Page 2 :
Production Team, , Anil Kumar Sharma, , Published at Delhi Bureau of Text Books , 25/2 Institutional Area, Pankha, Road, New Delhi-110058 by Prabhjot Singh, Secretary, Delhi Bureau of, Text Books and Printed by Arihant Offset, New Delhi-110043
Page 3 :
MANISHA SAXENA, IAS, , DO No. DE. 5/228/Exam/Message/S.M./2018, Dated, , MESSAGE, The importance of adequate practice during examinations can never be, overemphasized. I am happy that support material for classes IX to XII has been, developed by the Examination Branch of Directorate of Education. This material is, the result of immense hard work, co-ordination and cooperation of teachers and, group leaders of various schools. The purpose of the support material is to impart, ample practice to the students for preparation of examinations. It will enable the, students to think analytically & rationally and test their own capabilities and level of, preparation., The material is based on latest syllabus prepared by the NCERT and adopted, by the CBSE for the academic session 2020-21 and covers different levels of difficulty., I expect that Heads of Schools and Teachers will enable and motivate students to, utilize this material during zero periods, extra classes and regular classes best to, their advantage., I would like to compliment the team of Examination Branch for their diligent, efforts of which made it possible to accomplish this work in time. I also take this, opportunity to convey my best wishes to all the students for success in their, endeavours., , (MANISHA SAXENA)
Page 11 :
DIRECTORATE OF EDUCATION, Govt. of NCT, Delhi, SUPPORT MATERIAL, (2020-2021), , BIOLOGY, Class : XI, , NOT FOR SALE, , PUBLISHED BY : DELHI BUREAU OF TEXTBOOKS
Page 14 :
9. BIOLOGY (Code No. 044), The present syllabus reinforces the ideas introduced till the secondary classes., It provides the students with new concepts along with an extended exposure to, contemporary areas of the subject. The syllabus also aims at emphasizing on, the underlying principles that are common to both animals and plants as well as, highlighting the relationship of biology with other areas of knowledge. The format, of the syllabus allows a simple, clear, sequential flow of concepts without any, jarring jumps. The syllabus also stresses on making better connections among, biological concepts. It relates the study of biology to real life through the use of, technology. It links the discoveries and in novations in biology to everyday life, such as environment, industry, health and agriculture. The updated syllabus also, focuses on reducing the curriculum load while ensuring that ample opportunities, and scope for learning and appreciating basic concepts of the subject continue to, be available within its framework. The prescribed syllabus is expected to :, , , , , , , , , , , , Promote understanding of basic principles of Biology, Encourage learning of emerging knowledge and its relevance to individual, and society, Promote rational/scientific attitude towards issues related to population,, environment and development, Enhance awareness about environment issues, problems and their, appropriate solutions., Create awareness amongst the learners about diversity in the living, organisms and developing respect for other living beings, Appreciate that the most complex biological phenomena are built on, essentially simple processes, , It is expected that the students would get an exposure to various branches of, Biology in the syllabus in a more contextual and friendly manner as they study, its various units., , ii
Page 15 :
Time : 3 Hours, , BIOLOGY (Code No. 044), Course Structure, Class XI (2020-21), (Theory), , Unit , , Title, , Max. Marks : 70, , No. of Periods, , Marks, , I, , Diversity of Living Organisms, , 23, , 10, , II, , Structural Organisation in Plants and Animals, , 22, , 12, , III, , Cell : Structure and Function, , 35, , 14, , IV, , Plant Physiology, , 40, , 17, , V, , Human Physiology, , 40, , 17, , 160, , 70, , Total, , Unit–I Diversity of Living Organisms, 23 Periods, Chapter–1 : The Living World, What is living ? Biodiversity; Need for classification; three domains of, life : taxonomy and systematics; concept of species and taxonomical hierarchy;, binomial nomenclature; tools for study of taxonomy-museum, zoological parks,, herbaria, botanical gardens., Chapter–2 : Biological Classification, Two kingdom classification, Five kingdom classification; Salient features and, classification of Monera,Protista and Fungi into major groups; Lichens,Viruses, and Viroids., Chapter–3 : Plant Kingdom, Salient features and classification of plants into major groups – Algae,, Bryophyta, Pteriodophyta, Gymnospermae and Angiospermae (three to five, salient and distinguishing features and at least two examples of each category);, Angiosperms –classification upto class , characteristic features and examples., Chapter–4 : Animal Kingdom, Salient features and classification of animals non-chordates up to phyla, level and chordates up to class level (three to five salient features and at least two, examples of each category)., (No live animals or specimen should be displayed.), iii
Page 16 :
Unit–II Structural Organisation in Animals and Plants, , 22 Periods, , Chapter–5 : Morphology of Flowering Plants, Morphology and modifications : Internal morphology of different plants :, root, stem, leaf, Inflorescence, flower, fruit and seed. (to be dealt with relevant, experiments of the Practical Syllabus)., Chapter–6 : Anatomy of Flowering Plants, Anatomy and functions of different tissues., Chapter–7 : Structural Organisation in Animals, Animal tissues : Morphology, anatomy and functions of different systems, (digestive, circulatory, respiratory, nervous and reproductive) of an insect, (cockroach), (a brief account only), Unit–III Cell : Structure and Function, , 35 Periods, , Chapter–8 : Cell-The Unit of Life, Cell theory and cell as the basic unit of life : Structure of prokaryotic and, eukaryotic cells; Plant cell and animal cell; cell envelope; cell membrane, cell, wall; cell organelles–structure and function; endomembrane system, endoplasmic, reticulum, Golgi bodies, lysosomes, vacoules ; mitochondria, ribosomes, plastids,, microbodies; cytoskeleton, cilia, flagella, centrioles (ultrastructure and function);, nucleus., Chapter–9 : Biomolecules, Chemical constituents of living cells : biomolecules, structure and function of, proteins, carbohydrates, lipids, nucleic acids, enzymes, types, properties, enzymes, action., Chapter–10 : Cell Cycle and Cell Division, Cell cycle, mitosis, meiosis and their significance., Unit–IV Plant Physiology, , 40 Periods, , Chapter–11 : Transport in Plants, Movement of water, gases and nutrients; cell to cell transport, Diffusion,, facilitated diffusion, active transport; plant-water relations, Imbibition, water, potential, osmosis, plasomlysis; long distance transport of water–Absorption,, iv
Page 17 :
apoplast, symplast, trranspiration pull, root pressure and guttation; transpiration,, opening and closing of stomata; Uptake and translocation of mineral nutrients–, Transport of food, phloem transport, massflow hypothesis., Chapter–12 : Mineral Nutrition, Essential minerals, macro-and micronutrients and their role; deficiency, symptoms; mineral toxicity; elementary idea of hydroponics as a method to study, mineral nutrition; nitrogen metabolism, nitrogen cycle, biological nitrogen fixation., Chapter–13 : Photosynthesis in Higher Plants, Photosynthesis as a mean of autotrophic nutrition; site of photsynthesis,, pigments involved in photosynthesis (elementary idea); photochemical and, biosynthetic phases of photo-synthesis, cyclic and non cyclic photophosphorylation;, chemiosmotic hypothesis; photorespiration; C3 and C4 pathways; factors affecting, photoshynthesis., Chapter–14 : Respiration in Plants, Exchange of gases; cellular respiration–glycolysis, fermentation (anaerobic),, TCA cycle and electron transport system (aerobic); energy relations–number of, ATP molecules generated; amphibiotic pathways; respiratory quotient., Chapter–15 : Plant–Growth and Development, Seed germination; phases of plant growth and plant growth rate; conditions, of growth; differentiation, dedifferentiation and redifferentiation;’ sequence of, developmental processes in a plant cell; growth regulators–auxin, gibberellin,, cytokinin, ethylene, ABA; seed dormancy; vernalisation; photoperiodism., Unit–V Human Physiology, , 40 Periods, , Chapter–16 : Digestion and Absorption, Alimentary canal and digestive glands, role of digestive enzymes and, gastrointestinal hormones; Peristalsis, digestion, absorption and assimilation of, proteins, carbohydrates and fats; calorific values of proteins, carbohydrates and, fats; egestion; nutritional and digestive disorders–PEM, indigestion, constipation,, vomiting, jaundice, diarrhoea., v
Page 18 :
Chapter–17 : Breathing and Exchange of Gases, Respiratory organs in animals (recall only); Respiratory system in human;, mechanism of breathing and its regulation in humans–exchange of gases, transport, of gases and regulation of respiration, respiratory volume; disorders related to, respiration–asthma, emphysema, occupational respiratory disorders., Chapter–18 : Body Fluids and Circulation, Composition of blood, blood groups,coagulation of blood; composition of, lymph and its function; human circulatory system–structure of human heart and, blood vessels; cardiac cycle, cardiac output, ECG; double circulation; regulation, of cardiac activity; disorders of circulatory system–hypertension, coronary artery, disease, angina pectoris, heart failure., Chapter–19 : Excretory Products and Their Elimination, Modes of excretion–ammontelism, ureotelism, uricotelism; human excretory, system–structure and function; urine formation, osmoregulation of kidney function–, renin–angiotensin, atrial natriuretic factor, ADH and diabetes insipidus; role of, other organs in excretion;’ disorders– uraemia, renal failure, calculi, nephritis;, dialysis, artificial kidney and kidney transplant., Chapter–20 : Locomotion and Movement, Types of movement–Ciliary, flagellar, muscular; skeletal muscle–contractile, proteins and muscle contraction; skeletal system and its functions; joints; disorders, of muscular and skeletal system–myasthenia gravis, tetany, muscular dystrophy,, arthritis, osteoporosis, gout., Chapter–21 : Neural Control and Coordination, Neuron and nerves;Nervous system in humans–central nervous system;, peripheral nervous system and visceral nervous system; generation and conduction, of nerve impulse; reflex action; sensory perception sense organs;elementary, structure and functions of eye, ear, nose and tongue., , vi
Page 19 :
Chapter–22 : Chemical Coordination and Integration, Endocrine glands and hormones; human endocrine system–hypothalamus,, pituitary, pineal, thyroid, parathyroid, adrenal, pancreas, gonads; mechanism of, hormone action (elementary idea); role of hormones as messengers and regulators,, hypo–and hyperactivity and related disorders; dwarfism, acromegaly, cretinism,, goiter, exopthalmic goitre, diabetes, Addison’s disease., Note—Diseases related to all the human physiological systems to be taught, in brief., , vii
Page 20 :
Practicals, Time Allowed : Three hours, , Max.Marks : 30, , Evaluation Scheme, One Major Experiment Part A (One from Experiment No. 1,3,7,8), One Minor Experiment Part A, , 5 Marks, 4 Marks, , Slide Preparation Part A (One from Experiment No. 2,4,5), Spotting Part B, Practical Record + Viva Voce, Project Record + Viva Voce, , 5 Marks, 7 Marks, 4 Marks, 5 Marks, , (One from Experiment No. 6,9,10,11,12,13), , Total, A. List of Experiments, , 30 Marks, 60 Periods, , 1. Study and description of three locally available common flowering, plants, one from each of the families Solanaceae, Fabaceae and Liliaceae, including dissection and display of floral whorls, anther and ovary to show, number of chambers (floral formulae and floral diagrams). Types of root, (Tap and adventitious); stem (herbaceous and woody); leaf (arrangement,, shape,venation, simple and compound)., 2. Preparation and study of T.S. of dicot and monocot roots and stems (primary)., 3. Study of osmosis by potato osmometer., 4. Study of plasmolysis in epidermal peels (e.g. Rhoeo leaves)., 5. Study of distribution of stomata in the upper and lower surface of leaves., 6. Comparative study of the rates of transpiration in the upper and lower surface, of leaves., 7. Test for the presence of sugar, starch, proteins and fats. Detection in suitable, plant and animal materials., 8. Separation of plant pigments through paper chromatography., 9. Study of the rate of respiratioin in flower buds/leaf tissue and germinating, seeds., 10. Test for presence of urea in urine., 11. Test for presence of sugar in urine., 12. Test for presence of albumin in urine., 13. Test for presence of bile salts in urine., viii
Page 21 :
B. Study/observation of the following (spotting), 1. Study of the parts of a compound microscope., 2. Study of the specimens/slides/modles and identification with reasons–, Bacteria, Oscillatoria, Spirogyra, Rhizopus, mushroom, yeast, liverwort,, moss, fern, pine, one monocotyledonous plant, one dictoyledonous plant, and one lichen., 3. Study of virtual specimens/slides/models and identification with, reasons–Amoeba, Hydra, liverfluke,Ascaris,leech, earthworm, prawn,, slikworm,honeybee,snail, starfish, shark, rohu, frog, lizard, pigeon and rabbit., 4. Study of tissues and diversity in shapes and sizes of plnat and animal cells, (palisade cells, guard cells, parenchyma, collenchyma, sclerenchyma, xylem,, phloem, suquamous epithelium, muscle fibers and mammalian blood smear), through temporary/permanent slides., 5. Study of mitosis in onion root tip cells and animals cells (grasshopper) from, permanent slides., 6. Study of different modifications in roots, stems and leaves., 7. Study and identification of different types of inflorescence (cymose and, racemose)., 8. Study of imbibition in seeds/raisins., 9. Observation and a comments on the expeirmental set up for showing :, (a) Anaerobic respiration, (b) Phototropism, (c) Effect of apical bud removal, (d) Suction due to transpiration, 10. Study of human skeleton and different types of joints with the help of virtual, images/models only., 11. Study of external morphology of cockroach through virtual images/models., Practical Examination for Visually Impaired Students, Class XI, Note : Same Evaluation scheme and general guidelines for visually impaired, students as given for Class XII may be followed., A. Items for Identification/Familiarity with the apparatus/equipments/, animal and plant material/chemicals etc. for assessment in practicals, (All experiments), Plants of—, , Solanaceae–Brinjal, Petunia, any other, , Fabaceae–Rice, Wheat, any other, , Liliaceae–Any of the Lilies, ix
Page 22 :
A compound microscope, seeds of monocot and dicot–maize and gram or, any other Model of Human skeleton to show., , Ball and socket joints of girdles and limbs, , , Rib cage, , Test tube, honey comb, Mollusc shell, Models of Pigeon and Star fish,, mushroom, petridish, succulents such as Aloe vera/kalenchoe, raisins, beaker,, potatoes, scalpel, chromatography paper, chromatography chamber, alcohol,, specimen/model of cockroach., B. List of Practicals, 1. Study three locally available common flowering plants of the families–, Solanaceae, fabaceae, Liliaceae and identify :, , Types of roots as Tap and Adventitious, , , Types of stems as Herbaceous or Woody, , , Types of leaves as Compound or Simple, , 2. Study the parts of a compound microscope–eye piece and objective lense,, mirror, stage, coarse and fine adjustment knobs., 3. Differentiate between monocot and dicot plants on the basis of venation, patterns., 4. Study the following parts of human skeleton (Model);, , Ball and socket joints of thigh and shoulder, , , Rib cage, , 5. Study honey bee through comb, snail through shell,Starfish through model,, Pigeon through model., 6. Identify the given specimen of a fungus–Mushroom., 7. Study the adaptive features of xerophytic plants., 8. Study the process of osomosis through endosmosis in raisins., 9. Identify and releate the given experimental set up with aim of experiment :, , Paper Chromatography, , or, , Potato Osmometer, , 10. Study the external features/morphology of cockroach through model, Note : The above practicals may be carried out in an experimental manner rather, than recording observations., Prescribed Books :, 1. Biology Class-XI, Published by NCERT, 2. Other related books and manuals brought out by NCERT (consider multimedia, also), x
Page 23 :
BIOLOGY (Code No. 044), Question Paper Design, Class-XI (2020–21), Time : 3 Hours, , Max. Marks : 70, , S. Typology of Questions, No. , , , Very, short, Answer, , Short, Answer-I, (SA–I), , Short, Answer-II, (SA-II), , Long, Answer, (LA), , Total, Marks, , %, Weightage, , , , (VSA), , (2 marks), , (3 marks), , (5 marks), , 2, , 1, , 1, , –, , 7, , 10%, , –, , 2, , 4, , 1, , 21, , 30%, , –, , 2, , 4, , 1, , 21, , 30%, , 2, , 01, , 1, , 1, , 12, , 17%, , 1, , 1, , 2, , –, , 09, , 13%, , 5×1=5, , 7×2=14, , 12×3=36, , 3×5=15, , 70(27), , 100%, , (1 marks), , 1. , Remembering–(Knowedge, based Simple recall questions, to know specific facts,, terms, concepts, principles,, or theories, Identify, define,, or recite, information), Understanding–(Com2. , prehension–To be familiar with meaning and to, understand conceptually,, interpret,compare,contrast,, explain, paraphrase information), Application (Use abstract, 3. , information in concrete situation, to apply knowledge, to new situations, Use given, content to interpret a situation, provide an example, or, solve a problem), High Order Thinking, 4. , Skills (Analysis & Synthesis–Classify, Compare,, Contrast, or differentiate, between different pieces of, information, Organize and/, or integrate unique pieces of, information from a variety, of sources), Evaluation– (Appraise,, 5. , judge, and/or justify the, value or worth of a decision, or outcome,or to predict, outcomes based on values), TOTAL, , xi
Page 24 :
Question Wise Break Up, Types of, , Mark(s) per, , Total No. of, , Total, , Question, , Question, , Questions, , Marks, , VSA, , 1, , 5, , 05, , SA-I, , 2, , 7, , 14, , SA-II, , 3, , 12, , 36, , LA, , 5, , 3, , 15, , 27, , 70, , Total , , 1. Internal Choice : There is no overall choice in the paper. However, there, is an internal choice in one question of 2 marks weightage, one question of, 3 marks weightage and one question of 5 marks weightage (Content based, question)., 2. The above template is only a sample. Suitable internal variations may be, made for generating similar templates keeping the overall weightage to, different form of questions and typology of questions same., , xii
Page 25 :
BIOLOGY – XI, Index, S. No., , Chapter Name, , Page No., , 1., , The Living World, , 2., , Biological Classification, , 3., , Plant Kingdom, , 16 - 26, , 4., , Animal Kingdom, , 27 - 38, , 5., , Morphology of Flowering Plants, , 39 - 53, , 6., , Anatomy of Flowering Plants, , 54 - 65, , 7., , Structural Organization in Animals, , 66 - 75, , 8., , Cell : The Unit of Life, , 76 - 85, , 9., , Biomolecules, , 86 - 95, , 10., , Cell Cycle and Cell Division, , 11., , Transport in Plants, , 105 - 117, , 12., , Mineral Nutrition, , 118 - 128, , 13., , Photosynthesis in Higher Plants, , 129 - 141, , 14., , Respiration in Plants, , 142 - 152, , 15., , Plant Growth and Development, , 153 - 161, , 16., , Digestion and Absorption, , 162 - 170, , 17., , Breathing and Exchange of Gases, , 171 - 179, , 18., , Body Fluids and Circulation, , 180 - 190, , 19., , Excretory Products and their Elimination, , 191 - 199, , 20., , Locomotion and Movement, , 200 - 207, , 21., , Neural Control and Coordination, , 208- 216, , 22., , Chemical Coordination and Integration, , 217- 225, , Practice paper with Solution, , 226 - 250, , , , 1-5, 6 - 15, , xiii, , 96 - 104
Page 26 :
xiv
Page 27 :
Points to Remember, 1. Organism (Microorganism, plant and animals) who posseses life is living., 2. Life is a complex organisation expressing itself through chemical reactions, and exhibit characteristics of living organisms., 3. Characteristics of Living Organisms : Growth, reproduction, metabolism,, cellular organisation, consciousness (ability to sense environment), selfreplicating and self regulation., , Reproduction and growth are NOT defining properties., , Metabolism (Catabolic + Anabolic), cellular organisation and consciousness, are defining properties., , Living organisms are self-replicating, evolving, self-regulating and, interactive systems capable of responding to external stimuli., 4. Biodiversity : Term used to refer to the variety of microorganisms, plant, and animals on earth., 5. Need for classification : To organise the vast number of microorganisms,, plants and animals into categories that could be named, remembered, studied, and understood., 6. Three Domains of Life : Proposed by Carl Woese in 1990 who also proposed, the six kingdom classification for living organisms. The three Domains of, life are Archaea, Bacteria and Eukarya., , 1 , Kingdom, , Archaea → 1. Archaebacteria, , 2, Prokaryotic organisms in extreme conditions, , Domains, Bacteria → 2. Eubacteria, , of life, 3, , Eukarya → 3. Protista, Eukaryotic, , → 4. Fungi, Organisms, , → 5. Plantae, , → 6. Animalia, The Living World, , 1
Page 28 :
7. Taxonomy : Study of principles and procedures of identification, nomenclature, and classification., 8. Systematics : It deals with classification of organisms based on their, diversities and relationships among them. Term was proposed by Carolus, Linnaeus who wrote ‘Systema Naturae’., 9. Concept of Species : All the members that can interbreed among themselves, and can produce fertile offsprings are the members of same species. This is, the biological concept of species proposed by Mayr., 10. Taxa : Each category (i.e., unit) of classification is called as a taxon., 11. Taxonomic Hierarchy : Classification of organisms in a definite sequence, of taxon or category or rank in a descending order., , Kingdom → Phylum /Division → Class → Order → Family → Genus → Species., 12. Binomial Nomenclature : Given by Carolus Linnaeus. Each scientific name, has two components-Generic name + Specific epithet., 13. ICBN : International Code for Botanical Nomenclature (for giving scientific, name to plants.), 14. ICZN : International Code of Zoological Nomenclature (for giving scientific, name to animals.), 15. Rule for Nomenclature :, , , Latinised names are used., , , First word is genus, second word is species name., , , Printed in italics; if handwritten then underlined separately., , , First word starts with capital letter while species name written in small, letter., 16. Scientific names of some organisms :, Man , —, Homo sapiens, Housefly, —, Musca domestica, Mango, —, Mangifera indica, Wheat , —, Triticum aestivum, 17. Taxonomical Aids are the tools for study of taxonomy., 18. Museums in educational institutes (school and colleges) have collection of, skeletons of animals, stuffed and preserved specimens of organisms for study, and reference., 19. Zoological Parks (Places where wild animals are kept in protected environment, under human care) Example : National Zoological Park, Delhi., 20. Herbarium : Store house of dried, pressed and preserved plant specimen, on sheets, kept systematically according to a widely accepted system of, classification, for future use., 2, , Biology Class - 11
Page 29 :
21. Botanical Garden : Collection of living plants for reference., , Example : Royal Botanical garden Kew (England), National Botanical, Research Institute (Lucknow), Indian Botanical Garden Howrah., 22. Keys : (Used for identification of plants and animals on the basis of similarities, and dissimilarities.) two types < Indented key, Brackeed key, 23. Couplet : are the two alternate characteristic statement used in key to identify, organisation., 24. Each Statement of the key is called a lead., 25., , , , 26., , , , 27., , , , Flora (Index to plant species found in a particular area., Manuals (Provide information for identification of name of species in an, area.) It is a handy book., Monographs (Contain information on any one taxon.), , Question, , Very Short Answer Question , 1., 2., 3., 4., , (1 mark each), , Define species., What is systematics ?, Give the names of two famous botanical gardens., Define Life, , Short Answer Question-I , , (2 marks each), , 4. What is the basis of modern taxonomical studies ?, 5. Why growth and reproduction cannot be taken as defining property of all, living organisms ?, 6. How is a taxon (pl. taxa) defined ?, , Short Answer Question-II (3 marks each), 7. What is the difference between Botanical Garden and Herbarium ?, 8. Keys are analytical in nature and are helpful in identification and classification, of organisms. How ?, 9. Define : (a) Genus , (b) Family, (c) Order, , Long Answer Questions , , (5 marks each), , 10. What are the universal rules of nomenclature ? What does ‘Linn.’ Refers to, in Mangifera indica Linn ?, The Living World, , 3
Page 30 :
11. Illustrate taxonomical hierarchy with suitable examples from plant and animal, species., 12. Define classification. What is the significance of classification ? What is the, six kingdom classification ?, , Answers, Very Short Answers , , (1 marks each), , 1. Members that can interbreed to produce fertile offspring., 2. Systematic arrangement which also takes into account evolutionary, relationships between organisms., 3. Kew (England) and National Botanical Research Institute (Lucknow), Indian, Botanical Garden (Howrah)., 4. Life is unique, complete functioning of metabolic activities, , Short Answers-I, , (2 marks each), , 4. External and internal structure, structure of cell, development process and, ecological information., 5., , , , Non-living things can also increase in mass by accumulation of material, on surface (accretion.), , , , Many organisms do not reproduce (e.g., mules, sterile worker bees.), 6. Each category in a taxonomical hierarchy represents a rank and is called, taxon., , Short Answers-II , , (3 marks each), , 7. Botanical Garden : Collection of living plants., Herbarium : Collection of dried, pressed and prerserved plant specimens on, sheets., 8. Key is a list of alternate characters arranged in such a manner that by, acceptance and rejection one can easily identify an organisms as to its name, and position. Keys are generally analytical in nature., 9. (a) Genus : Group of related species;, (b) Family : Group of related genera;, 4, , Biology Class - 11
Page 31 :
(c) Order : Group of related families., , Long Answers , , (5 marks each), , 10. Refer page no. 7, NCERT, Text Book of Biology for Class XI., ‘Linn.’ indicates that the species was first described by Linnaeus., 11. Refer table 1.1, page no. 11, NCERT, Text Book of Biology for Class XI., 12. Grouping organisms on the basis of their similarities and differences., Significance : – Aids in study, better understanding, predicting the features, of the group known., Refer ‘Points to Remember’ for six kingdom classification in three domains, of life., , , The Living World, , 5
Page 32 :
Points to Remember, Systems of Classification :, , , Earliest classification was given by Aristotle. Divided plants into herbs,, shrubs and trees., , Animals into those with red blood and those who do not have it., , , , , , , Two kingdom classification : Given by Carolus Linneaeus–Kingdom–, plantae and kingdom–Animalia., Five kingdom classification : By R.H. Whittaker, Monera, Protista, Fungi,, Plantae and Animalia are the five kingdoms., The main criteria for classification of organisms into five kingdoms include, cell structure, thallus organisation, mode of nutrition, reproduction and, phylogenetic relationships., , Kingdom Monera :, , , Has bacteria as sole members., , , , Cell wall madeup of peptidoglycan., , , , , , Bacteria can have shapes like : Coccus (spherical), Bacillus (rod-shaped),, Vibrium (comma shaped) and spirillum (spiral shaped)., Bacteria found almost everywhere and can be Photosynthetic autotrophs,, Chemosynthetic autotrophs or Heterotrophs., , , , 6, , Archaebacteria, Bacteria, , Biology Class - 11, , Eubacteria
Page 33 :
, , Halophiles (salt-loving), , , , Thermoacidophiles (in hot springs), , , , , , , , , , , , , , Methanogens (in marsh and in gut of ruminant animals. Produce methane, gas.), Photosynthetic autotrophs like Cyanobacteria (Blue-green algae BGA)., Some like Anabaena and Nostoc have specialized cells called heterocysts, for nitrogen fixation., Algae bloom is rich growth of blue green algae over the surface of polluted, water bodies., Algae bloom releases neurotoxins, deplete oxygen and makes water unfit, for use., Chemosynthetic autotrophs : Oxidise various inorganic substances like, nitrates/nitrites, ammonia and use released energy for their ATP production., They helps in nutrients recycling of N, P, Fe and S., Heterotophic bacteria : Decomposers help in making curd, production of, antibiotic, N2 fixation, casuse diseases like cholera, typhoid, tetanus and, citrus canker., , Mycoplasmas : Completely lack cell wall. Smallest living cells. Can survive, without oxygen. Pathogenic in animals and plants., 1., , Artificial System of Classification, 1. It utilise one or two morphological trail, 2. Homology is never standard, 3. The system does not employ chracter from anatomy cytology,, biochemistry, genetics etc. for grouping of organisms., , 2., , Natural System of Classification, 1. The system employs several morphological chracter for grouping of, orgaism, 2. It studies homology in all chracters including morphology, anatomy etc., 3. This system gives information about both Natural relationship and, phylogeny., , Biological Classification, , 7
Page 34 :
3., , Phylogenetic System of Classification, It was proposed by Engler and Prantl. They arranged flowering plants, according to increasing complexity of their floral morphology., It was based on possible evolution of different traits., , 4., , Objections to two kingdom system, 1. Lichen with dual mode., 2. Fungi remain fixed but nutrition saprophytic., 3. No distribution of unicellular and multicellular organism., 4. No distribution of prokaryotic and eukaryotic organisation., , Kingdom PROTISTA, , (Comprises of all single celled eukaryotes), , , Forms a link between plants, animals and fungi., , (i), , Chrysophytes (Has diatoms and golden algae/desmids), , , , Fresh water/marine, photosynthetic, microscopic plankton., , , , , , , , , , , , , , Their accumulation forms ‘Diatomaceous Earth” (gritty soil), , , , , , Used in polishing, filtration of oils and syrups., , Chief producers in Ocean., Cell walls have silica which makes it indestructible and cell walls, overlap to fit together like a soap box., , (ii) Dinoflagellates :, , , , , , , , , , , , , Marine, photosynthetic, cell wall has stiff cellulose plates., Two flagella–one longitudinal and other transverse in a furrow, between wall plates., Example : Gonyaulax multiples rapidly, make sea appear red, (red tides) and produce toxins to kill marine animals., , (iii) Euglenoids :, , 8, , , , Found in stagnant fresh water., Biology Class - 11
Page 35 :
Have protein rich layer ‘pellicle’ which makes body flexible., , , , , , , , , Photosynthetic in presence of sunlight but become heterotrophs if, they do not get sunlight. (Mixotrophic nutrition), Example : Euglena, , , (iv) Slime Moulds :, , , , , , , , , , , , , , , , , Saprophytic protists, Under suitable conditions form an aggregates called plasmodium,, grows on decaying twigs and leaves., During unfavourable conditions, plasmodium differentiates and, forms fruiting bodies bearing spores at their tips., Spores have true walls which are extremely resistant and survive for, many years and dispersed by air currents., , (v) Protozoans : Are heterotrops and live as parasites. Have four major, groups., , , Amoeboid : Catch prey using pseudopodia, e.g., Amoeba. Entamoeba, are parasite., , , , Flagellated : Have one or more flagella. Cause disease like Sleeping, Sickness e.g., trypanosoma., , , , Ciliated : Have clilia to move food into gullet and help in locomotion., e.g., Paramoecium., , , , Sporozoans : Have infective spore like stage in life cycle, e.g.,, Plasmodium which causes malaria., , Kingdom Fungi, 1. Heterotrophic organisms, 2. Non chlorpohyllous hyphae, 3. Network of hyphae called mycelium, 4. Hyphae which have multinucleated cytoplasm are called coenocytic hyphae, 5. Cell wall of chitin and polysaccharides, 6. Cosmopolitan. Grow in warm and humid places., Biological Classification, , 9
Page 37 :
e.g., Aspergillus, Neurospora, Saccharomyces (Unicellular fungi),, Claviceps, morels, truffles, , (iii) Basidiomycetes :, , Mycelium septate and branched., , , Generally asexual spores are not found., , , Vegetative reproduction by fragmentation., , , Sexual reproduction by fusion of vegetative or somatic cells to form basidium, , produced in basidiocarp., , Basidium produces four basidiospores exogenously after meiosis., , , e.g., Agaricus, Ustilago, Puccinia, (iv) Deuteromycetes :, , Called as ‘Fungi Imperfecti’ as sexual form (perfect stage) is not known for, , them., , Once sexual form is discovered the member is moved to Ascomycetes or, , Basidiomycetes., , Mycelium is septate and branched., , , Are saprophytic parasitic or decomposers., , , e.g., Alternaria, Colletotrichum, Trichoderma., , Viruses :, , , They did not find a place in biological classification., , , , Not truly living., , , , , , , , , , , Non-cellular organisms which take over the machinery of host cell on entering, it and become living but as such they have inert crystalline structure appear, non-living. So, difficult to call them living or non-living., Virus means venom or poisonous fluid. Pasteur gave the term ‘virus’., D.J. Ivanowsky found out that certain microbes caused Tobacco Mosaic, Disease in tobacco plant., M.W. Beijerinek called fluid as ‘Contagium vivum fluidum’ as extracts of, infected plants of tobacco could cause infection in healthy plants., W.M. Stanely showed viruses could be crystallized to form crystals of protein, which are inert outside their specific host., Biological Classification, , 11
Page 38 :
, , Viruses are obligate parasites., , Structure of Virus :, , , , , It is a nucleoprotein made up of protein coat called Capsid. Capsid is made, up of capsomeres arranged in helical or polyhedral-geometric forms. Have, either DNA or RNA as genetic material which may be single or double, stranded., Usually plant viruses have single stranded RNA; bacteriophages have double, stranded DNA and animal viruses have single or double stranded RNA or, double stranded DNA., , Diseases caused in humans :, Mumps, Small pox, herpes, influenza and AIDS etc. In plants, symptoms can, be mosaic formation, leaf rolling and curling, yellowing and vein clearing,, dwarfing and stunted growth., , Viroids :, , , Infectious agent, free RNA (lack protein coat), , , , RNA has low molecular weight., , , , Causes potato spindle tuber disease., , , , Discovered by T.O. Diener., , Prions, , , They are highly resistant glycoproteins molecule which function as infectious, agent., , Lichens :, , , , , 12, , Symbiotic association between algal component (Phycobiont) and fungal, component (mycobiont). Algae provides food. Fungi provides shelter and, absorb nutrients and water for alga., Good pollution indicators as they do not grow in polluted areas., , Biology Class - 11
Page 39 :
Questions, Very Short Answer Question, , (1 mark each), , 1. Nostoc and Anabaena have specialized cells called heterocysts. What is the, function of these cells ?, 2. Which group comprises of single celled eukaryotes only ?, 3. Which organisms are the chief producers in oceans ?, 4. Name the fungus which causes disease in wheat (i) rust (ii) smut., 5. Which Ascomycetes has been used extensively in biochemical and genetic, work ?, 6. What is the principle underlying the use of cyanobacteria in agriculture ?, , Short Answer Question-I , , (2 marks each), , 7. How are bacteria classified on the basis of their shapes ?, 8. What is the mode of reproduction in bacteria ?, 9. Why are red tides caused and why are they harmful ?, 10. Viruses and viroids differ in structure and the diseases they cause. How ?, 11. Which class of kingdom fungi has both unicellular as well as multicellular, member ? When is a fungus called coprophilous ?, , Short Answer Question-II , , (3 marks each), , 12. Who gave five kingdom classification ? What was the criteria used for such, classification ?, 13. What are the modes of nutrition in fungi ?, 14. Some symbiotic organisms are very good pollution indicators and composed, of a chlorophyllous and a non-chlorophyllous member. Describe them., , Biological Classification, , 13
Page 40 :
15.Who gave two kingdom classification? Write its draw backs?, , Long Answer Questions , , (5 mark each), , 15. Some primtive relatives of animals live as predators or parasites and are, divided into four major groups. Elaborate., 16. differentiate between various classes of kingdom Fungi on the basis of their, (i) Mycelium, (ii) Types of spores and (iii) Types of fruiting body. Also give, two examples for each class., 17. Describe sexual reproduction in fungi., 18. Draw a lablled diagram of bacter phage. Write its chracter also., , Answers, Very Short Answers , , (1 mark each), , 1. Help in nitrogen fixation., 2. Kingdom Protista., 3. Diatoms, 4. (i) Puccinia, (ii) Ustilago, 5. Neurospora, 6. Capability of nitrogen fixation, , Short Answers-I , , (2 marks each), , 7. Bacillus (rod-shaped), Coccus (spherical), Vibrio (comma shaped) and, Spirillum (spiral shaped)., 8. Mainly by fission; Production of spores in unfavourable conditions. Sexual, reproduction by DNA transfer., 9. Rapid multiplication of dinoflagellates like Gonyaulax. Harmful as they, release toxins which kill marine animals., 10. Refer ‘Points to Remember’., 14, , Biology Class - 11
Page 41 :
11. Ascomycetes : Yeast (Unicellular), Penicillum (Multicellular), Coprophilous,, means fungi which grow on dung., , Short Answers-II , , (3 marks each), , 12. R.H. Whittaker, Criteria for classification : Cell structure, thallus organisation,, mode of nutrition, reproduction and phylogenetic relationships., 13. Saprophytes, Parasites, Symbionts-Lichens and Mycorrhiza., 14. Lichens, Refer ‘Points to Remember’., 15. Carolous linneous. Refer to points., , Long Answers , , (5 marks each), , 15. Protozoans. Refer page no 21-22, NCERT Text Book of Biology for Class, XI., 16. Refer NCERT Text Book of Biology for Class XI, Page no. 23-24., 17. Refer NCERT text book of Biology for Class XI Page 23. (Plasmogamy,, Karyogamy, Meiosis in zygote, Dikaryophase), The steps are :, (i) Plasmogamy : fusion of protoplasm of two motile or non-motile gametes., (ii) Karyogamy : fusion of two nuclei., (iii) Zygotic Meiosis to form haploid spores., (iv) Dikaryophase in ascomycetes and basidiomycetes where before, karyogamy two nuclei per cell (dikaryon) are found., 18. NCERT page no. 26 Fig 2.6(mb), , , Biological Classification, , 15
Page 43 :
Points to Remember, Classification :, , , Artificial System of Classification, , By Carolus Linnaeus, based on androecium structure and vegetative, , characters., , , Natural System of Classification, , Based on natural affinities among organisms, , Included external as well as internal features, , By Geroge Bentham and J.D. Hooker, , , , Phylogenetic System of Classification, , Based on evolutionary relationships between the various organisms, , By Engler and Prantl, , Later on By Hutchinson, , , Numerical Taxonomy :, , , Carried out using computers, , , , Based on all observable characteristics, , , , Data processed after assigning number and codes to all the characters., , , Advantages : Each character gets equal importance and a number of, characters can be considered., , Cytotaxonomy :, , , Based on cytological informations., , , , Gives importance to chromosome number, structure and behaviour., , Chemotaxonomy :, , , Based on Chemical constituents of the plants., , Algae :, , , Chlorophyll bearing, simple, thalloid, autotrophic and largely aquatic, organisms., Plant Kingdom, , 17
Page 44 :
Importance of Algae :, , , Help in carbon dioxide fixation by carrying out photosynthesis and have, immense economic importance., , , , At least half of the total carbon dioxide fixation on earth carried out by them., , , , Increases dissolved oxygen level in their environment., , , , Many species like Laminaria, Sargassum, Porphyra etc. are used as food., , , , , , , , , , Agar obtained from Gelidium and Gracilaria which is used in ice-creams, and jellies and to grow microbes., Algin obtained from brown algae and carrageen from red algae used, commercially as hydrocolloids., Chlorella and Spirullina are unicellular algae, rich in protein and used even, by space travellers., Algae are unicellular like Chlamydomonas, colonial like Volvox or or, filamentous like spirogyra and Ulothrix. Occur in water, soil, wood moist, stones etc., , Algae are divided into 3 classes., (i) Chlorophyceae, , Green algae, Main pigment is chlorophyll ‘a’ and ‘b’., , Cell wall has inner layer of cellulose and outer layer of pectose., , Has pyrenoids made up of starch and proteins., , Pigment and pyrenoids are located in Chloroplast., e.g., Chlamydomonas, Volvox, Spirogyra, Ulothrix, Chara., , 18, , Biology Class - 11
Page 47 :
Sphagnum in from of peat is used as fuel and also used as packing material, for trans-shipment of living material, as it has water holding capacity., Prevents soil erosion, alongwith lichens are first colonizers on barren rock., , , Is divided into two classes Liverworts (thalloid body, dorsiventral, e.g.,, Marchantia) and Mosses (have two stages in gametophyte–creeping, green,, branched, filamentous protonema stage and the leafy stage having spirally, arranged leaves e.g., Funaria, Polytrichum and Sphagnum)., , Reproduction in Bryophytes, , , Vegetative reproduction by fragmentation., , , , Asexual reproduction by gemmae formed in gemma cups., , , , Sexual reproduction : Main plant body is haploid, produces gametes and so, called Gametophyte. By fusion of antherozoids produced in antheridium, and egg cell produced in archegonium, results in formation of zygote which, develops into sporophytic structure differentiated into foot, seta and capsule., Spores produced in a capsule germinate to from free-living gametophyt e, (Protonema). Sporophyte is not free living but attached to photosynthetic, gametophyte from which derives nutrition., , Pteridophytes :, , , First terrestrial plants., , , , Prefer cool, damp and shady places to grow., , , , Grown as ornamentals., , , , Used for medicinal purpose, as soil binder., , , , , , , , , , Main plant body is sporophyte which is differentiated into true root, stem, and leaves., Leaves may be small as in Selaginella or large as in ferms., Sporangia having spores are subtended by leaf-like appendages called, sporophylls. (Sporphylls may be arranged to form strobili or cones.), In Sporangia, the spore mother cells give to spores after meiosis., Spores germinate to form haploid gametophytic structure called prothallus, which is free living, small, unicellular and photosynthetic., Plant Kingdom, , 21
Page 49 :
Angiosperms :, , , , , Called flowering plants and have seeds enclosed in fruits., Divided into two classes–Dicotyledons (have two cotyledons) and, Monocotyledons (have one cotyledon)., , , , Smallest angiosperm : Wolfia, , , , Large tree : Eucalyptus (Over 100 meters), , , , , , , , , , , , Stamen has filament and anther. Anthers bear pollen grains. Pollen grains, have two male gametes., Pistil has stigma, style and ovary. Ovary has ovule in which female gametophyt, e (embryo sac) develops., Embryo sac has 7 cells and 8 nuclei.One egg cell 2 synergids, 3 antipodals, and two polar nuclei which fuse to form secondary nucleus., Pollen grain is carried by wind, water, insects and other agents reaches to, stigma and produces pollen tube which enters embryo sac., Double fertilisation : One male gemate fuses with egg cell (Syngamy) to, form zygote which develops into embryo., , Other male gamete fuses with secondary nucleus (triple fusion) which forms, triploid primary endosperm nucleus (PEN). PEN develops into endosperm which, nourishes the developing embryo., , , Ovules develop into seeds and ovaries into fruits., , Questions, , Very Short Answer Question, , (1 mark each), , 1. What is a pyrenoid body ?, 2. Define gemma., 3. Which group of plants is regarded as first terrestrial plants ? Why ?, 4. Which organism is regarded as one of the tallest tree species ?, 5. The gametes and spores of phaeophyceae have a distinct morphology. Give, its name., Plant Kingdom, , 23
Page 50 :
6. Which substance has structural similarity to floridean starch ?, 7. Name the organism which exhibit heterospory and seed habit., , Short Answer Question-I, , (2 marks each), , 8. Sphagnum has a lot of economic importance. Justify., 9. Gymnosperms can show polyembryony. Why do you think so ?, 10. How is leafy stage formed in mosses ? How is it different from, protonema ?, , Short Answer Question-II , , (3 marks each), , 11. The leaves in gymnosperms are adapted to withstand xerophytic conditions., Justify., 12. The gametophytes of bryophytes and pteridophytes are different from that, of gymnosperms. How ?, 13. Roots in some gymnosperms have fungal or algal association. Give examples,, their names and role in the plants., 14. Why is presence of water a must for fertilisation in pteridophytes ?, , Long Answer Questions , , (5 marks each), , 15. Draw the life cycle of an angiosperm alongwith a brief note on double, fertilisation., 16. Explain alternation of generation in plants., 17.Explain various classes of Algae., , Answers, , Very Short Answers , , (1 mark each), , 1. Proteinaceous body usually surrounded by starch found in algae., 2. Gemma are green, multicullular, asexual buds which develop in receptacles, called as gemma cups., 3. Pteriodphytes. As they possess vascular tissues–xylem and phloem., 4. Sequoia, 24, , Biology Class - 11
Page 51 :
5. Pyriform (pear-shaped), bear two laterally attached flagella., 6. Amylopectin and glycogen., 7. Selaginella and Salvinia., , Short Answers-I , , (2 marks each), , 8. Provide peat used as fuel : used as packing material for trans-shipment of, living material., 9. Have two or more archegonia, so polyembryony can occur., 10. Leafy stage develops from secondary protonema as a lateral bud. Protonema, is creeping, green, branched frequently filamentous stage whereas leafy stage, is upright with spirally arranged leaves., , Short Answers-II (3 marks each), 11. Gymnosperms like conifers have : needle shaped leaves to reduce surface, area, thick cuticle and sunken stomata to reduce water loss., 12. Male and female gametophyte have free existence in bryophytes and, pteridophytes but not in Gymnosperms. They remain within sporangia, retained on sporophytes., 13. Pinus has fungal association to form mycorrhiza which helps in absorption, of water and minerals. Cycas has algal association in coralloid roots which, are associated with N2 fixing cyanobacteria., 14. The antheridia produces male gametes, antherozoids which swim in water, to reach archegonia, bearing non-motile egg. Thus fertilisation can occur, only when water is present in the surrounding medium., , Long Answers (5 mark each), 15. Refer Figure 3.6, page no. 41, NCERT, Text Book of Biology for Class XI., 16. Refer ‘Points to Remember’ and Page No. 42,NCERT, Text book of Biology, for class XI., 17. Rhodophycae/Phoeophyceqe and chlorophyceae with correct explanation., , , Plant Kingdom, , 25
Page 52 :
26, , Biology Class - 11
Page 53 :
Point to Remember, Basis of Classification :, , Animals are classified on the basis of following few fundamental features—, 1. Levels of Organisation :, , (1) Cellular level : Cells are arranged as loose cell aggregates, e.g.,sponges., (2) Tissue level : The cells performing the same function are arranged into, tissues, e.g., Coelenterates., (3) Organ level : Tissues are grouped together to form organs, each, specialised for a particular function. e.g., platyhelminthes., (4) Organ system level : organs are associated to form functional systems, e.g., Annelids, Arthropods, Molluscs, Echinoderms and Chordates., Example : Circulatory System., , Open type : Blood pumped out through heart. Not confined to blood vessels., Cells and tissues are directly bathed in it., , Closed types : Blood is circulated through blood vessels (arteries,veins and, capillaries), 2. Symmetry :, Asymmetrical : Cannot be divided into equal halves through median plane, , e.g., Sponges., Radial symmetry : Any plane passing through central axis can divide organism, , into identical halves. e.g., coelentrates,Ctenophores and echinoderms., Bilateral symmetry : Only one plane can divide the organism into two identical, , left and right halves e.g., Annelids and Arthropods., 3. Germinal Layers :, Diploblastic : Cells arranged in two embryonic layers i.e., external ectoderm, and internal endoderm. (Mesoglea may be present in between ectoderm and, endoderm) e.g., porifers and Coelentrates. (Cnidarians), , Triploblastic : Three layers present in developing embryo i.e., ectoderm,, mesoderm and endoderm. e.g., Platyhelminthes to Chordates., Animal Kingdom, , 27
Page 54 :
4. Coelom (Body cavity which is lined by mesoderm), , Coelomates : Have coelom e.g., Annelids, Arthropods, molluscs, Echinoderms,, Chordates etc., , Pseudocoelomates : No true coelem as mesoderm is present in scattered, pouches between ectoderm and endoderm. e.,g., Aschelminthes., , Acoelomates : Body cavity is absent e.g., Platyhelminthes., 5. Segmentation (A) True Metamerism : Found Annelida,Arthropoda,, Chordata :, Segmentation is external as well as a internal in Annelids., , Segmentation is external in Arthropods., Segmentation is internal in chordates., , Metamerism : If body is externally and internally divided into segments, , (metameres) with serial repetition of atleast some organs, then phenomenon is, called metamerism e.g., Earthworm. (B) Pseudometamerism : Found in, tapeworm. The proglottids (segments of tapeworm) budded off from neck, not embryonic in origin., 6. Notochord :, Rod-like structure formed during embryonic development on t he dorsal side., , It is mesodermally derived e.g., Chordates., Non-chordates do not have notochord .e.g., porifera to echinoderms., , , Phylum Porifera :, , , , , , , , , , , Also called sponges., Are usually marine and asymmetrical., Have cellular level of organisation and diploblastic animals., Food gathering, respiratory exchange and removal of wastes occurs through, water canal system. Digestion intracellular., Ostia (minute pores on body), spongocoel (body cavity) and osculum help, in water transport. They are lined by choanocytes (collar cells)., Body wall has skeleton of spicules or spongin fibres., Animals are hermaphrodite. Fertilisation internal. Development is indirect, (i.e., has a larval stage distinct from adult stage) e.g., Sycon, Euspongia., Spongilla (Fresh water sponge), , Phylum Coelenterata :, , , , , 28, , Also called Cnidarians., Are usually marine and radially symmetrical., Sessile or free swimming., Biology Class - 11
Page 55 :
Animal Kingdom, , 29
Page 56 :
, , , , , , , , , , , , , , , Have tissue level of organisation., Are diploblastic (with mesogloea), Capture of prey, anchorage and defence occurs through cnidoblasts/cnidocytes, (have stinging capsules nematocytes) present on tentacles., Digestion extracellular and intracellular., Have a central gastro-vascular cavity and an opening, hypostome., Body wall of some composed of calcium carbonate. e.g. corals., exhibit two body forms : polyp and medusa e.g., Hydra, Aurelia., Alternation of generation between body forms called metagenesis ocurs in, Obelia where :, Polyp. (Sessile and cylindrical), Medusa, (free swimming &, umbrella shaped), e.g., Physalia, Adamsia, Pennatula, Gorgonia,Meandrina., , Phylum Ctenophora :, , , Also called as sea walnuts or comb jellies., , , , Are exclusively marine, radially symmetrical., , , , Have tissue level organisation, are diploblastic., , , , Digestion both extra and intracellular., , , , Body has eight external rows of ciliated comb plates for locomotion., , , , Show Bioluminescence (Property of living organisms to emit light)., , , , Hermaphrodite (sexes are not separate)., , , , Only sexual reproduction occurs. Exernal fertilization. Indirect development., e.g., Ctenoplana, Pleurobrachia., , Phylum Plathyhelminthes :, , , , , , , , , 30, , Also called as ‘flat worms’., Have dorsoventrally flattened body. Are mostly endoparasites in animals., Are bilaterally symmetrical, triploblastic, acoelomate,with organ level of, orgnisation., Absorb nutrients through body surface., Parasitic forms have hooks and suckers., ‘Flame cells’ help in osmoregulation and excretion., Biology Class - 11
Page 57 :
, , , Sexes not separate., Fertilisation internal. Many larval stages present. Planaria has high, regeneration capacity. e.g., Taenia, Fasciola., , Phylum Aschelminthes :, , , , , , , , , , Also called ‘round worms’., May be free living, parasitic, aquatic or terrestrial., Are bilaterally symmetrical, triploblastic, pseudocoelomate., Alimentary canal complete (has muscular pharynx), wastes removed through, excretory pore., Sexes separate. (dioecious), Females longer than males., Fertilisation internal. Development direct or indirect. e.g., Ascaris,Wuchereria,, Ancylostoma., , Phyum Annelida :, , , , , , , , , , , , , , , Are aquatic or terrestrial, free-living or parasitic., Are bilaterally symmetrical, triploblastic, organ-system level of organisation, and metamerically segmented body., Are coelomate animals., Have longitudinal and circular muscles for locomation., Have closed circulatory system., Nereis (dioecious and aquatic annelid) has lateral appendages called parapodia, for swimming., Have nephridia for osmoregulation and excretion., Neural system consists of paired gangila connected by lateral nerves to a, double ventral nerve cord., Reproduction is sexual., e.g., Earthworm (Pheretima) and Leech (Hirudinaria) which are hermaph, rodites (i.e., monoecious)., , Phylum Arthropoda :, , , , , , Largest phylum of Animalia., Are bilaterally symmetrical, triplobastic, segmented externally and organ, system level of organisation, coelomate., Body divisible into head, thorax, abdomen and has a chitinous exoskeleton., Jointed appendages are present., Animal Kingdom, , 31
Page 59 :
Respiration by gills, book gills, book lungs or tracheal system. Excretion, through malpighian tubules., Sensory organs : Antennae, eyes; Organs of balance : Statocysts., Fertilisation usaully internal. Development is indirect or direct. Are mostly, oviparous., , e.g., Apis, Bombyx, Laccifer, Anopheles, Culex, Aedes, Locusta, Limulus., , , Phulum Mollusca :, Second largest phylum of Animalia., Terrestrial or aquatic, Are bilaterally symmetrical, triplobastic and organ system level of organisation,, coelomate., Body vidisble into head, muscular foot and visceral hump and is covered, by calcareous shell and is unsegmented., Mantle : Soft and spongy layer of skin; Mantle cavity : Space between, visceral hump and mantle., Respiration and excretion by feather like gills in mantle cavity., Head has sensory tentacles. Radula a rasping organ for feeding in mouth., Are oviparous, dioecious, have indirect development., , e.g., Plia, Pinctada, Octopus, Sepia, Loligo, Aplysia, Dentalium, Chaetopleura., , , Phylum Echinodermata :, , , , , , , , , , , , Are spiny bodied organisms with endoskeleton of calcareous ossicles., Are exclusively marine, radially symmetrical in adult but bilaterally, symmetrical in larval stage. Organ system level of organisation., Triploblastic and coelomate., Digestive system complete. Mouth ventral, Anus on dorsal side., Food gathering, respiration, locomotion carried out by water vascular system., Excretory system is absent., Reproduction–sexual, sexes are separate., Fertilisation external. Development indirect (free swimming larva), e.g., Asterias, Cucumaria, Antedon, Echinus, ophiura., , Phylum Hemichordata :, , , , Represents small group of worm-like organisms., Was earlier placed as sub-phylum of Phyum Chordata., Animal Kingdom, , 33
Page 60 :
Bilaterally symmetrical, triploblastic and coelomate with organ system level, of organisation., Body cylindrical, has proboscis, collar and trunk., Circulatory System–open., Respiration by gills, excretion by proboscis gland., Sexes separate, external fertiliastion, indrect development., , e.g, Balanoglossus, Saccoglossus., , , Phylum Chordata :, , , Presence of Notochord., , Have dorsal hollow nerve cord., , , Have paired pharyngeal gill slits., , , Bilaterally symmetrical, triploblastic, coelomate, organ system level of, , organisation., , Heart is ventral., , , Post anal tail present, closed circulatory system., , , (i) Sub-Phyla Urochordata /Tunicata, Notocohord present only in larval tail., e.g., Ascidia, Salpa, Doliolum, , , (ii) Sub-phyla Cephalochordata, Notochord extends from head to tail (Persistent), e.g., Amphioxus., , , (iii) Sub-Phyla Vertebrata, Have notochord only during embryonic period., , Notochord gets replaced by bony or cartilaginous vertebral column., , , Have ventral muscular heart, kidneys for excretion and osmoregulation, paired, , appendages (fins or limbs), , , Vertebrata have two Division :, (a) Agnatha (Lacks Jaw) : Class : Cyclostomata, , Live as ectoparasites on some fishes., , Have sucking and circular mouth without jaws., , Have 6-15 paris of gill slits for respiration., , No scales, no paired fins., , Cranium and vertebral column is cartilagenous., 34, , Biology Class - 11
Page 61 :
Marine, Migrate to fresh water for spawning and die after spawning., , Larva returns to ocean after metamorphosis., e.g., Petromyzon, Myxine, (b) Gnathostomata (Bear Jaws)–divides into two super classes :, , Super-class : Pisces, 1. Class : Chondrichthyes :, , Have cartilagenous endoskeleton, are marine with streamlined body., , Mouth ventral., , Gill slits without operculum (gill cover)., , Skin has placoid scales; jaws–very powerful., No air bladder, so swim constantly to avoid sinking., , Teeth are backwardly directed, modified placoid scales., , Notochord is persistent throughout life., , Two chambered heart; poikilotherms (cold-blooded), , Sexes separate; males have claspers on pelvic fins., , Internal fertilisation; viviparous., , e.g., Tarpedo, Trygon, Scoliodon, Pristis, Carcharodon, 2. Class : Osteichthyes, Have bony endoskeleton, Aquatic, Mouth is usually terminal. Body-Streamlined, , Four pairs of gill slits covered by operculum, heart two chambered, cold, , blooded., Sking has cycloid/ctenoid scales., , Have air bladder which regulates buoyancy., , Sexes separate., , Usually oviparous, fertilisation external., , Development direct., , e.g., Hippocampus, Labeo, Catla, Betla, Clarias, Exocoetus, , , Sub-Phylum Vertebrata : Gnathostomata, Super Class : Tetrapoda, 1. Class : Amphibia, Can live in aquatic as well as terrestrial habitats., Body divisible into head and trunk, paired limbs., , Animal Kingdom, , 35
Page 62 :
Skin moist. No scales., Tympanum represents ear. Eyes have eyelids., , Cloaca is the common chamber where alimentary canal, urinary and, , reproductive tracts open., Respiration by gills, lungs or skin., , Heart is 3-chambered; cold-blooded; Sexes separate; fertilisation external., , Oviparous. Indirect development., , e.g., Bufo, Rana, Hyla, Salamandra, Ichthyophis, , 2. Class : Reptilla, Creep or crawl to locomote. Mostly terrestrial., , Body has dry and cornified skin and epideremal scales or scutes., , Tympanum represents ear., , Limbs, when present, are two pairs, , Snakes and lizards shed scales as skin cast., , Heart 3-chambered but 4-chambered in crocodiles., , Sexes Separate; fertilisation internal., , Oviparous. Direct development., , e.g., Testudo, Naja, Vipera, Calotes, Crocodilus, Hemidactylus, 3. Class : Aves, Presence of feathers except flightless birds and beak (modified jaws), without teeth., Forelimbs are modified into wings., , Hind limbs have scales, modified for walking, swimmng or clasping., , Skin is dry as no glands on skin except oil gland at base of tail., , Endoskeleton bony with air cavities (pneumatic) and hollow bones to, , assist in flight., Crop and Gizzard—Additional chamber in digestive tract., , Air sacs are connected to lungs to supplement respiration., , Warm blooded (homoiothermous), Heart–Four chambered., , Sexes separate, fertilization internal, , Oviparous. Direct development., e.g., Columba, Struthio, Pavo, Corvus, Neophron, Pstittacula Aptenodytes., , 4. Class : Mammalia, , Have mammary glands to nourish young ones., , , Have two pairs of limbs, adapted to perform special work., , , Skin has hairs., 36, , Biology Class - 11
Page 63 :
, External ears or, pinna present., , , Different types of teeth in jaw., , , Homoiothermous; Heart–Four chambered, Lungs for respiration., , , Sexes are separate, fertilisation internal., , , Viviparous. Direct development., , , e.g., Rattus, Canis, Elephas, Equus. Oviparous mammal is, Ornithorhynchus., , Questions, , Very Short Answer Questions , , (1 mark each), , 1. What is mesogloea ? Where is it found., 2. When is the development of an organism called as Indirect ?, 3. Why are corals important ?, 4. What is the difference between class Amphibia and class Reptilia in respect, of their skin ?, 5. Which phylum consists of organisms with cellular level of organisation ?, 6. Name the arthropod which is a (i) Living fossil, (ii) Gregarious pest., 7. Which organ helps in excretion in (i) Arthropods, (ii) Hemichordates ?, , Short Answer Questions-I , , (2 marks each), , 8. Distinguish between poikilothermous and homoiothermous organisms., 9. Define metagenesis with a suitable example., 10. List the characteristic features of class Mammalia., , Short Answer Questions-II , , (3 marks each), , 11. What is the difference between organisms on the basis of the coelom ? Give, examples for each., 12. Compare the water transport (vascular) system of poriferans and the, echinoderms., 13. What are the feature of class Aves which help them in flying ?, , Long Answer Questions , , (5 marks each), , 14. Distinguish between the chordates and non-chordates., 15. Differentiate between class Chondrichthyes and class Osteichthyes., Animal Kingdom, , 37
Page 64 :
Answers, , Very Short Answers , , (1 mark each), , 1. Undifferentiated layer present between ectoderm and endoderm. It is found, in Coelenterates., 2. Have a larval stage morphologically distinct from adult., 3. Have skeleton composed of calcium carbonatge which gets deposited and, can lead to formation of land forms, e.g., Lakshadweep (a coral island)., 4. Class Amphibia : Have moist skin without scales., , Class Reptilia : Have dry cornified skin with scales., 5. Phylum Porifera., 6. (i) Limulus (King crab), (ii) Locusta (Locust), 7. (i) Malpighian tubules, (ii) Proboscis gland., , Short Answers-I , , (2 marks each), , 8. Poikilothermous (cold blooded); Lack ability to regulate their body, temperature., , Homoiothermous (Warm) : Can regulate body temperature., 9. Refer ‘Points to Remember’., 10. Refer ‘Points to Remember’., , Short Answers-II , , (3 marks each), , 11. Refer ‘Points to Remember”., 12. Refer ‘Points to Remember, NCERT, Text Book of Biology for Class XI., 13. Wings, bones long and hollow with air cavities, air sacs connected to lungs, to supplement respiration., , Long Answers , , (5 marks each), , 14. Refer Table 4.1, page 55, NCERT, Text Book of Biology for Class XI., 15. Refer ‘Points to Remember’., , , 38, , Biology Class - 11
Page 65 :
Morphology of Flowering Plants, , 39
Page 66 :
Points to Remember, Morphology : The study of various external features, forms and relative, position of different organs of the organism is known as morphology. It may be, further divided into internal and external morphology., External Morphology : It deals with external forms like shape, size, colour,, structure and relative position of different organs., Internal Morphology : Further divided into anatomy and histology., Anatomy : It deals with the study of internal structure exposed after dissection, and opening of various parts of an organ., Histology : The study of tissues, their composition and structure., Adaptation : Any alteration in the structure or function of an organism, or any of its part that results from natural selection and by which the organism, becomes better fitted to survive and multiply in its environment., The Root : The root is underground part of the plant and develops from, elongation of radicle of the embryo., Characteristics : It is inside the soil, chlorophyll is absent, absence of nodes,, internodes, leaves and buds; positive geotropic and hydrotropic and negative, phototropic., Main functions of root system :, 1. Absorption of water and minerals from the soil., 2. Provides anchorage to plant parts., 3. Stores reserve food material and synthesises plant growth regulators, (cytokinins), 40, , Biology Class - 11
Page 67 :
Various types of root, ↓, Tap root, ↓, , Fibrous root Adventitious root, ↓, , ↓, , Originates from radical Originates from base of Originates from parts of, , the stem , the plant other than radicle, Dicotyledonous plants, Monocotyledonous, , Banyan tree (Prop roots), , e.g., gram, pea, mango, plants, e.g., wheat,, , Maize (stilt roots), , mustard. , , Rhizophora (Respiratory, , paddy, grasses., , , , roots), , Regions of Roots, Root Cap : The root is covered at the apex by the thimble-like structure, which protect the tender apical part., Region of meristematic activity : Cells of this region have the capability, to divide; cells are small, thin walled with dense protoplasm., Region of elongation : Cell of this region are elongated and enlarged. This, region is responsible for the growth of root in length., Region of Maturation : This region has differentiated and matured cells., Some epidermal cells form very fine and delicate thread like structures called, root hairs., Modifications of Root : Roots are modified for support, storage of food,, respiration., , , For support : Prop roots in banyan tree, stilt roots in maize and sugarcane., , , , For respiration : Pneumatophores in Rhizophora (Mangrove)., , , , For storage of food : Fusiform (radish), Napiform (turnip), Conical (carrot),, Fasiculated fleshy roots (Asparagus)., , The Stem : Stem is the aerial part of the plant and develops from plumule, of the embryo. It bears nodes and internodes., Functions of stem : Exposure of leaves, conduction of water and minerals,, translocation of food, exposure of flowers and fruits., Morphology of Flowering Plants, , 41
Page 68 :
Modifications of Stem :, In some plants the stems are modified to perform the function of storage of, food, support, protection and vegetative propagation., , , , , , , , , , For food storage : Rhizome (ginger, turmeric), Tuber (potato), Bulb (onion),, Corm (Colocasia, Amorphophallus/Zamin-kand), For support : Stem tendrils of watermelon, grapevine, cucumber, pumpkins., For protection : Axilliary buds of stem of Citrus, Bougainvillea get modified, into pointed thorns. They protect the plants from animals., For vegetative propagation : Underground stems of grass (runner), strawberry, (stolons), leateral branches of mint and jasmine, Eichhornia (offsets)., For assimilation of food : Flattened stem of Opuntia and cylindrical stem, of Euphorbia contains chlorophyll and performs photosynthesis., , The Leaf : Develops from shoot apcial meristem, flattened, green structure, acropetally arranged manufacture the food by photosynthesis. It has bud in axil., A typical leaf has leaf base, petiole and lamina (leaf blade). In some leguminous, plants the leaf base may become swollen which is called as pulvinus., Leaf base → bears two lateral outgrowth called stipules, Expanded to enclose stem, , Swollen, Pulvinus, , Sheathing leaf base , Covers stem totally, (Gram, wheat), , Partially, (Butter cup), , Mimosa, (Leguminous plant), , Types of Leaf, Simple , (Single leaf blade) , e.g., mango, peeple, Pinnately, Compound, (Leaflets present on common,, axis rachis), (Neem, rose), 42, , Biology Class - 11, , Compound, (Leaf has number of leaflets), Palmately, Compound, (Leaflets attached to common, point at petiole tip), (Silk, cotton)
Page 69 :
Venation : The arrangement of veins and veinlets in the lamina of leaf., Types of Venation :, 1. Reticulate : Veinlets form a network as in leaves of dicotyledonous plants, (China rose, peepal)., 2. Parallel : Veins are parallel to each other as in leaves of monocotyledonous, plants (grass, maize,sugarcane)., , Phyllotaxy : The pattern of arrangement of leaves on the stem or branch., Types of phyllotaxy, Alternate, , Opposite, , Whorled, , (Single leaf at a node)in, alternate manner, e.g., China rose Mustard,, , (Two leaves at a node) in, opposite manner, e.g., Calotropis, guava, , (More than two leaves in a, whorl at a node), e.g., Nerium, Alstonia, , Functions of Leaf, photosynthesis, gaseous exchange, transpiration, protection of buds and, conduction., , Morphology of Flowering Plants, , 43
Page 70 :
Modifications of Leaves :, Type Function Example, Tendrils, : (Climbing), — Sweet Pea, Pea, Spines, : (Protection), — Aloe, Opuntia, Argemone, Pitcher, : (Nutrition), — Nepenthes, Hook, :, (Support), —, Cat’s nail, Fleshy Leaves :, (Storaged food), —, Onion and Garlic, , , Inflorescene : The arrangement of flowers on the floral axis (Peduncle), Main types of Inflorescence, , , Main types of Inflorescence, , Recemose, 1., 2., , , , Cymose, , It is indefinite inflorescence, 1., Main axis continues to grow and, 2., flowers borne in acropetal succession , e.g. : Radish, Mustard, Amaranthus , , It is definite inflorescence, Main axis terminates in flowers and the, flowers borne in basipetal succession, e.g. : Cotton, Jasmine, Calotropis, , Special Inflorescence type—Ficus, Salvia, Euphorbia,Sunflower, Flower—Modified shoot meant for reproduction, Gamopetalous, , , Diagram, , Petals United, , Petal Free (Polypetalous), , On the basis of symmetry flower can be :, ↓, , ↓, , ↓, , Actinomorphic, , Zygomorphic, , Asymmetric, , (Radial symmetry), , (Bilateral symmetry), , (Irregular), , ↓, ↓, Flower can be divided, Flower can be divided into, into two equal halves, two similar halves only in, in any radial plane, one plane, passing through centre , eg : Mustard, Datura,, eg : Pea, bean, Gulmohar,, Chilli, Cassia, 44, , Biology Class - 11, , ↓, Flower cannot be divided, in two similar halves by, any vertical plane passing, through centre, eg : Canna
Page 71 :
On the basis of floral appendages flower can be :, ↓, ↓, ↓, Trimerous, Tetramerous, Pentamerous, (multiples of 3), (multiples of 4), (multiples of 5), On the basis of position of Calyx, corolla and androecium in respect of ovary,, flower can be—, of position of Calyx, corolla and androecium, ↓, Hypogynous, (Superior Ovary), , ↓, Perigynous, (Half inferior ovary), , ↓, Epigynous, (inferior ovary), , ↓, ↓, ↓, Mustard, China rose,, Plum, Rose, Peach, Guava, Cucumber, Brinjal , ray florets (sun flower), Thalamus/Receptacle : Swollen end of flower stalk (pedicel) which bears four, whorls of flower viz., Calyx (K), Corolla (C), Androecium (A) and Gynoecium (G)., , made of, , made of, , or, , Flower can be, Bisexual , Unisexual, Staminate flower, Pistillate flower, if have both Androecium , can, (Male, (Female, flower), and Gynoecium, flower), have only, have only Gynoecium, Androecium/Stamen, Carpel, Morphology of Flowering Plants, , 45
Page 72 :
Bract—Reduced leaf base found at the base of pedicel. Flowers with bracts, are called bracteale and without bracts are called ebracteate., Perianth : If calyx and corolla are not distinguishable, they are called, perianth., Example : Lily, Aestivation: The mode of arrangement of sepals or petals infloral bud., , Types of aestivation :, 1. Valvate : Sepals or petals just touch one another at the margin, withut, overlapping. e.g., Calotropis, 2. Twisted : Sepals or petals overlap the next sepal or petal e.g., China rose,, Cotton, lady’s finger., 3. Imbricate : The margins of sepals or petals overlap one another but not in, any definite direction, e.g., Cassia, Gulmohar., 4. Vexillary : The largest petal overlaps the two lateral petals which in turn, overlap two smallest anterior petals, e.g., Bean, Pea., Placentation : The arrangement of ovules within the ovary., , Types of Placentation :, 1. Marginal : Placenta forms a ridge along the ventral suture of ovary, e.g.,, Pea., 2. Axile : Margins of carpels fuse to form central axis, e.g., China rose, Tomato,, Lemon, 3. Perietal : Ovules develop on inner wall of ovary, e.g., Mustard, Argemone, 4. Free central : Ovules borne on central axis, lacking septa, e.g., Dianthus,, Primrose, , 5. Basal : Placenta develop at the base of ovary, e.g., Sunflower, Marigold, 46, , Biology Class - 11
Page 73 :
Placenta : Parenchymatous flattened cushion inside ovary where ovules are, borne., The fruit : After fertilisation, the mature ovary develops into fruit. The, parthenocarpic fruits are formed from ovary without fertilisation (seedless fruitBanana), Fruit (Ripened Ovary), Pericarp (Fruit Wall), Epicarp, (outer), , Mesocarp, (middle), , Seed, , Endocarp, (inner), , Seed coat, , Embryo, , Embryonal axis (Plumule + Cotyledons (Store, Radicle), food), Monocotyledonous seed—Endosperm bulky and stores food, covered by, proteinaceous Aleurone layer. Seed has single large cotyledon–scutellum., Plumule is enclosed in Coleoptile and Radicle is enclosed in Coleorrhiza., Dicotyledonous Seed—, Testa (Outer layer), Seed Coat, Tegmen (Inner Layer), , Hilum —is a scar on the seed coat through which seeds attached to the fruit., Micropyle—small pore, above hilum, Cotyledons—two; fleshy, full of preserve food materials, Morphology of Flowering Plants, , 47
Page 74 :
Embryonal axis—Radicle and plumule., Endospermous seed—endosperm present in mature seed. eg. castor, Non-endospermous seed—endosperm not present in mature seeds, eg. bean,, , Questions, Very Short Answer Question, , (1 mark each), , 1. Which part of Opuntia is modified to form spines ?, 2. Name one plant in which leaf is pinnately compound., 3. In mangroves, pneumatophores are the modified adventitious roots. How, are these roots helpful to the plant ?, 4. Which part in Ginger and Onion are edible ?, 5. Why do various plants have different type of phyllotaxy ?, 6. State the main function of leaf tendril., 7. Which plant family represent the following floral formula :, , 8. The endosperm is formed as a result of double fertilisation (triple fusion)., What is its function ?, 9. Which type of venation do you observe in dicot leaf ?, 10. In pea flower, the aestivation in corolla is known as vexillary. Give reason., 11. What is the name given to the cotyledon in case of Monocots., 12. Name the part modified for food storage in the following (a) carrot (b) Radish, (c) Potato (d) Dahlia (e) Turmeric (f) Sweet potato, , Short Answer Questions-I , , (2 marks each), , 13. Flower is a modified shoot Justify., 14. Name the type of root of the following :, (a) Roots performing the function of photosynthesis., (b) Roots come above the surface of the soil to absorb air., (c) The pillar like roots developed from lateral branches for providing, mechanical support., (d) Roots coming out of the lower nodes of the stem and provide the support, to the plant., 15. Identify the type of tendrils found in the following plants—, (a) Cucumber (b) Pea (c) Grape vines (d) Water Melon, 16. Fill up the blank spaces (a), (b), (c) and (d) in the table given below :, 48, , Biology Class - 11
Page 75 :
Hypogynous, , 17., , , , , 18., , Provide the scientific terms for the following :, (i) The leaf without a petiole (stalk)., (ii) The flat and expanded portion of a leaf., (iii) Orderly arrangement of leaves on the node., (iv) Lateral appendages on either side of the leaf., Differentiate between peduncle and Pedicel, , Short Answer Question-II , , (3 marks each), , 19. Observe the given figure showing various types of placentration. Identify, the type of placentation. Give one example of each., , 20. ‘Potato is a stem and sweet potato is a root.’ Justify the statement on the, basis of external features., 21. Define aestivation. Which type of aestivation is found in China rose,, Calotropis Gulmohar and Pea., 22. Give two example of each type of phyllotaxy., 23. Differentiate between :, (a) Actinomorphic flower and Zygomorphic flower, (b) Apocarpous ovary and Syncarpous ovary, (c) Racemose inflorescence and Cymose inflorescence, 24. In the given structure of a Monocotyledonous seed label the parts a, b, c, d,, e. Give the function of part ‘a’., Morphology of Flowering Plants, , 49
Page 76 :
25. Maize grain usually called as a fruit and not a seed. Why ?, , Long Answer Questions (5 marks each), 26. Describe various stem modifications associated with food storage, climbing, and protection., , Answers, , Very Short Answers , 1., 2., 3., 4., , (1 mark each), , Leaves, Neem, Rose’, Acacia., Pneumatophores is mangroves help in respiration., Ginger–Rhizome and Onion–bulb, , 5. For proper exposure of leaves to get sunlight., 6. The leaf tendrils help the plant for climbing., 7. Lilliaceae, 8. Endosperm stores the food., 9. Reticulate venation., 10. In peas, there are five petals. The largest one (standard) overlaps the two, lateral petals (wings) which in turn overlap the two smallest anterior petals, (keel)., 11. Scutellum., 12. (a) and , , (b) Fleshy tap root, , (e) Rhizome, , (f) Fleshy root tuber, , 50, , Biology Class - 11, , (c) Stem tuber , , (d) root tuber
Page 77 :
Short Answers-I, , (2 marks each), , 13. The flower is considered to be a modified shoot because the internodes, in flower are highly condensed and the appendages such as sepals, petals,, stamens and carpels(pistil) are generally large in number., 14. (a) Assimilatory roots, (b) Respiratory roots, (c) Prop roots, (d) Stilt roots, 15. (a) Stem tendril, (b) leaf tendril, (c) and, (d) both stem tendrils, 16. (a) Floral parts are situated below the ovary., (b) Half inferior, (c) Epigynous, (d) Floral parts are situated above the ovary., 17. (i) Sessile, (ii) Lamina, (iii) Phyllotaxy, (iv) Stipules, , Short Answers-I, , (3 marks each), , 18. Penduncle is the axis of inflorescence which generally bears a number of, flowers., , Pedicel is the stalk of the flower which bears a single flower., , Short Answers SA-II , , (3 marks each), , 19. (a) Marginal placentation —, , Pea, , (b) Parietal placentation , , —, , Mustard, Argemone, , (c) Free central plancentation , , —, , Dianthus, Primrose, , 20. Potato is the swollen tip of an underground stem branch (stolon). It has, nodes (eyes) which consist of one or more buds subtended by a leaf scar., Adventitious roots also arise during sprouting. On the other hand sweet potato, is a swollen adventitious root (tuberous root). It has no nodes, internodes, and buds like a stem., 21. The mode of arrangement of sepals or petals in a floral bud is known as, aestivation., China rose – twisted Calotropis – valvate, Gulmohar – imbricate Pea – vexillary, Morphology of Flowering Plants, , 51
Page 78 :
22. Type of phyllotaxy, , Examples, , , (i) Alternate, , China rose, mustard, , (ii) Opposite, , Calotropis, guava, , (iii) Whorled, , Nerium, Alstonia, , 23. (a) Actinomorphic Flower, , Zygomorphic flower, , , , (1) Two equal havles are produ-, , (1), , Two equal halves are formed, , , , by any vertical division passing , , ced only by one vertical, , , , through the centre. , , division, , , , It has a radial symmetry., , (2), , (2) It has a bilateral symmetry., , , (b) Apocarpous Ovary, , Syncarpous Ovary, , , , (1) The flower has fused carpels., , (1), , The flower has several free, , , , free carpels (ovary)., , , , On maturity it forms fruitlet, , (2), , , , (2) On maturity it forms a single, , of aggregate type. , , fruit., , , (c) Racemose inflorescence, , Cymose inflorescence, , , , (1) The main axis has a limited, , (1), , The main axis has unlimited, , , , growth. , , , , Flowers are arranged, , (2) Flowers are arranged, , , , acropetally i.e., the lower, , basipetally i.e., the lower, , , , flower are younger , , (2), , growth., , flowers are older, , 24. (a) Endosperm, (b) Scutellum, (c) Coleoptile, (d) Coleorrhiza, (e) Aleurone layer, Function of (a)—Provide nutrition., 25. Maize grain is a single seeded fruit in which the seed covering or testa is, fused with pericarp or fruit wall. A micropyle is not found but base of style, is present., 52, , Biology Class - 11
Page 79 :
Long Answers , , (5 marks each), , 26. Stem Modification :, , For food storage : Ginger (Rhizome), Potato (Tuber), Onion (Bulb),, , Colocasia (Corm)., , For climbing (support) : Sterm tendril (cucumber,grapevine,watermelon), , , For protection : Thorn (Bougainvillea, Citrus, Duranta) Description :, , Refer page 68, NCERT, Text Book of Biology for Class XI., , , Morphology of Flowering Plants, , 53
Page 80 :
Points to Remember, Anatomy : Anatomy is the study of internal structure of organisms. Plant, anatomy includes organisation and structure of tissues., Tissue is a group is cells having a common origin and usually performing, a common function., There are two types of tissues (i) Meristematic (ii) Permanent, Meristematic tissues : The meristematic tissue is made up of the cells which, have the capability to divide. Meristems in plants are restricted to a specialised, regions and responsible to the growth of plants., Meristems, Apical meristem, , Intercalary meristem, , Lateral Meristem, , Occurs at the tips of, Occurs between, Occurs in the mature, roots and shoots mature tissue region of roots and, shoots, , Primary meristem, Primary meristem, Secondary meristem, , Increase the length of, Occur in grasses and, Appears later than, plant regenerate parts primary meristem, removed by grazers and responsible for, secondary growth, Axillary bud : The buds which are present in the axils of leaves (Consist, of cells left behind from shoot apical meristem) and are responsible for forming, branches of flowers., Permanent tissues : The permanent tissues are derived from meristematic, tissue, are composed of cells, which have lost the ability to divide and have become, structurally and functionally specialised., , , 54, , Biology Class - 11
Page 81 :
Types of Permanent Tissue, Simple (i) , Parenchyma, , Collenchyma, , Complex (ii), , Sclerenchyma, , Xylem, , Phloem, , Parenchyma : Living, thin walled isodiametric cells, with interceullar spaces,, cell wall is made up of cellulose. It performs the functions like photosynthesis,, storage, secretion., Collenchyma : It is formed of living, closely packed cells. Its cells are, thicknened at the corners due to depositon of celluose and pectin. It provide, mechanical support to the growing parts of the plant. It is either found in, homogenous layer or patches., Sclerenchyma : It is formed of dead cells with thick and lignified walls., Provide mechanical support to organs. They have two types of cells : fibres and, sclereids., (a) Fibers—are thick walled,elongated and pointed cells., (b) Sclereids—are spherical, oval or cylindrical, highly thickened dead cells, with narrow lumen. Found in walls of nut, pulp of fruits like guava, seed coat of, legumes and leaves of tea., Xylem : Xylem consists of tracheids vessels, xylem fibres and xylem, parenchyma. It conducts water and minerals from roots to other parts of plant., (a) Tracheids—Tube like cells with thick and lignified walls and tapering, ends; dead, without protoplasm., (b) Vessel—long cylindrical structure made up of many cells with large, central cavity, devoid of protoplasm. Present in angiosperms., (c) Xylem fibres—highly thickened walls; with obliterated lumens; septate, or aseptate., (d) Xylem parenchyma—living and thin walled; cell walls made up, cellulose, store food material in form of starch or fat., Radial conduction of water takes place by ray parenchymatous cells, Protoxylem : The first formed primary xylem elements., Metaxylem : The later formed primary xylem., Endarch : Protoxylem lies towards the centre and metaxylem towards the, periphery of the organ; in stem, Anatomy of Flowering Plants, , 55
Page 82 :
Exarch : Protoxylem toward periphery and metaxylem towards centre; in, roots., Phloem :Phloem consists of sieve tube elements, companion cells, phloem, fibres and phloem parenchyma; Phloem transports the food material from leaves, to various parts of the plant., (a) Sieve tube elements :, long tube like structures arranged longitudinally., associated with companion cells., end walls are perforated to form sieve plates., functions of sieve tubes are controlled by the nucleus of companion cells., (b) Companion cells, Specialised parenchymatous cells associated with sieve tube elements, Connected with sieve tube elements by pit fields present between their, common longitudinal walls, Help to maintain pressure gradient in sieve tubes., (c) Phloem Parenchyma, made up of elongated, tapering cylindrical cells with dense cytoplasm and, nucleus., cell wall made of cellulose with pits through which plasmodesmatal, connections exist between cells., store food material., (d) Phloem fibers (bast fibers), are sclerenchymatous; absent in primary phloem but present in secondary, phloem., elongated, unbranched pointed, needle like apices with thick cell walls., , Protophloem : First formed phloem with narrow sieve tubes., , Metaphloem : Later formed phloem with bigger sieve tubes., , The Tissue System :, 1. Epidermal tissue system : It includes cuticle, epidermis, epidermal hairs,, root hairs, trichomes and stomata., , The Tissue System :, (1) Epdiermal tissue system : It includes., (a) Cuticle—Waxy thick layer outside epidermis, prevents the loss of water., (b) Epidermis : Outer most layer of primary plant body., (c) Epidermal hair : help in absorbing water and mineral from soil., (d) Trichomes : help in preventing water loss due to transpiration., 56, , Biology Class - 11
Page 83 :
(e) Stomata : Regulate process of transpiration and gaseous exchange., Stomatal apparatus : The stomatal aperture, guard cells and surrounding, subsidiary cells are together called stomatal apparatus., , Nucleus, , 2. The ground tissue system : It is made up of parenchyma, collenchyma,, sclerenchyma. In dicot stems and roots (both monocots and dicots) the ground, tissue is divided into hypodermis, cortex, endodermis, pericycle, medullary, rays and pith., 3. The vascular tissue system : It includes vascular bundles which are made, up of xylem and phloem., , Anatomy of Flowering Plants, , 57
Page 84 :
Anatomy of Root, , , Dicot Root , , Monocot Root, , 1. Cortex is comparatively narrow., 1. Cortex is very wide., 2. Endodermis is less thicknened, 2. Endodermal cells are highly, casparian strips are more thickened Casparian strips are visible, prominent. only in young roots., 3. The xylem and phloem bundles, 3. Xylem and phloem are more than 6, varies from 2 to 5. (polyarch)., 4. Pith is absent or very small., 4. Well developed pith is present., 5. Secondary growth takes place, 5. Secondary growth is absent., with the help of vascular cambium, and cork cambium., Casparian Strips—The tangential as well as radial walls of endodermal, cells of dicot roots have deposition of water impermeable, waxy material, suberin, in the form of casparian strips., , Antomy of Stem, , , Dicot Stem , , 1. The ground tissue is differentiated, , Monocot Stem, , 1. The ground tissue is made up of similar, , into cortex, endodermis, pericycle cells., and pitch., 2. The vascular bundles are arranged, , 2. The vascular bundles are scattered, , in a ring. throughout the ground tissue., 3. Vascular bundles are open, without 3. Vascular bundles are closed,surrounded, bundle sheath and wedge-shaped by sclerenchymatous bundle sheath,, outline. oval or rounded in shape., 4. The stem shows secondary growth, due to presence of cambium, between xylem and phloem., , 4. Secondary growth is absent., , Secondary growth dicot stem—An increase in the girth (diameter) in plants., Vascular cambium and cork cambium (lateral meristems) are involved in secondary, growth., 58, , Biology Class - 11
Page 85 :
1. Formation of cambial ring : Intrafascicular cambium + interfascicular, cambium., 2. Formation of secondary xylem and secondary phloem from cambial ring., 3. Formation of spring wood and autumn wood., 4. Development of cork cambium(phellogen), , Cork (phellem) – From outer cells, Cork Cambium (Phellogen), , Sec. cortex (phelloderm) – from inner cells, (Phellogen + Phellem + Phelloderm) = Periderm, , Secondary growth in dicot roots : Secondary growth in dicot roots occur, with the activity of secondary meristems (vascular cambium). This cambium, is produced in the stele and cortex, and results in increasing the girth of dicot, roots., , Anatomy of Leaf, Dorsiverntral (Dicot) Leaf Isobilateral (monocot) Leaf, 1. Stomata are absent or less abundant 1. The stomtata are equally distributed, on the upper side. on both sides., 2. Mesophyll is differentiated into two 2. Mesophyll is undifferentiated., parts upper palisade parenchyma, and lower spongy parenchyma., 3. Bunldle sheath is single layered and 3. Bundle sheath may be single or, formed of colourless cells. double layered., 4. Hypodermis of the mid-rib region, is 4. Hypodermis of the mid-rib region, collenchymatous. is sclerenchymatous., 5. Stomata have kidney shaped guard 5. Stomata have dumb bell shaped, cells. guard cells., , 1., 2., 3., 4., 5., , Spring Wood , , Also called early wood., Cambium is active, Xylary elements more, Vessels with wide cavities, Light in colour, low density, , Autumn Wood, , 1. Also called late wood, 2. Cambium less active, 3. Xylary elements less, 4. Vessels narrow, 5. Dark, high denisty, Anatomy of Flowering Plants, , 59
Page 86 :
Heartwood , , Sapwood, , 1. Central or innermost region of stem 1. Peripheral region stem, light in, which is hard, durable and resistant colour, to attack of Microorganisms and, insects., 2. Not involved in conduction of water, 2. Involved in conduction of water and, gives mechanical support to stem mineral, Lenticels—Produced when phellogen cuts off parchymatous cells on outer, side. These cells rupture the epidermis forming lens shaped opening called lenticels., Function—Permit exchange of gases., Bulliform Cells—Large, empty, colourless adaxial cells with vein in leaves, which maintain turgidity of leaves., , Questions, , Very Short Answer Question, , (1 mark each), , 1. Name the tissue represented by the jute fibres used for making the ropes., 2. Which kind of roots have polyarch vascular bundles ?, 3. Write the significance and location of heart wood., 4. State the role of pith in stem., 5. Where are bulliform cells found in leaves ?, 6. Why are xylem and phloem called complex tissues ?, 7. Which meristem is responsible for longitudinal growth in plants ?, 8. What forms’ the cambial ring in a dicot stem during the secondary, growth ?, 9. Name the anatomical layer in the root from which the lateral branches of, root originate., 10. Which tissue of the leaf contains chloroplast ?, 11. A plant tissue when stained, showed the presence of hemicellulose and, pectin in cell wall of its cells. Name the tissue., 12. Write the function of phloem parenchyma., 13. Name the cells which make the leaves curl in plants during water stress., 14. Give the function of lenticels., 60, , Biology Class - 11
Page 87 :
15. The vascular bundles are surrounded by a thick layer of cells in leaves. What, is the name of cells ?, 16. Mention the signfiicance of casparian strips. Where do you find them ?, 17. Give the function of companion cells., , Short Answer Questions (SA-I), , (2 marks each), , 18. Why is cambium considered to be lateral meristem ?, 19. Give any four differences between tracheids and vessels., 20. How are open Vascular bundles differ from closed vascular bundles ?, 21. What are trichomes ? State their functions., 22. Give below are the various types of tissue and their functions. Which out of, these is not a matching pair arid why;, (a) Collenchyma :, , provides mechanical support to the, , , , growing parts of plant., , (b) Sclerenchyma :, , photosynthesis, storage and secretion., , (c) Chlorenchyma :, , perform the function of photosynthesis, , (d) Xylem :, , conduction of water and minerals., , 23. In which part of the plant you would see the following :, (a) Radial vascular bundle, , (b) Well developed pith, , Short Answer Question (SA-II), , (3 marks each), , 24. Give the points of difference between lenticels and stomata., 25. Even being a monocotyledonous plant the Palm increases in girth. Why and, how does it take place ?, 26. Differentiate between endarch and exarch conditions., 27. If you are provided with microscopic preparation of transverse section of a, meristemic tissue and permanent tissue, how would you distinguish them ?, 28. Differentiate between aerenchyma and collenchyma on the basis of their, structure and function., 29. Are there any tissue elements to pholoem which are comparable to those of, xylem ? Explain., Anatomy of Flowering Plants, , 61
Page 88 :
30. Observe the figure and answer the following questions :, (i) Name parts (a) and (b)., (ii) Are these types of stomata observed in monocot or in dicot plants ?, (iii) Which parts shown in figure constitute the stomatal apparatus ?, , Long Answer Questions, 31., , , 32., , (5 marks each), , (i), (ii), (iii), (i), , What are meristems ?, Name the various kinds of meristems in plants., State the location and functions of meristems., Suppose you are examining a cross section of a stem under compound, microscope, how would you determine whether it is monocot stem or dicot, stem ?, (ii) Write the characteristics of collenchyma., 33. What is secondary growth in plants ? Describe various steps of secondary, growth in dicot stem with the help of diagrams., , Answers, , Very Short Answers , , (1 mark each), , 1. Sclerenchyma., 2. Monocotyledonous roots., 3. The hard central region of tree trunk made up of xylem vessels, which provide, mechanical strength to stem., 4. Pith stores the food material., 5. Bulliform cells are found in the upper epidermis of monocot leaves., 6. As they are made up of more than one kind of cells., 7. Primary meristem., 62, , Biology Class - 11
Page 89 :
8., 9., 10., 11., 12., 13., 14., 15., 16., 17., , Fascicular and intrafascicular strips of meristem., Pericycle of mature zone., Mesophyll tissue., Collenchyma., Lateral conduction of food and supply of water from xylem., Bulliform or motor cells., Permit exchange of gases., Bundle sheath cells., Casparian strips are found in endodermis and make them water impermeable., Maintain pressure gradient in sieve tubes., , Short Answers (SA-I), , (2 marks each), , 18. The cambium is considered as a lateral meristem because it occurs along the, lateral sides of the stem and roots and appears later than primary meristem., Cells of this meristem divide periodically and increase the thickness of the, plant body., 19., , 1., , 2., , 3., 4., , Tracheid , , Vessels, , A tracheid is formed from a, 1. A vessel is made of a number of, single cell. cells., The ends are rounded or, 2. The ends are generally oblique and, transverse. tapering., They are comparatively narrower. 3. They are comparatively wider, The lumen is narrower., 4. The lumen is wide., , 20. Open Vascular bundles : These vascular bundles contain a strip of cambium, in between phloem and xylem. Open vascular bundles are collateral and, bicollateral., , Closed Vascular bundles : Intrafascicular cambium is absent. Closed, vascular bundles can be collateral or concentric., 21. Trichomes are multicellular epidermal hairs on the stem, seeds or fruits., Trichomes help in protection, dispersal of fruits and seeds and reduction in, water loss., 22. (b) Sclerenchyma : photosynthesis, storage and secretion is not a matchingpair., The function of sclerenchyma is to provide mechanical support to, organs., 23. (a) Root, (b) Monocot root, Anatomy of Flowering Plants, , 63
Page 90 :
Short Answers (SA-II), , (3 marks each), , 24. Lenticels : Opening that are found in old stems and roots in the cork tissues, containing a number of complimentary cells and they are permanently opened, pores., , Stomata : Opening that are found in leaves and young stems in the epidermis, and have two guard cells. They open and close in response to turgidity of, their guard cells., 25. Palms possess residual meristem below their leaf primordial, which adds, ground parenchyma and vascular bundles. The ground parenchyma can also, undergo further divisions even after the completion of elongation., 26., , Endarch condition, , Exarch condition, , , 1. Protoxylem towards pith and, 1. Protoxylem towards periphery and, metaxylem towards periphery metaxylem towards pith, 2. Found in Stem, 2. Found in root., 27. Meristematic tissues are composed of cells that have the capability to divide., These cells are exist in different shapes without intercellular space. Cells are, thin walled, rich in protoplasm, without vacuoles., , Permanent tissues are derived from meristematic tissue and are composed, of cells have their definite shape, size and function. These cells may be thin, walled (living) or thick walled (dead)., 28., , Aerenchyma , , Collenchyma, , , (a) Parenchymatous tissue containing (a) Tissue contains deposits of, large air space. cellulose and large pectin at the, corner of cells., (b) Thin walled cells, isodiametric in (b) Consists of oval and polygonal, in shape with intercellular space. cells without intercellular space., (c) Provides buoyancy to the plant., (c) Provides elasticity and mechanical, , strength., 29. (a) The sieve elements of phloem is comparable to the vessel of the xylem because, both lack nucleus., (b) Pholem fibre is similar to the xylem fibre because both provide tensile strength, to the tissue., (c) Phloem parenchyma and xylem parenchyma is the living components, of phloem and xylem respectively., 64, , Biology Class - 11
Page 91 :
30. (i) a : epidermal cell, , , b : guard cell, , (ii) In dicot plants., (iii) The stomatal apparatus includes the stomatal aperture, guard cells and, the surrounding subsidiary cells., , Long Answers, , (5 mark each), , 31. (i), (ii) and (iii) : Refer ‘Points to remember’, 32. (i) and (ii) : Refer ‘Points to remember’., 33., , , , Secondary growth : Refer ‘Points to remember., , Steps of secondary growth : Refer page 94–97, NCERT, Text Book of, , Biology for Class XI., Figure 6.9, page 95 NCERT, Text Book of Biology for Class XI., , , , Anatomy of Flowering Plants, , 65
Page 92 :
Points to Remember, Cell junctions—In nearly all animal tissues, specialised junction provide, structural and functional links between its individual cells., Three Types of Cell junctions—, 1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals., They help to stop substances from leaking across a tissue., 2. Adhering junctions : Perform cementing function to keep neighbouring, cells together., 3. Gap junction : Facilitate the cells to communicate with each other by, connecting the cytoplasm of adjoining cells for rapid transfer of ions, small, molecules and sometimes big molecules., Types of Fundamental Animal Tissues, S.No. , , Type, , 1. Epithelial Tissues, , Location, , Functions, , Free Surfaces, , Protection, Secretion,, , , , Excretion, absorption,, , , , Sensory and reproduction, , 2. Connective Tissues, , Inside body, in organs, , Holding or binding, support,, , , , other tissues and below, , transport and circulation,, , , , skin, , protection and storage., , 3. Muscular Tissues, , Inside movable parts, , Movements and locomotion, , 4. Nervous Tissues, , Central Nervous System, , Communication and control, , , , & every organ Peripheral, , , , Nervous System., , 66, , Biology Class - 11
Page 93 :
Animal Tissues, Epithelial, , Connective, , Muscular, , Neural, , Epithelial Tissue, (A) Simple : Composed of single layer of cells., , , , , Functions as lining for body cavities, ducts and tubes., , 1. Squamous, , , , single thin layer of flattened cells., , , , found in walls of blood vessels, air sacs of lungs., , , , single layer of cube like cells., , , , found in ducts of glands and tubular parts of nephron., , , , single layer of tall and slender cells., , , , , , free surface may have microvilli., , , , , , found in lining of stomach and intestine, , , , columnar or cubolidal cells with cilia., , , , move particles or mucus in specific direction, in, , , 2. Cuboidal, , 3. Columnar, , 4. Ciliated, , , bronchioles, fallopian tubes., , (B) Compound :, , , Made of more than one layer of cells., , , , Provide protection against chemical and mechanical stresses., , , , Cover dry surface of skin, moist cavity, pharynx, inner lining of ducts of, salivary glands and pancreatic ducts., Glandular epithelium, , , , Exocrine glands, , Endocrine glands, , secrete mucus, saliva,oil, milk, , secrete hormones., digestive enzymes, products released through ducts., , secrete directly into the fluid, bathing the gland., , , Structural Organisation in Animals, , 67
Page 94 :
Connective tissue : Link and support other tissues/organs of the body., Connective Tissues, Proper Connective Tissues, Loose connective, Tissues, , Dense connective, Tissues, , Specialised Connective Tissues, Skeletal, Tissues, , Areolar Adipose Dense, Dense Bone, regular, irregular, , eg. Tendon, ligament, , Cartilage, , Fluid Connective, Tissues, Blood, , Lymph, , Loose Connective Tissue, , , (has cells and fibres loosely arranged in semi-fluid ground substance), (i) Areolar Tissue :, present beneath the skin., , contains fibroblasts, macrophages and mast cells., , serves as a support framework for epithelium, (ii) Adipose Tissue :, , , located beneath the skin., , cells are specialised to store fats., , Dense Connective Tissue, , , Fibres and fibroblasts are compactly packed., (i) Dense Regular, , , Collagen fibres present in rows., , , Tendons attach skeletal muscle to bone., , Ligaments attach bone to bone., , (ii) Dense Irregular, , Has collagen fibres and fibroblasts oriented differently., , , This tissue is present in the skin., , , Specialised Connective Tissues, (i) Cartilage : made up of chondrocytes and collagen fibres; inter cellular, material is solid and resists compression. Present in tip of nose outer ear, joints, etc., 68, , Biology Class - 11
Page 95 :
(ii) Bones : Ground substance is rich in calcium salts and collagen fibres Osteocyt, es are present in lacunae. Bones support and protect softer tissues and organs., They interact with skeletal muscles to bring about movements. Bone marrow, in some bones is the site of blood cell formation., (iii) Blood : Fluid connective tissue, consists of plasma and blood cells., Vascular Tissues, , , Blood, , Plasma, , , Lymph, Formed, Elements, , Blood Corpuscles, , Neutrophils, , Leucocytes, , Blood Platelets, , Erythrocytes, (RBCs), , , Plasma, , Leucocytes, (WBC), Granulocytes, Eosinophils, , Agranulocytes, Basophils, , Monocytes, , Lymphocytes, , MUSCULAR TISSUES, (long, contractile cells called fibres, bring about movement and locomotion), Skeletal Muscle Smooth Muscle Cardiac Muscle, Striated, Non-striated, Striated with intercalated, disc for communication, Closely attached to, Forms wall of, Occurs in heart wall, sekeletal bones., Internal Organs Short cyclindrical, like blood vessels, uninucleated fibres, stomach, intestine, long cylindrical, Spindle like, multinucleated fibres uninucleated fibres., , , Structural Organisation in Animals, , 69
Page 96 :
Neural Tissues, , , Neurons are the functional unit and are excitable cells., , , , Neurogila cells make up more than half the volume of neural tissue., , They protect and support neurons., Cockroach— Periplaneta americana (Phylum-Arthropoda, Class-Insecta), Habitat : Cockroach is a terrestrial, nocturnal, ominivorous,unisexual,, oviparous insect. Body convered by a chitinous, hard exoskeleton of hard plates, called sclerities., Morphology :, Head : Triangular, formed by fusion of 6 segments. Bears a pair of antennae,, compound eyes. Mouth parts consists of labrum (upper lip), a pair of mandibles,, a pair of maxillae,labium (lower lip), hypopharynx (acts as tongue)., Thorax : 3 segments; prothorax, measothorax and metathorax., Bears 2 pairs of wings :, Forewings : tegmina (mesothoracic)., Hindwings : transparent, membranous (metathoracic), 3 pairs of legs in thoracic segments. (one pair in each thoracic segment.), Abdomen : 10 segments. Bears a pair of long, segmented anal cerci in, both sexes and a pair of short, unjoined anal styles in males only 7th segment is, boat shaped., Also has anus and genital aperture at the hind end. Genital aperture, surrouonded by external genitalia called gonapophysis or phallomere., , , Male Cockroach , , Female Cockroach, , 1. Abdomen long and narrow, , 1. Abdomen short and broad, , 2. All nine sterna visible, , 2. Seven sterna visible. (7th sternum, fused with 8th and 9th sterna), , 3. Anal style present, , 3. Anal style absent, , Anatomy : Study of the morphology of internal organs., Alimentary canal : Divided into foregut, midgut and hindgut., Mouth → Pharynx → Oesophagus → Crop (stores food) → Gizzard (grinding, of food) → Hepatic caecae (at junction of fore and midgut; secretes digestive, juice) → Hindgut (ileum, colon, rectum) → Anus., 70, , Biology Class - 11
Page 97 :
Alimentary Canal of Cockroach, Blood vascular system : Open type, visceral organs bathed in haemolymph, (colourless plasma and haemocytes)., Heart consists of enlongated muscular tube and differentiated into funnel, shaped chambers with ostia on either side. Blood from sinuses enters heart through, ostia and is pumped anteriorly to sinuses again. Blood is colourless (haemolymph)., Repiratory system : Network of trachea which open through 10 pairs of, spiracles. Spiracles regulated by sphincters. Oxygen delivered directly to cells., Excretion and osmoregulation : by malpighian tubules; uricotelic (Uric, acid as excretory proudct)., Nervous system : Consists of series of fused segmentally arranged ganglia, joined by paired longitudinally connectives on the ventral side, three ganglia in, thorax, six in abdomen. Brain represented by supraoesophageal ganglion. Each, eye consist s of 200 hexagonal ommatidia., , Reproductive system :, Male reproductive system : Pair of testes (4th-6th segments) → vas deferens, → ejaculatory duct → male gonophore., Glands–Seminal vesicle (stores sperms), mushroom shaped gland (6th-7th, segment)., Structural Organisation in Animals, , 71
Page 98 :
Female reproductive system :, A pair of ovaries (with 8 ovarian tubules) → Oviduct → Genital chamber., Sperms transferred through spermatophores female produces 9–10 Ootheca., Fertilised eggs encased in capsules called oothecae (contains 14-16 eggs on, an average) development of P. americana paurometabolous incompleted, metamorphosis). Nymph grows by moulting 13 times to reach adult form., Interaction with man, , Pests as destroy food and contaminate it., , Can transmit a variety of bacterial diseases (Vector)., , Questions, Very Short Answer Questions, 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., , (1 mark each), , Name the tissue which contains Haversian canals., Mention two special properties of nervous tissues., Name the large cells present in adipose tissue., Name the cells responsible for clotting of blood., What are exocrine glands ?, Differentiate between tendon and ligament., Where are RBC’s formed ?, A muscular fiber having no striations and tapers at both ends. Name it., Mention the site,where sclerite is present in cockroach., Name the mouth part of cockroach which is comparable to our tongue., “Sexual dimorphism is found in cockroach”. Explain the statement., , Short Answer Questions–I, , (2 marks each), , 11. What is the function of ciliated epithelium ? Where do we find this, epithelium ?, 12. What are the two types of fibres of connective tissues ? Distinguish between, the two., 13. To which tissue do the following belong to :, (a) Osteocytes, (b) Chondrocytes, (c) Neuroglia, (d) Intercalated discs, 14. Give the location of hepatic caecae in cockroach ? What is their function ?, 15. Name the locomotory appendages of cockroach on the basis of external, morphology., 72, , Biology Class - 11
Page 99 :
Short Answer Questions–II, , (3 marks each), , 16. Differnetiate between skeletal and smooth muscles., 17. Differntiate between male and female cockroach on the basis of external, morphology., 18. (a) What is open circulatory system ?, (b) Explain the respiratory system of cockroach., 19. (a) Give the common name of Periplaneta americana., (b) How many spermathecae found in cockroach ?, (c) What is the position of ovaries in cockroach ?, (d) How many segments are present in the abdomen of cockroach ?, (e) Where do you find malpighian tubules ?, (f) What is mosaic vision ?, 20. Name the different cell junctions found in tissues., 21. Mention the special features of eye in cockroach., 22. Write the appropriate type of tissue in column B accounting to the functions, mentioned is column A., , Column A , Column B, a. Linking and supporting frame work, ......................, b. Protective covering , ......................., c. Secretion and absorption ......................., , Long Answer Questions, 23., , , 24., , (5 marks each), , (a) What is compound epithelium ? What are their main function ?, (b) Where do we find areolar tissue ?, (c) How is adhering junction different from gap junction ?, Make a neat and well labelled diagram showing alimentary canal of cockroach., , Answers, Very Short Answers, 1., 2., 3., 4., 5., , (1 mark each), , Mammalian bone., Excitability and conductivity., Adipocytes., Blood platelets., Glands which discharge their secretions into ducts., Structural Organisation in Animals, , 73
Page 100 :
6. Tendon Ligament, , Attach skeletal muscles to bones, , Attach bone to bone, , 7. Bone narrow, 8. Smooth or non striated muscle fibre., 9. In the exoskeleton all over the body., 10. Hypopharynx = lingua, 11. Male and female cockroaches show morphological differences., , Short Answers–I, , (2 marks each), , 11. Refer ‘Points to Remember’., 12. White and yellow fibres. White fibres are thin, unbranched, inelastic, occur, in bundles and formed of protein collagen. Yellow fibres are thick, straight,, elastic, branched, occuring singly, formed of protein elastin., 13. (a) Bone tissue , , (b) Cartilage, , (c) Neural tissue , , (d) Cardiac muscle, , 14. Refer ‘Points to Remember’., 15. Three pairs of legs and two pairs of wings., , Short Answers-II, , (3 marks each), , 16. Refer ‘Points to Remember’., 17. Refer ‘Points to Remember’., 18. Refer ‘Points to Remember’., 19. (a) American Cockroach., (b) One pair, present in 6th segment., (c) Between 2nd and 6th abdominal terga., (d) 10 segments., (e) At the beginning of ileum in cockroach., (f) Vision where several images of an object are formed by compound eye., Helps to detect movement of objects very efficiently., 20. (i) Gap junctions , (iii) Adhering junctions, 74, , Biology Class - 11, , (ii) Tight junctions
Page 101 :
21. See text in NCERT at page No. 114., (i) Situated at dorsal surface of head., (ii) Each eye consists of about 2000 hexagon ommatidia., (iii) It can receive several images of an object., (iv) This kind of vision is known as mosaic vision., (v) It is more sensitivity but less resolution., 22. (a) Connective tissues, (b) Stratified epithelium, (c) Columnar epithelium, , Long Answers , , (5 marks each), , 23. Refer ‘Points to Remember’., 24. Refer Fig. 7. 16 NCERT Text Book of Biology class-XI., , , Structural Organisation in Animals, , 75
Page 102 :
Cell : The unit of life, Prokaryotic, CELL, , Basic Unit of Life, , Two Types, Eukaryotic, , Cell wall, (plant cell), , Cell, Membrane, , Outermost, covering of, plant cell, made, up of cellulose, , Cytoplarm, , Made of, phospholipid, bilayer and, proteins, , Fluid present, between, Nucleus and, Cell membrane, , No nuclear membrane and, no membrane bound cell, organelles, With nuclear membrane, and membrane bound cell, organelles, , Nucleus, , Vacuoles, (Plant Cell), , Consists of, nucleoplasm, and nuclear, membrane, , Store house, of water,, nutrients, mineral salts,, waste, , Contains cell organelles, , Endo membrane Mitochondria Plastids, System, , ER, golgi, apparatus,, lysosomes, and, vacuoles, have coordinated, function so, form, endo, membrane, system, , double, membranens, structure,, produce, energy in the, form of ATP., divided by, fission has, its own DNA, and, ribosomes, , ER –, , Found in, plant cell &, euglenoids, contains, pigments &, classified as, chloroplasts, &, leucoplasts, has DNA &, ribo somes, , Ribosomes, , Granular, structures,, made of, DNA and, protein,, acts as, protein, factories, , Cytoskeleten, , Proteinaceous, structures, made of, microtubule,, microfilaments, & intermediate, filaments ratemechanical, support,, motility, maintain, shapes of cell, , Cillia and Centrosome, Flegella, Centriole, , Cilia are, smaller, hair like, out, growths, and, flegella, are larger, both help, in, locomotion, , Form basal, body of cilia, and flagella,, and spindle, fibres during, cell division, animal cell, , Network of tiny tubular structures scattered in cytoplasm, which divide intracellular, space into two compartments. They are two types– SER and RER, , Golgibodies – Flat disc shaped sacs or cinternae, stacked parallel to each other, near nucles., Lysosomes – Membrane bound vescicles formed by packaging in Golgi apparatus, , 76, , Biology Class - 11
Page 103 :
Points to Remember, Cell Theory : Cell Theory was formulated by Schleiden and Schwann, and, was modified by Rudolf Virchow. Cell theory States., (A), , All living organisms are composed of cells and products of cells., , (B), , All cells arise from pre-existing cells., , Cell : Cell is the structural and functional unit of life., , , Prokaryotic Cell , , Eukaryotic Cells, , , , Generally small sized (1–10 µm), , , , Generally large sized (5–10 µm), , , , Well defined nucleus absent, , , , Well defined nucleus present, , , , Membrane bounded cell organelles, , , , Membrane bounded cell organelles, , absent present, , , DNA without histone protein, , , , DNA with histone protein, , , e.g., Bacteria, Mycoplasma, Blue e.g., Amoeba, Euglena and other, green Algae higher organism, Gram Positive Bacteria Gram Negative Bacteria, , , Bacteria that take up gram, , , , Bacteria do not take up gram stain, , Stain. e.g., Bacillus e.g., Escherichia coli, , PROKARYOTIC CELL :, Modification of cell envelope, , , , , , Cell envelope consists of tightly bound 3 layered structure – Outermost, Glycocalyx followed by cell well and plasma membrane, Glycocalyx in form of loose sheath, is called slime same layer, Glycocalyx in form of thick and tough sheath, is called capsule, , Cell : The Unit of Life, , 77
Page 104 :
Mesosomes : Extension of plasma membrane. These can be in the form of, vesicles, tubules and lamellae., , Functions : Cell wall formation, DNA replication and distribution to daughter, cells, respiration, secretion processes, to increase surface area of plasma, membrane and enzyme content., Flagella : Extension of cell wall. It is composed of three structures – filament,, hook and basal body. It help in motility of bacteria., Pili and fimbriae : Surface structure of some bacteria which attaches them, to rocks in streams and to host tissues., Genetic Material : It is not covered by nuclear envelope. In addition to, the genomic DNA (the single chromosome/circular DNA), many bacteria have, small circular self replicating, double stranded DNA which is called as plasmid,, plasmid contain genes like antibiotic resistance., Ribosomes : Associated with plasma membrene of prokaryatic cell, site of, protein synthesis. Several ribosomes may attach to a single mRNA and form a, chain called polyribosomes or polysomes. They translate mRNA into Proteins., Inclusion Bodies : Stores reserve material, lie freely in cytoplasm not bound, by any membrane. e.g. phasphote granules, cyanophycean granules and glycogen, granules., , , Eukaryotic cells, Possess an oragnized nucleus with nuclear envelope and have a variety of, complex locomotory and cytoskeletal structures., Cell Membrane — Singer and Nicolson (1972) gave ‘fluid mosaic model’., According to this the quasi-fluid nature of lipid enables lateral movement of, proteins within the overall bilayer; two types of proteins (Peripheral and integral, proteins) with cholesterol, glycolipids and glycoporteins. Erythrocyte membrane, has 52% protein and 40% lipids., Function—It is selectively permeable and helps in transport of molecule, across it., , Passive transport , Active transport, Transport of molecules from, Transport of molecules from lower to, higher to lower concentration. higher concentration, It do not utilise energy (ATP)., It utilises energy (ATP), , e.g., diffusion , e.g., Na+/k+ ATPase Pump., , 78, , Biology Class - 11
Page 105 :
Fluid Mosaic Model of Plasma Membrane, Cell Wall is non-living rigid structure which gives shape to the cell and, protects cell from mechanical damage and infection, helps in cell-to-cell interaction, and provides barrier to undesirable macromolecules., Cell wall of algae is made of cellulose, galactans, mannans and minerals like, calcium carbonate. Plant cell wall consists of cellulose, hemicellulose, pectins, and proteins., Middle lamella is made of calcium pectate which holds neighbouring cells, together., Plasmodesmata connect the cytoplasm of neighbouring cells., Endoplasmic Reticulum (ER), Consists of network of tiny tubular structure. ER divides the intracellular, space into two distinct compartments–luminal (inside ER) and extra luminal, (cytoplasm)., (i) Rough Endoplasmic Reticulum (RER) :, Ribosomes attached to outer surface., Function : Involved in protein synthesis and secretion., (ii) Smooth Endoplasmic Reticulum (SER) : Lack ribosomes., Function Site for synthesis of lipid., Golgi apparatus : First observed by Camillo Golgi (in 1898), Consist of cisternae stacked parallel to each other. Two faces of the organelle, are convex/cis or forming face and concave/trans or maturing face but inter, connected., Functions : Performs packaging of materials, to be delivered either to the, intra-cellular targets or secreted outside the cell. Important site of formation of, glycoproteins and glycolipids., , Cell : The Unit of Life, , 79
Page 106 :
Lysosomes :, Membrane bound vesicular structures formed by the process of packaging, in the golgi apparatus. Contain hydrolysing enzymes (lipases, proteases,, carbohydrases) which are active in acidic pH. Also called ‘Suicidal Bag’., Function : Intracellular digestion., Vacuoles : Member bound space found in the cytoplasm. Contain water, sap,, excretory product, etc. In plant cell, vacoule occupies 90% of space., Function : In plants tonoplast (single membrane of vacuole) faciliates, transport of ions and other substances., Contractile vacuole for excretion in Amoeba and food vacuoles formed in, protists for digestion of food., Mitochondria : Double membraned structure. Outer membrane smooth and, inner membrane forms a number of infoldings called cristae The inner compartment, is called matrix. The cristae increase the surface area., DNA (Circular), OUTER MEMBRANE, RIBOSOME (70S), CRISTA, MATRIX, INNER MEMBRANE, OUTER MEMBRANE, Mitochondria, Mitochondria, , Function : Sites of aerobic respiration. Called ’power houses’ of cell as, produce cellular energy in the form of ATP. Matrix possesses single circular DNA, molecule, a few RNA molecules, ribsomes (70S). It divides by binary fission., Plastids : Found in plant cells and in euglenoides. Chloroplasts, chromoplasts, and leucoplasts are 3 types of plastids depending on pigments contained., Types of Plastids, Chloroplast, (Green coloured plastids), , Chromoplast, , Leucoplast, (Colourless plastids), , • Contain chlorophyll, and, • Carotenoid (fat souble), • Amyloplast (Starch), corotenoids double stranded, like Carotene,, • Elaioplasts (oil + fat), DNA and, Xanthophylls and, • Aleuroplast, 70S ribosomes., Others., (store proteins), • Trap light energy for, • Gives the part of plant a, photosynthesis, yellow orange and red colour, 80, , Biology Class - 11
Page 107 :
Function : Site of photosynthesis, and imparts colours to fruits and flowers., , Chloroplast, , Ribosomes, Composed of RNA and proteins; without membrane. Eucaryotic ribosomes, are 80S. S = Svedberg’s unit), Function : Site of protein synthesis., Cytoskeleton : Network of filaments., Proteinaceous structure in cytoplasm made up of microtubules and micro, filaments., Function : Mechanical support, motility, maintenance of the shape of the cell., Cilia and Flagella, Cilia are small structures which work like oars which help in movement., Flagella are longer and responsible for cell movement. They are covered, with a plasma membrane. Core is called axoneme which has 9 + 2 arrangement, of axonemal microtubules., , Cell : The Unit of Life, , 81
Page 108 :
Centrosome and Centrioles, Centrosome contains two cylindrical structures called centrioles. Surrounded, by amorphous pericentriolar material. Made up of nine evenly spaced peripheral, fibrils of tubulin protein (9+0). Centrioles form the basal body of cilia or flagella, and spindle fibres for cell division in animal cells. They produces spindle apparatus, during cell divison., Nucleus : Double membranous with perinuclear space and nuclear pores;, has Chromatin, nuclear matrix and nucleoli (site for rRNA synthesis). (Named, by Robert Brown – 1831), Chromatin DNA + nonhistone proteins. (Named by Flemming), Nucleoplasm – Nucleolus + Chromatin, Nulear membrane—It is with perinuclear space and nucleopores., Chromosomes—DNA/RNA + Histone protein/Nonhistone protein., Centromere : Primary constriction–in every chromosome, Kinetochores : Disc shaped stucture on the sides of centsomere., No nucleus in Erythrocytes (RBC) of mammals and sieve tubes in vascular, plants., Chromosomes (on basis of position of centromere) :, Metacentric : Middle centromere., Sub-metacentric : Centromere nearer to one end of chromosomes., Acrocentric : Centromere situated close to its end., Telocentric :Has terminal centromere., , Metacentric, Sub metacentric, , Acrocentric, , Telocentric, , Satellite : Some chromosomes have non-staining secondary constrictions at, a constant location, which gives the appearance of small fragment called satellite., 82, , Biology Class - 11
Page 109 :
Questions, , Very Short Answer Questions, , (1 mark each), , 1., 2., 3., 4., 5., , Name the parts of bacterial flagella., Name the nutrient stored in (i) elaioplasts (ii) aleuroplasts, Name the scientist who first saw and described a living cell., What are plasmids ?, Name the scientist who first explained that new cells arose from pre-existing, cells (Omnis cellula-e-cellula), 6. What is the composition of plasma membrane of human erythrocyte., 7. Eukayotic ribosomes are 80S. What does ‘S’ stand for ?, 8. Write the function of cytoskeleton in a cell ?, , Short Answer Questions–I, 9., 10., 11., 12., 13., 14., 15., 16., , , , , 17., , , , (2 marks each), , What are nuclear pores ? State their function., State the cell theory., Differentiate between active and passive transport., Differentiate between RER and SER., List two functions of golgi apparatus., List two functions of mesosome., Differentiate between the electron microscopic structure of cilia/flagella and, centriole., Give the specific terms for the following :, (a) Cluster of ribosomes found in cytoplasm, (b) Extensive infolding to the inner membrane of mitochondria, (c) Stacks of closely packed thylakoids, (d) Stalked particles on the inner membrane of mitochondria, (a) Write the function of inclusion bodies in prokaryotic cells ?, (b) Where are they present ?, (c) Give two examples of inclusion bodies., , Short Answer Questions–II, , (3 marks each), , 18. With the help of labelled diagram explain the ‘fluid mosaic model’ structure, of cell membrane., 19. Differentiate between a prokaryotic and eukaryotic cell., 20. What are lysosomes ? How are they formed ? Write their functions., 21. Give the structural details of an eukaryotic nucleus along with its diagram., Cell : The Unit of Life, , 83
Page 110 :
22. The ribosomes of prokaryoters are of 70 S type ribosomes and while of, eukaryotes are of 80 S type as well as 70 S types., (a) Give the composition of 70 S type ribosomes and 80 S type ribosome, (two sub units, from each of them are made of), (b) Name two cell organelles of eukaryotic cells which have their own, independent ribosomes of 70 S type, , Long Answer Questions , 23., , , 24., , (5 marks each), , (a), (b), (c), (a), , Give the structural details of mitochondria., Draw its diagram., Why is it called ‘powerhouse of the cell’ ?, Diagrammatically represent the types of chromosomes based on the, position of centromere., (b) What does chromatin contain ?, (c) What is perinuclear space ?, , Answers, , Very Short Answers, 1., 2., , 3., 4., 5., 6., 7., 8., , (1 mark each), , Filament, hook, basal body., Elaioplasts : fats and oils., Aleuroplasts : proteins., Anton Von Leeuwenhoek, The small circular DNA, outside the genomic DNA of bacteria., Rudolf Virchow., 52% proteins, 40% lipids., Sedimentation coefficient (Svedberg unit), Mechanical support, motility, maintenance of shape of cell., , Short Answers–I , , (2 marks each), , 9. Minute pores present in the nuclear envelope; provide passage for movement, of RNA and proteins between nucleus and cytoplasm., 10. Refer ‘Points to Remember’., 12. Refer ‘Points to Remember’., 13. Refer ‘Points to Remember’., 14. Refer ‘Points to Remember’., 84, , Biology Class - 11
Page 111 :
15. , , Flegella/Cilia Centriole, , , (i) Possess (9 + 2) pattern of axoneme, , , : Possess (9 + 0) pattern,, , microtubules enclosed by a membrane membrane less organelle, , (ii) Each tubule is doublet, , : Each tubule is a triplet, , 16. (a) Polyribosome/Polysome, (b) Cristae, (c) Grana, (d) Fo–F1 particles ..., 17. (a) Reserve materials are stored,, (b) They are free in the cytoplasm, (c) e.g.,Phosphate granules, cyanophycean granules, glycogen granules., , Short Answers–II, , (3 marks each), , 18. Refer page no. 131–132, NCERT, Text Book of Biology for Class XI., 19. Differences in nucleus/chromosomes/mesosome/membrane bound cell, organelles/ribosomes/compartments in cell., 20. Refer page no. 134 NCERT, Text Book of Biology for Class XI., 21. Refer page no. 138, NCERT, Text Book of Biology for Class XI., 22. (a) 70 S ribosomes have 50 S and 30 S sub units; 80S ribosomes have 60, S and 40 S sub units., (b) Mitochondria and chloropolast., , Long Answers, , (5 marks each), , 23. Refer page no. 134-135, NCERT, Text Book of Biology for Class XI., 24. Refer page no. 138–139, NCERT, Text Book of Biology for Class XI., , , Cell : The Unit of Life, , 85
Page 112 :
Carbohydrates, , Lipids, , Proteins, , Nucleic Acids, , They are long chain of, fugass may be, homopolymers or, heteropolymers right, end of chain is reducing, end and left end of chain, is non-reducing end, , Long chain fatty acids,, may be saturated or, unsaturated many fatty, acids are found, esterified with glycerol, they may be mono bi or, tri-glycrides, , Polypeptides,, heteropolymers made, of 20 types of amino, acids, four levels of, structures- primary,, secondary, tertiary &, quaternary, , Polynucleotides (DNA,, RNA), censists of a, mono saccharide,, phosphate gp and, nitrogenes bases, Purines Pyrimidines, A, G, , C, T, U, , Molecular Weight more than 10000 daltons, found in and insoluble pool, Biomacromolecules, , Biomolecules, , Biomacromolecules, Molecular Weight less than 10000 daltons, eg inorganic sbstances, minerals, sugass,, amino acids and nucleotides, , Bring down activation, energy to entrance rate, of biochemical reactions, , Factors affecting enzyme, action-PH, temperature,, and concentration of, substrate, Inhibition of enzyme action, 1. competitive inhibition, 2. non-competitive, , 86, , Biology Class - 11, , Enzymes, Catalyk biochemical, reactions, , Nuclear Acid behaving, as enzymes - Ribozymes, , Cofactors : non-proteinaceous, constituents bound to the, enzyme to make enzyme, catalytically active eg, prosthatic gp, co-enzymes, and metal ions, , Classes of enzyme - (6), Dehydrogenases, transferases,, hydrolases, lyases, isomerases, and ligases
Page 113 :
Points to Remember, Biomolecules : All the carbon compounds that we get from living tissues., Biomicromolecules : Molecules which have molecular weights less than, one thousand dalton. They are also known as monomers. They are found in acid, soluble fraction., Biomacromolecules : A biomolecule with molecular weight in the range of ten, thousand daltons and above; found in acid insoluble fraction. e.g. polysaccharides,, nucleic acids, proteins and lipids., How to analyse chemical composition of living tissues?, Living tissue + Trichloroacetic acid, Grinding, Filter through cheese cloth, , Thick Slurry, , Filterate (Acid soluble), Retentate (Acid insoluble), , Primary and secondary metabolites :, , , , , Primary metabolites have identifiable functions and play important roles in, normal physiological process eg. Amino acids, nitrogenous bases, proteins, and nucleic acid., Secondary metabolites are product of certain metabolic pathways from, primary metabolites, eg. carotenoids, drugs, alkaloids, essential oils, rubber,, gum, cellulose and resins etc., , , Amino acids : Organic compounds containing an amino group and one, carboxyl group (acid group) and both these groups are attached to the same, carbon atom called α carbon and so they are called amino acids., , , e.g. (1) In Glycine R = H, (2) In alanine R = CH3, (3) In serine R = CH2 – OH, Biomolecules, , 87
Page 114 :
Twenty types of amino acids., Amino acid exists in Zwitterionic form at different pHs., , R, R, R, , |, |, |, , , , , , (A), , (B), (C), (Zwitterionic form), Based on number of amino and carboxyl groups, amino acids can be :, (i) Aromatic – Tryptophan, phenylalanine and Tyrosine are aromatic (give, , smell) amino acids., (ii) Acidic Amino Acids – (aspartic acid, glutamic acid). Basic amino acid, (Arginine) and Neutral amino Acids (valine, Proline), , Lipids :, Lipids are not strictly macromolecules as their molecular weight do not, exceed 800 Da but form a part of the acid insoluble pool., Water insoluble, containing C, H, O., Fats on hydrolysis yield fatty acids., Fatty acid has a carboxyl group attached to an R group (contains 1 to 19, carbons)., Fatty Acids : Saturated : With single bonds in carbon chain, e.g., Palmitic, acid, butyric acid., , Unsaturated : With one or more double bonds, e.g., oleic acid, linoleic acid., Glycerol : A simple lipid, is trihydroxy propane., , , , Some lipid have fatty acids esterified with glycerol., , Example of fatty acid (Palmitic acid) (CH3—(CH2)14—COOH), , , They can be monoglycerides, diglycerides and triglycerides., 1, , 2, , 88, , Biology Class - 11, , 3
Page 115 :
Triglyceride (R1, R2, R3 are alkyl groups in fatty acids.), Phospholipids (Lecithin) found in cell membrane and lipids made complex, structure in neural tissue., Phospholipids are compound lipids with phosphorus and a phosphorylated, organic compound e.g., Lecithin., Nitrogen bases, (Carbon compounds with heterocyclic rings), , Purine : Adenine, Guanine,, , Pyrimidine : Cytosine, Uracil, Thymine., , Nucleoside : Nitrogenous base + Sugar e.g. Adenosine, guanosine., Nucleotide : Nitrogenous base + Sugar + Phosphate group. e.g. Adenylic, acid, Guanylic acid. Thymidylic acid., Nucleic acids : Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)., DNA structure (Watson and Crick Model) : DNA is a right handed, double, helix of two polynucleotide chains, having a major and minor groove. The two, chains are antiparallel, and held together by hydrogen bonds (two between A, and T and three between C and G). The backbone is formed by sugar-phosphatesugar chain. The nitrogen bases are projected more or less perpendicular to this,, backbone and face inside. The pitch is 34A°. At each step of ascent, the strand, turns 36°. The rise per base pair is 3.4°A, so one full turn involves ten base pairs., Protein : proteins are polypeptides., , , They are polymers of aminoacids linked by peptide bond., , , , Is a heteropolymer (different monomers repeating ‘n’ number of times)., , , , Functions : Intercellular ground substance (collagen), as enzyme (Trypsin), as hormone (Insuline), to fight infections (Antibodies), as sensery releptors,, and to enable glucose transport in cells (GLUT-4), , Structure of Proteins, (a) Primary structure : Is found in the form of linear sequence of amino acids., First amino acid is called N-terminal amino acid and last amino acid is called, C-terminal amino acid., (b) Secondary structure : Polypeptide chain undergoes folding or coiling which, is stabilized-by hydrogen bonding. Right handed helices are observed; e.g.,, fibrous protein in hair, nails., Biomolecules, , 89
Page 116 :
(c) Tertiary structure : Long protein chain is folded upon itself like a hollow, woollen ball. Gives a 3-dimensional view of protein, e.g., myosin., (d) Quaternary structure : Two or more polypeptides with their foldings and, coilings are arranged with respect to each other, e.g., Human haemoglobin, molecule has 4 peptide chains - 2 α and 2 β Subunits., , Monosaccharides are joined by glycosidic bond, right end is reducing and, left end is non reducing, Polysaccharides : Are long chain of polymers of monosaccharides., (a) Starch : Store house of energy in plant tissues. Forms helical secondary, structures, made of only glucose monomers., (b) Cellulose : Homopolymer of glucose. It does not certain complex helices., Cotton fibre is cellulose., (c) Glycogen : Is a branched homopolymer, found as storage polysaccharide in, animals., (d) Inulin : Is a polymer of fructose., (e) Chitin : Chemically modified sugar (amino-sugars) N-acetyl galactosamine, form exoskeleton of arthropods; homopolymer., , Metabolic Pathways :, (a) Anabolic pathways : Lead to formation of more complex structure from a, simpler structure with the consumption of energy, e.g., Protein from amino, acids., also known as biosynthetic pathways., (b) Catabolic pathway : Lead to formation of simpler structure from a complex, structure, e.g., Glucose → Lactic Acid + energy, The most important energy currency in living systems is ATP (adenosine, tri – phosphate)., “There is no uncatalysed metabolic conversion in living system”, The living state is a non-equilibrium steady state to be able to perform work., Without metabolism, there cannot be a living state., , Bonds linking monomers in a polymer, Peptide bond—formed between the carboxyl (–COOH) group of one amino, acid, and the amino (– NH2) group of the next amino with the elimination of water, moiety, (dehydration)., Glycosidic bond—bond formed between two carbon atoms of two adjacent, monosaccharides., by dehydration., Phosphodiester bond—bond formed in nucleic acids where in a phosphate, 90, , Biology Class - 11
Page 117 :
moiety links the 3-carbon of one sugar of one nucleotide to the 5-carbon of the, sugar of the succeeding nucleotide. (The bond between phosphate group and, hydroxyl group of sugar), Ezymes : Are biocatalyst., Almost all enzymes are proteins., Ribozymes–Nucleic acid that behave like enzymes., Has primary, secondary and tertiary structure., Active site of an enzyme is a crevice or pocket into which substrate fits., Enzymes get damaged at high temperatures., Enzymes isolated from thermophilic organisms (live under high temperatures), are thermostable., Enzymes accelerate the reactions many folds., Enzymes lower the activation energy of reactions. (Fig. 9.6, Page no. 156,, NCERT Text Book of Biology for Class XI)., E + S == ES → EP → E + P, where E = Ezymes, S = Substrate, P = Product, , Factors affecting enzyme activity :, (a) Temperature : Show highest activity at optimum temperature. Activity, declines above and below the optimum value., (b) pH : Enzymes function in a narrow range of pH. Highest activity at optimum, pH. (Fig. 9.7, Page no. 157, NCERT, Text Book of Biology for Class XI)., (c) Concentration of substrate : The velocity of enzymatic reaction rises with, increases in substrate concentration till it reaches maximum velocity (Vmax)., Further increase of substrate does not increase the rate of reaction as no free, enzyme molecules are available to bind with additional substrate., Enzyme inhibition : When the binding of a chemical shuts off enzyme, activity, the process is called inhibition and chemical is called inhibitor., Biomolecules, , 91
Page 118 :
Competitive inhibition : Inhibitor closely resembles the substrate in its, molecular structure and inhibits the enzyme activity. E.g., inhibition of succinic, dehydrogenase by malonate. (Actual is succinic acid)., , Classification of enzymes :, 1. Oxidoreductase/dehydrogenases : Catalyse oxidoreduction between 2, substrates. S reduced + S′ oxidised → S′ oxidised + S′ reduced., 2. Transferases : Catalyse transfer of a group between a pair of substrates., S – G + S′ → S + S′ – G, 3. Hydrolases : Catalyse hydrolysis of ester, ether, peptide, glycosidic, C–C,, P-N bonds., 4. Lyases : Catalyse removal of groups from substrates by mechanisms other, than hydrolysis. Leave double bonds., 5. Isomerases : Catalyse inter-conversion of optical, geometrical or positional, isomers., 6. Ligases : Catalyse linking together of 2 compounds., C–O, C–S, C–N, P–O, Co-factors : Enzymes becomes catalytically become active when it binds, to non protein constituent called co-factors. Protein portion of enzyme is, called apoenzyme., , , Prosthetic group : These are organic compound which tightly bound to the, apoenzyme., , , e. g., Haem is prosthetic group in peroxidase and catalase., , , Coenzyme : These are organic compounds whose association with the, apoenzyme is only transient, usually occurring during the course of catalysis., , , e.g., Coenzyme Nicotinamide adenine dinucleotide (NAD) and NADP, contain vitamin niacin., , , Metal ions : Metal ions form coordination bond with side chains at the, active site and at the same time form one or more coordination bond with, substrate., , , e.g. zinc in enzyme carboxy peptidase., 92, , Biology Class - 11
Page 119 :
Questions, Very Short Answer Questions, , (1 mark each), , 1. Why do oils generally remain in liquid state even in winters ?, 2. Name an element found in proteins but not in lipids and carbohydrates., 3. What is the difference between RNA and DNA in terms of nitrogenous base ?, 4. What does an enzyme do in terms of energy requirement of a reaction ?, 5. What is the function of ATP in cell metabolism ?, 6. Name the protein which form the intercellular ground substance., 7. What are biomacromolecules ?, 8. Why enzymes are called bio-catalysts ?, , Short Answer Questions-I , , (2 marks each), , 9. Differentiate between prosthetic group and coenzyme ?, 10. What are glycosidic bonds and peptide bonds ?, 11. Why are aminoacids also known as substituted methane?, 12. Amino acids exist as zwitter ions. Give its structure. Why is it formed ?, 13. Why do starch give blue black colour with iodine ?, 14. Why are starch and glycogen more suitable than glucose as a storage, product ?, 15. What would happen when salivary amylase which acts on starch in mouth, enter in stomach ?, 16. Differentiate between homo polysaccharides saccharides and hetero poly, saccharides., 17. Why do physicians recommend vegetable oils rich in polyunsaturated fat, for persons suffering from cardiovascular diseases ?, 18. Why does the self life of fruits and vegetables increase in a refrigerator ?, Biomolecules, , 93
Page 120 :
Short Answer Questions-II , , (3 mark each), , 19. Differentiate between primary and secondary metabolites with examples ?, 20. List out some major proteins and their function ?, 21. Explain the structure of proteins., 22. Explain Watson-Crick model on DNA structure., 23. Explain peptide bond, glycosidic bond and phospodiester fond., 24. Explain competitive inhibition along with an example., , Long Answer Questions , , (5 marks each), , 25. List the 6 classes of enzymes along with their functions., , Answers, Very Short Answer , , (1 marks each), , 1. Oils are unsaturated lipids, hence have lower melting points., 2. Nitrogen., 3. RNA has uracil instead of thymine., 4. Lowers the activation energy of reaction., 5. Are the energy currency of cell., 6. Collagen., 7. Refer point to remember., 8. Enzymes are proteins that catalyze metabolic/chemical reactions inside the, living being. That’s why they are called biocatalysts., , Short Answer-I , , (2 marks each), , 9. Refer ‘Points to remember’., 10. Refer, ‘Points to remembers’., 11. The α-carbon has 4 substituted groups occupying the 4 valency positions :, H—COOH—NH2 and—R group., 12., , , 94, , 3, , Biology Class - 11
Page 121 :
Due to ionizable nature of — NH2 and — COOH groups., , 13. Starch form helical secondary structure which can hold I2., , 14. Occupy lesser space as less bulky and can be hydrolysed to glucose when, required., 15. In mouth, salivary amylase changes starch into maltose. Action of amylase, stops in stomach as it cannot act in an acidic medium., 16. Homopolysaccharides, , Heteropolysaccharides, , (a) Constituted of single type, , Constituted by two or more type of, , , , monosaccharide unit and their, derivatives, , of monosaccharide units, , (b) e.g., starch, glycogen, cellulose, , e.g., Peptidoglycans, chitin, , 17. Polyunsaturated oils contain fatty acids having one or more double bonds, which does not clog arteries due to high proportion of polyunsaturated fatty, acids., +, , 18. Low temperature prevents growth of food spoiling micro organisms and, also inhibits the action of enzymes present in the food, because, enzymes, are inactivated at low temperature., , Short Answers-I, , (3 marks each), , 19. Secondary metabolites—The metabolites like alkaloids lectins Drugs,, Pigments, Spices and scents etc. which are useful to human welfare and, have ecological importance., , Primary metabolites—The metabolites having identifiable functions and, play important role in normal physiological processes, e.g., sugars, amino, acids, fats and oils and nucleotides, etc., 20. Refer Page No. 147, Table 9, 5, NCERT, text book of biology class XI., 21. Refer ‘Points to remember’., 22. Refer ‘Points to remember’., 23. Refer Page No. 151. NCERT, Text Book of Biology for Class XI., 24. Refer ‘Points to remember’., , Long Answers , , (5 marks each), , 25. Refer Page No. 158., NCERT, Text Book of Biology for Class XI., , Biomolecules, , 95
Page 122 :
96, , Biology Class - 11
Page 123 :
Points To Remember, Cell cycle : The sequence of events by which a cell duplicates its genome,, synthesises the other constituents of the cell and eventually divides into two, daughter cells., Interphase (G1 phase + S phase + G2 Phase), , Phases of cell cycle, , Karyokinesis (division of nucleus), M Phase (Mitosis phases), , Cytokinesis (division of cytoplasm), , Interphase : (Resting Phase), , , G1 Phase : Cell metabolically active and grows continuously but does not, replicate DNA, , , , S Phase : DNA synthesis occurs, DNA content increases from 2C to 4C, but, the number of chromosomes remains same i.e., 2n., , , , G2 Phase : Proteins are synthesised in preparation for mitosis while cell, growth continues., M Phase (Mitosis Phase) : Starts with nuclear division, corresponding to, , separation of daughter chromosomes (karyokinesis) and usually ends with division, of cytoplasm, (cytokinesis)., Quiescent stage (G0) In adult animals cells that do not divide and exit G1, phase to enter an inactive stage called G0. Cells at this stage remain metabolically, active but do not proliferate., e.g., Heart cells, , Cell Cycle and Cell Division, , 97
Page 124 :
G2 phase, RNA and, Protein, Synthesis, , S Phase, DNA Duplicates, Replication of, Chromosomes, , G1 Phase, Protein Synthesis, Growth of nucleus, , Mitosis, Since the number of chromosomes in the parent and progeny cells is the, same, it is called as equational division. Mitosis is divided into four sub stages., 1. Prophase : (i) Replicated chromosomes, each consisting of 2 chromatids,, condense and become visible., (i) Microtubules are assembled into mitotic spindle., (iii) Nucleolus and nuclear envelope disappear., (iv) Centriole moves to opposite poles., 2. Metaphase : (i) Spindle fibres attached to kinetochores (small disc-shaped, structures at the surface of centromere) of chromosomes., (ii) Chromosomes line up at the equator of the spindle to form metaphase, plate., 3. Anaphase : (i) Centromeres split and chromatids separate., (ii) Chromatids move to opposite poles due to shortening of spindle fibres., 4. Telophase : (i) Chromosomes cluster at opposite poles., (ii) Nuclear envelope assembles around chromosomes clusters’., (iii) Nucleolus, Golgi Complex, E.R. reforms., 98, , Biology Class - 11
Page 125 :
Cytokinesis : The division of protoplast of a cell into two daughter cells, after karyokinesis (nuclear division), Animal Cytokinesis :, Appearance of furrow in plasma membrane which deepens and joins in the, centre, dividing cell cytoplasm into two., Plant cytokinesis : Formation of new cell wall begins with the formation, of a simple precursor — cell plate which represents the middle lamella between, the walls of two adjacent cells., , , When karyokinesis is not followed by cytokinesis, a multinucleated condition, arises. This is called syncytium., , Significance of Mitosis :, 1., 2., 3., 4., , Growth-addition of cells., Maintenance of surface/volume ratio. Maintain Nucleo–cytoplasmic ratio., Maintenance of chromosomes number., Regeneration., Cell Cycle and Cell Division, , 99
Page 126 :
5. Reproduction in unicellular organisms, lower plants and some insects., 6. Repair and wound healing., 7. Vegetative reproduction in plants takes place by mitosis., , Meiosis :, , , , , , , , , , , Specialised kind of cell division that reduces the chromosomes number by, half. hence it is called reductional division., Occurs during gametogenesis in plants and animals., Involves two sequential cycles of nuclear and cell division called Meiosis I, and Meiosis II., It results in 4 haploid daughter cells., Interphase occurs prior to meiosis which is similar to interphase of mitosis, except the S phase is prolonged., , Meiosis I, Prophase I : Subdivided into 5 phases., (i) Leptotene :, , Chromosomes make their appearance as single stranded structures., , , Compaction of chromosomes continues., (ii) Zygotene :, , Homologous chromosomes start pairing and this process of association, , is called synapsis., , , Chromosomal synapsis is accompanied by formation of Synaptonemal, complex., , , Complex formed by a pair of synapsed homologous chromosomes is, called bivalent or tetrad., (iii) Pachytene : Crossing over occurs between non-sister chromatids of, homologous chromosomes. The enzymes involved in the process is, ‘recombinase’. Recombination between homologous chromosomes is, completed. Exchange of genetic material., (iv) Diplotene : Dissolution of synaptonemal complex occurs and the recombined, chromosomes separate separate from each other except at the sites of crossing, over. These X-shaped structures are called Chiasmata. In oocytes of some, vertebrates diplotene can last for month or years., , 100, , Biology Class - 11
Page 127 :
(v) Diakinesis : Terminalisation of chiasmata., , Chromosomes are fully condensed and meiotic spindles assembled., , Nucleolus disappear and nuclear envelope breaks down., , Metaphase I : Bivalent chromosomes align on the equatorial plate., Microtubules from opposite poles of the spindle attach to the pair of, homologous chromosomes., Anaphase I : Homologous chromosomes, separate while chromatids remain, associated at their centromeres., , Telophase I :, Nuclear membrane and nucleus reappear., Cytokinesis follows (diad of cells)., Interkinesis : Stage between two meiotic divisions, (meiosis I and meiosis II), generally short lived, No replication of DNA during this., Meiosis II: (It resembles the normal mitosis)., , , Prophase II, Nuclear membrane disappears., Chromosomes again become compact., Metapahse II, Chromosomes align at the equator., Microtubules from opposite poles of spindle get attached to kinetochores of, sister chromatids., Anaphase II, Simultaneous splitting of the centromere of each chromosome, allowing them, to move towards opposite poles of the cell, by shortening of microtubules, attached to kinetochores., Telophase II, Two groups of chromosomes get enclosed by a nuclear envelope., Cytokinesis follows resulting in the formation of tetrad of cells i.e., 4 haploid, cells., , , Significance of Meiosis, 1. Formation of gametes : In sexually reproducing organisms., 2. Genetic variability : Variations are very important for evolution., 3. Maintenance of chromosomal number : By reducing the chromosome, number in gametes. Chromosomal number is restored by fertilisation of, gametes., Cell Cycle and Cell Division, , 101
Page 128 :
Questions, Very Short Answer Questions , 1., 2., 3., 4., 5., 6., , (1 mark each), , What are kinetochores ?, Name the term used for the stage between two meiotic divisions., Why is mitosis called equational division ?, Name the stage of meiosis during which synaptonemal complex is formed., What is Go phase of cell cycle ?, Where does mitosis take place in plants and animals ?, , Short Answer Questions-I , , (2 marks each), , 7. Differentiate between cytokinesis of plant and animal cell., 8. What is chaismata ? State its significance., 9. Differentiate between chromatin and chromatid., 10. Give the terms for the following :, (a) The period between 2 successive mitotic divisions., (b) Cell division in which chromosome number is halved., (c) Phase in cell cycle where DNA is synthesised., (d) Division of nuclear material., 11. What happens during S phase of interphase ?, 12. Distinguish between metaphase of mitosis and metaphase I of meiosis., 13. What will be the DNA content of a cell at G1 after S and G2 if the content, after M phase is 2C., , Short Answer Questions-II , , (3 marks each), , 14. Differentiate between mitosis and meiosis., 15. List the significance of mitosis., 16. Describe the following :, (a) Synapase, (b) Bivalent, (c) Leptotene, , Long Answer Questions , , (5 marks each), , 17. With the help of labelled diagram, explain the following :, (a) Diplotene, (b) Anaphase of mitosis, (c) Prophase I of meiosis, 102, , Biology Class - 11
Page 129 :
18. What is cell cycle ? Explain the events occuring in this cycle., 19. With the help of labelled diagrams, explain various stages of mitosis cell, divsion., 20. (a) Write a note on significance of meiosis., (b) Differentiate between anaphase 1 of meiosis and Anaphase of mitosis., (c) In which phase of interphase duplication of DNA will occur ?, , Answers, Very Short Answers, , (1 mark each), , 1., 2., 3., 4., 5., , Small disc-shaped structure at the surface of the centromeres., Interkinesis., The chromosomes number is daughter cells is equal to that of the parent., Zygotene., Cells which enter a stage where they are Metabolically active but no longer, proliferate., 6. Plant – Meristematic tissue; Animals–somatic cells., , Short Answers-I , , (2 marks each), , 7. Refer ‘Points to Remember’., 8. Refer ‘Points to Remember’., 9. Chromatin Chromatid :, , (a) Diffuse, deep staining hereditary material longitudinally split half of a, chromosome, light staining hereditary material., (b) Metabolically inert Metabolically active., 10. (a) Interphase, (b) Meiosis, (c) S phase, (d) Karyokinesis, 11. Refer ‘Points to Remember’ :, 12. , , Metaphase , , Metaphase I, , (a) Chromosome align along, (a) Bivalent chromosomes arrange, the equator of the cell along the equatorial plane., (b) Figure 10.2 (b) page 165, Text (b) Figure 10.3, meta phase I page 169,, Book of Biology for Class XI NCERT Text Book of Biology for, Class XI., Cell Cycle and Cell Division, , 103
Page 130 :
13. G1 – 2C, S1 – 4C, G2 – 4C, , Short Answers-II , 14. , (a), (b), , (c), , (d), , (3 marks each), , Mitosis , Occurs in Somatic cells, (a), Number of chromosomes, (b), remain same in daughter cells , No exchange of genetic, (c), material , Involve single division, (d), , Meiosis, , Occurs in germ cells, Number of chromosomes reduces, to half in daughter cells., Exchange of genetic material occurs, due to crossing over, Involve two successive division, , 15. Refer ‘Points to Remember’., 16. Refer ‘Points to Remember’., , Long Answer , , (5 mark each), , 17. Refer ‘Points of Remember’., 18. Refer ‘Points of Remember’., 19. Refer ‘Points of Remember’., 20. (a) Refer ‘Points of Remember’, (b) Refer ‘Points of Remember’., (c) During A phase or synthesis phase., , , 104, , Biology Class - 11
Page 131 :
Active transport :- movement, of substances from their lower, conc. to higher conc. through, selectively permeaile, membrane using energy., Facilitated transport :movement of substances from, higher conc. to lower conc. the, help of transport proteins, It may be symport antiport and, uni port., Diffusion :- movement of, substances from higher conc. to, lower conc. without involving, transport protein., , Means of transport, , Pressure Potential :Magnitude of increase in water, potential when measure greater, than atmospheric pressure is, applied to pure water., Soluton potential :- Magnitude, of lowering of water potential, when solute is added to water., Water potential :- It is the, measure of conc. of water or, kinetic energy of water in a, system. It is zero for pure water., , Plant water relations, , Osmosis :- movement of solvent, from their higher chemical, potential to their lower chemical, potential through selectively, permeable membrane., Plasmolysis :- Shrinkage of, protrolesm away from the cell, wall due to exosmosis in, hypertonic solution., Imbibition :- Absorption of water, by solid particles of an adsorbent, resulting in increase in value ., Transportation :- removal of, water in the form of water, vappours through stomata of, leaves guttation removal of water, droplets through hydathodes., Some important reaction, , TRANSPORT OF SUBSTANCES IN PLANTS, (source to link), , Uptake and transport of, mineral nutrients and food, , Features involved in water, movement upward, , Methods of water absorptions, and movement to root xylem, , Xylem Transport :- Uptake and, transport of mineral nutrients, through xylem. It occurs by, active or passive absorption and, moves along with water., Phloem Transport :- movement, of sugar, hormones and amino, acids by pressure flow or mass, flow hypothesis., Absorption of sugar takes plae, actively., , C o h e s i o n - Te n s i o n Transportation pull theory, :- Forces of adhesion and, cohesion maintain water, column and transporting pull, is major force driving water, upward., Root pressure theory :- A, hydrostatic pressure existing, in roots which pushes the, water up in xylem vessels, upto certain height in, herbaceous plants., , Apoplastic Pathway : movement, through inter cellular spaces or cell, well movement is fast and most of, water enters through this way., Symplastic Pathway :- water, enters the cell through cell, membrane and trael through, cytoplasm and plasmodesmata, movement is slow., At casparian strips region water, moves through symplast only., , Transport in Plants, , 105
Page 132 :
Points To Remember, Translocation (Long distance transport) : Transport of substances in, plants over longer distances through the vascular tissue (Xylem and Phloem), The transport of water and mineral in Xylem is unidirectional while transport of, organic and mineral nutrients in phloem is multi-directional., Means of transport (Short distance transport) : The transport of material, into and out of the cells is carried out by a number of methods. These are diffusion,, facilitated diffusion and active transport., (i) Diffusion : Diffusion occurs from region of higher concentration to region, of lower concentration. It is passive and slow process. No energy expenditure, takes place. No membrane required, Factors affecting diffusion : Permeability of membrane, Temperature,, pressure, gradient of concentration and the size of substances., (ii) Facilitated diffusion : The diffusion of hydrophilic substances along the, concentration gradient through fixed membrane transport protein without involving, energy expenditure. For this the membrane possess aquaporins and ion channels., No ATP energy is utilized in this process., Porins—The proteins that form huge pores in the outer membranes of the, plastids, mitochondria and some bacteria which allow the small size molecules, to pass through., Aquaporins—Proteins that facilitate diffusion of water molecules through/, across the plasma membrane of cell., Methods of Facilitated Diffusion, Symport, , Antiport, , Uniport, , (Two molecules cross the, (Two molecules move (Single molecule moves, membrane in the same, in opposite direction at across membrane indpendirection at the same time.) the same time.), dent of other molecules.), , 106, , Biology Class - 11
Page 133 :
Transport Proteins—They are present in the membrane. They allow the, passage of substances through membrane., (i) Carrier Proteins—They bind to the particular solute particle to be, transported and deliver these to other side of membrane., (ii) Channel Proteins—Ion Channel—They are specific for different ions like, K+, Cl–,, Water Channel—Surrounded by eight proteins called Aquaporins and allow, passage of water or water soluble substance., (iii) Active transport : Active transport is carried by the movable carrier, proteins (pumps) of membrane. Active transport uses energy to pump molecules, against a concentration gradient from a low concentration to high concentration, (uphill-transport). It is faster than passive transport., , Different Transport Mechanisms, S., Property, No. , 1., , 2., 3., , , , , , , , , , , , Required Special, membrane protein, Uphill transport, Requires ATP Energy, , Simple, Diffusion, , Faciliated, Transport, , Active, Transport, , No, , Yes, , Yes, , No, No, , No, No, , Yes, No, , Water potential—(ψw)–Greater the concentration of water in a system,, greater is its kinetic energy and greater is the water potential. It is measured, in pascal (Pa). or mega pascal., If two systems are in contact, then there is movement of water from the, solution with higher potential to lower water potential., Solute potential—(ψs)–Magnitude of lowering of water potential, when a, solute is added to the water., Pressure Potential—(ψp)—Magnitude of increase of water potential, when, pressure greater than atmospheric pressure is applied to pure water or a, solution., Water potential of pure water is zero (0)., Solute potential is always negative (–) and pressure potential is always, positive (+)., ψw = ψs + ψp, Transport in Plants, , 107
Page 134 :
Osmotic Pressure—External pressure applied to prevent the diffusion of, water. It depends upon solute concentration., Numerically, osmotic pressure is equal to osmotic potential. Osmotic pressure, has positive (+) sign. Osmotic potential has negative (–) sign., Turgor Pressure—Due to osmotic entry of water, the protoplasm of a plant, cell presses the cell wall towards the outside with a force, it is called Turgor, Pressure., Diffusion Pressure—The pressure exerted by the tendency of the particles to, diffuse from the area of higher concentration to lower concentration. It is directly, proportional to the concentration of particles of diffusing substance., Osmosis : Osmosis is movement of solvent or water molecules from the, region of their higher chemical potential to the region of their lower potential, across a semipermeable membrane., Water molecules move from higher water potential to lower water potential, until equilibrium is reached., Plasmolysis : Process of shrinkage of protoplasm away from its cell wall, due to exosmosis in hypertonic solution. If a plasmolysed cell is placed in water, or a hypotonic solution it becomes turgid., Hypotonic solution : The external solution which is more dilute than the, cytoplasm. Cell kept in Hypotonic solution become turgid., Hypertonic solution : The external solution, which is more concentrated, than the cytoplasm. Cell kept in hypertonic solution get plamolysed, Isotonic solution : When the external solution balances the osmotic pressure, of the cytoplasm.Cell kept in isotonic solution become flaccid., Casparian strip : It is the tangential as well as radial walls of endodermal, cells having the deposition of water impermeable suberin., Imbibition : Imbibition is the phenomenon of absorption of water by the, solid particles of an adsorbent causing it to enormously increase in volume without, forming a solution., , , Some examples of Imbibition :, (i) If a dry piece of wood is placed in water, it swells and increases in its volume., (ii) If dry gum or pieces of agar-agar are placed in water, they swell and their, volume increases., (iii) When seeds are placed in water they swell up., (iv) Swelling of wooden door during rainy season., , Conditions essential for imbibition, 1. Water potential gradient between the surface of the adsorbent and the imbibed, liquid, is essential., 2. Affinity between the adsorbent and the imbibed liquid., 108, , Biology Class - 11
Page 135 :
Transport of water in plants : Water is absorbed by root hairs by diffusion., Then water moves upto xylem by two pathways–apoplast and symplast pathway., Apoplast Pathway—Movement occurs through the intercellular spaces or, walls of the cell, without entering the cytoplasm. This movement is fast. In roots,, movement of water occurs via apoplast except at the carparian strip, most of water, enters through apoplast., Symplast Pathway—Water enters the cell through cell membrane and travels, intercellularly through plasmodesmata. This movement is slow. At casparian strip, region water moves through symplast., , Apoplastic And Symplastic Pathways of Water Transport, Ascent of Sap—Upward movement of water in the form of dilute solution of, mineral ions from roots to the top aerial parts of plants through tracheary elements, of xylem against the gravitational force is called ascent of sap. It involves two, theories—, (i) Cohesion—Tension-transpirtation pull theory., (ii) Root pressure theory., (1) Cohesion-Tension-transpiration pull theory—, (i) Continuity of water column—The transport of water to the top of trees, occurs through xylem vessels. The forces of adhesion and cohesion maintain a, thin and unbroken column of water in the capillaries of xylem vessels through, which it travels which is travels upward. Water is mainly pulled by transpiration, from leaves., (ii) Transpiration Pull—Transpiration accounts for loss of 99% of water in, the form of water vapours the surface of leaves. The loss is mainly through stomata., Pull of water as a result of tension created by transpiration is the major diving, force of water movement upward in a plant., Three physical properties of water which affect the ascent of xylem sap due, to transpiration pull., Transport in Plants, , 109
Page 136 :
(iii) Cohesion force or Tensile strength of water—, Cohesion—Mutual attraction between water molecules., Adhesion—Attraction of water molecules to polar surface., Surface tension—Attraction of water to each other in liquid phase to a, greater extent than to water in gaseous phase., (2) Root pressure Theory : A hydrostatic pressure existing in roots which, pushes the water up in xylem vessels upto certain height to herbaceons plant., Guttation : The water loss in its liquid phase in the form of water droplets at, night and early morning through special openings of vein near the tip of leaves., These opening are called hydathodes., Transpiration : The loss of water through stomata of leaves and other aerial, parts of plants in form of water vapours., Factors affecting transpiration : Temperature, light, relative humidity, wind, speed, number and distribution of stomata, water status of plant, canopy structure., Significance of transpiration—Advantages—Helps in ascent of sap removal, of excess water, cooling effect, distribution of mineral salts, supply water for, photosynthesis., Disadvantages—May cause reduced growth, wilting (loss of turgidity),, reduced yield and waste of energy., Since there are advantages as well as disadvantages of transpiration so—, ‘Transpiration is called a necessary evil’., Opening and closing of stomata—Mechanism of opening and closing of, stomata involves two steps—, (i) Change to the turgidity of guard cells., (ii) Orientation of cellulose microfibrils in the cell wall of guard cells., Endosmosis—When a cell is placed in water or hypotonic solution, water, enters into the cell. This in called endosmosis. Due to it the volume of cell increases, and it creates turgor pressure., Exosmosis—When a cell is placed in hypertonic solution, water comes out, of the cell, this is called exosmosis. It decreases volume of the cell., Uptake and transport of mineral nutrients—Ions are absorbed by the roots, by passive and active transport. The active uptake of ions require ATP energy., Specific proteins in membranes of root hair cells activity pump ions from the soil, into the cytoplasm of epidermal cells and then xylem. The further transport of ions, to all parts of the plant is carried through the water stream. Older dying leaves, export much of their mineral content to younger leaves. Elements phosphorus,, sulphur, nitrogen and potassium are most readily mobilised., 110, , Biology Class - 11
Page 137 :
Mass flow : Mass flow is the movement of substances (water, minerals and, food) in bulk from one point to another as a result of pressure differences between, two points., , The pressure or mass flow Hypothesis :, Leaf Mesophyll Cells, Photosynthesis, ↓, Glucose, ↓, Sucrose, ↓, Rise in Osmotic Pressure, ↓, Endosmosis, ↓, Rise in T.P. of Mesophyll Cells, ↓, Mass flow of H2O and Sucrose due to turgor gradient, ATP, ADP + ip, “In mass” comes in companion cell, and then into sieve tube cells, , Loading, , ↓, Transport in Plants, , 111
Page 138 :
Water comes in sieve tube cell from, Xylem and increase turgor Pressure gradient, ATP, ADP + i, Sucrose comes to Root cell and, convert into starch or energy or get, consumed in Respiration, , Unloding, , ↓, Decrease in O.P. of Root Cells, ↓, Water moves to Root Xylem, Mycorrhiza—A mycorrhiza is a symbiotic association of a fungus with a, root system. The fungal hyphae absorb mineral ions and water from the soil, and, provide them to the roots of plant, in turn the roots provide sugars and nitrogen, containing compounds to the mycorrhizae., , Questions, Very Short Answer Questions , , (1 mark each), , 1. Which part of the root is related with the absorption of water ?, 2. What makes the raisins to swell up when kept in water ?, 3. Casparian strip is made of a substance which is impervious to water. Name, this substance., 4. What will happen to water potential when a solute is added to water ?, 5. A plant cell when kept in a solution got plasmolysed. What was the nature, of the solution., 6. Mention two ways of absorption of water by root hairs in plants., 7. Which form of sugar is transported through phloem ?, 8. Give one example of imbibition., 112, , Biology Class - 11
Page 139 :
9. A flowering plant is planted in an earthen pot and irrigated. Urea is added, to make the plant grow faster, but after some time the plant dies. Give its, possible reason., 10. Why is energy required to develop root pressure ?, 11. Correct the statements :, (a) Imbibition is a special type of diffusion when water is absorbed by, living cell., (b) Most of water flow in the roots occurs via symplast., (c) Cells shrink in hypotonic solution and swell in hypertonic solution., , Short Answer Questions-I , , (2 marks each), , 12. A well watered potted herbaceous plant shows wilting in the afternoon of a, dry sunny day. Give reason., 13. Do different species of plants growing in the same soil show the same rate, of transpiration at a particular time ? Justify your answer., 14. What is casparian strip ? Write its significance in plants., 15. Xylem transport is unidirectional and phloem transport bi-directional, why ?, 16. How is transpiration different from guttation ? Give two points., 17. Suggest two methods to increase the life of cut plants in a vase., 18. Write the chemical composition of xylem and phloem sap., 19. Transpiration is a necessary evil in plants. Explain., , Short Answer Questions-II, , (3 marks each), , 20. Why is solute potential always negative ? Explain., ψw = ψs + ψp, 21. Water has a very important role in sustaining the life list properties of water, which make it useful for all biological processes on earth., 22. When any dry plant material or seeds is/are kept in water, they swell up., (a) Name the phenomenon involved in this change., (b) Define this phenomenon., (c) Give two conditions essential for the phenomenon to occur., 23. Differentiate between temporary and permanent wilting. Do any of them, indicate the water status of the soil ?, Transport in Plants, , 113
Page 140 :
24. Observe the diagram and answer the following :, , (a) Which of these guard cells show a higher water content, A or B ?, (b) Are these types of guard cells found in monocots or dicots ?, (c) Name the element which play an important role in the opening and, closing of stomata., 25. What is mycorrhiza ? How is the mycorrhizal association helpful in absorption, of water and minerals in plants ?, 26. Observe the given figure and give the answers of the following :, (a) Identify the process occurring in (I), (II) and (III)., (b) Differentiate between the process II and III., (c) How many types of aquaporins from the water channels in the cell, membrane., , 27. Give scientific term for the following statements/processes :, (a) Movement of water in roots exclusively, through the cell wall, (b) The positive hydrostatic pressure developed inside the cell or cell wall., (c) A solution having relatively less concentration., (d) Loss of water vapour from the aerial parts of the plants in the form of, water vapours., 114, , Biology Class - 11
Page 141 :
(e) Movement of a molecule across a membrane independent of other, molecule., (f) Water loss in its liquid phase through the special opening of veins near, the tip of leaves of many herbaceous plants., , Long Answer Questions, , (5 marks each), , 28. Minerals are present in the soil in sufficient amount. Do plants need to adjust, the types of solutes that reach the xylem ? Which molecules help to adjust, this ? How do plants regulate the type and quantity of solutes that reach, xylem., 29. How do plants absorb water ? Explain transpiration pull model in this regard., 30. (a) Describe the pressure flow hypothesis of translocation of sugar in plants., (b) Explain the mechanism of closing and opening of stomata., , Answers, , Very Short Answer, , (1 mark each), , 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., , Root hairs., Endosmosis., Suberin, Water potential will decrease., Hypertonic., Apoplast and symplast pathway., Sucrose., Swelling of seed when put in water/moist soil., Due to exosmosis i.e., water comes out the plant., Every activity requires energy. Root pressure develops due to activity of, living cell., 11. (a) Osmosis is a special type, of diffusion when water is absorbed by living, cells., (b) Most of the water flows in the roots occurs via the apoplast., (c) Cells shrink in hypertonic, solution and swell in a hypotonic solution., , Short Answers-I , , (2 marks each), , 12. During noon, the rate of transpiration becomes higher than the rate of water, absorption by plant. It causes loss of turgidity and leads to wilting., Transport in Plants, , 115
Page 142 :
13. Rate of transpiration is not same because transpiration is affected by numbers, and distribution of stomata, and their opening., 14. Refer page 185, NCERT, Text Book of Biology for Class XI, 15. Refer page 190, NCERT, Text Book of Biology for Class XI, 16. , , Transpiration, , Guttation, , (i) Loss of water by a plant in form (i) The loss of water in the form of, , , of vapours. liquid droplets from the plant., , (ii) Occurs through the general, , (ii) Occurs at the margins and the, , , , surface of leaves (stomata) and tips of the leaves., , , , the young stems., , 17. (a) By adding cytokinin into water of the vase., (b) Preventing entry of air in the cut plants by immediately immersing the, cut end in water., 18. Xylem Sap-Water, traces of all minerals., Phloem sap-5-10% sucrose, 1% amino acids, traces of bound mineral,, hormones, other organic substances and rest is water., 19. Refer to ‘Points of Remember’ (Significance and disadvantages of, Transpiration), , Short Answers-II, , (3 marks each), , 20. Refer to ‘Points of Remember’. (Solute Potential, Pressure Potential and, Water potential), 21. Refer to ‘Points of Remember’, (Cohesion, Adhesion and surface tension), 22. (a) Imbibition., (b) Refer to ‘Points to Remember.’, (c) Condition necessary to imbibition., , , (i) Water potential between the absorbent and the liquid imbibed., , , , (ii) Affinity between the adsorbent and the liquid imbibed., , 116, , Biology Class - 11
Page 143 :
23. , , Temporary wilting, , Permanent wilting, , (i) Plant recovers from temporary, (i), , wilting after sometimes. , , (ii) Much damage is not caused., (ii), (iii) It commonly occurs during, (iii), , mid-day only. , , Automatic recovery is not, possible. It may recover if water, is provided soon., Much damage is caused., It occurs throughout day and, night., , When wilting is permanent, water present in soil is largely unavailable form., The soil contains 10-15% water depending, upon its texture., 24. (a) A, (b) Dicots, (c) K+ (Potassium ions), 25. Refer points to remember., 26. (a) (i) Uniport (ii) Antiport (iii) Symport, (b) Refer ‘Points to Remember’., (c) 8 types of aquaporins., 27. (a) Apoplast pathway, (b) Turgor pressure, (c) Hypotonic, (d) Transpiration, (e) Uniport, (f) Guttation, , Long Answers , 28., 29., 30., , , (5 marks each), , Refer page 189, NCERT, Text Book of Biology for Class XI., Refer page 186-187, NCERT, Text Book of Biology for Class XI., (a) Refer points to remember., (b) Refer page 191, NCERT, Text Book of Biology for Class XI., , , Transport in Plants, , 117
Page 144 :
Vesicles Containng Rhizobia, , Based on functions :– Components of bio, molecules of C, H, O, N, – components of energy, related chemicals e.g. Mg, P, – Activator/Inhibitor of, 2+, enzymes e.g. Zn , Mo, – Alter osmotic potential of cell, e.g. K, Na, Cl, , Types of essential elements :(based on quantity), Macronutrients :- present in, plant tissue in excess of 10, mole/kg of dry matter. e.g. C, H,, O, N. P, S, K Ca, Mg, Micronutrients :Present in plant tissue less than, 10 mole/kg of dry matter., e.g. Fe, Mn, Cu, Mo, 2n, B, Cl,, Ni, , Criteria for Essentiality :– must be absolutely, necessary for supporting, normal growth and, reproduction., – requirement must be, specific not replaceable., – must be directly involved in, metabolism of the plant., * There are 17 essential, elements., , MINERAL NUTRITION, , Deficiency symptoms :Chlorosis :- loss of chlorophyll,, caused by deficiency of N,, Mg,S. Fe, Mn, Zn & Mo, Necrosis :- Death of tissue, caused by deficiency of Ca, Mg,, Cu, K, Initiating of cell division :caused by deficiency of N, K, S,, Mo, Delay flowering :, caused by deficiency of N, S Mo, , 118, , Toxicity of micro-nutrients :Moderate increase in micronutrient cench. causes toxicity, e.g Mn toxicity causes, appearance of brown spots, surrounded by chlorotic veins., , Biology Class - 11, , Minerals are absorbed as, ions :2–, 4+, Nitrogen as No3/NO /NH, Phosphorous as H 2 PO 4 /HPO42+, Potassium as K, 2+, Calcium as Ca, 2+, Magnesium as Mg, 2 Sulphur as SO4, 3+, Iron as Fe, 2+, Manganese as Mn, 2+, Zinc as 2N, 2+, Copper as Cu, 32 Boron as Bo3 or B4O7, 2+, Molybdenum as MoO2, Chlorine as Cl
Page 145 :
Points To Remember, Autotroph : An organism that sythesize its required nutrients from simple, and inorganic substance; Example—plants, blue green algae (cyanobacteria), Heterotroph : An organism that cannot synthesise its own nutrients and, depend on others. Example—Bacteria, protists, members of animalia., Biological nitrogen fixation: Conversion of atmospheric nitrogen into, organic compounds by living organisms., Chlorosis : Yellowing of leaves due to loss of chlorophyll., Nitrification : Conversion of ammonia (NH3) into nitrite and then to nitrate., Denitrification : A process of conversion of nitrate into nitrous oxide and, nitrogen gas (N2)., Leg-hemoglobin : Pinkish pigment found in the root nodules of legumes., It acts as oxygen scavenger and protects the nitrogenase enzyme from oxidation., Flux : The movement of ions is called flux. Influx is inward movement of, ions into the cells and efflux is the outward movement of ions., Inhibition of cell division : Deficiency of N, K, S. and Mo., Necrosis : Death of tissues particularly leaf tissue due to deficiency of Ca,, Mg, Cu, K., Delayed Flowering : due to deficiency of N, S, Mo., Mineral Nutrition : Plants require mineral elements for their growth and, development. The utilization of various absorbed ions by a plant for growth and, development is called mineral nutrition of the plant., Hydroponics : Soil-less culture of plants, where roots are immersed, in nutrient solution (without soil) is called hydroponics. The result obtained, from hydroponics may be used to determine deficiency symptoms of essential, elements., Active Transport : Absorption occuring at the expense of metabolic energy., Passive Transport : Absorption of minerals with concentration gradient by, the process of diffusion without the expense of metabolic energy., , Mineral Nutrition, , 119
Page 146 :
Essential Elements, Macronutnents, Macronutrients are present in plant, tissues in concentrations of more, than 10 m mole Kg–1 of dry matter., C, H, O, N, P, K, S, Ca, Mg, , Micro-nutrients, Micro-nutrients are needed in very, low amounts : less than 10 m mole, Kg – 1 matter., Fe, Mn, Cu, Mo, Zn, B, Cl, Ni, , In addition to the 17 essential elements, Na, Si, Co and Si are required by, some higher plants., , Criteria for essentiality :, 1. The element must be necessary for supporting normal growth and reproduction., 2. Requirement must be specific and not replaceable by another element., 3. The element must be directly involved in the metabolism of the plant., Role of Minerals Elements in Plants, MACRO NUTRIENTS, Element, Obtained as, Functions, , , Deficiency, symptoms, , Nitrogen (N), , Stunted growth, Chlorosis,, dormancy of, causal buds., , Mainly as, some, as NO2 or NH4+, , , Phosphorus (P), , Constituent of cell, membrane. Required, , for the synthesis, , of nucleic acids,, , nucleotides, ATP, , NAD and NADP, , for phosphory , lation reactions., , , 120, , Phosphate ions, , Constituent of, proteins, nucleic, acids, vitamins and, hormones., , Biology Class - 11, , Poor growth of, plant., Leaves dull green,, delay in seed, germination purple, or red spots on, leaves, premature, leaf fall.
Page 147 :
Potasium (K), K+, , , , , , , , , Calcium (Ca), Ca2+, , , , , , , , , Magnesium (Mg) Mg2+, , , , , , Helps to maintain an, anion-cation balance, in cells. Involved in, protein synthesis, in, opening and closing, of stomata; activation, of enzymes; maintenance of turgidity of, cells., Required in formation, of mitotic spindle;, involved in normal, functioning of cell, membranes; activates, certain enzymes; as, calcium pectate in, middle lamella of the, cell wall., Activates enzymes in, phosphate metabolism,, constituent of, chlorophyll; maintains, ribosome structure., , Sulphur (S), , , , , , Constituent of two, Chlorosis of, amino-acids-Crysteine younger leaves,, and methionine and, stunted growth, proteins, coenzymes,, vitamins and, , , , ferredoxin., , Stunted growth;, yellow leaves, edges of, leaves; mottled, appearance of, leaves. Premature, death., Stunted growth,, chlorosis of young, leaves., , Chlorosis between, the leaf veins, narcosis purple, colours spots on, older leave, , MICRO NUTRIENTS, Element, Obtained as, Functions, , , Deficiency, symptoms, , Iron (Fe), Fe3+, , , , , , Constituent of, Ferredoxin and, cytochrome; needed, for synthesis of, chlorophyll., , Chlorosis of, leaves, , Manganese (Mn) Mn2+, , , , , , Activates certain, enzymes involved, in photosynthesis,, respiration and nitrogen, metabolism., , Chlorosis, grey, spots on leaves., , Mineral Nutrition, , 121
Page 148 :
Zinc (Zn), Zn2+, , , , , Activates various, enzymes like, carboxylases. Required, for synthesis of auxins., , Malformation of, leaves, , Copper (Cu), Cu2+, Activates certain, , enzymes. Essential for, , overall metabolism, , , , , Stunted growth,, inter-veinal, chlorosis in leaves., Necrosis of the tip, of young leaves,, die back of shoot., , Required for uptake, Boron (B), BO33–, B4O72–, , of water and Ca, for, , membrane functioning,, , pollen germination, cell, , elongation carbohydrate, , translocation., 2+, MoO2 , Molybdenum, (molybdate ions), Activates certain, (Mo) , metabolism., , , , Chlorine (Cl), Cl–, Maintains solute, , concentration along, , with Na+ & K+; maintain, , anion-cation balance, , in cells; essential for, , oxygen evolution in, , photosynthesis., , Death of stem, and root apex,, loss of a foical, dominance,, abscission of, flowers, small size, of fruits, Nitrogen, deficiency interveinal chlorosis, retardation of, growth, Wilted leaves;, stunted root, growth and, reduced fruiting., , Critical Concentration : The concentration of the essential element below, which plant growth is retarted. The element is said to be deficient when present, below the critical concentration., Deficiency symptoms : Chlorosis, stunted growth, premature fall of leaves, and buds and inhibition of cell division., Toxicity of micronutrient : Any mineral ion concentration in tissues that, reduces the dry weight of tissues by 10% is considered toxic. Toxicity of one, element may lead to deficiency of other element since the former may inhibit the, uptake of latter., e.g., Mn competes with Fe, Mg for uptake and also inhibits Ca, translocation to shoot apex. Therefore Mn toxicity symptoms are actually same, as deficiency symptoms of Fe, Mg and Ca., 122, , Biology Class - 11
Page 149 :
Role of microbes in nitrogen cycle :, , , , , , Rhizobium, Azotobacter, Rhodospirillum; Fix atmospheric nitrogen, Nitrosomonas and/or Nitrococcus :—Conversion of ammonia to nitrite, Nitrobacter : Conversion of nitrite into nitrate., Pseudomonas and Thiobacillus : reduce nitrate into nitrogen., , Nitrogen Cycle, Nitrogen fixation—The process of conversion of Nitrogen (N2) into, ammonia (NH3)., Ammonification—The process of decomposition of organic nitrogen of, plants and animals (proteins) into ammonia., , Ammonifying, Protien in Dead Plants and Animals , → NH, 3, Bacteria, Nitrification—The ammonia so formed may volatilise and re-enter the, atmosphere, or some of the ammonia may be converted first into nitrite and then, into nitrate by soil bacteria, Nitrosomonas → 2NO – + 2H O + 2H +, 2NH 3 + 3O 2 , 2, 2, Nitrobactor → 2NO –, 2NO 2 – + O 2 , 3, Mineral Nutrition, , 123
Page 150 :
The Nitrate so formed can be easily absorbed by the plants and transported, to leaves. In leaves, nitrate is reduced to ammonia to form amino-acids, because, nitrate can not used by plants as such., –, , NO3, , Nitrate reductase, , NADH2 NAD, , Nitrite, Reductase, , –, , NO2, , H2O, , NO3, , Amino acid, Synthesis, , NADH2 NAD, , Denitrification—Process of reduction of the nitrate present in soil to nitrogen., It is carried out by bacteria like Pseudomonas and Thiobacillus., Biological Nitrogen Fixation—Reduction of nitrogen to ammonia by living, organisms. Certain prokaryotes are able to fix nitrogen because of presence of, ‘nitrogenase’ enzyme in them., , Nitrogen fixing microbes may be, (a), , Free living—(i) Aerobic—Azotobacter, (ii) Anaerobic—Rhodospirillum, (b) Cyanobacteria—Nostoc, Anabaena, (c) Symbiotic—(i) With leguminous plants—Rhizobium, (ii) With non-leguminous plants—Frankia, Enzyme nitrogenase—The enzyme nitrogenase is Mo-Fe protein and, catalysis the conversion of atmospheric nitrogen to ammonia (First stable product, of nitrogen fixation), Leg-hemoglobin—A pink colour pigment, similar to hemoglobin of, vertebrates and functions as an oxygen scavenger and protects nitrogenase from, oxygen., , Steps of nodule formation :, (a) Rhizobium bacteria present in soil contact a susceptible root hair., (b) Infection of the root hair cause it to curve and deformed due to chemical, secretion., (c) An infection thread is produced carrying the bacteria into the cortex of the, root., (d) The bacteria get modified into rod-shaped bacteria and cause inner cortical, and pericycle cells to divide plant produce cytokinin and auxin to stimulate, cell division and enlarge to form nodules., , 124, , Biology Class - 11
Page 151 :
(e) Division and growth of cortical and pericycle cells lead to nodule formation., , Mechanisms of N2 fixation, It require 4 components—, (a) A strong reducing agent like FADH2, NADPH2, (b) Nitrogenase enzyme, (c) ATP (as energy service), (d) Nitrogen gas molecule (as substrate), N2 + 8e– + 8H+ + 16 ATP, , 2NH3 + H2 + 16 ADP + 16Pi, , Fate of Ammonia :- At physiological pH, the ammonia is protonated to form, NH4+, which is quite toxic to plants and hence can not accumulate in them. It is, used by plants in following ways–, (a) Reductive amination :- α – ketoglutaric acid + NH4+ +, glutamate, Dehydrogenase, , NADP, , glutamate + H2O + NADP, , (b) Transamination :- Transfer of amino group from one amino acid to the keto, group of a keto acid to form amino acid with the help of enzyme transaminase., (c) Formation of Amides :- The hydroxyl part of the acid is replaced by another, amino radicle to form amides. e.g. asparagine and glutamine are formed from, aspartic acid and glutamic acid., Mineral Nutrition, , 125
Page 152 :
Questions, , Very Short Answer Questions, , (1 mark each), , 1. Name one symbiotic nitrogen-fixing bacteria., 2. Give two examples of photosynthetic microorganisms, which also fix, atmospheric nitrogen., 3. Name two organisms each which fix nitrogen symbiotically and asymbiotically., 4. Which substance impart pink colour to the root nodule of a leguminous plant, and also mention its role ?, 5. What is the term used for mineral deficiency symptom in plants in which, leaves become yellow in different pattern ?, 6. Define hydroponics., 7. Give the name of an insectivorous angiosperm plant., 8. Give the name of one non-symbiotic nitrogen fixing prokaryote., 9. Name the green house gas produced in rice fields., , Short Answer Questions-I , , (2 marks each), , 10. Differentiate between two types of absorption of minerals in plants from, soil., 11. Name the following :, (a) Bacteria which converts ammonia into nitrite., (b) Bacteria which oxidises nitrite into nitrate., 12. How does Leghemoglobin protect the enzyme nitrogenase ?, 13. Name the enzyme found in root modules for N2 fixation ? Name the pink, coloured pigment required for its functioning., , Short Answer Questions-II, , (3 marks each), , 14. Write the deficiency symptoms of the following three elements :, (a) Phosphorus, (b) Magnesium, (c) Potassium, 126, , Biology Class - 11
Page 153 :
15. Describe the following three deficiency symptoms and co-relate them with, concerned mineral deficiency :, (a) Phosphorus, (b) Magnesium, (c) Potassium, 16. Explain in brief the steps involved in biological nitrogen fixation., 17. Describe the two main processes of synthesis of amino acids from Ammonium, ion (NH4+) in plants., 18. Define critical concentration, also mention four deficiency symptoms of, nutrients in plants., 19. Write a short note on toxicity of micronutrient. Give an example which show, toxicity of one element may lead to deficiency of other element., , Long Answers , , (5 marks each), , 20. Describe all the steps of nitrogen cycle in nature., 21. Describe with diagrams how root nodules are formed in leguminous plants., 22. Explain adaptations in leguminous root nodules for N2 fixation., , Answers, , Very Short Answers, , (1 mark each), , 1. Rhizobium, 2. Anabaena, Nostoc, 3. Asymbiotically-Azotobacter, Bacillus polymyxa Symbiotically-Rhizobium,, Anabaena., 4. Leghemoglobin. It is an oxygen scavenger, which protects the enzyme, nitrogenase., 5. Necrosis., , Mineral Nutrition, , 127
Page 154 :
6. The technique of growing plants in a nutrient solution without soil is called, hydroponics., 7. Nepenthes (Pitcher plant), 8. Azotobacter, 9. Methane (CH4), , Short Answers-I, , (2 marks each), , 10. Refer to NCERT Book, Page no. 200 (12.3)., 11. (i) Nitrifying Bacteria—Nitrosomonas., (ii) Nitrifying Bacteria—Nitrobacter, 12. Refer to page no. 203., 13. Enzyme-Nitrogenase, Pink coloured pigment-Leghaemoglobin, , Short Answers-II, , (3 marks each), , 14. Refer to ‘Points to Remember’., 15. Refer to ‘Points to Remember’., 16. Refer to ‘Points to Remember’., 17. Refer to ‘Points to Remember’ (Fate of Ammonia), 18. Refer to ‘Points to Remember’., 19. Refer to ‘Points to Remember’., , Long Answers, , (5 marks each), , 20. Refer to ‘Points to Remember’., 21. Refer to ‘Points to Remember’., 22. Refer to NCERT Book Page No. 203., , , 128, , Biology Class - 11
Page 155 :
Higher Plants, , Photosynthesis in Higher Plants, , 129
Page 156 :
Points To Remember, Photosynthesis : Photosynthesis is an enzyme regulated anabolic process, for manufacture of organic compounds inside the chlorophyll containing cells, from carbon dioxide and water with the help of sunlight as a source of energy., 6CO 2 + 12H 2 O, , Sun Light, C6 H12 O6 + 6H 2 O + 6O 2 ↑, Chlorophyll + enzymes, , Historical Perspective, Josheph Priestley (1770) : Showed that plants have the ability to take up, CO2 from atmosphere and release O2. (Candle with bell jar and mouse expt.), Jan Ingenhousz (1779) : Release of O2 by plants was possible only in sunlight and only by the green parts of plants. (Expt. with aquatic plant in light & dark), Theodore de Saussure (1804) : Water is an essential requirement for, photosynthesis to occur., Julius Von Sachs (1854) : Green parts in plant produce glucose which is, stored as starch., T.W. Engelmann (1888) : The effect of different wavelength of light on, photosynthesis and plotted the first action spectrum of photosynthesis., C.B. Van Niel (1931) : Photosynthesis is essentially a light dependent, reaction in which hydrogen from an oxidisable compound reduces CO2 to form, sugar. He gave a simplified chemical equation of photosynthesis., , 2H 2 A + CO 2, , Sun Light, , 2A + CH 2 O + H 2 O, , Hill (1937) : Evolution of oxygen occurs in light reaction., Calvin (1954-55) : Traced the pathway of carbon fixation., Hatch.and Slack (1965) : Discovered C4 pathway of CO2 fixation., Site for photosynthesis : Photosynthesis takes place only in green parts of, the plant, mostly in leaves. Within a leaf, photosynthesis occurs in mesophyll cells, which contain the chloroplasts. Chloroplasts are the actual sites for photosynthesis., The thylakoids in chloroplast contain most of pigments required for capturing solar, energy to initiate photosynthesis : The membrane system (grana) is responsible for, trapping the light energy and for the synthesis of ATP and NADPH. Biosynthetic, phase (dark reaction) is carried in stroma., 130, , Biology Class - 11
Page 157 :
Importance of Photosynthesis—(1) Synthesis of organic compounds (2), Change of radiant energy into chemical energy (3) Useful products are obtained, from plants gums, oils timber fire wood, resins rubber, fibers and drugs, etc. (4), Balance the percentage of O2 and CO2 in atmosphere (5) Fossil fuels like coal,, natural gas and petroleum have been formed inside the earth indirectly as a product, of photosynthesis., , Pigments involved in photosynthesis :, Chlorophyll a : (Bright or blue green in chromatograph). Major pigment,, act as reaction centre, involved in trapping and converting light into chemical, energy. It is called universal photo-synthetic pigment., Chlorophyll b : (Yellow green), Xanthophylls : (Yellow), Carotenoids : (Yellow to yellow-orange), In the blue and red regions of spectrum shows higher rate of photosynthesis., Light Harvesting Complexes (LHC) : The light harvesting complexes are, made up of hundreds of pigment molecules bound to protein within the photosystem, I (PS-I) and photosystem II (PS-II). Each photosystem has all the pigments (except, one molecule of chlorophyll ‘a’) forming a light harvesting system (antennae)., The reaction centre (chlorophyll a) is different in both the photosystems., , Light Harvesting Complex, Photosynthesis in Higher Plants, , 131
Page 158 :
Photosystem I (PS-I) : Chlorophyll ‘a’ has an absorption peak at 700 nm, (P700)., Photosystem II (PS-II) : Chlorophyll ‘a’ has absorption peak at 680 nm, (P680),, Process of photosynthesis : It includes two phases-Photochemical phase, and biosynthetic phase. (Formerly known as Light reaction and dark reaction), (i) Photochemical phase (Light reaction) : This phase includes-light, absorption, splitting of water, oxygen release and formation of ATP and NADPH., It occurs in grana region of chloroplast., (ii) Biosynthetic phase (Dark reaction) : It is light independent phase,, synthesis of food material (sugars). (Calvin cycle). It occurs in stroma region of, chloroplast., Photophosphorylation : The process of formation of high-energy chemicals, (ATP and NADPH) in presence of light., Non-Cyclic photophosphorylation : Two photosystems work in series–First, PSII and then PSI. These two photosystems are connected through an electron, transport chain (Z. Scheme). Both ATP and NADPH + H+ are synthesised by, this process. PSI and PSII are found in lamellae of grana, hence this process is, carried here., , 132, , Biology Class - 11
Page 159 :
The electron transport (Z-Scheme) : In PS II, reaction centre (chlorophyll, a) absorbs 680 nm wavelength of red light which make the electrons to become, excited. These electrons are taken up by the electron acceptor that passes them to, an electron transport system (ETS) consisting of cytochromes. The movement of, electron is down hill. Then, the electron pass to PS I and move down hill further., The splitting of water : It is linked to PS II. Water splits into H+, [O] and, 4H+ + O2 + 4e–, electrons. 2H2O, , Cyclic photophosphorylation : Only PS-I works, the electron circulates, within the photosystem. It happens in the stroma lamellae (possible location), because in this region PSII and NADP reductase enzyme are absent. Hence only, ATP molecules are synthesised. It occurs when only light of wavelengths beyond, 680 nm are available for excitation., Chemiosmotic, Hypothesis, :, Chemiosmotic hypothesis explain the, mechanism of ATP synthesis in chloroplast., In photosynthesis, ATP synthesis is linked, to development of a proton gradient across, a membrane. The protons are accumulated, inside of membrane of thylakoids (in, lumen). ATPase enzyme has a channel, of that allow diffusion of protons back, across the membrane. This release energy, to activate ATPase enzyme that catalyses, the formation of ATP., Photosynthesis in Higher Plants, , 133
Page 160 :
Biosynthesis phase in C3 plants :, ATP and NADPH, the products of light reaction are used in synthesis of food., The first CO2 fixation product in C3 plant is 3-phosphoglyceric acid or PGA. The, CO2 acceptor molecule is RuBP (ribulose bisphosphate). The cyclic path of sugar, formation is called Calvin cycle on the name of Melvin Calvin, the discover of, this pathway. Calvin cycle proceeds in three stages., (1) Carboxylation : CO2 combines with ribulose 1, 5 bisphosphate to form, 3 PGA in the presence of RuBisCo enzyme (present in stroma), (2) Reduction : Carbohydrate is formed at the expense of ATP and NADPH., It involves 2ATP for phsophorylation and 2NADPH for reduction per CO2, molecule fixed., (3) Regeneration : The CO2 acceptor ribulose 1, 5-bisphosphate is formed, again., 6 turns of Calvin cycles and 18 ATP molecules are required to synthesize, one molecule of glucose., , Triose, Phosphate, , 134, , Biology Class - 11
Page 162 :
Adaptations in C4 Plants :, , (i) Kranz Anatomy, (ii) Occurrence of two types of cells, (iii) Dimorphic chloroplast, , (iv) Presence of RuBisCO in Bundle, Sheath cells and PEPcase in mesophyll cells., (v) Mechanism to increase CO2 concen-, , tration near RuBisCO in Bundle Sheath cells., , CAM (Crassutacean Acid Metabolism), Plants—Stomata open at night. e.g., Cacti,, Bryophyllum, Pineapple., , Figure 13.9 diagrammatic representation of the, Hatch and Slack Pathway, , Law of Limiting Factors : If a chemical process is affected by more than, one factor, then its rate will be determined by the factor which is nearest to its, minimal value. It is the factor which directly affects the process if its quantity is, changed. Factors affecting photosynthesis :, 1. Light : Rate of photo-synthesis increases at low light intensities. At high, intensities of light beyond a point the rate of CO2 fixation decreases. Longer, hours of light duration favour more photosynthesis rate., 2. Carbon dioxide : Increase in CO2 concentration causes increases in CO2, fixation. It is the major limiting factor for photosynthesis., 3. Temperature : The rate of photosynthesis at optimum temperature is, high., It is 20°C-25°C For C3 plants and 30-45°C for C4 plants., 4. Water : Water is one of the reactant in photosynthesis, but it effects the rate, of CO2 fixation. Low water content causes the stomata to close and reduces, the CO2 availability., , Questions, Very Short Answer Questions, , (1 marks each), , 1. Name two photosynthetic pigments belonging to Carotenoids :, 2. How many molecules of ATP are required for synthesis of one molecule of, glucose in C3 and C4 pathways ?, 3. What part of sunlight is most suitable for photosynthesis ?, 4. Which one of the photosystems can carry on photophosphorylation, independently ?, 136, , Biology Class - 11
Page 163 :
5., 6., 7., 8., 9., 10., 11., , Name two plants that can carry out photosynthesis at night., Name the most abundant enzyme found in the world., Name the scientist who proposed the C4 pathway. Name one such plants., Where does carbon fixation occur in chloroplast ?, Which compound acts as CO2 acceptor in Calvin cycle ?, Name the end products of light reaction., Does the photosynthesis occur in moon light ? Why ?, , Short Answer Questions-I , , (2 marks each), , 12. Why does the rate of photosynthesis decline in the presence of continuous, light ?, 13. Why do green plants start evolving carbon dioxide instead of oxygen on a, hot sunny day ?, 14. Fill in the space, left blank in the given table to bring the difference between, C3 and C4 plants :, S.No., , Characteristics, , C3 plants, , 1., Cell type, mesophyll, , ...(b)..., 2., CO2 acceptor, 3-PGA, 3., First CO2 fixation, , product, 4., Optimum, ...(d)..., , temperature, , C4 plants, ...(a)... and mesophyll, Phosphoenol, pyruvate (PEP), ...(c)..., 30° C to 45° C, , 15. State two functions of accessory pigments, found in thylakoids., 16. Why do C4 plants are more expensive (in energy requirement) than C3, plants ?, 17. What is limiting factor ? State the law of limiting factors., , Short Answer Questions-II , , (3 marks each), , 18. The figure shows the effect of light on the rate of photosynthesis. Based on, the graph, answer the following questions :, (i) At which point(s) A, B or C in the curve, light is a limiting factor ?, (ii) What could be the limiting factor(s) in region A ?, (iii) What do region C and D represent on the curve ?, Photosynthesis in Higher Plants, , 137
Page 164 :
19. When and why does photorespiration take place in plants ? How does this, process result in a loss to the plant ?, 20. What are the steps that are common to C3 and C4 photosynthesis ?, 21. Two potted plants were kept in an oxygen free environment in transparent, containers, one in total darkness and the other in sunlight. Which one of the, two is likely to survive more ? Justify your answer by giving the reason., 22. (a) In the diagram shown below, label A, B and C. What type of, phosphorylation is possible in this ?, , (b) Give any two points of difference between cyclic and non-cyclic, photophosphorylation., 23. Name the pigment found in tomato, carrots, chillies etc. which gives red, colour to them. Is it a photosynthetic pigment ?, 24. Chloroplast and mitochondria are believed to be semi-autonomous organelles., Justify the statement., 25. Mention the conditions under which the C4 plants are superior to C3 plants., , Long Answer Questions, , (5 marks each), , 26. Describe C4 pathway in a paddy plant. How is this pathway an adaptive, advantage to the plant ?, 138, , Biology Class - 11
Page 165 :
27. Explain, the process, of biosynthetic plase of photosynthesis occurring in, chloroplast., 28. (a) Give steps to ATP synthesis in chloroplasts through chemiosmosis., (b) Schematically represent non-cyclic photophosphoryation in plants., , Answers, Very Short Answer , , (1 mark each), , 1. Carotene and Xanthophyll., 2. In C3 pathway = 18 ATP molecules In C4 pathway = 30 ATP molecules, 3. Blue and red regions of the light spectrum are the most effective in, photosynthesis., 4. PS-I., 5. Opuntia, Chenopodium, Bougainvillea., 6. RuBisCO., 7. Hatch and Slack. Maize and Sorghum., 8. Carbon fixation takes place in stroma., 9. Ribulose 1, 5 bisphosphate., 10. ATP, NADPH and O2., 11. No, the moonlight is unable to perform light reactions of photosynthesis, (ATP-NADPH Synthesis as it is 1/50,000 the intensity of sunlight and not, strong enough to enable plants to photsynthesise., , Short Answers-I, , (2 marks each), , 12. Increase incident light beyond a point causes the breakdown of chlorophyll., 13. On a hot suny day, enzyme RuBP carboxylase becomes active and its, affinity for CO2 decreases and for O2 increases. Consequently more and, more photosynthetically fixed carbon is lost by photorespiration., 14. (a) Bundle sheath, (b) RuBP, (c) OAA (oxaloacetic acid), (d) 20°C-25°C, Photosynthesis in Higher Plants, , 139
Page 166 :
15. (a) Absorption of light and transfer of energy to chlorophyll ‘a’., (b) Protect chlorophyll ‘a’ from photo oxidation., 16. Because they require more energy (30 ATPs) in synthesizing one glucose, molecule as compared to C3—(18ATPs)., 17. Limiting Factor—A factor which is deficient to such an extent that increase, in its concentration directly increase the rate of the process., (For the law of limiting factors see text in NCERT Book.) Page 222, , Short Answers-II , , (3 marks each), , 18. (i) ‘B’, (ii) CO2 and temperature, , (iii) ‘C’ represents to constant rate of photosynthesis, ‘D’ is the light saturation, intensify at which rate of photosynthesis is maximum., 19. Refer Page no. 220, NCERT, Text Book Biology for class XI., 20. Hints :, , (a) Photolysis of H2O and photophosphorylation occurs in both C3 and C4, plants., (b) In both, dark reaction occurs in stroma., (c) Calvin cycle results in the formation of starch in both the plants., (d) During dark reaction both types of plants undergo the phases of, carboxylation and regeneration :, 21. Hints :, , , The plant in sunlight will survive for longer period., , , Light is essential for photosynthesis., 22. (a) (A) e– acceptor, , , (B) Electron transport system, , , , (C) Chlorophyll P700, , (b) Refer A Page no. 212, NCERT Text Book of Biology for Class XI., 23. Carotenoid : It is an accessory photosynthetic pigment which takes part in, harvesting light energy only if chlorophyll is present., 140, , Biology Class - 11
Page 167 :
24. Mitochondria and chloroplast both contain DNA and can reproduce, independently of the cell and chloroplasts even have a built in feeding, mechanism both have their own ribosomes of 70S type and capable of, synthesising their own kind of proteins., 25. C4 Plant grow in regions with high temperatures and intense light. The rate, of transpiration in C4 plant is 25% of a C3 plant, thus they conserve water, and have greater photosynthetic rate gives greater rate of growth in intense, sunshine and high temperature., , Long Answers, , (5 marks each), , 26. Refer Page no. 218, NCERT Text Book of Biology for Class XI., 27. Refer Points to Remember., , Hints : Three stages of Calvin cycle : Carboxylation, Reduction and, Regeneration., 28. (a) Refer Page no. 213 (Chemiosmotic Hypothesis), NCERT Text Book of, Biology for Class XI., (b) Refer Fig. 13.5 (Z-Scheme of light reaction), NCERT Text Book of, Biology for Class XI., , , Photosynthesis in Higher Plants, , 141
Page 168 :
Points To Remember, Aerobic respiration : Complete oxidation of organic food in presence of, oxygen thereby producing CO2, water and energy., Anaerobic respiration : Incomplete breakdown of organic food to liberate, energy in the absence of oxygen., ATP Synthetase : An enzyme complex that catalysis synthesis of ATP during, oxidative phosphorylation., Biological oxidation : Oxidation in a series of reaction inside a cell., Cytochromes : A group of iron containing compounds of electron transport, system present in inner wall of mitochondria., Dehydrogenase : Enzyme that catalyses removal of H atom from the, substrate., Electron acceptor : Organic compound which receive electrons produced, during oxidation-reduction reactions., Electron transport : Movement of electron from substrate to oxygen through, respiratory chain during respiration., Fermentation : Breakdown of organic substance that takes place in certain, microbe like yeast under anaerobic condition with the production of CO2 and, ethanol., Glycolysis : Enzymatic breakdown of glucose into pyruvic acid that occurs, in the cytoplasm., Oxidative phosphorylation : Process of formation of ATP from ADP and, Pi using the energy from proton gradient., Respiration : Biochemical oxidation food to release energy., Respiratory Quotient : The ratio of the volume of CO2 produced to the, volume of oxygen consumed., Proton gradient : Difference in proton concentration across the tissue, membrane., 142, , Biology Class - 11
Page 169 :
Respiration in Plants, , 143
Page 171 :
A. Glycolysis : The term has originated from the Greek word, glycos =, glucose, lysis = splitting, or breakdown means breakdown of glucose molecule, to pyruvic acid. It was given by Embden Meyerhof and Parnas. It is a chain of 10, reactions to convert glucose into pyruvate. It is common for aerobic and anaerobic, respiration., , Steps for Glycolysis—(EMP Pathway), 1., , Phosphorylation of Glucose into Glucose-6-phosphate (ATP used), , 2., , Isomerisation of Glucose-6-Phosphate into fructose-6-phosphate, , 3., , Second phosphorylation in which Fructose-6-phosphate changes into Fructose-1,, 6-biphosphate (ATP used), , 4., , Splitting of Fructiose-1, 6-biphosphate into DiHAP and PGAL, , 5., , Isomerisation of DiHAP into PGAL, , 6., , Oxidation of PGAL into 1, 3-biphosphosphoglycerate (NADH Produced), , 7., , Synthesis of ATP and converssion of 1, 3-biphosphoglycerate into 3-phospholycerate, , 8., , Isomerisation of 3-phosphoglycerate into 2-phospholycerate, , 9., , Dehydration of 2-phosphoglycerate into PEP (Removal of water), , 10., , Substrate level ATP synthesis and formation of Pyruvic Acid., , , , , , , , , , , It is also called Embden—Meyerhof—Paranas pathway. (EMP pathway), It is common in both aerobic and anaerobic respiration., It takes place outside the mitochondria, in the cytoplasm., One molecule of glucose (Hexose sugar) ultimately produces two molecules, of pyruvic acid through glycolysis.’, , During this process 4 molecules of ATP are produced while 2 molecules, , ATP are utilised. Thus net gain of ATP is of 2 molecules., , Input and Output of glycolysis, S. No., , Input, , Output, , 1., , Glucose (6—C) —1, , Pyruvate (3—C) 2 molecules, , , , molecule, , 2., , 2 ATP, , 2 ADP, , 3., , 4 ADP + 2 Pi, , 4., , 2 NAD+, , 4 ADP + 2H2O, 2 NADH (H+), , Net out put ...... 2 Pyruvate + 2ATP + 2NADH (+ H+) OR 2 Pyruvate + 8 ATP, , The pyruvate, so produced, may under go (i) Lactic acid fermentation, (ii), Alcoholic fermentation (iii) Aerobic Respiration (Krebs Cycle), Respiration in Plants, , 145
Page 172 :
B. Oxidative decarboxylation : Pyruvic acid is converted into Acetyl CoA, in presence of pyruvate dehydrogenase complex., Pyruvic acid + CoA + NAD +, , , + H +, , Mg2, pyruvate, dehydrogenase, , Acetyle CoA + CO2 + NADH, , The Acetyle CoA enters in TCA cycle., , C. Tri Carboxylic Acid Cycle (Kereb’s cycle) or Citric acid Cycle : This cycle, starts with condensation of acetyl group with oxaloacitic acid and water t o, yield citric acid which under goes a series of reactions., , , It is aerobic and takes a place in, mitochondrial matrix., , Each pyruvic acid molecule, , , produces 4 NADH + H+, one, FADH2, one ATP., , , , One glucose molecule has been, broken down t o release, CO2 and eight molecules, of NADH + H+, two molecules, of FADH2 and 2 molecules, of ATP., , Compensation Point : It is the, value of a factor at which the rate, of photosynthesis controlled by it is, just equal to the rate of respiration and photorespiration so that there is not, net exchange of gases between the phtosynthetic organ and the environment., At compensation point the photosynthetic tissue manufacture only such, amount of food which of sufficient for it to remain alive. No food is supplied, to rest of the plant. Therefore, net photosynthesis is zero., (D) Oxidative Phosphorylation, , The synthesis of ATP from ADP and inorganic phosphate using energy from, proton gradient is called oxidative phosphorylation. This takes place in, elementry particles present on the inner membrane of cristae of mitochondria., 146, , Biology Class - 11
Page 174 :
Fermentation : It is the process of anaerobic respiration which occurs in, yeast and some bacteria. Fermentation involves incomplete oxidation of food into, enthanol and carbon-dio-oxide. It results in the production of 2 ATP molcules., , (i) Conversion of Acetyl CoA into fatty acid and PGA., (ii) Synthesis of chlorophyll and cytochromes from Succinyl CoA, (iii) Synthesis of Amino acids from OAA and α-ketoglutaric acid, (iv) Synthesis of Alkaloid from OAA., Enzymes involved-Pyruvic acid decarboxylase, Alcohol dehydrogenase, Anaerobic respiration in muslces : During vigrous exercise a person feels, pain and fatigue in his muscles. This is due to accumulation of lactic acid in, muscles. When oxygen is inadequate pyruvic acid is reduced to lactic acid in, presence of enzyne-lactic dehydrogenase., , During rest lactic acid is reconverted to pyruvic acid., , Amphibolic Pathway :, During the process of cellular respiration Carbohydrates, fats and protiens, are broken down to release energy and hence respiration is a catabolic process/, catabolic pathway. From this pathway many compound are withdrawn for synthesis, of substrates. Some anabolic processes are formation of pyruvic acid from amino, acids, and formation of Acetyl CoA from Fatty acid. So—Respiratory pathway is, involved in both catabolism and anabolism, it is better to consider the respiratory, pathway as an amphibolic pathway., , RQ (Respiratory quotient), (a) RQ = 1 (When carbohydrate is used as substrate), C6H12O6 + 6O2 → 6CO2 + 6 H2O + Energy, (b) RQ is less than 1 (i.e., < 1) for fats., 148, , Biology Class - 11
Page 175 :
2C51H98O6 + 145O2 → 102CO2 + 98 H2O + Energy, R.Q. ⇒, , = 0.7, , (c) RQ is 0.9 for proteins., (d) RQ is more than 1 (i.e., > 1) for organic acids., (e) RQ is inifinite in case of anerobic respiration, because CO2 is evolved but, O2 is not consumed., , Questions, Very Short Answer Question, , (1 mark each), , 1. Name the molecule which is terminal acceptor of electron., 2. How many ATP molecules are produced from a molecule of glucose on it, complete oxidation in eukaryotes ?, 3. Where does ETC found in eukaryotic cell ?, 4. Name the enzyme which convert sugar into glucose and fructose., 5. How many molecules of ATP are produced by the oxidation of one molecule, of FADH2 ?, , 6. Why do the person with sufficient white fibres get fatigued in a short, period ?, , 7. Write the name of end product of glycolysis., 8. Name the first product formed in Kreb’s cycle., 9. Define the term ‘Respiratory substrate’., 10. Which intermediate undergoes lysis in glycolysis ?, 11. Write the other two names of Krebs cycle., 12. Name the acceptor molecule of Krebs cycle., 13. Name the substrate entrant of Krebs cycle., 14. Name the first chemical produced in Krebs cycle., 15. What is Electron Transport Chain ? (ETC)., 16. F0–F1 Protein complexes participate in the synthesis of .........., Respiration in Plants, , 149
Page 176 :
Short Answer Questions-I , , (2 mark each), , 17. Differentiate between aerobic respiration and anerobic respiration., 18. Mention two steps of glycolysis in which ATP is utilised., 19. Why does anaeriobic respiration produces less energy than aerobic respiration?, 20. Define Respiration Quotient. What is its value for fat and protein ?, 21. Distinguish between glycolysis and fermentation., 22. What are respiratory substrates ? Name the most common respiratory, substrate., , Short Answer Questions-II, , (3 marks each), , 23. Pyruvic acid is the end product of glycolysis. What are the three metabolic, fates of pyruvic acid under aerobic and anaerobic conditions ?, 24. Give the schematic representation of an overall view of TCA cycle., 25. Where does electron transport system operative in mitochondria ? Explain, the system giving the role of oxygen ?, 26. Give a brief account of ATP molecules produced in aerobic respiration in, eukaryotes., 27. Discuss the respiratory pathway is an amphibolic pathway., 28. Exapnd ETC., ETS and TCA., , Long Answer Questions, , (5 marks each), , 29. What is glycolysis ? Where does glycolysis takes place in a cell ? Give, schematic representation of glycolysis., , 150, , Biology Class - 11
Page 177 :
Answers, Very Short Answers , , (1 mark each), , 1. Oxygen., 2. 36 ATP., 3. Mitochondrial membrance., 4. Invertase., 5. 2 ATP molecules., 6. due to formation of Lactic acid., 7. Pyruvic acid., 8. Citric acid., 9. The organic substances which is catabolised or brokendown enzymatically, in cellular respiration for releasing energy., 10. Fructose, 6-bisphosphate., 11. (i) Citric acid cycle (ii) Tricarboxylic acid cycle., 12. Oxaloacetate., 13. Acetyl Co-A., 14. Citrate, 15. See text (Points to remember), 16. ATP, , Short Answers-I, , (2 mark each), , 17. Refer NCERT Text Book Chapter 14 (14.3 and14.4)., 18. (i) Phosphorylation of Glucose into Glucose-6-phosphate., (ii) Phosphorylation of Fructose-6-phosphate into Fructose-1,6-biphosphate., 19. Refer NCERT Text Book Chapter 14, Page 230., Respiration in Plants, , 151
Page 178 :
20. Refer NCERT Text Book Page no. 236., 21. Refer NCERT Text Book Page no. 229 and page no. 230., 22. Refer NCERT Tex Book Page no. 227., , Short Answers-II, , (3 marks each), , 23. (i) Aerobic conditions–CO2 + H2O + Energy, (ii) Anaerobic conditions–(fermentation), (a) In muscles – Lactic acid + Energy, (b) Yeast-Ehtanol + CO2 + Energy, 24. Refer NCERT Text Book Fig. 14.3 Page 232., 25. Refer NCERT Text Book Page no. 232 and page no. 233., 26. Refer notes., 27. Refer NCERT Text Book Page no. 235., 28. Seet text (abbreviations)., , Long Answers, , (5 mark each), , 29. Refer NCERT Text Book Page no. 228 and page no. 229., , , 152, , Biology Class - 11
Page 179 :
Plant Growth Regulators, , Growth, An irreversible permanent, increase in size of an organ or, its parts or a cell, Growth is indeterminate and, reasurable. It is accompanied, by metabolic process., , Phases of Growth, Meristematic : constantly, dividing cells., Elongation : Increased, vaconlatin, cell enlargement,, new cell wall depositions., Maturation : Cells attain, maximum size in terms of well, thickening & protoplasmic, modifications., , Growth Promoters, Auxins : 1-AA, 1-BA, NAA & 2, 4-D., isolated by F W went from tips of, coleoptiles of oat seedling., Main role : apical deminance, initiate, rooting for plant propagation, promote, flowering induce parthenocarpy., , Response of plants to, period of day/night is, called photo periodism., plants can be LDP, SDP, and DNL., , Verna lisation, , Giberellins : GA1, GA2, GA3 etc, isolated by E. Kurosawa, 1926., Role : Increase in stem height,, delay senescence, speed up, m a l t i n g p r o c e s s , p r o m o te, bolting., , Promotion of flowering by a period of, low temperature. It affect flowering, quantitatively or qualitatively., , Cytokinins : Skoog & miller., Role : Rapid cell division, over, come apical dominance,, promote nutrient mobilisation, delay leaf senescence., , The period in which a seed fail to, germinate even when external, conditions are favourable., , Growth Inhibitors, , Impermeable & hard seed coat,, immature embryos’ presence of, chemical inhibitors like ABA,, Phenelic Acid, Para- ascorbic acid., , Growth Rates, Arithmetic Growth : Linear, curve on ploting length of organ, against time Lt = Lo + rt., Geometric Growth Rate :, Shows leg phase, exponential, phase and stationary phase in, growth., rt, W1 = W e, , Rate of light & temperature, in flowering, , Abscisic Acid : ABA discovered, by F. T. Addicott., Role : Intibit sead germination,, induce dormancy, closure of, stomata, increase to lerance to, stressful conditions., , Ethylene - neither promoter, nor inhibitor stristly, Important Processes, , Differentiation - Cell stop dividing and, lead to maturation., Dedifferentiation - Differentiated cells, regain the capacity to divide., Redifferentiation - Dedifferentiated, cells again lose the capacity to divide., , Discovered by H. H. Cousins, (1910) only gaseous PGR., , Seed Dormancy, , Causes of seed dormancy., , Means to break seed dormancy:, • By mechanical abrasions., • Microbiapaction as passing, through digestive tract of, animals., • Subjecting to chieling conditons., • Applying GA and nitrates., • Changing environmental, conditions like light &, temperature., , Role : Ripening of fruits, apical hook formation in dicot, seeding, promote senescence and abscission, break, seed and bud dormancy, promote root growth and root, hair formation, initate germination in peanut seeds, and, sprouting of potato tubers., , Conditions of Growth, , Development, , Need water, oxygen, nutrients,, optimum temperature, light., , Include all the changes that an organism, goes during its life cycle., , Plant Growth and Development, , 153
Page 180 :
Points To Remember, Seed Germination : The seed germinates only when favourable conditions, for growth exists in the environment. In absence of favourable conditions it goes, into a period of suspended growth or rest, called dormancy., Abscission : Shedding of plant organs like leaves, flowers and fruits etc., from the mature plant., Apical dominance : Suppression of the growth of lateral buds in presence, of apical bud., Dormancy : A period of suspended activity and growth usually associated, with low metabolic rate. Some, seeds undergo a period of dormancy and can, germinate only after dormancy period gets over., Phytochrome : A pigment, found in plants which control the light dependent, developmental process., Phytohormone : Chemicals’ secreted by plants in minute quantities which, influence the physiological activities., Senescene : The last phase of growth when metabolic activities decrease., Vernalisation : A method of promoting flowering by exposing the young, plant to low temperature., Growth : An irreversible permanent increase in size, volume and weight of, an organ or its parts or even of an individual., Quiescence : Non germination of a viable seed due to non-availability of, proper environmental conditions., Vivipary : It is the germination of seed while it is still attached to the parent, plant and is nourished by it. e.g., Rhizophora and Sonneratia. As the germinating, seed forms a seedling. It fall down into the mud due to increase in weights. In the, mud, lateral roots develops for anchorage., Heterophylly :Occurrence of more than one type of leaves in plants e.g.,, larkspur, Coriander leaves of Juvenile plant are different in shape from mature, plant., Bolting : Elongation of internodes prior to flowering in plants like Cabbage., Photoperiodism : Response of Plants to relative periods of day/night to, induce flowering., According to duration of exposure of plants to light, plants are divided in, 3 categories :, 1. Long Day Plants (LDP)—Plants which need exposure to light for period, exceeding critical duration e.g., wheat, rice, cucumber., 154, , Biology Class - 11
Page 181 :
2. Short Day Plants (SDP)—Plants that need exposure to light for period less, than the critical length e.g., Cabbage., 3. Day Neutral Plants (DNP)—There is no correlation between exposure to, light duration & induction of flowering e.g., Tomato., Abbreviations, IAA, Indole acetic acid, NAA, Napththalene acetic acid, ABA, Abscisic acid, IBA, Indole-3 butyric acid, 2.4D, 2.4 dichlorophenoxy acetic acid, PGR, Plant growth regulator, , , Seed Dormancy, , Quiescence, , It is the condition of seed when it is , unable to germinate in spite of the, availability of all environmental conditions suitable for germination. , , The condition of a seed when it is, unable to germinate because the, conditions for germination are not, available., , Measurement of growth : Plant growth can be measured by a variety of, ft parameters like increase in fresh weight, dry weight, length, area, volume and, cell number., Phases of growth : The period of growth is generally divided into three, phases, namely, meristematic, elongation and maturation., (i) Meristematic zone : New cell produced by mitotic division at root-tip and, shoot-tip thereby show increase in size. Cells are rich in protoplasm and, nuclei., (ii) Elongation zone : Zone of elongation lies just behind the meristematic zone, and concerned with enlargement of cells., (iii) Maturation zone : The portion lies proximal to the phase of elongation., The cells of this zone attain their maximum size in terms of wall thickning, and protoplasmic modification., Growth rate : The increased growth per unit time is termed as growth rate., The growth rate shows an increase that may be arithmetic or geometrical., Plant Growth and Development, , 155
Page 182 :
Growth, , Mathematical expression, , In Arithmetic growth :, , L1 = L0 + rt, , Curve, Linear curve, , Only one daughter cell continues L1 = Length at time t, to divide mitotically while other, differentiate and matures., , L0 = Length at time zero, r = growth rate, , Lag Phase, , Sigmoid Growth Curve, Geometrical growth, , Formula, , Shape of curve, , The initial growth is, , W1 = W0ert, , Sigmoid or, , slow (lag phase) and increase, , W0 = Initial size, , S-curve, , rapidly there-after at an, , W1 = Final Size, , exponential rate (log phase), , r = growth rate, , In both, the progeny cells divide, , t = time of growth, , mitotically and continue to do so. e = base of natural, However, with limited nutrient, , logarithms, , supply, the growth slow down, leading to stationary phase., , Sigmoid growth curve, Lag phase : Growth is slow in initial stage., Exponential phase : Period of maximum growth, Stationary phase : When the nutrients become limiting, growth slows down., 156, , Biology Class - 11
Page 183 :
Relative Growth : The growth per unit time as percentage of initial size, × 100, , RGR =, , Differentiation : A biochemical or morphological change in meristemic, cell (at root apex and shoot apex) to differentiate into permanent cell is called, differentiation. e.g. loss of protoplasm by tracheary elements., Dedifferentiation : The phenomenon of regeneration of permanent tissue to, become meristematic is called dedifferentiation. eg. formation of interfascicular, crmbium and cork combium from parenchymatous cells., Redifferentiation : Meristems/tissue are able to produces new cells that, once again lose the capacity to divide but nature to perform specific functions., eg secondary cortex, secondary xylem etc., , Conditions or factors influencing Growth, 1. Nutrition 2. Availability of water 3. Temperature 4. Oxygen 5. Light, 6. Gravity 7. Stress factors like minerals, water or temperature etc., Phytohormone or Plant Growth-Regulator, Growth promoting hormones : These are involved in growth promoting, activities such as cell division, cell enlargement, flowering, fruiting and seed, formation. e.g., Auxin, gibberellins, cytokinins., Growth inhibitor : Involved in growth inhibiting activities such as dormancy, and abscission. e.g., Abscisic acid and Ethylene., Hormones, 1. Auxins (Growth Promoters), e.g.Indole 3-Acetic Acid, [2, 4-D and 2, 4, 5,-T etc.], 2. Gibberellins, GA 3 (C19 H 22 O6 , eg. GA 4 , GA 7 , GA19 and , , , GA 20 etc., , Functions, 1. Apical dominance, cell elongation,, Promote flowering prevent premature, leaf and fruit falling, initiate rooting, in stem cutting, as weedicide, induce, parthenocarpy., 2. Delay senescence, speed up malting, process, increase in length of axis, (grape stalk), increase in length of stem, (sugarcane), bolting in beet, cabbages and, many plants with rosette habit., Plant Growth and Development, , 157
Page 184 :
3. Cytokinins (Growth Promoters), e.g. Zeatin (trans 6-purine , DMAA-Dimethylalyl , , , adenine and Isopentyl , , , adenine (IP) etc., , 4. [Ethylene (H2C = CH), A goreous PGR which acts, as Growth Promoters as well, growth inhibitor (mainly as, growth inhibitor), 5. Abscisic acid (ABA), , eg. (Abscisin II Dormin), , , , 3. Promote cell division, induce cell, enlargement, reduce apical dominance,, induce growth in auxiliary bud, chlorophyll, preservation, lateral shoot growth,, adventitious root formation., 4. Promotes senescence and abscission of, leaf and fruits, promotes ripening of fruits,, break seed and bud domancy, initiate, germination in peanut, sprouting of potato, tuber, promotes root growth and root hair, formation., 5. Inhibit seed germination, stimulate closer, of stomata, increase tolerance to various, stress, induce dormancy in seed and bud,, promotes ageing of leaf (senescence)., Can delay the ripening of stored fruits as, it absorbs the ethylene., , Vernalisation : The phenomenon in which flowering is either quantitatively or, qulitatively dependent on exposure to low temperature. eg wheat, barley, rye, biennial plants like sugarbeet cabbage, carrots. It prevents precocious reproductive, development late in the growing season and enables the plant to have sufficient, time to reach maturity, , Questions, Very Short Answer Question, , (1 mark each), , 1. Write the cause of ‘Bakane’ disease of rice., 2. Name the plant hormone which was first isolated from human urine., 3. Name the only gaseous plant hormone., 4. How does abscisic acid acts as stress hormone in drought condition ?, 5. A farmer observed some broad-leaved weeds in a wheat crop farm. Which, plant hormone would you suggest remove them ?, 158, , Biology Class - 11
Page 185 :
6. Name the plant growth regulators you should use to (a) Increase the yield, of sugarcane (b) Promote lateral growth (c) Cause sprouting of potato tuber, (d) Inhibit seed germination., 7. Why do lateral buds start developing into branches when apical bud is, removed ?, 8. Flowering in certain plant occur only when they are exposed to low temperature, for a few weeks. Name this phenomenon., 9. Name, the hormone released from over-ripe apples and affects all other, apples in a small wooden box., , Short Answer Question-I, , (2 marks each), , 10. How will you induce lateral branching in a plant which normally does not, produce them ? Give reason., 11. What induces ethylene formation in plants ? Give any two different action, of ethylene on plants., 12. What is meant by abscission ? Name phytohormone involved in it., 13. What is meant by apical dominance ? Which hormone control it ?, 14. Differentiate between photoperiodism and vernalization., 15. Name a hormone which is :, (a) gaseous in nature (b) responsible for photo tropism (c) used for killing, dicot weeds (d) Induces flowering in long day plants., , Short Answer Questions-II, , (3 marks each), , 16. A primary root grows from 5 cm to 19 cm in a week. Calculate the growth, rate and relative growth over the period., 17. Where are the following hormones synthesised in plants (a) IAA (b), Gibberellins (c) cytokinins., 18. What would be expected to happen if :, (a) GA3 is applied to rice seedling., (b) a rotten fruit get mixed with unripe fruits., (c) you forget to add cytokinin to the culture medium., 19. Which growth hormone is responsible for the following :, (a) induce rooting in a twig, Plant Growth and Development, , 159
Page 186 :
20., 21., 22., 23., , (b), (c), (d), (e), , quick ripening of a fruit, delay leaf senescence, ‘bolt’ a rosette plant, induce immediate stomatal closure in leaves (f) Induce growth in axillary, buds., Define differentiation, dedifferentiation and redifferentiation., Where are auxins generally produced in a plant ? Name any one naturally, occurring plant auxin and any one synthetic auxin., Define growth rate. Name two types of growth. Give the shape of curve for, these growth., Mention various parameters taken into consideration for measuring the, growth., , Long Answer Question , , (5 marks each), , 24. In list the five categories of phytohormone. Write atleast two uses of each., , Answers, Very Short Answer , 1., 2., 3., 4., 5., 6., , 7., 8., 9., , (1 mark each), , Gibberella fujikuroi., Auxin, Ethylene, ABA cause rapid closure of stomata, preventing loss of water by transpiration., 2.4-D, (a) Gibberellin, (b) Cytokinin, (c) Ethylene, (d) Abscisic acid, Due to inhibit activity of Auxin lateral growth starts., Vernalisation, Ethylene, , Short Answers-I, , (2 marks each), , 10. When apical bud is removed, lateral branches are produced. Removal of, apical bud effect the auxin is destroyed inducing the lateral buds to grow, rapidly., 11. Refer NCERT Book Page no. 250., 160, , Biology Class - 11
Page 187 :
12. Premature fall of leaf and fruit is called abscission., , Abscisic acid, , 13. Refer NCERT Boof Page no. 250., 14. Refer NCERT Boof Page no. 252., 15. (a) Ethylene C2H2 (b) Auxin (c) 2, 4-D (d) Gibberellin, , Short Answers-II, , (3 marks each), , 16. (a) Growth = 19 – 5 = 14 cm, Period = 7 days, , , Growth rate =, , = 2cm/day, , (b) Inititial growth =, , cm, , , , Growth rate per day, , , , Relative growth rate =, , = 2 cm, × 100 = 40%, , 17. (a) 1AA = Shoot apex, (b) Gibberellin – young leaves of buds, root tips, (c) Cytokinins – Root apical meristan, 18. (a) Hyper elongation of intenodes of rice seedlings will occur., (b) Unripe fruit s will lead to early ripening and ultimately it will result in, rottening., (c) Short but formation will not occur., 19. Refer NCERT Book., 20. Refer NCERT Text Book Page no. 245., 21. Refer NCERT Text Book Page no. 248., 22. Refer NCERT Text Book Page no. 242 and 243., 23. Refer NCERT Text Book Page no. 241., , Long Answers, , (5 marks each), , 24. Refer NCERT Text Book Page no. 241-250., , Plant Growth and Development, , 161
Page 188 :
Absorption, Points To Remember, Digestion : The process in alimentary canal by which the complex food is, converted mechanically and biochemically into simple substances suitable for, absorption and assimilation in the body of animals/organisms., Food : A substance which is taken and digested in the body to provide, material for growth, repair & energy for reproduction and resistance from disease, or regulation of body processes., Thecodont : The teeth embedded in the sockets of the jaw bone, e.g., in, mammals., Diphyodont : The teeth formed twice in life time e.g., in mammals., Heterodont : Different types of teeth. An adult human has 32 permanent, teeth which are of four different types., Crown, Root, , (for tearing), , (cutting), , (grinding), , (churning & grinding), , Different Types of Teeth, DENTAL FORMULA OF HYMANS, Milk Teeth, I C PM M., 21 2 0, 21 2 0, , 162, , Permanent Teeth, X2 = 20, , Biology Class - 11, , Upper half jaw, Lower half jaw, , 32 = 2x, , I C PM M., 21 2 3, 21 2 3
Page 189 :
Peristalsis : The involuntary moveent of the gut by which the food bolus, is pushed forward., Deglutition : The process of swallowing of food bolus. It is partly voluntary, and partly involuntary., Ruminants : The herbivours animals (e.g., cow, buffalo etc.) which have, symbiotic bacteria in their rumen of their stomach which synthesize enzymes to, hydrolyse cellulose into monosaccharides., Diarrhoea : The abnormal frequent discharge of semisolid or fluid faecal, matter from the bowel., Vomitting : The ejection of stomach contents through the mouth, caused, by antiperistalsis., Dysentery : Frequent watery stools often with blood and mucus and with, pain, fever and causes dehydration., Chyme : The semifluid mass into which food is converted by gastric secretion, and which passes from the stomach into the small intestine., Gastric : Anything associated with stomach is given a prefix ‘gastric’., Proenzyme : The inactive forms of enzymes., Sphincter : A flap like structure at various junctions of the alimentary canal, which facilities one way traffic (movement of material) in the alimentary canal., Bolus : The masticated food mixed with saliva., Hepatic : Anything associated with liver is given a prefix ‘hepatic’., Goblet cells : The cells of intestinal mucosal epithelium which secrete, muscus., Glisson’s capsule : The connective tissue sheath which covers the hepatic, lobules of liver., Hepatic lobules : The structural and functional units of liver containing, hepatic cells which are arranged in the form of cords., Sphincter of Oddi : The sphincter which guard the opening of common, hepatopancretic duct., Villi : The small finger-like folding in the small intestine which increase the, surface area for absorption of digested food., Digestion and Absorption, , 163
Page 190 :
Crypts of Lieberkuhn–pits of intestine, Succus entericus—Intestinal juices., , Basic Steps of Holozoic Nutrition :, (1) Ingestion : Intake of food., (2) Digestion : Breaking down of complex organic food materials into simpler,, smaller water soluble molecules., (3) Absorption and assimilation : Absorption of digested food into blood or, lymph and its use in the body cells for synthesis of complex components., (4) Egestion : Elimination of undigested food as faeces :, , Digestive glands : (A) Salivary gland—3 types are (1) Parotids (cheek), (ii) Sublinguals (Below the tongue) (iii) Submaxillary or submandibular, (lower jaw) Secrete saliva which contains ptyalin (Salivary Amylase)., (B) Pancreas : A dual gland that secretes pancreatic juice and also secretes, Hormones., , Malnutrition—When a person is not getting enough food or getting, unbalanced diet., , 164, , Biology Class - 11
Page 191 :
COMPLETE PROCESS OF DIGESTION, , ABSORPTION OF FATS, •, , Fatty acids and monoglycerides and Glycerol (insoluble)., , •, , Micelles (tiny spheres with hydrophilic ends) formed., , •, , Absorbed by epithelial cells of small intestine (simple diffusioin), , •, , They are reformed into very small protein coated fat globules called chylomicrons., , •, , Chylomicrons transported into lymph vessels (lacteals) in the villi., , •, , Lymph vessels release the absorbed substances into bloodstream, , PEM—Protein Energy Malnutrition, , , Kwashiorkar, , Marasmus, , , The word means ‘rejected child’, Word marasmus means working, away, , It is a disorder found in children, Child remaining under-nourished, 1-5 years of age, where child is suffer from marasmus. Usually, weaned off mother’s milk very early. found in children below the age, of 1 year., , Children get low protein and low, It is caused by deficiency of, carbohydrate diet are affected. protein & carbohydrate & fat., , Digestion and Absorption, , 165
Page 193 :
Symptoms, Kwashiorkar , Marasmus, , 1. Stunted growth, 1. Low body weight, 2. Dry & scaly skin, 2. Wasting of muscles, 3. Odema (retention of water in tissues) 3. Prominent ribs, 4. Match stick lags, 4. Sunken Eyes, 5. Protruted Belly, 5. Lean body with thin limbs, , 6. Mental retardation, , Cure, , Feeding the child with protein rich, diet including milk, soyabean,, egg etc. , , , Child should be given protein, diet with enough quantity of, carbohydrates & fats., , Calorific Value : Amount of heat energy released by 1 gm of substrate after, complete Oxidation., Calorific value of Carbohydrates is 4.1 k.cal/g = 17.1 kj/g, Protein is 5.6 kcal/g = 23.4 kj/gm, Fats is 9.4 kcal/g (app.) = 39.2 kj/gm, , Questions, Very Short Answer Questions, , (1 mark each), , 1. What do you mean by the term malnutrition ?, 2. Name the hardest substance in the body., 3. What is a lacteal and what is its function ?, 4. Name the small projections, found on the upper surface of tongue., 5. Mention the function of epiglottis., 6. Write the names of major parts of stomach., 7. Name the enzyme that digest fats. Mention the end products of fat digestion., 8. In which part of alimentary canal absorption of water, simple sugars and, alcohol takes place ?, 9. Why are proteases generally released in inactive form ?, Digestion and Absorption, , 167
Page 194 :
10. Trypsinogen is an inactive enzyme of pancreatic juice. An enzyme,, enterokinase, activates it. Which tissue/cell secrete this enzyme ? How is it, activated ?, 11. What is the role of insulin ?, 12. Name any one country where children affected from PEM are found more., , Short Answer Questions-I , , (2 marks each), , 13. What is emulsification ? Where and how does it occur ?, 14. Name three parts of large intestine. Which vestigial organ arises from the, first part of it ?, 15. Name the digestive gland which acts as exocrine and endocrine. Also name, the products which are secreted by it., 16. The wall of alimentary canal is made up of four layers. Give the names of, these four layers., 17. Hydrochloric acid is found in our stomach. What purpose does it serve in, alimentary canal ?, 18. In which part of the digestive system the absorption of following substances, takes place ?, (a) Certain drugs, (b) Glucose, fructose and fatty acids, (c) Water, some minerals and drugs, (d) Simple sugar and alcohol, 19. Differentiate between chylomicron and micelles., , Short Answer Question-II , , (3 mark each), , 20. In the following diagram of duct system of liver, gallbladder and pancreas, label, a, b, c, d, e and f :, , 168, , Biology Class - 11
Page 195 :
21. Give a diagrammatic representation of transverse section of gut., 22. Draw the sketch of anatomical regions of human stomach and label any four, parts in it., 23. How does the nervous system control the activities of gastro-in-testinal, tract ?, 24. Draw a labelled figure of digestive system of human., 25. Give a summary of cause and symptoms of following disorders of digestive, system :, (a) Jaundice, (b) Vomiting, (c) Diarrhoea, (d) Constipation, (e) Indigestion, , Answers, Very Short Answer, , (1 mark each), , 1. The state of health due to improper intake of food or nutrients. It covers both, under nutrition as well as over nutrition., 2. Enamel, 3. Lymph vessel found in villi. They help in absorption of fat globules and then, release them into blood stream., 4. Papillae. Some Papillae have taste buds., 5. Prevent the entry of food into the glottis., 6. Cardiac, fundic, pyloric., 7. Lipase, fatty acids and glycerol., 8. Stomach, 9. If released in active form, they will start digesting the membrances and, muscular walls of the alimentary canal., 10. Intestinal Mucosa., , , (In active) , , (Active), , 11. Metabolism of sugar., 12. African countries– Somalia & others., Digestion and Absorption, , 169
Page 196 :
Short Answer Questions–I , , (2 marks each), , 13. The process of breakdown of large fat droplets into smaller ones. It occurs, in duodenum of small intestine. It is brought about by bile salts through, reduction of surface tension of large fat droplets., 14. Caecum, colon and rectum. Vermiform appendix., 15. Pancreas. Exocrine secretion is pancreatic juice containing enzymes and, endocrirne secretions are hormones : Insulin and glucagon., 16. Serosa, muscularis, submucosa and mucosa., 17. (i) Killing of germs present in food, (ii) Conversion of inactive pepsinogen into active form pepsin., 18. (a) Mouth, (b) Small intestine, (c) Large intestine, (d) Stomach, 19. , , 1., , , 2., , , Chylomicron, , Micelles, , Protein coated water soluble, fat droplets released into the, lymph., In this form fats lipids are put, into circulation, , Formed by combination of fatty acid,, monoglycerides and bile salts., , Short Answers Questions–II, , (3 marks each), , In this form digested fats are absorbed, in intestinal cells in alimentary canal., , 19. Refer Fig. 16.6, Page no. 261 (NCERT Text Book, XI Biology)., 20. Refer Fig. 16.4, Page no. 260 (NCERT Text Book, XI Biology)., 21. Refer Fig. 16.3, Page no. 259 (NCERT Text Book, XI Biology)., 22. Refer page. 264 (NCERT Text Book, XI Biology)., , Long Answers, , (5 marks each), , 23. Refer Fig. 16.1, Page no. 258 (NCERT Text Book, Class XI Biology)., 24. Refer Page no. 265-266 (NCERT Text Book, Class XI Biology)., , , 170, , Biology Class - 11
Page 197 :
Points To Remember, Breathing : (External respiration) The process of exchange of O2 from the, atmosphere with CO2 produced by the cells., Carbamino haemoglobin : Compound formed in RBCs when CO2 combine, with haemoglobin., Inspiration : Oxygen from fresh air taken by lungs and diffused into the blood., Expiration : CO2 given up by venous blood in the lungs is sent out to exterior., Respiration : The sum total of physical and chemical processes by which, oxygen and carbohydrates (main food nutrient) etc are assimilated into the system, and the oxidation products like carbon dioxide and water are given off., Diaphragm : A muscular, membranous partition separating the thoracic, cavity from the abdominal cavity., Hypoxia—Shortage of oxygen in tissues., Partial Pressure—The pressure contributed by an individual gas in a mixture, of gases. It is represented as pO2 for oxygen and pCO2 for carbondioxide., Pharynx : The tube or cavity which connects the mouth and nasal passages, with oesophagus. It has three parts (i) Nasopharynx (anterior part) (ii) Oropharynx, (middle part) and (iii) Laryngopharynx (posterior part which continues to larynx), Adam’s Apple : The projection formed by the thyroid cartilage and surrounds, the larynx at the front of the neck., Tidal volume (TV) : Volume of air taken in/given out during normal, respiration (500 mL.), Inspiratory Reserve Volume (IRV) : Additional volume of air inspired by, a forcible inspiration. 2500mL to 3000mL., Expiratory Reserve Volume (ERV) : Additional volume of air, a person, can expire by a forcible expiration., Residual volume (RV) : Volume of air remaining in the lungs even after a, forcible expiration (1100 mL to 1200 mL), Breathing and Exchange of Gases, , 171
Page 198 :
PULMONARY CAPACITIES : Use in clinical diagnosis., Inspiratory capacity (IC) = (TV + IRV) Total volume of air a person can, inspire after a normal expiration., Expiratory Capacity—Total Volume of air a parson can expire after a normal, inspiration E.C. = TV + ERV, Functional Residual Capacity—Volume of air that will remain in lungs, after a normal expiration (FRC) = (ERV + RV), Vital Capacity (VC) = (ERV + TV + IRV) or the maximum volume of air, a person can breath out after a forced inspiration., Total Lung Capacity : It includes RV, ERV, TV and IRV or vital capacity, + residual volume., Pulmonary—Anything associated with the lungs is given the prefix, ‘pulmonary’ steps involved in respiration—, (i) Breathing or pulmonary ventilation (intake or atmospheric air and releasing, out CO2 rich alveolar air), (ii) Diffusion of gases (O2 and CO2) across alveolar membrane & blood vessel, (capillaries)., (iii) Transport of gases by the blood., (iv) Diffusion of O2 and CO2 between blood and tissues., (v) Utilisation of O2 by the cells for catabolic reactions and resultant release of, CO2., , 172, , Biology Class - 11
Page 199 :
Mechanism of Breathing, , , , Inspiration, , Expiration, , , Contraction of diaphragm and external, intercostal muscles, , ↓, , Increase in the volume of thoracic, chamber, , ↓, Lungs expand, , ↓, Pressure inside the lungs fall, , ↓, Air rushes into lungs from Atmosphere, , , , Relaxation of diaphragm and sternum, ↓, Decrease in the volume of thoracic, chamber, ↓, Lungs contract, ↓, Pressure inside the lungs increase, ↓, Air rushes out from lungs in, to Atmosphere, , Respiratory Tract :, , , A pair of external nostrils → nasal chamber through nasal passage →, pharynx → glottis → larynx → trachea → Left and right primary bronchi, → secondary and tertiary bronchi → bronchioles → vascularised bag like, structures (alveoli) or air-sacs. Each lung is covered with double layered, membrane known as pleura with pleural fluid between them., , Respiratory organs in animals :, , (i) Protozoans, annelids Frogs—Body surface, Breathing and Exchange of Gases, , 173
Page 200 :
(ii) Fishes, tadpole stage of frog and many other aquatic animals—Gills (Branchial, Respiration), (iii) Insects and a few other arthropods—Tracheal tubes, (iv) All land vertebrates (amphibians, reptiles, aves and mammal)—Lungs., (Pulmonary Respiration), , Conditions required for (cutaneous respiration), Skin should be moist and thin. It should be highly vascularised., , Physiology of Respiration :, , (a) Exchange of gases—Diffusion of gases takes place from the region of higher, partial pressure to lower (lesser) partial pressure), (i) pO2 in alveolar air = 104 mm Hg., (ii) pO2 in venous blood = 40 mm Hg., , O2 diffuses from alveoli to venous blood., (iii) pCO2 in venous blood = 45 mm Hg., , pCO2 in alveolar air = 40 mm Hg., , CO2 diffuses from venous blood to alveoli, Inspired air, , Expired air, , Alveolar air, PO2 = 104 mm Hg, , Alveolus, , PCO2 = 40 mm Hg, CO2 O2, Pulmonary, artery, , CO2, , O2, , Systemic veins, Carrying, deoxygenated, blood, , Systemic arteries, (carrying oxygenated), blood, PO2 = 95 mmHg, , PO2 = 40 mmHg, PCO2 = 45 mmHg, , CO2, , O2, , Body tissue, , 174, , Biology Class - 11, , Pulmonary, vein, , PCO2 = 40 mmHg
Page 202 :
• Increase in them activates this centre, which in turn signal the rhythm centre, to make necessary adjustments and respiratory process by which these, substances can be eliminated., , Disorders of Respiratory System, • Emphysema– chronic disorder in which alveolar walls damaged due to, cigarette smoking, • Asthma–difficulty in breathing due to inflammation of brounchi or bronchioles,, • Occupational disorders– people working in stone grinding or breaking, industries, the dust produced damage the defence system of body leading, to servere lung damage., , Questions, Very Short Answer Questions , , (1 mark each), , 1. Name the organ in human respiratory system which produces sound., 2. How many oxygen molecules can be carried out by one haemoglobin, molecule., 3. Give the name and function of a fluid filled double membranous layer which, surrounds the lungs., 4. Which organ of our respiratory system acts as primary site of exchange of, gases ?, 5. Cigarette smoking causes emphysema. Give reason., 6. Name the principle or process of exchange of gases., 7. What is the role of oxyhaemoglobin after releasing molecular oxygen in the, tissues ?, 8. Name the muscles which facilitate breathing., 9. How is the entry of food prevented in the respiratory tract ?, 10. About 97% of O2 is transported by RBCs in the blood. How does the remaining, 3% of O2 transported ?, , Short Answer Questions, , (2 marks each), , 11. Draw a labelled diagram of a section of an alveolus with a pulmonary, capillary., 12. Following is the table showing partial pressure (in mm Hg) of oxygen and, carbondioxide) at different parts involved in diffusion in comparison to those, in atmosphere. Fill in the blank – a, b, c and d., 176, , Biology Class - 11
Page 203 :
Respiratory Atmospheric Alveoli, gases, air , O2, CO2, , (a), 0.3, , Blood, Blood, (Deoxygenated) (Oxygenated), , 104, (b), , 40, (c), , (d), 40, , Tissue, 40, 45, , 13. Name the organs of respiration in the organisms., (a) Flatworms, , (b) Birds, , (c) Frog, , (d) Cockroach, , 14. What are occupational respiratory disorders ? What are their harmful effects, ? What precautions should a person take to prevent such disorders ?, 15. How is respiration different from breathing ?, , Short Answer Questions-II, , (3 marks each), , 16. Explain the role of neural system in regulation of respiration is human., 17. Explain the neural control of respiration in human., , Long Answer Questions, , (5 marks each), , 18. With the help of labelled diagram explain the structure of human respiratory, system., 19. Explain the mechanism of breathing with the help of labelled diagram, involving both stages—inspiration and expiration., 20. Explain the process of exchange of gases with the help of a diagrammatic, representation in human respiratory system., , Breathing and Exchange of Gases, , 177
Page 204 :
Answers, , Very Short Answers , , (1 mark each), , 1. Larynx (Sound box), 2. Four molecules of O2., 3. Pleura. It reduces the friction and the two pleura together and the protect, the lungs., 4. Alveoli of lungs., 5. Cigarette smoking damages alveolar walls due to alveolar sacs remaining, filled with air leading to decreased respiratory surface for exchange of gases., 6. Diffusion., 7. Amino group of reduced haemoglobin combines with CO2 forming, carbaminohaemoglobin to transport CO2., 8. External and internal intercostals muscles, situated between ribs., 9. During swallowing a cartilaginous flap like structure called epiglottis covers, the glottis and prevents the entry of food into respiratory tract., 10. In simple solution form through plasma., , Short Answers-I, , (2 marks each), , 11. Refer fig 17.4, page 273 (NCERT Text Book Class XI Biology), 12. Refer fig 17.1, page 272 (NCERT Text Book Class XI Biology), 13. (a) Body surface (b) lungs (c) skin and lungs (d) Network of trachea, 14. Refer Topic 27.6 at page 275 (NCERT Text Book Class XI Biology), 15. Slow oxidation of food to release energy is called respiration while breathing, is a biophysical process which is the first step of respiration., 178, , Biology Class - 11
Page 205 :
Short Answers-II, , (3 marks each), , 16. Refer page 275 (17.5) (NCERT Text Book Class XI Biology), 17. Refer content 17.5 regulation of respiration on page no. 275 (NCERT Text, book XI Biology), , Long Answers-II, , (5 marks each), , 18. Refer content 17.1.1 page 29, diagrams 17.1, page 29 (NCERT Text Book, Class XI Biology), 19. Refer content 17.2 and fig 17.2 page 270–271 (NCERT Text Book Class XI, Biology), 20. Refer content 17.3 and fig 17.3 page 272–273 (NCERT Text Book Class XI, Biology), , , Breathing and Exchange of Gases, , 179
Page 206 :
Points To Remember, Blood : A special connective tissue that circulates in principal vascular, system of man and other vertebrates consisting of fluid matrix, plasma and formed, elements (Blood = Plasma + All blood cells)., Plasma : (Blood – All blood cells = Plasma) The liquid part of blood which, is straw coloured, viscous fluid and contains about 90-92% of water and 6-8%, proteins., Lymph : A clear yellowish, slightly alkaline, coagulable tissue fluid,, containing white blood cells (Only lymphocytes), a liquid resembling blood, plasma., Serum : Blood plasma from which fibrinogen and other clotting factors, have been removed. (Plasma– (fibrinogen & other clotting factor) = blood serum., Heart Beat : The rhythmic contraction and relaxation of the heart, which, includes one systole (contraction phase) and one diastole (relaxation phase) of, the heart. Heart beat count of healthy person is 72 times per minute., Stroke Volume : The volume of blood pumped out by the heart during a, systole. If is approximately 70 ml., Cardiac output : The amount of blood pumped by heart per minute is called, cardiac or heart output. The value of cardiac output of a normal person is about, 72 × 70 = 5040 mL or about 5L per minutes., Cardiac Cycle : The rhythmic contraction and dilation of different parts of, heart in one beat., Systole : Contraction of heart muscles., Diastole : Relaxation of heart muscles, 180, , Biology Class - 11
Page 207 :
TYPES OF BLOOD CELLS THEIR NUMBER, STRUCTURE & FUNCTIONS, Name and Number/, Structure, Percentage , , Life Span and, Formation, , Function, , (A) Erythrocytes RBCs Red colour, , Formed from birth, , Transport of oxygen, , - 4.5 to 5.5 million, , Circular, biconcave, , onward by red bone, , and some amount, , per cubic millimetre of, , denucleated, elastic, , marrow Life-120 days of carbon dioxide, , blood, , lack of cell organelles excess RBCs are, like ER, ribosomes,, , through haemoglobin, , stored in spleen, , mitochondria etc., (B) Leucocytes, , Colourless rounded, , Formed in red bone, , Acts as soldiers, , (WBCs) 5000-8000, , or irregular,, , marrow, Lymph, , scavenger and some, , per cubic mm of, , nucleated 12 to, , nodes, spleen and, , help in healing, , blood, , 20mm wide, life 1-4, , thymus, , days, (i) Agranulocytes, , Large rounded, , Lymph nodes,, , Non Phagocytic, , (a) Lymphocytes 20-45% nucleus, 6-10 mm, , spleen, thymus red, , secrete antibodies, , of leucocytes , , bone marrow, life few, , , , days to months or, , , , even years, , (b) Monocytes 6-8% of, , Largest of all (12-15, , Red Bone marrow,, , phagocytic, very, , leucocytes,, , mm) bean shaped, , life 10-20 hours, , motiles engulf, , nucleus , , germs, , (a) Eosinophils 2-3%, , bilobed nucleus,, , play role in immunity, , of leucocytes, , granules in cytoplasm life 4 to 8 hrs. in, , (ii) Granulocytes, Red Bone marrow,, , non phagocytic, , blood, (b) Basophils 0-5% of, , Three lobed nucleus, , Red Bone marrow,, , release heparin and, , leucocytes, , (s-shaped), , life 4 to 8 hours in, , histamine, , blood, (c) Neutrophils 60-65%, , Many lobed nucleus, , Red Bone marrow,, , phogocytic, engulf, , of leucocytes, , fine granules, , life 4 to 8 hours in, , germ and dead cells, , blood, (C) Platelets, , Colourless, rounded, , Red Bone marrow, , thrombocytes, , or oval, or irregular, , worn out ones, , 1,50,000-3,50,000 per, , non-nucleated, , phagocytized in blood, , cubic mm of blood, , fragments, , help in blood clotting, , Body Fluids and Circulation, , 181
Page 208 :
Blood Pressure—The resistance offered by the lumen of the artery to the, flow of Blood., Hypertension : The condition when blood pressure is higher than normal, (120/80 mmHg), Electrocardiograph : (ECG) the machine used to record electrocardiogram., Electrocardiogram ECG : The print out of pattern of heart beat taken on, a graph paper from Electrocardiograph. (ECG machine), , Lymph, The colourless mobile fluid connective tissue drains into the lymphatic, capillaries from the intercellular spaces. It is formed by squeezing of blood through, capillaries, within tissues. Its flow is unidirectional i.e., from tissues to heart., Composition : It is composed of fluid matrix, plasma having only lymphocytes, of white blood corpuscles or leucocytes., Functions : (i) It drains excess of tissue fluid from extra cellular spaces, back into the blood., (ii) It contain lymphocytes and antibodies., (iii) It transport digested fats., , Blood Clotting :, , Coagulation of Blood :, Injured Tissue, Blood Platelets, Releases, Disintegrate, ↓, and release ↓, Thromboplastins, Platelet thromboplastin, Ca++ Proteins, Ca+ Proteins, , ↓ ↓, Thrombokinase, , Inactivates heparin and, catalyses, Ca++, Thrombin, Prothrombin, , ↓ Catalyses, Fibrin, Fibrinogen, Clot or Coagulum), (Fibrin + Blood cells, 182, , Biology Class - 11
Page 209 :
Functions of Blood, Transport, of food, respiratory gases (O2 and CO2), hormones, metabolic, intermediates, waste products, supply of raw materials, regulation of water balance,, regulation of pH and body temperature, and provides immunity., , Blood Groups : Based on presence of Antigens and Antibodies in blood., Blood Antigen (on Anti body : (in Possible recipients, Group the Surface, plasma), having blood group, , of R.B.Cs) , , Possible donors Remarks, having blood, group, , A, , A, , Anti B, , A, AB, , O, A, , —, , B, , B, , Anti A, , B, AB, , O, B,, , —, , AB, A and B, None, AB, O, A, B, AB, , , , Universal, recipient, , O, None, , , Universal, Donor, , Anti A and, O, A, B, AB, O, Anti B , , Rh (Rhesus) Group :, • Rh positive (Rh + ve) – Rh antigen similar one present in rhesus monkey., Observed on the surface of RBCs (nearly 80% of humans), • Rh negative (Rh–ve) – those in whom this antigen is absent., • Compatibility is crucial during transfusion and pregnancy as if Rh -ve person, exposed to Rh +ve blood forms specific antibodies against Rh antigens., Rh incompatibility in pregnancey, 1st PREGNANCY, Rh+ve (Father), First newborn Rh +ve (safe), No mixing of two bloods due to placenta, Rh-ve (Mother) Foetal maternal blood mixes during delivery But mother (Rh-ve) prepare, Rh+ve (Foetus), antibodies, against Rh factor, , 2nd PREGNANCY, , , Rh+ve (Father), Antibodies leak into the blood of foetus Destroy foetal RBCs, Rh-ve (Mother), Leads to erythroblastosis foetalis, Rh+ve (Foetus), , Body Fluids and Circulation, , 183
Page 210 :
→ SAN (Sino-atrial node) : A patch of tissues present in the right upper, corner of the right atrium, acts are pacemaker due to having a unique property, of self excitation., → AVN (Atrio Ventricular Node) : A mass of tissues seen in the lower, left corner of the right atrium close to the atrio-ventricular septum. Fresh wave of, contraction generated here, passes over both the ventricles simultaneously along, the bundle of HIS., , Human Heart, , Human Heart, , , , , , , , , , It is the mesodermally derived organ situated in thoracic cavity in between, the two lungs. Protected by a double membrane covering called Pericardium., Four chambers–two (left and right) atria, and two ventricels (left and right), Inner-artrial septum separates the two atria and inter ventricular septum, separates the two ventricles, while the atria and ventricles are separated by, atrioventricular septum., The valves between right atrium and right ventricle is tricuspid while between, left atrium and ventricle is bicuspid or mitral value., The opening of the right ventricle into the pulmonary artery and the opening, of left ventricle in to aorta are guarded by semilunar values., , 184, , Biology Class - 11
Page 211 :
, , The valves allow the flow of blood only in one direction, i.e., from atria to, ventricles and from ventricles to pulmonary artery or aorta., , Heart Valves, Tricuspid Valve : The valves formed of three muscular flaps or cups, which, guard the opening between the right atrium and the right ventricle., Bicuspid Valve (Mitral Valve) : The valves which guard the opening, between the left atrium and the left ventricle, made up of two flaps., Semilunar Valves : The valves present at the opening of the right and the, left ventricles and allow the entry of blood into pulmonary artery and the aorta, respectively., Standard ECG and Reading of ECG : ‘P’ Wave represents the electrical, excitation (or depolarisation) of the atria and leads to the contraction of both the, atria., Electrocardiogram ECG : The graphic record of the electric current, produced by the excitation of the cardiac muscles. It is composed of a ‘P’ wave,, ‘QRS’ wave. (complex) and ‘T’ wave (for a standard ECG) (Refer fig. 18.3, page, 286 (NCERT class XI Biology), , Diagrammatic presentation of a standard ECG., , ‘QRS’ complex : represents the depolarisation of the ventricles, which, initiates the ventricular contraction., ‘T’ Wave : represents the return of the ventricles from excited to normal, state (repolarisation). The end of T-wave marks the end of sytole., , Double circulation :, Right, Ventricle, , Deoxygenated, Blood, , Lungs, Pulmonary Circulation, , Right, Auricle, , Deoxygenated, Blood, , Systemic circulation, Body, (Except Lungs, , Oxygenated, Blood, , Left, Auricle, , Oxygenated, Blood, , Body Fluids and Circulation, , Left, Ventricle, , 185
Page 212 :
CARDIAC CYCLE : The rhythmic contraction and dilation of different parts, of heart in one beat., Systole : contraction of heart muscles., Diastole : relaxation of heart muscles., q Joint diastole :-All chambers of heart in relaxed state., , , •, , •, , q, , Tricuspid and bicuspid valves– open, Blood from pulmonary vein and vena cava flows into left and, right atrium respectively., , Atrial systole :- contraction of atrias, , • SAN generates action potential to stimulate atrias to contract, simultaneously, , q, , •, , Blood flows to respective ventricles, , Ventricular systole : contraction of ventricles, , •, , , AV node and AV bundle conduct the wave of contraction to the, ventricles via bundle of HIS., , •, , , Ventricles contract as a closed chamber (as AV valves and, semilunar valves are close)., , , •, , , Pressure of blood opens the semilunar valves and blood flows to, respective arteries., , q, , Joint diastole : Relaxation of all chambers., , HEART SOUNDS, • Closure of bicuspid and tricuspid valves produces first heart sound, ‘lub’, •, , Closure of semilunar valves produces second heart sound ‘dub’, , Disorders of circulatory System, Hypertension (High blood Pressure) : It results from narrowing of arterial, lumen and reduced elasticity of arterial walls in old age. It can cause rupturing of, capillaries. It is a silent killer., Coronary Artery Disease : (CAD) Atherosclerosis. The supply of the blood, to heart muscles is affected. It is “caused by deposits of Calcium, fat, cholesterol, and fibrous tissues to make the lumen of arteries narrower., Angina Pectoris : Caused due to arteriosclerosis, when no enough oxygen, is reaching the heart muscle due to which the person experiences acute chest pain., 186, , Biology Class - 11
Page 213 :
Heart attack : Caused when the heart muscle is suddenly damaged by an, inadequate blood supply., Cardiac arrest : The state in which the heart stops beating., Arteriosclerosis : The state of hardening of arteries and arterioles due, to thickening of the fibrous tissue and consequent loss of elasticity. It causes, hypertension., , Questions, Very Short Answer Questions, , (1 mark each), , 1. Name the instrument used for measuring blood pressure., 2. What is lymph node ?, 3. A cardiologist observed an enlarged QRS wave in the ECG of a patient., What does it indicate ?, 4. Name the enzyme that catalyses the formation of carbonic acid in erythrocytes., 5. What is systemic circulation ?, 6. Give two examples of extra-cellular fluids., 7. What name is given to the blood vessels which generally bring blood to an, organ ?, 8. Which adrenal hormone accelerates heart beat under normal conditions ?, 9. Name the blood vessel that carries blood from the intestine to liver., 10. Define cardiac cycle., 11. Name the protein found in RBCs., 12. What happens to a person suffering from hemophilia ?, , Short Answer Questions-I, , (2 marks each), , 13. Explain when and how the two sounds of heart are produced., 14. Define joint diastole. What are constituents of the conducting system of, human heart ?, 15. Give the names of various types of formed elements present in the blood., Body Fluids and Circulation, , 187
Page 214 :
Short Answer Questions-II, , (3 marks each), , 16. Draw a diagram showing schematic plan of blood circulation in human., 17. Why is the SA node called pacemaker of the heart ? Write its full from., 18. In the following diagram of section of a human heart, label a, b, c, d, e, and f., , 19. What is lymph ? Describe its circulation in brief., 20. What is stroke volume ? What is its relation with cardiac output ?, 21. A person suffering from fever is advised to take blood test. What may happen, to his WBC count and why ?, , Long Answer Questions, , (5 marks each), , 22. Neena is having blood group A-ve while her husband’s blood group is O +ve., Their first child is having blood gp. A +ve. Her second child was born with, severe anemia and jaundice. What could be the reason ? How this situation, could have been avoided ?, 23. Draw a diagram to show the internal structure of human heart. Lable any, two heart chambers, any two heart valves and chordae tendinae in it., 24. Describe the structure of human heart., 25. What is cardiac cycle ? Describe the event that occur during it., 26. Explain Rh grouping and its incompatibility in humans., 188, , Biology Class - 11
Page 215 :
Answers, Very Short Answer , , (1 mark each), , 1. Sphygmomanometer., 2. A lymph node is speicalised structure in lymphatic vessel concerned with, the filtration of foreign bodies by the lymphocytes., 3. QRS waves denotes ventricular contraction of heart which may be normal, or abnormal., 4. Carbonic anhydrase., 5. The kind of blood circulation that is concerned with the supply of oxygenated, blood from the left ventrice to all body parts and return of oxygenated blood, to the right atrium of heart., 6. Interstitial fluid and blood plasma., 7. Afferent blood vessel., 8. Noradrenalin., 9. Hepatic portal vein., 10. A regular sequence of three events (i) auricular systole (ii) ventricular systole, and (iii) Joint diastole during the completion of one heart beat., 11. Haemoglobin., 12. The person suffering from haemophilia lacks clotting factors in blood, which, result the defective clotting mechanism. In case of injury the person is at a, risk of blood loss., , Short Answer-I , , (2 mark each), , 13. (i) ‘Lubb’ the first sound which is low pitched, is caused by the closure of, bicuspid and tricuspid valves., (ii) ‘Dub’ the second sound which is high pitched, is caused by the closure, or semilunar valves., 14. In a cardiac cycle when both atria and ventricles are in a diastole and are, relaxed simultaneously is called a joint diastole., Conducting system constitutes : SA node → AV node → Bundle of His →, Purkinje fibres., Body Fluids and Circulation, , 189
Page 216 :
15. Erythrocytes, lymphocytes, monocytes, neutrophils, eosinophils, basophils, and platelets., 16. SA node being self excitatory initiate a wave of contraction in the heart., SA node — Sino–Atrial Node., , Short Answer-II, , (3 marks each), , 17. Refer fig. 18.4, page 287 (NCERT Text Book Class XI-Biology), 18. Refer fig. 18.2, page 283 (NCERT Text Book Class XI-Biology), 19. Refer content fig. 18.2, page 282 (NCERT Text Book Class XI-Biology), 20. During one cardiac cycle or one heart beat the volume of blood pumped by, the heart is called stroke volume. This is normally 70 mL., In one minute the heart beats about 72 times and the amount of blood pumped, per minute is called cardiac output. This is usually 4900 mL. or 5 litres., 21. The WBC count of this person may show an increase from the normal range., As pathogens may be present in his body, so the body is producing more, WBCs to fight against those pathogens. WBC count is a good tool to asses, the presence of infection in a sick person., , Long Answer , , (5 marks each), , 22. During her first pregnancy after exposure with blood of her first Rh +ve, child, her body prepared antibodies against Rh antigen in her blood. In second, pregnancy these Rh antibodies from mother leaked into the blood of foetus, (Rh +ve) and destroyed foetus RBCs. It could cause of severe anemia and, Jaundice could be fetal to the foetus., This situation could have been avoided if she had got herself administered, anti; Rh antibodies immediately after first delivery to kill Rh antibodies, entered in mother’s blood from foetus., 23. Refer fig. 18.2, page 283 (NCERT Text Book Class XI-Biology), 24. Refer content 18.3.1., page 283 (NCERT Text Book Class XI-Biology), 25. Refer content 18.3.2., page 284 (NCERT Text Book Class XI-Biology), 26. Refer content 18.3.2., page 281 (NCERT Text Book Class XI-Biology), , 190, , Biology Class - 11
Page 217 :
Points To Remember, Ammonotelism :, , EXCRETION, (On the basis of type of excreatory end products), , Ammonotelism, • Excretion of ammonia, • Bony Fishes, Aquatic, Amphibians & Aquatic, Insects., , Ureotelism, Uricotelism, • Excretion of urea, • Excretion of Uric acid, • Mammals, Many, • Mammals, Many, Mammals, Many Terrestrial, Terrestrial Amphibians, Reptiles, Birds & Insects, & Marine Fishes, , Nephrons :, The structural and functional unit of kidneys. Each kidney contains about, one million of nephrons., , Structure of Nephron :, A nephron consists of Glomerulus, Bowman’s capsule, PCT (Proximal, Convoluted Tubule). JG A (Juxtaglomerular Apparatus), DCT (Distal Convoluted, Tubule) and the collecting duct. (Refer fig., 19.3, page 292 (NCERT Text Book, of Biology for Class XI), , Structure of Kidney :, , Size 10-12 cm in length, 5-7 cm in width, 2-3 cm thick, average weight, about 120-170 g., The blood vessels, ureter and nerves enter in the kidney through hilum, (a notch)., The outer layer of kidney is a tough capsule., The outer zone of kidney is cortex and the inner is medulla., The medulla is divided into few conical masses (medullary pyramids), projecting into calyces., The cortex extends between medullary pyramids called columns of Bertini., Refer figure 19.2, page 292 (NCERT—Class XI Biology), Excretory Products and their Elimination, , 191
Page 218 :
Glomerular Filtration :, The filtration of blood in glomerulus, about 1100-1200 ml of blood is filtered, by the kidney per minute., , Glomerular Filtration Rate (GFR) :, The amount of filtrate formed by the kidney per minute is called GFR. In a, healthy individual it is about, 125 ml/minute, i.e. 180 litres per day., , Types of Nephrons :, (i) Juxtamedullary Nephron—About 15% of total nephrons, Glomeruli are, found in inner region of cortex, large in size, long loop of Henle and found, deep in medulla, associated with vasa recta control plasma volume when, water supply is short., (ii) Cortical Nephron—About 85% of total nephron mainly lie in renal cortex,, glomeruli found in outer cortex, short loop of Henle, extends very little in, medulla. They do not have vasa recta or vasa recta is highly reduced., , Functions of Tubules :, (i) PCT—absorption of all essential nutrients and 70-80% of electrolytes and, water, helps to maintain the pH and ionic balance of body fluids by selective, secretion of H+, ammonia and K+ into filtrate., (ii) Henele’s Loop—reabsorption in this segment is minimum, it plays a, significant role in maintenance of higher molarity of medullary interstitial, fluid., (iii) DCT—conditional reabsorption of Na+ and water takes place here,, reabsorption of HCO3– and selective secretion of H+ and K+ and ammonia, to maintain the pH and sodium-potassium balance in blood., (iv) Collecting duct—Large amount of water is absorbed from this region to, produce concentrated urine, it plays a role in maintenance of pH and ionic, balance of blood by selective secretion of H+ and K+ ions., , Steps of Urine Formation, 1. Glomerular Filtration—Blood is filtered by glomerulus through three, membranes i.e., endothelium of blood vessel, filtration slits of Bowman’s, capsule and basement membrane between these two layers. This filtration is, called ultrafiltration as all constituents of plasma comes into filterate except, proteins., 192, , Biology Class - 11
Page 219 :
2. Reabsorption—90% of filtrate is reabsorbed by the renal tubules by active, or passive mechanism., It is evident by the fact that out of 180L of filtrate formed per day only 1.5, L of urine released., 3. Secretion—Tubular cells secrete H+, K+, ammonia into the urine. It maintains, acid-base balance of body fluids., , Mechanism of concentration of the Filtrate (Countercurrent Mechanism) :, Refer fig 19.6 page 296 (NCERT-Class XI Biology), This mechanism is said to be countercurrent mechanism because the out, flow (in the ascending limb) runs parallel to and in the opposite direction of, the inflow (in the descending limb)., NaCl is transported by the ascending limb of Henle’s loop which is exchanged, with the descending limb of vasa-recta., NaCl is returned to the interstitium by the ascending portion of vasa recta., Henle’s loop and vasarecta as well as the counter current in them help to, maintain an increasing osmolality towards the inner medullary interstitium, i.e., from 300 mosmol/L in cortex to about 1200 mosmol/L in inner medulla., Small amount of urea enter, the thin segment of ascending limb of Henle’s, loop which is transported back to the interstitium by the collecting tubule., This mechanism helps to maintain a concentration gradient in the medullary, tubule interstitium., It helps in an easy passage of water from the collecting tubule to concentrate, the filtrate i.e. urine., ADH (ANTIDIURETICHORMONE), (VASOPRESSIN), , Decrease in body fluid volume, , Increase in body fluid volume, , Activation of osmoreceptors, , Switch off the osmoreceptors, , Stimulation of hypothalamus., , Signal to hypothalamus, , Release of ADH (from posterior pituitary gland), , Supress the ADH release, , Facilitates water reabsorption from DCT., , Reduce water reabsorption, , Prevent Diuresis, (Excessive loss of water from body, , Excretory Products and their Elimination, , 193
Page 220 :
Renin Angiotensin System, , , Fall in GFR, , , , ↓ Renin from JG cells, Angiotensinogen → Angiotensin I → Angiotensin II, , , , ↓ Acts on, , , , Adrenal Cortex, , , , ↓ Secretes aldosterone, , , , , Reabsorption of Na+ and water, from DCT, , , , ↓, , , , Increase in GFR, , Atrial natriuretic factor (ANF), • Increase in blood flow to Atria of heart release of ANS, • Causes vasodilation and does decrease blood pressure, • ANF acts as a check on renin-angiotensin mechanism., , Micturition :, The expulsion of urine from the urinary bladder is called micturition. It is, a reflex process but can be controlled voluntarily up to some extent in grown up, children and adults., The CNS (Central Nervous System) sends the signal which cause the, stretching of the urinary bladder when it gets filled with urine., In response, the stretch receptors on the walls of the bladder sends signals, to the CNS., The CNS passes on motor message to initiate the contraction of smooth, muscles of the bladder and simultaneous relaxation of the urethral sphincter, causing the release of urine., An adult human excretes on an average 1 to 1.5 Litres of urine per day., On an average 25-30 gram of urea is excreted out per day., , Role of other organs in excretion :, , , , Lungs—removes CO2 (18L/day) and water., Liver—secretes bilirubin, biliverdin etc. helps to eliminate these substances, along. with cholesterol, vitamins, drugs and degraded steroid hormones, through digesive wastes., , 194, , Biology Class - 11
Page 221 :
, , , , Sweat and sebaceous glands—These glands of skin help to eliminate small, amount of urea, NaCl and lactic acid etc. through sweat while sebaceous, glands help to eliminate some substances like steroids, hydrocarbons and, waxes through sebum., Saliva—It can help to eliminate small amount of nitrogenous wastes., , Disorders of Excretory system :, Uremia—The accumulation of urea in blood due to malfunctioning of kidney., , Hemodialysis—The process; of removal of urea from the blood artificially., In this process the blood from an artery is passed into dialysing unit after, adding an anticoagulant like heparin. The blood passes through coiled, cellophane tube surrounding by dialysing fluid. The nitrogenous wastes, from the concentration gradient and the blood becomes clear. This blood is, pumped back to the body through vein after adding anti-heparin to it., Renal calculi—The format ion of insoluble mass of crystallised salts (oxalates, or phosphates of calcium., Glomerulonephritis—Inflamation of glomeruli of kidney., , , Kidney Transplantation, , , Kidney transplantation is done in a patient in which both the kidneys fail to work i.e., at total failure of kidney. Kidney transplantation is the ultimate method for treatment, of renal failure. In case of kidney transplantation both the damaged kidneys of patient, are removed by surgery. And a functional kidney from a healthy donar preferably, from close relative is taken and transplanted in the body of patient. After successful, transplantation the patient and donar can survive on one kidney., , Precautions taken for successful transplantation of Kidney :, 1. Kidney should be taken from a healthy donor preferably from close relative., 2. Matching of blood group and other factor and compatibility should be done, carefully before transplantation., 3. The patient (recipient) has to take some prescribed medicines, immunosuppresses through out the life to suppress the immune system., , Excretory Products and their Elimination, , 195
Page 222 :
Questions, , Very Short Answer Questions, 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., , (1 marks each), , Which gland secretes sebum ?, One part of loop of Hanle is impermeable to water. Name it., Besides water, name any two contents of human sweat., Explain the function of vasa recta., Name two types of nephrons found in human kidney., Define GFR (Glomerular Filtration Rate)., The mechanism of concentration of filtrate is also known as counter current, mechanism. Justify the statement., What is micturition ?, Write the function of hormone ‘renin’ produced by kidney., Name the excretory product of (i) reptiles (ii) Prawns (iii) Tapeworm, (iv) Marine fish (v) Insects (vi) Birds., What is vasa recta ?, , Short Answer Questions-I , , (2 marks each), , 12., , , , , Mark the odd ones is each of the following—, (a) Renal pelvis, medullary pyramid, renal cortex, ureter., (b) Afferent arteriole, Henle’s loop, vasa recta, efferent arteriole., (c) Glomerular filtration, antidiuretic hormone, hypertonic urine, collecting, duct., (d) Proximal convoluted tubule, distal convoluted tubule, Henle’s loop, renal corpuscle., 13. In the following diagram of longitudinal section of kidney (Fig.–1) identify, and label a, b, c and d respectively., , fig. (i), , 196, , Biology Class - 11, , fig. (ii)
Page 223 :
14. In the diagram (Fig.-2) showing malpighian body (renal corpuscle) identify, and label p, q, r, s., 15. Name two metabolic disorder which can be diagnosed by analysis of, urine., , Short Answer Questions-II, , (3 marks each), , 16. In the following diagram (Fig.-3) showing structure of a nephron label a, b,, c, d, e and f., , 17. Describe the hormonal feed back circuit in controlling the renal functions., 18. Give three points of difference between renin and Renin., 19. What are Ammonotelic, ureotelic and uricotelic animals ? Give an example, of each type of these., 20. Why do urine formation less during summers ?, , Long Answer Questions, , (5 marks each), , 21. Draw a labelled diagram of human urinary system and write one function, of each adrenal gland, ureter, urinary bladder, kidney and urethra., 22. Describe how urine is formed in the nephron through filtration reabsorption, and secretion., Excretory Products and their Elimination, , 197
Page 224 :
OR, , Explain the steps involved in the process of urine formation., 23. Distinguish between (i) Uricotelism and Ureotelism (ii) Sebum and sweat, (iii) Proximal and distal convoluted tubules (iv) Ascending and descending, limbs of Henle’s loop (v) Cortical and Medullary nephrons., OR, Explain the process of reabsorption and secretion of major substances at, different parts of nephron with the help of schematic diagram., , Answers, Very Short Answer , , (1 mark each), , 1. Sebaceous glands (wax–glands), 2. Ascending limb., 3. Sodium chloride, lactic acid, glucose (any two)., 4. It helps to retain reabsorbed ions and urea in the interstitial fluid of the, medulla, to maintain its high osmotic pressure., 5. (i) Juxta medullary nephron (ii) Cortical nephron, 6. The amount of filtrate formed by the kidney per minute., 7. (in the ascending limb) the out/flow runs parallel to and in the opposite, direction of the inflow in the descending limb., 8. The act of passing out urine from urinary bladder., 9. Renin is used to convert angiotensinogen to angiotensin., 10. (i) Uric acid (ii) Ammonia (iii) Ammonia (iv) Urea (v) Uric Acid, (vi) Uric acid., 11. Capillary network running parallel to loop of Henle is known as Vasa recta., , Short Answer-I , , (2 marks each), , 12. (a) Ureter (b) Henle’s loop (c) Glomerular filtration (d) Renal Corpuscle., 13. Refer fig. 19.2, page 292 (NCERT Class XI-Biology), 198, , Biology Class - 11
Page 225 :
14. Refer fig. 19.4 page 293 (NQERT class XI-Biology), 15. Glycosuria, Ketonuria, , Short Answer-II , , (3 marks each), , 16. Refer fig. 19.3, page 292, (NCERT class XI-Biology), 17. Refer content 19.5, page 297 (NCERT class XI-Biology)., 18., , Rennin , , Renin, , , (i) It is a proteolytic enzyme., , (i) It is a hormone that acts as an enzyme., , (ii) It helps in the digestion of milk, , (ii) It converts the protein angiotensinogen, , , , Protein. into angiotensin, , (iii) It is secreted as an inactive, , , form Prorennin which is, , , , activiated to rennin by HC1., , (iv) Its secretion is stimulated by, , , (iii) It is secreted as renin., , (iv) It secretion is stimulated by a reduction, , food. of Na+ level in tissue fluid., , 19. Refer content given in the beginning of the chapter or NCERT Text Book, page 290 class XI-Biology., 20. Due to sweating in summers blood volume is decreased. ADH is secreted, from hypothalamus which increase reabsorption from D.C. tubules thus, amount of urine is decreased., , Long Answer, , (5 mark each), , 21. Refer fig. 19.1, page 291 and content 19.1 (NCERT Text Book page Class, XII-Biology), 22. Refer content points to remember., 23. Refer the content given in the chapter or NCERT Text Book Class-XI Biology, at pages 290, 298 (19.7), 292 and 293 respectively., 24. Refer content 19.3 and content 19.5 at page 294-295 (NCERT Text Book, Class XI-Biology), , , Excretory Products and their Elimination, , 199
Page 226 :
Points To Remember, Arthritis : an inflammatory joint disease characterised by inflammation of, joints., Coccyx : tail bone formed by fusion of four coccygeal vertebrae in man., Dicondylic Skull : A Skull with two occipital condyles., Endo Skeleton : A skeleton present in side the body., Fascicle : Bundles of muscles fibres held together by connective tissue., Fascia : Collagenous connective tissue layer that surrounds muscle bundles., Floating ribs : The ribs that remain free anteriorly, (last 2 pairs), False ribs : 8th, 9th and 10th pair of ribs not directly joins the sternum but, to seventh pair of ribs, hence called pseudoribs., Myoglobin : A red colored pigment present in sarcoplasm of muscle., Sarcomere : A portion of myofibril between two successive ‘Z’ lines., Sarcolema : The plasma membrane of a muscle., Gout : Inflammation of joints due to accumulation of uric acid crystal., Suture : immovable joints between skull bones., Synovial joints : Freely movable joints between limb bones., Patella : A seasmoid bone acting as kneecap., Intervertebral disc : Fibro cartilaginous pad present between the vertebrae, that act as shock absorbers., Tendon—Connective tissue made of yellow fibrous tissue which connect, muscle to bone. It is not flexible., Ligament—Connective tissue made of white fibrous tissue which joins two, bones. It is flexible., LMM : Light meromyosin, HMM : Heavy meromyosin, Types of Movement :, 200, , Biology Class - 11
Page 227 :
1. Amoeboid movement : These movements takes place in phagocytes, where leucocytes and macrophages migrate through tissue. It is affected by, pseudepodia formed by the streaming of protoplasm (as in amoeba), 2. Ciliary movement : These movement occurs in internal organs which are, lined by ciliary epithelium., 3. Muscular Movement : This movements involve the muscle fibers, which, have the ability to contract and relex., Properties of Muscle : (i) Excitability, (ii) Contractility, , (iii) Extensibility, (iv) Elasticity, , Types of Muscles :, (a) Skeletal muscles or striated muscles—These involved in locomotion and, change of body postures. These are also known as voluntary muscles., (b) Visceral muscles or smooth muscles—These are located in inner wall of, hollow visceral organ, smooth in appearance and their activity are not under, control of voluntary nervous system. They are called involuntary muscles., (c) Cardiac muscles—The muscles of heart, involuntary in nature, striated and, branched, These are uninucleated., Characteristic Skeletal Muscle, , Smooth Muscle, , Cardiac Muscle, , Location, Muscles attached with, , skeletal components, Appearance, Striated having light and, , dark bands., , Control, They are controlled by, , our will hence called, , voluntary muscles., , muscles found in the inner walls of hollow visceral organs, unstriped, smooth in, appearance with tapering, ends., They are not under the, control of our will hence, called involuntary muscles., , Muscles found only, in heart., Striated in, appearance and, branched, not under the, direct control of, nervous system., , Structure of myofibril :, , , , , , , , , , Each myofibril consist of alternate dark and light band., Dark band—contain myosin protein and is called A-band or Anisotroic band., Light band—Contain actin protein and is called I Band or Isotropic band., I Band is bisected by an elastic fiber called ‘Z’ line. Actin filament (thin, filament) are firmly attached to the ‘Z’ lines., Myosin filament (thick filament) in the ‘A’ Band are also held together in, the middle of T Band by thin fibrous membrane called ‘M’ line., The portion between two successive ‘Z’ lines is considered as functional, unit of contraction and is called a sarcomere., Locomotion and Movement, , 201
Page 228 :
Structure of Actin and Myosin Filament, I-Band, , Thin, filament, Thick, filament, , 1. Actin filament : An actin filament is made of two ‘F’ actins which are, helically wound to each other. Two filaments of tropo myosin protein also, run close to ‘F’ actins throughout its length. A complex protein Troponin is, distributed at regular intervals on tropomyosin which mask the actin binding, site for myosin., 2. Myosin filament : Each myosin filament is a polymer of meromyosin., Each meromyosin has two components—a globular head with a short arm, and a tail. Head is made of heavy meromyosin while tail is made of light, meromyosin. The head with its short arm project outward at regular distance, and angle from each other and is known as cross arm. The head has an active, site for actin and binding site for ATP., , Red muscle fibres :, —, —, —, —, , These are red in colour due to presence of high content of myoglobin., These contain plenty of mitochondria., Sarcoplasmic reticulum is less in these fibres., Show slow but sustained contractions for longer periods., , 202, , Biology Class - 11
Page 229 :
White muscle fibres, — These are pale or whitish due to presence of less content of myoglobin., — These contain fewer mitochondria, — Sarcoplasmic reticulum is more/high, — During sternous exercise, lactic acid accumulates in large quantity so muscle, fatigues, , Mechanism or Muscle contraction : Sliding filament theory, The contraction of muscle fiber takes place by the sliding of actin (thin, filament) on myosin (thick filament), , , Muscle contraction is initiated by a signal sent by the CNS via a motor, neuron., , , , Impulse from motor nerve stimulates a muscle fiber at neuro muscular, junctions., , , , Neurotransmitter releases here which generates an action potential in, sarcolema., , , , This causes release of Ca++ into sarcoplasm. These Ca++ binds with troponin,, thereby remove masking of active site., , , , Myosin head binds to exposed active site on actin to form a cross bridge,, utilising energy from ATP hydrolysis., , , , This pulls the actin filament towards the centre of ‘A’ band., , , , ‘Z’ lines also pulled inward thereby causing a shortening of sarcomere i.e., contraction., , , , I band get reduced, whereas the ‘A’ band retain the length., , , , During relexation, the cross bridge between the actin and myosin break., Ca++ pumped back to sarcoplasmic cisternae. Actin filament slide out of ‘A’, band and length of I band increase. This returns the muscle to its original, state., Locomotion and Movement, , 203
Page 230 :
Vertebral formulae of man C7T12L5S(5) C(4) = 33, Human skeleton – 206 bones, Axial skeleton (80 bones), , skull (29 bones), cranium-8 face-14, Ear ossicle-6, Hyoid-1, , Appendicular, skeleton (126 bones), , vertebrae (26) (33) , 1, Cervical-7, Sternum, Ribs, Thoracic-12, 1, 12 pairs (24), Lumber-5, sacral-1 (5-fused to form 1 sacrum), Caudal-1 (4-coccygeal fused to form 1 coccyx), , Girdles (6 bones) , Clavicle 2, Pectoral (Shoulder girdle) , Pelvic (Hip girdle) (2), Scapula-2, Fore limbs (60 bones) - 30 in each limb, Humerus-2 , Radius-2 , Ulna-2 , Carpals-16 , Meta Carpals-10 , Phalanges-28=2× (2, 3, 3, 3, 3) , , Joints, , Fibrous joints, do not allow, movement, , Cartilaginous joints, allow very slight, movement, , e.g., joints between, the bones of skull, , e.g., joint between, adjacent vertebrae, , Limbs (120 bones), , Hind limbs (60) 30 in each limb, Femur-2, Tibia-2, Fibula-2, Patella-2, Tarsals-14, Meta Tarsal-10, Digits-28, , Synovial joints, Freely, movable, , Ball and socket, Hinge, Pivot, Gliding, Joints, Joints, Joints, Joints, e.g., between humerus e.g., knee, e.g., Atlas, e.g., between, and pectroal girdle, Joint, and axis, carpals, between femur, Elbow joint , and pelvic girdle, , 204, , Biology Class - 11, , Saddle, Joints, e.g., between, Carpals and meta, carpals of thumb
Page 231 :
Questions, Very Short Answer Questions, , (1 mark each), , 1. What is the total number of bones present in left pectoral girdle and left arm, respectively in human beings., 2. Why do skeletal muscle show striation., 3. Why are 11th 12th pair of ribs called floating ribs ?, 4. Write the name of chemical that causes fatigue in the muscles., 6. What lubricate the freely movable joints at the shoulder ?, 7. Name of longest bone of human body., 8. Give the name of first vertebra., 9. Define a sarcomere., 10. Name the cup shaped bone that constitutes the knee cap., 11. Which muscle fibre work during long flight of eagle ?, 12. Name the cavity in the girdle into which the head of femur fits ?, , Short Answer Questions-I , , (2 marks each), , 13. Write any two difference between cardiac muscle and skeletal muscle., 14. Distinguish between red fibre and white fibre., 15. Name the two types of girdles found in human body and write their role., 16. State the role of calcium ions and ATP in muscle contraction., 17. Name the bones of fore limb (hand) of human body. Give their number in, each limb., Locomotion and Movement, , 205
Page 232 :
Short Answer Questions-II, , (3 marks each), , 18. What makes the synovial joints freely movable ? List any four types of, synovial joints., 19. Name the category of bones forming the ribcage. How are these articulated, to each other to form the cage ?, 20. How are actin and myosin filament arranged in a muscle fibre ?, 21. Mention the factor which is responsible for the following :, (i), , Tetany (ii) Gout (iii) Osteoporosis, , Long Answer Questions, , (5 mark each), , 22. Explain the important steps of sliding filament theory of muscle contraction., , Answers, Very Short Answers, , (1 mark each), , 1. Left pectoral girdle has 2 bones (1 clavicle and 1 scapula). Left Arm has 30, bones., 2. Due to distribution pattern of actin and myosin protein., 3. These ribs are not ventrally attached to sternum, 4. Actin and myosin, 5. Lactic acid, 6. Synovial fluid, 7. Femur, 8. Atlas, 206, , Biology Class - 11
Page 233 :
9. A portion of myofibril between two successive ‘Z’ lines., 10. Knee cap, 11. Red muscle fibre, 12. Acetabulum, , Short Answers-I, , (2 marks each), , 13. Refer NCERT Text book Class XI Page 303, 14. Refer Points to remember, 15. Refer NCERT Text book Class XI Page 311, 16. Refer NCERT Text book Class XI Page 307 and 308., 17. Refer Points to remember, , Short Answers-II, , (3 marks each), , 18. Refer NCERT Text book Page 312. Class XI, 19. Refer NCERT Text book Page 310. Class XI, 20. Refer NCERT Text book Page 305. Class XI, 21. Refer NCERT Text book Page 312. Class XI, , Long Answer, , (5 marks each), , 21. Refer Points to remember, , , Locomotion and Movement, , 207
Page 234 :
Points To Remember, Coordination : Process through which two or more organs interact and, complement the functions of one another surrounding the brain., Action potential : A sudden change in the electrical charges in the plasma, membrane of a nerve fibre., Aqueous humour : The thin watery fluid that occupy space between lens, and cornea in eye., Blind spot : A spot on retina which is free from rods and cones and lack, the ability for vision., Cerebrospinal fluid : An alkaline fluid present in between inner two layer, of meninges, surrounding the brain and spinal cord., Cerebellum : A part of hind brain that controls the balance and posture of, the body., Cochlea : A spirally coiled part of internal ear which is responsible for, hearing., Corpus callosum : A curved thick bundle of nerve fibres that joins two, cerebral hemisphere., Depolarisation : A condition when polarity of the plasma membrane of, nerve fibre is reversed., Endolymph : The fluid filled within membranous labyrinth., Eustachian Tube : A tube which connect ear cavity with the pharynx., Fovea : An area of highest vision on the retina which contain only cones., Meninges : Three sheets of covering of connective tissue wrapping the brain., Grey Matter : This shows many convolutions which increase the amount, of vital nerve tissue., Medula oblongata : Posterior most part of the brain which is continuous, with spinal cord and control respiration, heart rate,swallowing,vomiting., 208, , Biology Class - 11
Page 235 :
Pons : Thick bundles of fibres on the ventral side of brain below cerebellum., Foramen magnum : A big aperture in the skull posteriorly through which, spinal cord emerges out., Spinal cord : A tubular structure connected with medulla oblongata of brain, and situated in the neural canal of the vertebral column, covered by meninges., Synaptic cleft : A narrow fluid filled space which separates two membranes, of the two neurons at the synapse., Synaptic vesicles : These are membrane bound vesicles in the axoplasm of, the axon terminal and these store neurotransmitter., Neurotransmitter : These are chemicals stored in synaptic vesicles, diffuse, to reach the membrane of next neuron for its stimulation., Synapse : A physiological junction between axon of one neuron and dendrite, of next neuron., CNS—Central neural system, PNS—Peripheral neural system, ANS—Autonomic neural system, Neural System, Central neural System, Brain, , Peripheral neural System, , Spinal cord, , Cranial nerve, , Spinal nerve, , 12 pairs, , 31 pairs, , Nerve fibres of PNS, Afferent fibres Tansmit impulse, from Tissue/organ to CNS, , Efferent fibres Transmit impulse, from CNS to Peripherel tissue/organ, , Division of PNS, Somatic neural System, , Automatic neural system Transmit, , Relays impulse from CNS, , impulse from CNS to involuntary, , to Skeletal muscle, , Organ and smooth muslces, Neural Control and Coordination, , 209
Page 236 :
Visceral Nervous System : whole complex of nerves, fibres, ganglia and plexuses, by which impulses travel from CNS to the viscera and from viscera to CNS, Cell body = Cytoplasm with nucleus, cell organelles and, Nissl’s granules, Parts of Neuron, , Dendrites = Short fibres which branch rapidly and project, out of cell, Axon =, , Single, long fibre, branched at distal end, , (Refer fig. 21.1, page 317, NCERT - Biology, Class-XI), Multipolar = : One axon and two or more dentrites, : Found in cerebral Cortex, Neuron, , Bipolar =, , : One axon and one dendrite, : Found in retina of eye, , Unipolar = : Cell body with axon only, : Found usually in the embryonic stage, , Conduction of Nerve Impulse, Polarization : Resting potential, • Before stimulation axoplasm contain –vely high concentration of K+, and low concentration of Na+ Inner surface is –vely charged., • Fluid outside axon – low concentration of K+ and high concentration of, Na+. Outside the membrane is + vely charged., • Most membrane channels are closed., Depolarization: Action potential, • Stimulation of nerve., • Permeability of membrane to Na+ increases., • Na+ channels opens allowing Na+ to diffuse into the cell quickly., • As a result inside become +ve and outside -ve., Repolarization : Normalising, • K+ gates open in order to allow K+ to diffuse out of the axon. This, restores the membrane. (+ve outside -ve inside), , 210, , Biology Class - 11
Page 237 :
Transmission of Impulses at Synapse, (i) At electrical synapses : Here the membrane of pre and post-syneptic neuron, are in very close proximity. Electric current can flow directly from one neuron, into other across these synapses, like impule conduction along a single axon., (ii) At chemical synapses : Here the membrane of pre and post-syneptic neuron, are separated by fluid filled space called synaptic cleft. Neurotransmitter are, involved here., When an impulse arrives at the axon terminal, it stimulates the movement of, the synaptic vesicles towards membrane and they fuse with the plsama membrane, and release their neurotransmitter in the syneptic cleft. These chemicals bind to, specific receptors, present on the post-syneptic membrane. Their binding opens, ion channels and allow the entry of ion which generate new potential in post, synaptic neuron., Human brain : Human brain is the major portion of central neural system., Which is well protected by the skull., The brain is surrounded by three cranial meninges—, (i) Duramater—outer layer, (ii) Arachnoid—middle layer, (iii) Piamater—Inner layer-remain incontact with brain, Parts of Brain, Fore brain, Mid brain, (a) Cerebrum , (b) Thalamus , (c) Hypothalamus , , Hind brain, (a) Cerebellum, (b) Pons, (c) Medulla oblongata, , Functions of pars of brain :, Cerebrum : Centre of intelligence, memory and imagination, reasoning,, judgement, expression of will power., Thalamus : Acts as relay centre to receive and transmit general sensation, of pain, touch and temperature., Hypothalamus : Centre for regulation of body temperature, urge for eating, and drinking., Midbrain : Responsible to coordinate visual reflexes and auditory reflexes., Cerebellum : Maintains posture and equilibrium of the body as well as, coordinates and regulates voluntary movement., Neural Control and Coordination, , 211
Page 238 :
Pons : Relays impulses between medulla oblongata and cerebral hemisphere, and between the hemisphere of cerebrum and cerebellum. It also heps to regulate, breathing., Medulla oblongata : Centre that control heart beat, breathing, swallowing,, salivation, sneezing, vomitting and coughing., Reflex action : It is spontaneous, autonomic and mechanical response to, a stimulus that occurs at the level of spinal cord, without involvement of brain., Reflex arc : The flow of nerve along the specific during reflex action. It, consist of—, (a) A receptor, (b) An Afferent neuron (sensory neuron), (c) An inter neuron, (d) An efferent neuron (motor neuron), (e) An effector organ, Sensory neuron, Stimulus, Receptor, (REFLEX - ARC), Inter neuron of spinal cord, Response, Effector organ, motor neuron, Organ of Sight-Eye, Layer, , Component, , Function, , 1. External layer, , Sclera, , Protects and maintain shape of the, , , , eye ball, , , , Outermost transparent portion of, , Cornea, , , , eye which allows light to enter, , 2. Middle layer, , Absorb light and prevent light from, , Choroid, , , , Ciliary body, , , being reflected within the eye ball., Holds lens, regulate shape of the, lens., , , , Iris, , Control amount of light entering., , 3. Inner layer, , Retina, , Vision in dim light, colour vision,, , , , , , vision in bright light. Sends the, image to brain through optical, nerves., , (Refer-Fig. 21.6, Page 323 NCERT-Biology, Class XI), 212, , Biology Class - 11
Page 239 :
Organ of Hearing–Ear, Portion of the ear Component, Function, 1. External ear, Pinna, Collect sound waves, , External, Direct sound waves towards ear drum,, , auditory canal, ear wax prevents the entry of foreign, , bodies., 2. Middle ear, Tympanic, Acts as resonator that reproduces, , membrane, the vibration of sound., , Ear ossicles, Transmit sound waves to internal ear., , Eustachian tube Helps in equalising the pressure, , on either side of ear drum., 3. Internal ear, Cochlea, Hearing organ., , Vestibular, Balancing of body., , apparatus, (Refer Fig. 21.7, page 325-NCERT-Biology, Class XI), , Organ to smell – Nose (Factor Organ), NOSE, Olfactory Epithelium, Olfactory Receptors – Receives sense of smell (air/chemicals), (mucus coated), Olfactory Neurons, Olfactor bulbs (limbic system of brain), Organ to Taste – Tongue (Gustatory Organ), TONGUE, Papillae, Taste buds, Gustatory Nerves, Brain (integrates the differential inputs from taste buds)., Neural Control and Coordination, , 213
Page 240 :
Questions, Very Short Answer Questions, , (1 mark each), , 1., 2., 3., 4., 5., , Name the fluid present in membranous labyrinth., Name the area of retina where only cones are densly packed., Name the inner most meninges of the brain., To which part of the brain communication and memory are associated ?, Name the bundle of fibres that connect two cerebral hemisphere in human, being., 6. Name the photo pigment present in the rod cells., 7. Why do impulses flow only in one direction ?, 8. Where is hypothalamus located in the brain ?, 9. Which cells are responsible for scotopic vision ?, , Short Answer Questions-I , 10., 11., 12., 13., 14., 15., , (2 marks each), , Distinguish between electrical synapses and chemical synapses., What is iris ? Give the function of iris., What is organ of corti ? Where is it located ?, Differentiate between cerebrum and cerebellum., What is synapse ? Name its two types., Fill in the blanks in the different columns A to D :, , Part/Organ, , Function, , , Pinna , ........(A)........., ........(B)........., Equalise the pressure on either side of ear drum., Cone cells, ........(C)........., ........(D)........., regulate amount of light to pass into the eye., 16. why are grey matter and white matter contained in human nervous system, named so ?, , Short Answer Questions-II, , (3 marks each), , 17. Observe the diagram given right and answer the following questions :, , 214, , Biology Class - 11
Page 241 :
(i), , Label the parts A, B, C & D., , (ii), , Give the function of C and D., , (iii) Name the layers which wrap this organ., 18. What is a synapse ? How does the nerve impulse cross the chemical, synapse ?, 19. Give the function of the following :, (i), , Cerebrum, , (ii) Hypothalamus, , (iii) Mid brain, , 20. What is meant by reflex action ? Name the components of a reflex arc in, correct sequence from receptor upto effector. Support your answer by a, diagram., 21. Draw a diagram of V.S. of human eye and label the following :, Iris, Retina, Cornea, Blind spot, Ciliary body and Vitreous chamber., , Long Answer Qeustions , , (5 mark each), , 22. Describe in detail, how conduction of nerve impulse takes place through a, nerve fibre., , Answers, Very Short Answers, , (1 mark each), , 1. Endolymph, 2. Fovea, 3. Piamater, Neural Control and Coordination, , 215
Page 242 :
4., 5., 6., 7., 8., 9., , Cerebrum, Corpus callosum, Rhodopsin, Because each synapse allows impulse to cross it in a single direction., At the base of thalamus., Rods, , Short Answers-I, 10., 11., 12., 13., 14., 15., , 16., , (2 marks each), , Refer NCERT text book, Class XI Page no. 319., Refer NCERT Text book, Class XI Page no. 323., Refer NCERT Text book, Class XI Page no. 326., Refer NCERT Text book, Class XI Page no. 321., Junction between two nerves Chemical synapse and electrical synapse, (A) To collect sound waves (B) Eustachina tube, (C) Colour vision , (D) Iris, Refer NCERT book, Page no. 321., , Short Answers-II , , (3 marks each), , 17. (i) A : Cerebrum , C : Cerebellum, B : Corpus callosum , D : Medulla oblongata, (ii) C : Balancing of body and maintain posture, D : Vomiting , coughing, breathing, salivation or any other correct answer, (anyone)., (iii) Pia mater, arachnoid and dura mater., 18. Refer NCERT Text book, Class XI Page no. 319., 19. Refer NCERT Text book, Class XI Page no. 321., 20. Refer NCERT Text book, Class XI Page no. 322., 21. Refer NCERT Text book, Class XI Page no. 323., , Short Answer, , (5 mark), , 22. Refer NCERT Text book, Class XI Page no. 317 and 318., , , 216, , Biology Class - 11
Page 243 :
Points To Remember, Endocrine glands : These are ductless glands which secrete hormones, directly into the blood stream., Hormones : Non-nutrient chemicals synthesised in trace amount by, Endocrine glands that act as intracellular messengers and are specific in their, action which are transported by blood from site of production to site of action., , Hypothalamus :, , , , , , It is basal part of diencephalon., Has neurosecretory cells called nuclei which produce hormones to regulate, the synthesis and secretion of pituitary gland hormones., Two types of hormones released are :, , , Releasing hormones : Stimulate secretion of pituitary hormones, e.g.,, Gonadotrophin releasing hormone stimulates pituitary gland to synthesise, gonadotrophins., Inhibiting hormones : Inhibit secretions of pituitary hormones, e.g.,, Somatostatin inhibits secretion of growth hormone., , Pituitary Gland :, , , Located in bony cavity called as sella tursica., , , , Attached to hypothalamus by a stalk., , , , , , , , Divided anatomically into : Adenohypophysis (Anterior lobe) and, Neurohypophysis (Posterior lobe)., Hormones released from hypothalamic neurons reach anterior pituitary, through portal system and through neurons in Posterior pitutary., Posterior pituitary is under neural control of hypothalamus., Chemical Coordination and Integration, , 217
Page 244 :
1. Pituitary Gland, Pituitary Gland, Adenohypophysis (Anterior lobe), Neurohypophysis (Posterior lobe), (It stores hormones secreted by hypothalamus, , Pars distalis, Pars intermedia, Pars nervosa, Secretes, GH, , PRL, , MSH, TSH, , ACTH, , LH, , FSH, , Oxytocin Vasopressin, (ADH), , Adenohypophysis : (Anterior lobe of Pituitary), , , , , , , , , , , , , Growth hormone (GH) : Oversecretion leads to gigantism and low secretion, causes dwarfism and Proper secretion leads to proper growth of body., Prolactin (PRL) : Growth of mammary gland and formation of milk in, them., Thyroid stimulating hormone (TSH) : Stimulates synthesis and secretion, of thyroid hormones from thyroid gland., Adrenocorticotrophic hormone (ACTH) : Stimulates synthesis and, secretion of steroid hormones called glucocorticoids from adrenal cortex., Luteinizing hormone (LH) : Synthesis and secretion of hormones called, androgens in males, and helps in ovulation and maintenance of corpus luteum, in females., Follicle stimulating hormone (FSH) : Regulate spermatogenesis in males,, and growth and development of ovarian follicles in females., , Neurohypo physis (Posterior lobe of Pituitary), , , , , Oxytocin helps in contraction of uterus during child birth and milk ejection, from mammary gland in females., Vasopressin : Acts on kidney and stimulates reabsorption of water and, electrolytes by distal tubules to reduce water loss through urine. It is also, called as Anti Diuretic Hormone (ADH)., , Diabetes insipidus : Impairment of synthesis of ADH, (i) Diminished ability of kidney to conserve water., (ii) Water loss and dehydration., (iii) Can be overcome by taking more water., 218, , Biology Class - 11
Page 245 :
Excessive Secretion of Growth Hormone, , , Acromegaly : It is a condition when the pituitary gland makes too much, growth hormone. It is due to a tumour in pituitary gland. Person suffering, from acromegaly (acro means tip and megaly means enlargement) may, gradually develop a long face with protruding lower jaw, enlarged nose and, wider spacing between teeth and enlarged hands and feet., , 2. Pineal Gland :, Located on dorsal side of forebrain., Secretes Melatonin to regulation 24-hours rhythm, sleep-wake cycle,, menstrual cycle, pigmentation etc., 3. Thyroid Gland :, Has two lobes on either side of trachea interconnected by isthmus (connective, tissue)., Composed of follicles and stromal tissues., Follicular cells synthesis thyroxine (T ) and tri-iodothyronine (T )., 4, 3, Iodine is necessary for normal functioning in of thyroid., Goitre (Hypothyroidism) : Enlargement of thyroid gland; Hypothyroidism, may lead to mental retardation and stunted growth (cretinism) Deaf-mutism, in the baby if it occurs during pregnancy., Hyperthyroidism : Occurs due to cancer or due to development of nodules, in thyroid glands. Effects body physiology as abnormal high levels of thyroid, hormones is synthesised. Basic metabolic rate increase., Exophthalmic goitre : It is a form of hyperthyroidism, characterised by, enlargement of thyroid gland, protrusion of eye balls and increased BMR, Thyroid hormone controls protein, carbohydrate metabolism., Also secretes a protein hormone called Thyrocalcitonin (TCT) which regulates, blood calcium level., 4. Parathyroid Gland :, Present on back side of thyroid gland. Each lobe of thyroid gland has its one, pair., Secrete peptide hormone called parathyroid hormone (PTH) which increases, calcium levels in blood so called hypercalcemic hormone., PTH stimulates bone resorption, and reabsorption of calcium from blood and, reabsorption of calcium by renal tubules, thus increasing blood Ca++ level., , Chemical Coordination and Integration, , 219
Page 246 :
5. Thymus Gland, Located on dorsal side of heart and aorta., Secrete peptide hormones called Thymosins which play role in differentiation, of T-lymphocytes (help in cell mediated immunity.), Thymosins also produce antibodies and provide humoral immunity., Immunity of old people usually becomes weak as thymus gets degenerated, with age., 6. Adrenal Gland, Located at anterior part of each kidney., Has centrally located adrenal medulla and at periphery in adrenal cortex., Adrenal medulla secretes adrenaline (epinephrine) and nor adrenaline, (norepinephrine), commonly called as catecholamines or emergency, hormones or hormones of fight or flight., These hormones increase heart beat, rate of respiration, breakdown of, glycogen thus increase blood glucose level, breakdown of lipids and protein,, alertness, raising of hairs, sweating etc., Adrenal Cortex-(3 layers) :, Zona reticularis (inner layer), , Zona fasciculata (middle layer), , Zona glomerulosa (outer layer), , , Adrenal cortex secretes :, , 1. Androgenic steroids :, Secreted in small amounts., Play role in growth of axial pubic and facial hair during puberty., 2. Glucocorticoids :, Involved in carbohydrate metabolism., Stimulates gluconeogenesis, lipolysis and proteolysis., e.g., Cortisol which is also involved in cardio-vascular and kidney functions., It also suppresses immune response and stimulates RBC production., 3. Mineralocorticoids :, Regulate balance of water and electrolytes in body., +, e.g., Aldosterone which also helps in reabsorption of NA and water excretion, of K+ and phosphates ions from renal tubules., , 220, , Biology Class - 11
Page 247 :
, , , , When adrenal cortex is damaged, it does not produce enough cortisols (which, regulate body’s reaction to stressful situations) and aldosterone., It result in Addison’s disease. Symptons of addison’s disease are weak, muscles, extreme fatigue, increased skin pigmentation, weight loss, sores, in mouth and depression., , Two major causes :, 1. Primary adrenal insufficiency where our immunity system mistakes adrenal, for an antigen and tries to damage it., 2. Secondary adrenal insufficiency-when pituitary gland can’t produce ACTH, 7. Pancreas : It is called composite/dual gland. As it acts as Exocrine and, endocrine gland i.e. has both exocrine and endocrine function., Contains about 1-2 million islets of Langerhans which has glucagon secreting, α-cells and insulin secreting β-cell., Glucagon : Peptide hormone, stimulates glycogenolysis by acting on, liver cells. Also, stimulates gluconeogenesis. Hence called hyperglycemic, hormone., Insulin : Peptide hormone, acts on hepatocytes and adipocytes to enhance, cellular glucose uptake, stimulates conversion of glucose to glycogen, (glycogenesis), so decrease blood glucose level called hypoglycemic, hormone., Deficiency of insulin causes diabetes mellitus in which loss of glucose occurs, through urine. Excessive hunger and thirst (polydipsia) are other symptoms, of Diabetes., Insulin and glucagon are antagonistic hormones i.e. play opposite role., , Glycogenolysis : Breaking of glycogen into glucose., , Gluconeogenesis : Formation of glucose from substances other than glycogen., , Glycogenesis : Conversion of glucose into glycogen., 8. Testis :, A pair of testis composed of seminiferous tubules and interstitial cells is, present in the scrotal sac of males., Leydig cells (interstitial cells) produce androgens (mainly testosterone) which, regulate development and maturation of male accessory sex organs, formation, of secondary sex characters and play stimulatory role in spermatogenesis., Chemical Coordination and Integration, , 221
Page 248 :
Male sexual behaviour (libido) is influenced by androgens., Ovary : A pair of ovaries which produce one ovum in each menstrual cycle are, present in abdomen in females., Ovary composed of ovarian follicles and stromal tissue., Estrogen synthesised by growing ovarian follicles helps in stimulation of, growth of female secondary sex organs, female behaviour, mammary gland, development and female secondary sex characters., , , Ruptured follicle form corpus luteum which secretes progesterone., Progesterone supports pregnancy and stimulates alveoli formation and milk, secretion in mammory glands., , Hormones secreted by tissues which are not endocrine, glands :, (a) Heart : Atrial wall secrets Atrial Natriuretic factor (ANF) which decreases, blood pressure by dilation of the blood vessels., (b) Kidney : Juxtaglomerular cells secretes erythropoietin which stimulates, erythropoiesis (RBC formation)., (c) Gastro-intestinal tract : it secrets four peptide hormones., , , , , Gastrin : Acts on gastric glands and stimulates secretion of hydrochloric, acid and pepsinogen., Secretin : Acts on pancreas and stimulates secretion of water and bicarbonate, ion., , Cholecystokinin (CCK) : Act on pancreas and gall bladder to stimulate, secretion of pancreatic juice and bile juice respectively., Gastric inhibitory peptide (GIP) : Inhibits gastric secretion and motility., Mechanism of hormone action : By hormone receptors of two kinds, i.e.,, (a) Located on membrane of target cell, These are membrane bound receptors., Form hormone receptor complex., ↓, Leads to biochemical changes in tissue., ↓, Release of second messengers like (cyclic AMP, IP3, Ca2+ etc.) which regulate, cellular metabolism., , , 222, , Biology Class - 11
Page 249 :
(b) Located inside the target cell, These are intra cellular receptors., Hormones (steroid hormones iodothyronines etc.) interact with them and, cause physiological and developmental effects of regulating gene expression., , Questions, Very Short Answer Questions, , (1 mark each), , 1. Which two system Coordinate and regulate physiological functions of our, body ?, 2. What is the role of melanocyte stimulating hormone ?, 3. Name the hormones which act antagonistically in order to regulate calcium, levels in the blood., 4. Give the names of any one glucocorticoid and one mineralocorticoid., 5. How does artrial natriuretic factor decreases blood pressure ?, 6. Which structure is formed from ruptured follicle in females ? What is its, role ?, 7. Immunity of old persons becomes very week. Give reason., , Short Answer Questions-I, , (2 marks each), , 8. What happens if a person suffers from prolonged hyperglycemia ?, 9. What are the two modes through which the hypothalamus causes the release, of hormones by pituitary gland ?, 10. Androgen regulated the development, maturation and other important, functions in human male. List them., 11. Mr. Akshay notices that his shoe size has progressively increased. He also, observes that shape of his face has gradually changing with protruding lower, jaw. What can be the cause for all changes. Name the disorder., , Chemical Coordination and Integration, , 223
Page 250 :
Short Answer Questions-II, , (3 marks each), , 12. Define hormone and classify them on basis of their chemical nature., 13. How do oxytocin, progesterone and estrogen differ from each other ?, 14. What are the disorders caused and the effects produced due to malfunctioning/, improper secretion from thyroid gland ?, 15. Name the disease/disorder caused by :, (a), , Excessive secretion of Thyroid hormone in adults., , (b), , Insufficient amount of insulin secreted by pancreas., , (c), , Damage of adrenal cortex., , Long Answer Questions, , (5 mark each), , 16. ‘The master gland regulates a number of physiological functions in our body.’, Give reasons and explain., , Answers, Very Short Answers, , (1 mark each), , 1. Nerual system and endocrine system., 2. Acts on melanocytes and regulates pigmentation of skin., 3. Thyrocalcitonin (TCT) and parathyroid hormone (PTH)., 4. Glucocorticoid—Cortisol; Mineralocorticoid—aldosterone., 5. By dilation of the blood vessels., 6. Corpus luteum which secrets progesterone., 7. Thymus gland degenerates with age., , Short Answer Questions-I , , (2 marks each), , 8. Gets affected by diabetes mellitus which causes loss of glucose through urine, and formation of harmful ketone bodies., 224, , Biology Class - 11
Page 251 :
9. Through hypothalamic neurons control anterior pituitary gland. Through, neural regulation controls posterior pituitary gland., 10. Refer Points to Remember., 11. Increased secretion of growth hormone Acromegaly, , Short Answers Questions-II , , (3 marks each), , 12. Refer Points to Remember and page no. 338, NCERT, Text Book of Biology, for class XI., 13. Oxytocin causes milk ejection and contraction of uterus at time of child birth., Progesterone–causes milk secretion and maintains pregnancy., Estrogen : Refer Points to Remember., 14. Refer Points to Remember., 15. (a), , Expotthalmic goitre, , (b), , Diabetes, , (c), , Addison’s disease, , Long Answers Questions-II, , (3 mark each), , 16. Explain the role of pituitary gland + Refer Points to Remember., , , Chemical Coordination and Integration, , 225
Page 252 :
Practice, , Practice Paper–I (Solved), Subject : BIOLOGY (044) (Theory), Time : 3 Hrs.], , Class : XI Session-2016-17, , [MM : 70, , SECTION ‘A’, 1., 2., 3., 4., , 5., , Write full form of DCT., Name the tissues which has intercalated disc. What is its function?, Ribosomes in prokaryotes is of 70 S type. What does ‘s’ stands for and, what does it measure?, Complete the given sequence of taxonomic categories:, Species. ------------ genus --------- (a) ------- (b) ------ phylum ------kingdom., Name the type of placentation shown in the figure A and B., , (a) (b), , SECTION ‘B’, 6., , 226, , Define the following with an example of each :, a), Bilateral symmetry in animals, b), Acoelomate animals, Biology Class - 11
Page 253 :
7., , Why are deuteromycetes commonly known as imperfect fungi? Mention, two characteristics of mycelium of such fungi., 8., Water droplets are observed near the tip of grass blades in early morning., a), What is the loss of water in liquid phase called?, b), Why does this phenomenon occur?, 9., Which pigment is found in phaeophyceae and rhodophyceae other than, chlorophyll?, Give an account of stored food in these classes., 10. Figure given below shows the effect of light on the role of photosynthesis., Based on graph answer the following questions:, a), At which point/points (A,B or C) in the curve light is a limiting factor?, b), What could be the limiting factor/factors in region A?, , SECTION ‘C’, 11., , 12., , 13., , Answer the following questions in respect to areolar tissue :, a), Where is areolar tissue present?, b), What is the function of this tissue?, c), Name any two cells it contains., Write the main modification in the plant part of :, a), Opuntia, b), Garden pea, c), Bougainvillia, Draw a diagram of T.S. of monocot root and label the following parts:, Epidermis, cortex, pericycle, xylem, phloem and endodermis, Paper, , 227
Page 254 :
14., 15., 16., 17., 18., , 19., 20., 21., 22., , Write any three diffferences between mitosis and meiosis., What is a synapse? How does the nerve impulse cross the chemical, synapse?, Explain the phases of interphase of a cell cycle., a), Distinguish between aerobic and anaerobic respiration, b), Respiratory quotient (RQ) for carbohydrates is 1. Why?, Explain how butter in your food gets digested and absorbed in your body?, OR, a), Name the bones of pectoral girdle., b), Give an example of fibrous joint., Describe the steps involved in formation of root nodules in leguminous, plants., Classify plastids on the basis of type of pigments found in them. State the, function of each type., Explain cyclic photophosphorylation along with its pathway., (a) List two factors which affect the rate of diffusion of a gas, (b) What is the term given to a maximum volume of air a person can, breathe in after a forced expiration?, (c) What is one of the major cause of Emphysema?, , SECTION ‘D’, 23., , Vineet observes the gardener removing the shoot tips of plants for hedge, making. He asks his brother the reason for this. His brother explains it to, him., (a) What does Vineet brother tell him. Explain (give two points), (b) List two values you observed in Vinnet’s brother, , SECTION ‘E’, 24., , 228, , (a) Explain the effect of substrate concentration on enzyme activity., (b) Describe the primary, secondary and tertiary structures of proteins., OR, Who proposed the fluid mosaic model of plasma membrane. Describe this, model with the help of diagram., , Biology Class - 11
Page 255 :
SOLUTION - (2016-17), SUBJECT : BIOLOGY (THEORY), CLASS : XI, SECTION ‘A’, 1., 2., 3., 4., 5., , Distal convoluted tubule, Cardiac muscle tissue, allow the cells to contract is a unit., Svedberg’s unit. Density and size of ribosome., Order, class, Parietal, Axile., , SECTION ‘B’, 6., 7., 8., 9., , 10., , (a) Body divides into two identical left and right halves. E.g. arthropods., (b) body cavity is absent. Eg. Platyhelminthes., Reproduce only by asexual mode. Mycelium is septate and branched., (a) guttation. (b) high root pressure and low transpiration rate, Phaeophyceae – pigment fucoxanthin, stored food ----- Mannitol and, laminarin, Rodophyceae – pigment phycoeryrhrin, Stored food ----- Floridean starch, (a) In a region A., (b) Water, temperature and concentration of carbod dioxide could also, be the limiting factors., , SECTION ‘C’, 11., 12., , 13., 14., , (a) beneath the skin (b) serves as a support framework for epithelium (c), fibroblasts macrophages and mast cells., (a) Flattened stem contain chlorophyll and carry out photosynthesis., (b) Leaflet tendrils support the plants., (c) Stem thorns protect from browsing animals., Refer fig. NO. 6.6 (b) from NCERT of Biology, Mitosis, 1. same number of chromosomes in, daughter cells, so called equational, division, , Meiosis, 1. number of chromosomes get reduced to half, so called reductional, division, Paper, , 229
Page 256 :
2. Two daughter cells formed, 3. Occurs in somatic cells, 15., 16., , 17., , Junction between the two neurons. Neurotransmitters are involved in the, transmission of impulse through chemical synapses., G1 Phase (Gap 1) : Cell metabolically active and grows., S Phase : synthesis of replication of DNA, G2 Phase (Gap 2) proteins are synthesized and cell grows, (a), Aerobic respiration, 1. takes place in the presence of, oxygen, 2. glucose breaks down into carbon, dioxide and water, 3. it occurs in cytoplasm and, mitochondria, 4. 36 to 38 ATP molecules are, produced, , 18., , 19, 20., , 230, , 2. Four daughter cells formed, 3. Occurs in reproductive cells, , Anaerobic respiration, 1. takes place in the absence of, oxygen, 2. glucose breakdown into ethyl, alcohol carbon dioxide and energy, 3. it occurs in cytoplasm only, 4. only 2 ATP molecules are, produced, , (b), Substrate carbohydrate is completely oxidised. 6 CO2/6O2, Digestion of butter – emulsified by bile juice (secreted by liver) – pancreatic, lipase and intestinal lipase – fatty acids and glycerol. Absorption of lipid, – fatty acids and glycerol – micelles formed – absorbed by epithelial, cells of small intestine – reformed into protein coated fat globules called, chylomicrons – chylomicrons transported into lymph vessels (lacteals) –, lymph vessls release it into bloodstream., OR, (a) Calvicle and scapula. (b) Cranium. (c) Calcium binds with troponin on, actin filaments and remove the masking of active site of mysoin., Description in Fig. 12.4 of NCERT of Biology., Chloroplast: chlorophyll – to trap sunlight for photosynthesis. Chromoplasts, : fat soluble carotenoids – gives yellow, orange or red colour to parts, of plants (fruits, flowers etc.) Leucoplasts: colourless plastids – store, nutrients; Amyloplasts (starch), elaioplasts (oils), aleuroplasts (proteins)., , Biology Class - 11
Page 257 :
21., 22., , Refer Fig. 13.6 and pg no. 213 of NCERT of biology., (a) Pressure/concentration gradient, solubility of gases and thickness of, the membrane. (b) Vital capacity. (c) Cigarette smoking., , SECTION ‘D’, 23., , (a) Growing apical bud inhibits the growth of lateral buds, called apical, dominance. Removal of shoot tips results in the growth of lateral, buds., (b) Awareness, knowledge of life sciences, helping., , SECTION ‘E’, 24., , (a) With increase in substrate concentration the velocity of enzymatic, reaction rises at first. The reaction ultimately reaches a maximum, velocity (Vmax) which is not exceeded by any further rise in, concentration of the substrate., Enzymes are fewer than the substrate molecules and after saturation, of these molecules, there are no free enzymes to bind with the, additional substrate molecules., (b) primary proteins – the sequence of amino acids i.e., the positional, information in a protein., , Secondary proteins – a protein thread is folded in the form of helix., , Tertiary proteins – a long protein chain is folded upon itself like a, hollow woollen ball., , Paper, , 231
Page 258 :
QUESTION PAPER SOLVED, (2017-18), SUBJECT : BIOLOGY (044) THEORY, CLASS : XI, SECTION ‘A’, 1., 2., , 3., 4., 5., , Write the name of most abundant enzyme in the world., Pepsinogen is an inactive enzyme released by the gastric gland of stomach., (a), How is it activated?, (b), On which nutrient does it act upon?, What is cytokinesis?, Define the term species., To which bone are the ribs ventrally attached to?, , SECTION ‘B’, 6., 7., 8., 9., 10., , 11., , 13., 14., , 232, , Write two chracteristic features of Englenoids., Name the main nineral corticoid in our body. What is its function?, Both gymnosperms and angiosperms bear seeds. Then why are they, classified separately?, Diagrammatically represent sectional view of trophoblastic organisation, in animals., (a) What is partial pressure of a gas?, (b) Which are the two factors which affect the rate of diffusion of a gas?, Or, (a) In old age, people often suffer from stiffness and inflammation in, joints. What is this condition called?, (b) What is the cause of osteoporoses?, (a) Differentiate between apocarpous and syncarpous ovory., (b) What is a Parthenocarpic fruit?, (c) What are Pneumatophores?, Explain the three types of cell functions., (a) Differentiate between ‘RER’ and ‘SER’., (b) Why is mitochondria called the power house of the cell?, , Biology Class - 11
Page 259 :
15., 16., , 17., 18., , 19., , 20., , 21., , 22., , (a) Explain competitive inhibition along with an example., (b) Name the pyrimidines found in DNA., Answer the following questions with references to anatomy of dicot stem:, (a) Type of cells present in the Hypodermis., (b) Why is the endodermis layer referred to as starch sheath?, (c) Why are the vascular bundles present referred to as open and, conjoint?, Write any three points of difference between mitosis and meiosis., Explain how butter in your food gets digested and absorbed in the body?, Or, Fill in the blanks (i) to (vi) in different colums of the table given below :, Endocrine Gland, (a) Ovary, (b) (ii) ...................., , Hormone, (i) ...................., Glucagon, , (c) Pituitary, (d) Thyroid, , TSH, (iv) ....................., , (e) (v) ................., , Melatonin, , (f) Pituitary, , Oxytocin, , Functions, Support pregnancy, maintain, blood, glucoselevel, (iii) .............................., Metabolism of carbohydrate, fat proteins, Regulation of diurnal, Rhythm, (vi) ........................, , (a) Define vernalisation., (b) What are short day plants?, (c) Name the plant growing regulator which is synthesised by ripening, fruits., Answer the following questions in respect to approach :, (a) What is meant by paurometabolous?, (b) What is the function of gizzard and malpighian tubules?, (c) Write scientific name of cockroach., (a) Define respiratory quotient (RQ). Give R Q of fat and protein., (b) Where does glycolysis occur and what does glucose breakdown into, during this process?, (a) Differentiate between apoplast and symplast pathway of water, movement in root., Paper, , 233
Page 260 :
(b) Where are casparion strip found in plants and what are they made, up of?, , SECTION ‘D’, 23., , Disha is suffering from high blood pressure and her doctor advised her to, start medication to control her blood pressure. But she is reluctant to take, medicines. Her friend Sanya convinces her to take the medicines., (a) Mention the normal blood pressure of a healthy person., (b) Which organ can be affected due to high blood pressure (Name any, two), (c) Which values do you observe in Somya? (any two), , SECTION ‘E’, 24., , (a) Explain the mechanism of urine formation., (b) Write the full form of the following :, (i) GFR (ii) ADH, Or, (a) What is resting membrane potential? Give the role of sodium, potassium pumps in maintaining it. How does resting potential, change into action potential?, (b) Give one function of the following :, , (i) Medulla (ii) Hypothalamus., 25. Where does the calvin cycle take place? Describe its three phases (draw, the cycle also), Or, Why is the Kreb's cycle also called citric acid cycle? Explain the major, steps of the cycle. (Draw the cycle also)., 26. (a) Describe the effect of substrate concerntration on enzyme activity., (b) Explain the primary, secondary and tertrary structure of proteins., Or, (a) Describe the structure of chloroplast along with its diagram., (b) What are nuclear poes? State their function., , 234, , Biology Class - 11
Page 261 :
SOLUTION, (2017-18), SUBJECT : BIOLOGY (044) THEORY, CLASS : XI, SECTION ‘A’, 1., 2., , 3., 4., 5., , RUBISCO (Ribulose Biphosphate Carboxylase), (a) Zymogen get activated by HCl. Part of protein blocks the active site, of the enzyme cleaving off peptide activate the enzyme., (b) Proteins., The cytoplasmic division of a cell at the end of Mitosis or Meiosis bringing, about the seperation into two daughter cells., A group of closely relarted organisms which can freely interbreed in nature, and can produce its own kind's called as subspecies., Sternum (Breast Bone), , SECTION ‘B’, 6., , 7., 8., , (i) Bear two flagella on the anterior end of the body (ii) They are, unicellular protists found in fresh water (iii) Instead of cell wall, protein, rich membrane pellicle is present., Aldosterone. Regulation of salt. It also affects the heart and blood vessls, and maintain water in the body., In Gymnosperms there are nacked seeds which are exposed and develop, on scaly cones. In angiosperms seeds are covered and enclosed into the, Ovary (Fruit)., , 9., , 10., , (a) In a mixture of gases each gast can conributes to the total pressure, of the mixture. This contribution is the partial pressure. The partial, pressure is the pressure of the gas if the gas were in the same volume, and temperature by itself., Paper, , 235
Page 262 :
(b) Temperature, concentration gradient, viscocity of media, size of, molecules., Or, (a) Rheumatoidal Arthritis, (b) Due to decrease in bone density, reduction in sex hormones, lack of, calcium in bone, less estrogen level., , SECTION ‘C’, 11., , (a) When more than one carpel is present and they are free than ovary is, apocarpous. e.g. Lotus, Rose. When the carpels are fused than ovary, is called as syncarpous eg mustard, tomato., (b) The seedless fruit formed without fertilization are called as, parthenocarpic fruit., (c) In some plants such as Rhizophora growing in swampy areas, Roots, come out of the ground and grow vertically upwards. Such roots are, called as pneumatophores., 12. (a) Rhizobium bacteria contact a susceptible root hair, divide near it, (b) infection of the root causes it to curl (c) infected thread carries, the bacteria to the inner cortex. The bacteria get modified into root, shaped bacteriods and cause inner cortical and pericycle cells to, divide. (d) Division and growth of coritical and pericycle cells lead, to nodule formation., 13. Three types of cell junctions are :, (i) Tight junctions → help to stop substances from leaking across a, tissue., (ii) Adhering junctions → cementing for neighbouring cells together., (iii) Gap junctions → facilitate the cells to communicate with each other., 14. (a) RER have ribosomes on their surface, They are made up of cisternae, mainly, They produce proteins mainly., , SER donot have ribosomes on their surface– They are made up of, tubules mainly. They produce lipids and proteins., (b) Mitochondria called as power house of the cell as they produce, energy in the form of ATP for the cell., 15. (a) Competitive inhibition is interruption of a chemical pathway, owing to once chemical substance inhibiting the effect of another, by competing with it for binding or bonding. Non-competitive, 236, , Biology Class - 11
Page 263 :
16., , (b), (a), (b), (c), , , , inhibition of enzyme is binding of an inhibitor that prevents binding, of the target molecule known as subsrate. This is accomplished by, blocking the binding site of the substrate. eg; Inhibition of succenic, dehydrogenase by malonate which closely resembles the substrate, succinate in structure., Thymine and cytosine are pyrimides in DNA., Cells are collenchymatous in hypodermis without spaces., The cells of endodermis are rich in starch grains hence this layer is, also called as the starch sheath., Presence of cambium having ability to form secondary xylem and, phloem tissue so called as open vascular bundles., In conjoint type of vascular bundles the xylem and phloem are, situated at the same radius of vascular bundles., , MITOSIS, 17. 1. Takes place in somatic cells, 2. Crossing over is absent., 3. It is called as equational division as number of chromosome remain, same., MEIOSIS, 1. It occurs in reproductive cells or at the time of germination of zygote, or zygospore., 2. Crossing over takes place during pachytene stage., 3. It is called as reductional division as number of chromosome reduced, to half., 18. Digestion of butter in the body :, Lipase, Fat, Diglycerides → Monoglycerides → Fatty Acids, + Glycerol., Absorption of fat : Fatty acid and glycerol being insoluble can not be, absorbed into blood., Fatty acids break down into micelles → move to mucosa converted into, chylomicrons → which are transported into lymph vessels (Lacteals), in villi., Or, (a) Ovary, (i), Progesterone, Paper, , 237
Page 264 :
(b) (ii), Pancreas Glucagon, (c) Pituitory, TSH (iii) Stimulate Thyroid gland, (d) Thyroid, (iv) Thyroxine, (e) Pineal, (v) Melatonin, (f) Pituitory, Oxytocin (vi) Cause contraction of uterus for, Parturition., 19. (a) Exposure of plant to low temperature for flowering is called as, vernalization., (b) The exposure of the plant to light for a period less than the critical, day length for flowring such plant are called as short day plants., (c) Ethylene., 20. (a) Metamorphosis to the adult state from the juvenile state gradually is, called as paurometabolous., (b) Gizzard has chitinous Teeth so help in grinding of food. Malpighian, tubules help in excretion of waste products outside the body., (c) Periplaneta americana., 21. (a) The ratio of the volue of CO2 evolved to the volume of O2 consumed, in respiration is called the respiratory quotient (RQ), , RQ for fat is less than 1., , RQ for ptotein is about 0.19., (b) Glycolysis occur in the cytoplasm of the cell glucose undergoes, partial oxidation to form two molecules of pyruvic acid., 22. (a) Apoplast Pathway :, , 1. It consist of non-living parts of plant body (cellwall), , 2. There is little resistance in the movement of water. It is faster., , 3. Matabolic state of root does not affect apoplast pathway., Symplast Pathway, , 1. It consist of living part of plant body (protoplast plasmodesmata)., , 2. Resistance takes place. It is slower., , 3. Metabolic state of root directly affects symplast pathway., (b) The young endodermal cells posses a band of thickening which runs, along their Radial and tangential walls. This band of thickening is, called casparian strip. They are made up of both suberin and lignin., 238, , Biology Class - 11
Page 265 :
SECTION ‘D’, 23. (a) Normal blood pressure of healthy person is :, 120 mm Hg, 80 mm Hg., (b) Heart and Brain, (c) (i) Sanya is caring and responsible, , (ii) She is aware of the affects of high blood pressure., , SECTION ‘E’, 24., , (a) Mechanism of urine formation is completed in three steps :1. Ultra filteration or glomerular filteration : Due to high pressure in, arteriole blood filter by glomerulus through endothelium membranes, of blood vessel. The filterate in bowman's capsule is called as, ultrafiltrate or glomerular filterate. It contains everything like plasma, except proteins., 2. Tubular Reabsorption : Most of the glucose is absorbed in PCT., 75% Na+ and Kt are absorbed in all 90% of filterate is reabsorbed by, renal tubules by active or passive mechanism., 3. Tubular Section : Tubular cells secrete H+, K+ and ammonia into, urine. It maintanins acid base balance of body ........, (b) (i) GFR → Glomerular filteration rate, , (ii) ADH → Antidiuretic Hormone., Or, (a) Resting potential : It is the voltage (charge) difference across the, cell membrane when the cell is at rest. Resting membrane potential, (RMP) is a product of the distribution of charged particles A xoplasm, inside the axon contain high conc. of K+ and low conc. of Na+., , The outside the axon contain low conc. of K+ and high conc. of Na+., , As a result outer surface, of axonal membrane is positively charged, and in inner surface is negatively charged. The electric positively, difference across the resting plasma membrane is called resting, potential., , When a nerve fibre is stimulated the permeability of membrane, to Na+ increased at a point of stimulus and polarity of membrane, reversed due to influx of Na+. The electic potential difference across, the plasma membrane at that site is called as action potential., (b) (i) Medulla controls respiration, heart rate, vomiting and swallowing., , (ii) Hypothalamus Regulate body temperature, usage for eating and, drinking, Paper, , 239
Page 267 :
Co2, , Pyruvate, (3c), , Acetyl Co-enzyme A, (2C), , oxaloacetic, acid (4c), , +, , NAD, +, NADH + H, Co2, , Citric Acid, (6C), Co2 NAD+ NADH + H+, , NADH +H+ NAD+, , 2 - ke to glutaric acid, (5c), , Malic acid, (4c), FADH2 FAD+, , Succenic acid, (4c), , Co2 NAD+ NADH + H+, GDP, GTP, , 26., , (a) With the increase in substrate concentration the velocity of the, enzymatic reaction rises at first. This reaction ultimately reaches a, max velocity (Vmax) which is not exceeded any further because, the enzyme molecules are fewer than the substrate molecule so, after saturation, no free enzyme molecules to bind with additional, substrate., (b) Primary Structure : It is found in the linear sequence of amino acids., First amino acid is N–terminal and last amino acid is C–terminal., , Secondary structure : polypeptide chain undergoes folding or coiling, stabilized by hydrogen bond., , Tertiary structure : Long protein chain is folded upon itself like a, Hollow wooden ball. Gives 3 dimensional view of protein., Or, (a), , , , It is green coloured plastid. It contain green pigment chlorophyll,, double straded DNA and 70S ribosomes. It has stacks like grana and, stroma region. It carry out photosynthesis. It also gives colour to the, fruit and flower., (b) Nuclear pore are the protein based channels in the nuclear envelope., Paper, , 241
Page 268 :
Time : 3 Hrs., , QUESTION PAPER (2018-19), SUBJECT : BIOLOGY THEORY, CLASS : XII, , M.M. : 70, , SECTION ‘A’, 1., 2., 3., 4., 5., , Write two codes of nomenclature of living organism., What is an ‘endarch’ arrangement? Which one out of the root and stem, shows this arrangement?, Iodine turns the starch into blue black colour. Why?, What do you understand by the term facilitated diffusion?, Name the region of brain, which constitutes ‘brainstem’., , SECTION ‘B’, 6., 7., 8., 9., 10., 11., 12., , Give any four characteristics of mycoplasm., The spread of living pteridophytes is limited and restricted to narrow, geographical regions. Why?, Some animals of phylum ‘Cnidaria’ show metagenesis. What is it? Give, an example of animal that shows metagenesis., What are exocrine glands? Name the secretions of any two exocrine, glands., Name the two types of lymphocytes and write one difference between the, two., A frog's tadpole becomes ammonotelic while the adult frog becomes, ureotelic. Why?, Mention the three types of joints found in human body. Which of these, play a significant role in locomotion., Or, Ovary produces two groups of steriod hormones called estrogen and, progesterone. Mention at least two actions of each of these two hormones, in human females., , SECTION ‘C’, 13., , 242, , (a) Differentiate between racemose and cymose inflorescence., (b) What is phyllotaxy? Name the type of phyllotaxy found in (i) Mustard, (ii) Alstonia (iii) Calotropis, Biology Class - 11
Page 269 :
14., 15., 16., 17., , 18., 19., , 20., 21., , 22., , Give at least three points of difference between springwood and autumn, wood., Draw a diagram of alimentary canal of cockroach and label any six parts, in it. (description not required), Name the scientists who proposed cell theory. Also list its main postulates., Enlist the different types of amino acids based on the number of carboxyl, and amino groups in them. Also give one example of each of these amino, acids., OR, Explain a glycosidic, peptide and a phosphodiester bond., Describe briefly the various stages of cell cycle during the interphase, preceding mitosis., Study the given figure in which two chambers A and B, containing, solutions are separated by a semipermeable membrane :, (a) Solution of which chamber has a lower water potential?, (b) Solution of which chamber has a lower solute potential?, (c) In which direction will osmosis occur?, (d) Which solution has a higher solute potentials?, (e) At equilibrium which chamber will have lower water potential?, (f) If one chamber has Psi of - 2000 kPa and the other-1000 k Pa, which, is the chamber that has higher Psi?, , Discuss, “The respiratory pathway is an amphibolic pathway.”, What would be expected to happen if :, (a) GA3 is applied to rice seeding., (b) A rotten fruit gets mixed with unripe fruits., (c) You forget to add cytokinin to the culture medium., Name any three enzymes secreted by pancreas. Specify the substrate and, product of each., Paper, , 243
Page 270 :
23., 24., , Describe the role of haemoglobin in transport of respiratory gases., Explain in brief the nitrogen cycle,, , SECTION ‘D’, 25., , 26., , 27., , 244, , Name the scientist who proposed the fluid mosaic model about the, structure of plasma membrane. Describe the stucture of plasma membrane, according to the model., Or, Why meiosis is called reductional division? Describe the key events of, prophase-I of meiosis-I cell division. Write the significance of meiosis cell, division., Name CO2 acceptor in the mesophyll cells of a C4 plant. Explain the, synthesis of glucose in such plants., Or, Explain the major steps in kreb's cycle. Why is this cycle also called citric, acid cycle?, Describe the sequence of events which occur in the cardiac cycle in, humans. Where and how are the sound ‘lub’ and ‘dub’ produced in the, heart during this cycle?, Or, Explain the sliding filament theory of the mechanism of muscle, contractions., , Biology Class - 11
Page 271 :
SOLUTION (2018-19), SUBJECT : BIOLOGY (THEORY), CLASS : XII, SECTION ‘A’, 1., 2., 3., 4., 5., , ICBN : International Code for Botanical Nomenclature., ICZN : International Code for Zoological Nomenclature., Protoxylem lies towards the pith, in stem, Helical secondary structure of starch hold l2 molecules. The starch-l2 is, blue in colour., Proteins help to move substances across membranes without expenditure, of ATP., Mid brain, Hind brain (pons, medulla oblongata), , SECTION ‘B’, 6., 7., 8., 9., , 10., 11., 12., , (i), (iii), (i), (ii), (i), (ii), (i), (ii), , Lack of cell Wall, (ii) Smallest living cells, Survive without oxygen., (iv) Pathogenic, gametophyte require cold, damp, shady places., Need of water for fertilisation., Alternation of generation between sexual and asexual reproduction., Obelia, Glands with ducts, Pancreas – pancreatic juice, Salivary glands – Saliva (salivary, amylase), B lymphocytes (mature in bone marrow(; T lymjphocytes (mature in, thymus), Tadpole – aquatic adaptations, so ammonotelic. Frog - terrestrial, adaptation, so ureotelic, Fibrous joints - do not allow movement, Cartilaginous joints - slight movement, synovial joints - freely movable (help in locomotion), OR, Estrogen- development of secondary sexual characters and organs, – regulation of sexual behaviour, progesterone - support pregnancy., Stimulate mammary glands for milk secretion, Paper, , 245
Page 272 :
SECTION ‘C’, 13., , Recemose, Cymose, Main Axis grow continuously., Main axis - limited growth, Flowers born in acropetal succession, Flowers born in basipetal order, (b) arrangement of leaves on the stem (i) Mustard - alternate (ii) Alstonia, - whorled (iii) Calotropis - opposite, , 14., , Springwood, – Form during spring season, – Large number of xylary elements with, – wider cavities, – Called earlywood, , 15., , NCERT Figure - 7.16, , 16., , By Schleiden & Schwann, – All living organisms are composed of cell and products of cell., – All cells arise from pre–existing cells (by Virchow), , 17., , Acidic amino acids - glutamic acid, basic amino acids - lysine, neutral amino - acids valine, OR, Glycosidic Bond - between two carbon atoms of two adjacent, monosaccharides Peptide Bond - amino acids are linked when carboxyl, group of one amino acid reacts with amino group of other amino acid., Phosphodiester Bond - bond between phosphate and hydroxyl group of, sugar on either side., , 18., , G1 phase - cell metabolically active and grows, S phase (synthesis phase) - DNA replication, G2 phase - proteins synthesize, cell grows., , 19., , (a) B, , 20., , Respiratory pathway involved in borth anabolism and catabolism (refe, NCERT biology for explaination), , 21., , (i) ‘Bakane’ (foolish seedling disease), elongation of axis., (ii) Release of ethylene, ripening of other fruits., (iii) No shoot formation., , 246, , (b) B, , (c) A to B, , Biology Class - 11, , (d) A, , Autumn wood, – form during autumn season, – fewer xylary elements with, – narrow vessles, – called latewood, , (e) None, , (f) -1000 kp
Page 274 :
PRACTICE PAPER - I, UNSOLVED, SUBJECT : BIOLOGY (044) THEORY, CLASS : XI, SECTION ‘A’, 1., Name two genera placed in the family solanaceae, 1, 2., What do the term phycobiant and Mycobiont signify, 1, 3., Name the type of bond by which monomers in the following are held, together (a) polysacchrides (b) Poly peptides., 1, 4., What happens to a plant cell if it is kept in a higher water potential., 1, 5., Define mesosomes?, 1, Or, Trypsin acts at an alkaline pH. what provides this alkaline medium? Write, two actions of trypsin., , SECTION ‘B’, 6., , Fill in the blanks : ‘a’ to ‘d’ in different column & of the table given, below, 2, Class, Chlorophyceae, Phaeophycae, , 7., 8., , 9., , 10., 11., 248, , Pigments, (a), (c), , Stored Food, (b), (d), , What is the significance of juxtaglomerular apparatus in kidney function., , 2, Name the class of chordata that has :, ½×4 =2, (a) Placoid scales, powerful jaws and internal fertilisation., (b) Scutes, no external ears and oviparous., (c) Operculum, air bladder and external fertilization, (d) No neck, smooth skin, with mucous glands, What are trichomes? Mention their function., 2, OR, How is fascicular cambium different from inter fascicular combium?, Show only by schematic diagram the nitrogen cycle., 2, Differentiate between simple epithelium and compound epithelium, 2, Biology Class - 11
Page 275 :
12., 13., 14., 15., 16., , 17., 18., , 19., 20., 21., 22., 23., , 24., 25., , 26., , Based on the position of the centromere classify the chromosomes into, four grups, 2, How does temperature and pH affect the activity of enzymes., 3, Write functions of chloroplast and mitochondria., 3, Draw a neat labelled diagram of the duct system of liver, gall bladder and, pancreas., 3, (a) What is the role of calcium ions and troponin during contraction in, striated muscles of Humans?, 2, (b) Describe any two disorders of muscular system?, 1, Explain with suitable examples, the different types of phyllotaxy?, 3, (a) Beiefly explain systemic and pulmonary circulation in human beings, , (2+1), (b) What is SA Node? Write its function., What are the assumptions made during the circulation of Net gain of, ATP?, 3, State few comparisons between ‘C3’ and ‘C4’ pathways?, 3, With the help of a well labelled diagram describe the process of plasmolysis, in plants giving appropriate examples., 3, Explain the process of Nodule formation in Legume Plant., 3, Write at least six differences between Mitosis and meiosis process., 3, OR, Name the three permanent tissues found in flowering plants. Write one, function for each., Write the main steps in aerobic respiration? Where does it takes place? 3, Write scientific term for each of the following :, 1×5=5, (i) Exchange of genetic material between two homologous chromosome., (ii) Point at which two sister chromotids are held together, (iii) Nuclear division in mitosis, (iv) Inactive stage shown by the cells which donot divide further, (v) Division of cell (cytokinesis) in animal cell, OR, Explain the mechanism of urine formation in human beings., (a) Draw a neat labelled diagram of human eye, 2½, Paper, , 249
Page 276 :
27., , 250, , (b), , (a), , (b), , Write the hormone produced by endocrine gland (a) Thyroid, (b) pancreas. Write functin of any one hormone?, 2, Describe transpiration pull model of water transport in plants. How is, it useful to plants?, 3, What are porins? What role do they play in diffusion?, Or, List five main groups of natural plant growth regulators. Write a note on, their discovery and physiological functions., , Biology Class - 11
