarthroses., It is characterized by presence of a space, called synovial cavity between articulating, bones that renders free movement at the joint., Articulating surfaces of bones at a synovial, joint are covered by a layer of hyaline cartilage., (Bones do not touch to each other). It reduces, friction during movement and helps to absorb, shock. Synovial cavity is lined by synovial, membrane that forms synovial capsule., Synovial membrane secretes synovial fluid., , If the joint is immobile for a while, the, synovial fluid becomes viscous and as joint, movement starts, it becomes less viscous., The joint is provided with capsular ligament, and numerous accessory ligaments. The, fibrous capsule is attached to periosteum of, articulating bones. The ligament helps in, avoiding dislocation of joint. Let us study, types of synovial joints. Note that any type, of synovial joint will show above mentioned, components., Pivot joint : Here, the rounded or pointed, surface of one bone articulates with a ring, formed partly by another bone and partly, by ligament. Rotation only around it’s own, longitudinal axis is possible. Example : In joint, between atlas and axis vertebrae, head turns, side ways to form ‘NO’ joint., , Ligament, Synovial cavity, (contains synovial, fluid), Articular, (hyaline) cartilage, , Odoytoid, process, Transverse, ligament, Atlas, , Fibrous, layer, , Axis, Articular, capsule, , Fig. 16.39 Pivot joint, , Synovial, membrane, , Fig. 16.38 Synovial joint, Synovial fluid is a clear, viscous, straw, coloured fluid similar to lymph. It is viscous, due to hyaluronic acid. Fluid also contains, nutrients, mucous and phagocytic cells to, remove microbes. Synovial fluid lubricates, the joint, absorbs shocks, nourishes the, hyaline cartilage and removes waste materials, from hyaline cartilage cells (as cartilage is, avascular) phagocytic cell destroy microbes, and cellular debris formed by wear and tear of, the joint., , Use your brain power, , Ball and socket joint : Ball like surface of one, bone fits into cup like depression of another, bone forming a moveble joint. Multiaxial, movements are possible. This type of joint, allows movements along all three axes and in, all directions. Example : Shoulder and hip joint, Neck of femur, , Pelvis, Cartilage, Head of, femur, , Fig. 16.40 Ball and socket joint, , Why are warming up rounds essential before regular exercise?, , 210

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Hinge joint : In a hinge joint, convex surface, of one bone fits into concave surface of another, bone. In most hinge joints one bone remains, stationery and other moves. Angular, opening, and closing motion like that of a hinge is, possible. In this joint only monoaxial movement, takes place like flexion and extension. Example, : Elbow and knee joint., Bicep, , Humerus, Tricep, , Joint capsule (with, synovial fluid), , Saddle joint : This joint is a characteristic of, H omo sapiens. Here, articular surface of one, bone is saddle-shaped and that of other bone, fits into such saddle as a sitting rider would sit., i.e. each bone has both concave and convex, areas. It is a modified condyloid joint in which, movement is somewhat more free. It is a biaxial, joint that allows flexion, extension, abduction,, adduction and circumduction. Example :, Carpometacarpellar jont between trapezium, carpal and metacarpal of thumb., , Radius, Cartillage, , Ulna, , Fig. 16.41 Hinge joint, , Carpal (Trapezium), , Condyloid joint : It is an ellipsoid joint. The, convex oval shaped projection of one bone fits, into oval shaped depression in another bone. It, is a biaxial joint because it permits movement, along two axes viz. flexion, extension,, abduction, adduction and circumduction is, possible. Example : Metacarpophalyngeal joint, Radius, , Ulna, , Synovial, cavity, , Synovial, membrane, , Fig. 16.43 Saddle joint, Can you tell?, 1. Classify various type of joints found in, human body. Present the information in, the form of chart. Give examples of each, type., 2. Human beings can hold an object in a, better manner than monkeys. Why?, 3. What makes the synovial joint freely, moveable?, , Ligament, , Articular, cartilage, , Metacarpal #1, , Carpals, , Fig. 16.42 Condyloid joint between, radius and carpals, , Internet my friend, , Gliding joint : A planar joint, where articulating, surfaces of bones are flat or slightly curved., These joints are non-axial because motion they, allow does not occur along an axis or a plane., Example : Intercarpal and intertarsal joints., , 211, , Now a days we hear from many, elderly people that they are undergoing knee, replacement surgery. Find out why one has to, undergo knee replacement; how it is carried, out and how it can be prevented.

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16.11 Disorders related to muscles :, Muscular dystrophy : It is a gradual wasting, disease affecting various groups of muscles., These are genetically inherited in families., Usually voluntary skeletal muscles are, weakened whereas internal muscles such as, diaphragm are not affected. Duchenne type, usually occurs in boys affecting lower limbs., Limb girdle muscular dystrophy affects the, muscles of shoulders or hips and it usually, starts in adults of 20-35 years. No treatment, appears to cure the disease., Myasthenia gravis : It is a weakness of skeletal, muscles. It is caused by an abnormality at the, neuromuscular junction that partially blocks, contraction. It is an autoimmune disorder, caused by an excess of certain antibodies, in the blood stream. Antibodies bind to, accetylecholine receptors of neuromuscular, junction. Thus transmission of nerve impulses, to the muscle fibres is blocked. This causes, progressive and extensive muscle weakness., It may affect the eye and eyelid movements,, facial expression and swallowing. The degree of, muscle weakness varies form local to general., Example of symptoms are – Ptosis, (diplopia, or double vision) difficulty in swallowing,, chewing and speech., 16.12 Disorders related to bones :, Arthritis : It is an inflammation of joints. It is, a painful disorder of bones, ligaments tendons, etc. In this disorder, joints become swollen, stiff, and painful. It can lead to disability. Arthritis is, of three types., i. Osteoarthritis : In this, joint cartilage is, degenerated. It is caused by various factors, like aging, obesity, muscle weakness, etc., This is most common type of arthritis that, affects hands, knees and spine., ii. Gouty arthritis (Gout) : In this disorder, joint pain occurs due to deposition of uric, acid in joints. If uric acid is produced in, excess or is not excreted, it accumulates, in joints as sodium urate and degenerates, cartilage, causing inflammation and pain., It generally affects joints of feet., , iii. Rheumotoid arthritis : It is an autoimmune, disorder where body’s immune system, attacks it’s own tissues. In rheumatoid, arthritis, synovial membrane swells up and, starts secreting extra synovial fluid. This, fluid exerts pressure on joint and makes it, painful. Membrane may develop abnormal, granulation tissue called pannus. Pannus, may erode cartilage. Fibrous tissue gets, ossified and may lead to stiffness in joints., Find out, You must have heard of Sachin, Tendulkar suffering from 'tennis elbow', a, cricketer suffering from a disorder named, after another game. Can common people too, suffer from this disorder?, Find out more information about this, disorder., Internet my friend, Find out information about types of, fractures and how they heal., Osteoporosis : In this disorder, bones become, porous and hence brittle. It is primarily age, related disease more common in women than, men. As age advances, bone resorption outpaces, bone formation hence bones loose mass and, become brittle. More calcium is lost in urine,, sweat etc. than it is gained through diet. Hence, prevention of disease is better than treatment, by consuming adequate amount of calcium, and exercise at young age. Osteoporosis may, be caused due to decreasing estrogen secretion, after menopause, deficiency of vitamin D,, low calcium diet, decreased secretion of sex, hormones and thyrocalcitonin., Apart from fractures, osteoporosis may, lead to shrinkage of vertebrae, height loss,, hunched back and bone pain., , 212

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Exercise, 1. Choose the correct option, A. The functional unit of striated muscle is, .............., a. cross bridges, b. myofibril, c. sarcomere, d. z-band, , G. Hyper-secretion of parathormone can, cause which of the following disorders?, a. Gout, b. Rheumatoid arthritis, c. Osteoporosis d. Gull's disease, H. Select correct option between two nasal, bones, , B. A person slips from the staircase and, breaks his ankle bone. Which bones are, involved?, a. Carpals, b. Tarsal, c. Metacarpals, d. Metatarsals, C. Muscle fatigue is due to accumulation of, ........, a. pyruvic acid, b. lactic acid, c. malic acid, d. succinic acid, D. Which one of the following is NOT, antagonistic muscle pair?, a. Flexo-extensor, b. Adductor-abductor, c. Levator-depressor, d. Sphinetro-suprinater, , b., , c., , d., , 2. Answer the following questions, A. What kind of contraction occurs in your, neck muscles while you are reading your, class assignment?, B. Observe the diagram and enlist, importance of 'A', 'B' and 'C'., , E. Swelling of sprained foot is reduced by, soaking in hot water containing a large, amount of common salt,, a. due to osmosis, b. due to plasmolysis, c. due to electrolysis, d. due to photolysis, F., , a., , Role of calcium in muscle contraction, is .........., a. to break the cross bridges as a, cofactor in the hydrolysis of ATP, b. to bind with troponin, changing its, shape so that the actin filament is, exposed, c. to transmit the action potential, across the neuromuscular junction., d. to re-establish the polarisation of, the plasma membrane following an, action potential, , 213, , A, B, , C, , C. Raju intends to train biceps; while, exercising using dumbbells, which joints, should remain stationary and which, should move?, D. In a road accident, Moses fractured his, leg. One of the passers by, tied a wodden, plank to the fractured leg while Moses, was rushed to the hospital Was this, essential? Why?, E. Sprain is more painful than fracture., Why?, F. Why a red muscle can work for a, prolonged period whereas white muscle, fibre suffers from fatigue after a shorter, work? (Refer to chapter animal tissues.)

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3. Answer the following questions in detail, A. How is the structure of sarcomere suitable, for the contractility of the muscle?, Explain its function according to sliding, filament theory. (Refer to chapter animal, tissues.), B. Ragini, a 50 year old office goer, suffered, hair-line cracks in her right and left, foot in short intervals of time. She was, worried about minor jerks leading to hair, line cracks in bones. Doctor explained, to her why it must be happening and, prescribed medicines., What must be the cause of, Ragini's problem? Why has it occurred?, What precautions she should have taken, earlier? What care she should take in, future?, C. How does structure of actin and myosin, help muscle contraction?, D. Justify the structure of atlas and axis, vertebrae with respect to their position, and function., E. Observe the blood report given below, and diagnose the possible disorder., , 4. Write short notes on following points, A. Actin filament, B. Myosin filament, C. Role of calcium ions in contraction and, relaxation of muscles., 5. Draw labelled diagrams, A. Synovial joint., B. Different cartilagenous joints., Practical / Project :, Identify the following diagrams and, demonstrate the concepts in classroom., , Report D, PERFECT PATHOLOGY, Reg. No. :_______, Dr.________________________, Date:________, Patient Name :________________ Age:_____ M/F, Reference:, , Examination of Blood, Test, Uric Acid, Blood Urea, Nitrogen (Bun), , Result, 9.2, 24, , Normal value, 2.5 - 7.0 mg/l, 10 - 20 mg/dl, , 214, , A, , B, , C

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Reference (Book list), 1. Textbook of Medical Physiology (11th edition, 2006) Guyton and Hall. - Elsevier Saunders., 2. Principles of Anatomy and Physiology (13th edition) Tortora and Derrickson. - John Wiley and, sons., 3. The Insects - Structure and Function (5th edition) R. F. Chapman- Cambridge University Press., 4. IMM's General Textbook of Entomology (Vol-I) (10th edition) Richard and Davies. - Chapman, and Hall, John Wiley and Sons., 5. Anatomy and Physiology in Health and Illness (9th edition, 2004) Waugh, A. and Grant, A.Churchill Livingstone., 6. Cell and Molecular Biology (1987) - E. D. P. DeRobertis and E.M.P. DeRobertis. - Lea and, Febiger, USA., 7. Cell Biology (3rd edition, 1983) - C. B. Powar, Himalaya Publisher., 8. Advanced Biology- Principles and Applications (2nd edition, 2008) C. J. Clegg, Hodder edition., 9. Basic Botany (1971) (1st edition) - Mridula Datta - Allied Publication., 10. Plant Physiology (3rd edition, 2002) Taiz and Zeiger, - Sinauer Associates., 11. Plant Physiology (4th edition) Pandey and Sinha, Vikas Publisher., 12. Plant Classification (2nd edition, 1976) Lyman Benson - Oxford and IBH Publisher., 13. Advanced Plant Taxonomy (2016), A. K. Mondal, New Central Book Age., 14. Plant Physiology (1986) Salisbury and Ross, CBS Publishers., 15. Biology for IB DIPLOMA (2007), C. S. CLEGG, HODDER Edition., 16. Biology for Cambridge International AS and A Level - C. J. Clegg - Cambridge., 17. Biology Course Book (3rd edition) Jones, Fosbery, et. al, (2013) - Cambridge., 18. Principles of Biochemistry (4th edition, 2004), Nelson and Cox W. H. Freeman and Co., 19. Harper's Illustrated Biochemistry (26th edition), Murray, et. al, - The McGraw - Hill Co., 20. Molecular Biology of the Cell (5th edition), Bruce Alberts, et. al, - Garland Science., 21. Plant Systematics - Michael G. Simpson, Elsevier Aca. Press., 22. A Modern Text book of Zoology - Invertebrates - (2009), R. L. Kotpal. - Rastogi Publications., 23. A Modern Text book of Zoology - Vertebrates - (2009), R. L. Kotpal. - Rastogi Publications., 24. Invertebrates (3rd edition), Richard Brusca, et. al, Sinaur Associates Inc., 25. Invertebrates - Britannica Illustrated Science Library., 26. Vertebrates - Comparative Anatomy, Function, Evolution (5th edition), - Kenneth V. Kardong,, McGraw Hill., , 215

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