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1, , VIJAYABHERI, MALAPPURAM DISTRICT PANCHAYATH EDUCATIONAL, PROJECT 2021-22, , STEP-UP, BOTANY-CLASS XI, (Higher secondary / V H S E Supporting Material)

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3, , Dear students and teachers,, STEP-UP 2022 of botany has been written in accordance with the, latest syllabus framed by SCERT and NCERT for class XI by a team of, higher secondary botany teachers in Malappuram district for, Malappuram District Panchayath VIJAYABHERI PROGRAMME., Students and teachers will definitely find it very much helpful, in understanding the various concepts. This book includes short notes,, diagrammes and main points., It is our sincere hope that the booklet will continue to motivate, the students’ interest in botany., , With regards,, Botany Team, Malappuram, , Vijayabheri, Malappuram Dist. Panchayat Project

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4, , CONTENTS, Sl No, 1, , Chapters, Biological Classification, , Page No, 5-15, , 2, , Plant Kingdom, , 15-20, , 3, , Morphology of Flowering Plants, , 20-30, , 4, , Anatomy of Flowering Plants, , 30-40, , 5, , Cell: The Unit of Life, , 41-46, , 6, , Cell cycle and Cell Division, , 46-50, , 7, , Transport in Plants, , 50-56, , 8, , Mineral Nutrition, , 56-60, , 9, , Photosynthesis in Higher Plants, , 60-66, , 10, , Respiration in plants, , 66-76, , 11, , Plant Growth and Development, , 76-82, , Vijayabheri, Malappuram Dist. Panchayat Project

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5, , CHAPTER 1: BIOLOGICAL CLASSIFICATION, Two kingdom system of classification., , , , , Proposed by Carolous Linnaeus, He divided all living organisms in to two - Kingdom Plantae & Kingdom Animalia, , Drawbacks, , , , , , , It did not distinguish between eukaryote & prokaryote, unicellular & multicellular, organisms & photosynthetic (green algae) & non- photosynthetic (Fungi) organisms., Based on the presence of cell wall prokaryotes (bacteria & cyanobacteria) were, included under plants. But they are widely differed in other characteristics., Unicellular & multicellular organisms were placed under algae., Eg:- Chlamydomonas & Chara., Fungi are heterotrophic & they have chitinous cell wall, while the green plants are, autotrophic & have cellulose in cell wall. Both comes under same group., , Five Kingdom classification, , , , , , Proposed by R.H Whittaker (1969), It includes Monera, Protista, Fungi, Plantae & Animalia., This classification is based on cell structure, thallus organisation, mode of nutrition,, reproduction & phylogenetic relationship

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6, , 1. Kingdom Monera (BACTERIA), , , , , , Bacteria are the most abundant micro organisms. Bacteria occur almost everywhere., Hundreds of bacteria are present in a handful of soil., They also live in extreme habitat such as hotsprings, deserts, snow & deep oceans, where few other life forms can survive. Many are parasites., Bacteria are grouped under 4 categories based on their shape, Coccus - Spherical, Bacillus - rod - shaped, Vibrium - comma - shaped, Spirillum - spiral, , , , , , , Bacterial structure is very simple but, they are complex in behaviour., Bacteria show most extensive metabolic diversity., Some bacteria are autotrophic (they synthesis their own food from inorganic, substrate.), The vast majority of bacteria are heterotrophic. (They do not synthesis their own food,, but depend on other organism/ on dead organic matter for food)., , Kingdom monera is classified into three, 1. Archaebacteria, , , , , These bacteria live in extreme salty areas (halophiles), hot springs, (thermoacidophiles), & marshy areas (methanogens)., Archaebacteria survive in extreme condition because they have different cell wall, structure., Methanogens are present in the gut of several ruminant animals (cow, buffaloes etc.)., They produce methane (biogas) from dung of these animals., , 2. Eubacteria (True bacteria), , , , , Known as true bacteria, They are characterized by the presence of rigid cell wall & flagellum (if motile)., Cyanobacteria, chemosynthetic autotrophic bacteria and heterotrophic bacteria are, included in Eubacteria.

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7, , (i) Cyanobacteria (Photosynthetic autotrophs), , , , , , , Known as Blue green algae, They are unicellular, colonial or filamentous, fresh water or marine or terrestrial, algae., The colonies are generally covered by a gelatinous sheath., They often form bloom in polluted water., Some of these organisms can fix atmospheric nitrogen in specialized cell called, heterocyst., Eg:- Nostoc & Anabaena., , (ii) Chemosynthetic autotrophic bacteria., , , , It oxidizes various inorganic substrate such as nitrite, nitrate & ammonia & use the, released energy for ATP production., They play a great role in recycling nutrients like nitrogen, phosphorus, iron & sulphur., , (iii) Heterotrophic bacteria, , , , , , They are the most abundant in nature. They are important decomposers., They have significant impact on human affair., They are helpful in making curd from milk, production of antibiotics, fixing nitrogen, in legume root etc.., Some are pathogens causing damage to human beings, crop, farm animal & pets., Eg:- Cholera, typhoid, tetanus, citrus canker., , Reproduction, , , , , Bacteria reproduce mainly by fission., Under unfavorable conditions they produce spores., They reproduce sexually by adopting a primitive type of DNA transfer from one, bacterium to other., (iii) Mycoplasma, , , , They completely lack a cell wall., They are the smallest living cell known.

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8, ,  They can survive without oxygen.,  They are pathogenic in animals & plants., II. Kingdom protista, , , , , , It includes all single celled Eukaryotes., They are aquatic., This kingdom form a link with others dealing with plants, animals & fungi., Their cell body contain a well defined nucleus & other membrane bound cell, organelles.,  Some have flagella/Cilia., Reproduction, , , , They reproduce asexually & sexually by a process involving cell fusion & zygote, formation., It includes chrysophytes, Dinoflagellates, Euglenoids, slime moulds & protozoans., , (a) Chrysophytes,  It includes diatoms & golden algae (desmids),  They are found in freshwater as well as marine environment.,  They are microscopic & float passively in water current (plankton),  Most of them are photosynthetic., Diatoms, , , In diatom, the cell wall form 2 thin overlapping shell, which fit together as a soap, box.,  Cell walls are embedded with silica, thus walls are indestructible. Thus, diatoms have, left behind large amount of cell well deposit on their habitat, this accumilation over, billions of years is referred as diatomaceous earth. Being gritty, this soil is used in, polishing, filteration of oil & syrups.,  Diatoms are the chief producers in ocean., (b) Dinoflagellates, , , , , , , They are mostly marine & photosynthetic., They appear yellow, green, brown, blue or red depending on main pigment present in, their cell wall., Their cell wall has stiff cellulose plate on the outer surface., Most of them have two flagella. One lies longitudinally & other transversely in the, furrow between wall plates., Red dinoflagellates (Eg:- Gonyaulax) undergo rapid multiplication that they make the, sea appear red (red tide). Toxin released by such large number may even kill other, marine animal such as fishes.

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9, , (c) Euglenoids, , , , , , , They are freshwater organisms found in stagnant water., Instead of a cell wall, they have a protein rich layer called pellicle which makes their, body flexible., They have 2 flagella a short & long one., Though they are photosynthetic in the presence of sunlight, when deprived of sunlight, they behave like heterotrophs by predating other small organism., The pigment of Euglenoids are identified to those present in higher plants., Eg:- Euglena., , (d) Slime moulds, , , , , They are saprophytic protists., The body moves along decaying twigs & leaves engulfing organic material., Under suitable conditions, they form an aggregation called plasmodium which may, grow & spread over several feet.,  During unfavourable condition, plasmodium differentiate & form fruting bodies, bearing spores at their tip.,  The spore possess true wall. They are extremely ressistant & survive for many years,, even under adverse conditions. The spores are dispersed by air currents., (e) Protozoans,  They are heterotrophs and behave as predator or parasitic,  There are primitive relatives of animals.,  Their are 4 major group of protozoans., (i) Amoeboid Protozoans, , , , These organisms grow in fresh water, sea water or moist soil., They move & capture prey by putting out pseudopodia (false feet), Eg:- Amoeba., ,  Marine forms have silica shell on their surface.,  Some are parasite Eg:- Entamoeba., (ii) Flagellated protozoans., , , , , They are free- living or parasite., They have flagella., The parasite form cause disease., Eg:- Trypanosoma causing sleeping sickness., , (iii) Ciliated protozoans, , , , , , They are aquatic, They have thousands of cilia., They have a cavity (gullet) that opens to outside of cell surface., The co- ordinated movement of rows of cilia cause the water laden with food to be, steered into gullet., , Eg:- Paramoecium

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10, , (iv) Sporozoans., , , , It includes diverse organisms that have infectious spore like stage in their life cycle., Plasmodium (malarial parasite) cause malaria., , III. KINGDOM FUNGI, , , , , It’s a unique kingdom of heterotrophic organism., Fungi are cosmopolitan & occur in water, soil, air & on animals &plants., They prefer to grow in warm & humid places., Eg:- bread mould, orange rots, mushroom, toadstool etc.., , , , , Some unicellular fungi are used to make bread & beer. Eg:- yeast, Fungi cause disease in plants & animals., Eg:- Puccinia causing rust in wheat., , , , Some are source of antibiotics., Eg:- Penicillium., , , , , Except yeast, fungi are filamentous., Their body consist of long, slender thread like structure called hyphae. The network, of hyphae is called mycelium., Some hyphae are continuous tube filled with multinucleated cytoplasm called, coenocytic hyphae. Others have septae or cross wall in their hyphae., Cell walls of fungi are composed of chitin and polysacchrides., Most fungi are heterotrophic and absorb soluble organic matter from dead substrate, and are called saprophytes., Some are parasites, Some are symbiotics., Eg:- Lichen (Fungi in association with algae)., , , , , , , , Mycorrhiza (Fungi inhabiting in the root of higher plants)., Reproduction, , , , , Vegetative reproduction:- By fragmentation, Fission and budding., Asexual reproduction :- By spore called conidia or sporangiospore or zoospores, Sexual reproduction:- By Oospore, ascospore, and basidiospore., · They are produced in distinct fruiting bodies., · The sexual cycle involves 3 steps., Plasmogamy - Fusion of protoplast between two motile or non- motile gametes., Karyogamy - Fusion of two nuclei, Meiosis in zygote results in haploid spores., , , , , , When a fungus reproduce sexually, two haploid hyphae of compatible mating type, come together and fuse., In some fungi, fusion of two haploid cell immediately results in diploid cell (2n), In other fungi (ascomycetes & basidiomycetes) an intervening dikaryotic stage (n+n, ie, 2 nuclei per cell) occurs. Such a condition is called dikaryon& the phase is called, dikaryotic phase of fungus. Later, the parental nuclei fuse & cell become diploid., , Vijayabheri, Malappuram Dist. Panchayat Project

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13, , 4. Deuteromycetes (Imperfect fungi)., , , , , , , , , They are known as imperfect fungi because only the asexual or vegetative phase of, the fungi are known., When the sexual form of the fungi where discovered, they were moved into classes, they rightly belong to., It’s also possible that asexual & vegerative phase has been given one name (and, placed under deuteromycetes) and the sexual stage another (and placed under another, class). Later when linkages were established, fungi were correctly identified & moved, out of deuteromycetes., Once perfect (sexual) stage of members of deuteromycetes were discovered, they, were often moved to ascomycetes and bascidiomycetes., Deuteromycetes reproduce only by asexual spores (conidia)., Mycelium is septate and branched. Majority are decomposers of litter and help in, mineral cycling., Eg:- Alternaria, Colletotrichum and Trichoderma., , IV. KINGDOM PLANTAE, , , , , , , , , , It includes all eukaryotic, chlorophyll containing organisms commonly called plants., Some are partially heterotrophic such as insectivorous plants eg:- Bladderwort and, venus fly trap and parasite Eg:- cascuta., Plant cells have an eukaryotic structure with prominant chloroplast and cell wall, mainly made of cellulose., Plants include algae, bryophytes, pterido phytes. Gymnosperms and angiosperms., Life cycle of plants has 2 distinct phases., The diploid sporophyte and the haploid gametophyte, that alternate with each other., The length of haploid and diploid phase are free living or dependent on others, vary, among different group in plants., This phenomenon is alternation of generation., , V. KINGDOM ANIMALA, , , , , Its characterized by heterotrophic eukaryotic organisms, that are multicellular and, their cell lack cell wall., They directly or indirectly depend on plants for food., They digest their food in an internal cavity and store food reserve as glycogen or fat.

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14, , , , , Their mode of nutrition is holozoic - by ingestion of food., They follow definite growth pattern and grow into adult that have definite size and, shape.,  Higher forms show elaborate sensory and neuromotor mechanism.,  Most of them are capable of locomotion., Sexual reproduction, It’s by copulation of male and female followed by embryogenal developement., VI. Viruses, Viroids, Prions And Lichens., , , In five kingdom classification of Whittaker, there is no mention of some acellular, organisms like virus, viroid and lichens.,  Viruses are not ‘truly living’. So they are not included in five kingdom classification.,  Viruses are non - cellular organisms that are characterized by having an inert, crystalline structure outside the living cell.,  They are obligate parasite (They require a host cell to complete their life cycle).,  Once they infect a cell, they take over machinery of host cell to replicate themselves, and kill the host.,  In addition to protein, viruses also contain genetic material, it can be either RNA or, DNA. No virus contains both DNA and RNA.,  So virus is a nucleoprotein and the genetic material is infectious.,  In general, viruses that infect plant have single stranded RNA and virus that infect, animal have either single or double stranded RNA or double stranded DNA.,  The name virus means venom or Poisonous fluid was given by Louis Pasteur,  D.J. Ivanowsky (1892) recognized certain microbes as casual organism of mosaic, disease of tobacco.,  These are found to be smaller than bacteria, because they passed through bacteriaproof filters.,  M.W. Beijerinek (1898) demostrated that the extract of infected plant of tobacco can, cause infection in healthy plants. The fluid is called Contagium vivum fluidum, (infectious living fluid).,  W.M.Stanley (1935) showed that viruses could be crystallized and crystals consist, largely of proteins.,  Viruses that infect bacteria are called Bacteriophages.,  Bacterialviruses or bacteriophages are usually double stranded DNA virus.,  The protein coat called capsid made of small subunit called capsomeres. It protects, the nucleic acid.,  Capsomeres are arranged in helical or polyhedral geometric forms.,  Virus cause disease like mumps, small pox, herpes & influenza.,  AIDS in human is also caused by a virus (HIV).,  In plants, the attacks of virus can cause the symptom like mosaic formation, rolling, of leaf, curling of leaf, yellowing and vein clearing, dwarfness and stunted growth., Viroids, , , , , In 1971, T.O. Diener discovered a new infectious agent that was smaller than virus, and cause potato spindle tuber disease., It was found to be a free RNA, it lack protein coat that is found in viruses, hence the, name viroid., RNA of viroid was of low molecular weight., , Vijayabheri, Malappuram Dist. Panchayat Project

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15, , Prions, , , , , It is an agent consisting of abnormally folded protein which can cause infectious, neuroligical diseases., It is similar in size to viruses, The disease caused by prions are bovine spongi form encephalopathy (BSE), Commonly called mad cow disease in cattle and its analogous variant of Cr - Jacob, desease (CJD) in, humans, , Lichens, , , , , , , Lichens are symbiotic associations. ie, mutually usefull associations between algae, and fungi. Algal component is phycobiont & Fungal component is mycobiont, which, are autotrophic and heterotrophic respectively., Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients &, water for its partner., Lichens are very good pollution indicator they do not grow in polluted area., Litmus is obtained. It is commonly used as acid - base indicator in laboratories, , CHAPTER 1: PLANT KINGDOM, Eukaryotic, multicellular, chlorophyll containing and having cell wall, are grouped, under the kingdom Plantae. It is popularly known as plant kingdom., , Types of Classification System, These includes artificial system, natural system and phylogenetic system of, classification., Artificial System of Classification, This system is based on comparison of one or a few superficial characteristics, which, are helpful in easy identification of organisms. This system use only few superficial, characters (i.e., habits, numbers, colours and shapes of leaves, etc) which leads to

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16, , many organisms grouped together,, Natural System of Classification, It is also known as phenetic system of classification. The natural system of, classification is based on natural affinities among the organisms. It considers both, external and internal features like structure, anatomy, embryology and, phytochemistry., Phylogenetic System of Classification, The phylogenetic system of classification indicates the evolutionary as well as genetic, relationships among organisms. This system is based on fossil records of biochemical,, anatomical, morphological, physiological, embryological and genetical., If there is no supporting fossil evidences, we now use information from many other, sourses to help to resolve the difficulties in classification.These are the following, branches, , , , , Numerical Taxonomy use computer by assigning code for each character and, analyzing the features., Cytotaxonomy is based on cytological information like chromosome number,, structure and behaviour., Chemotaxonomy uses chemical constituents of plants to resolve the confusion., , ALGAE: These include the simplest plants which possess undifferentiated or thallus like, forms, reproductive organs single celled called gametangia. It includes only Algae., Characteristic of Algae, , , , , , , , Plant body is thallus, which may be unicellular, colonial, filamentous or, parenchymatous., Usually aquatic but a few are also found in moist terrestrial habitats like tree trunks,, wet rocks, moist soil, etc., Vascular tissues and mechanical tissues are absent., Reproduction is vegetative by fragmentation, asexual by spore formation (zoospores), and sexual reproduction by fusion of two gametes which may be Isogamous, (Spirogyra), Anisogamous (Chlamydomonous) or Oogamous (Volvox)., Life cycle is various- haplontic, diplontic or diplohaplontic., , Green Algae, Brown Algae, Mostly fresh water and sub, Mostly marine., aerial., Unicellular species are, absent., Unicellular organisms abundant., The plant body has holdfast,, stipe and frond, Chlorophyll a, c, Chlorophyll a,b, ,Fucoxanthin, Reserve food is starch., Reserve food is laminarin., Members have storage bodies, , Red Algae, Mostly marine., , Unicellular species fewer., Chlorophyll a,d, ,Phycoerythrin, Reserve food is floridean, starch., , Vijayabheri, Malappuram Dist. Panchayat Project

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17, , called pyrenoids in chloroplast, Cell wall is of cellulose., , Cell wall contains cellulose, and algin., , Zoospores present.2-8 equal, flagella,apical, , Zoospores are pyriform.2, flagella,unequal and lateral, , Chlamydomonas, Ulothrix,, spirogyra., , Focus, Sargassum,, ectocarpus., , Cell wall contains cellulose, and poly-sulphate esters., Zoospores absent.Sexual, reproduction is oogamous ., Post fertilisation, developments present, Polysiphonia, Gelidium,, Porphyra etc., , Economic importance1. A number of brown algae ( Porphyra,Laminaria, Sargassum) are used as food in, some countries., 2. Fucus, and Laminaria are rich source of Iodine., 3. Certain brown algae and red algae produce large amount of hydrocolloids (Algin and, carageen), 4. Agar obtained from Gelidium and Gracilaria used to grow microbes,used for the, preparation of icecreams and jelliies, 5. Chlorella,a unicellular green algae is used as a food suppliment, , BRYOPHYTES – They are non-vascular mosses and liverworts that grow in moist shady, region. They are called amphibians of plants kingdom because these plants live on soil but, dependent on water for sexual reproduction., Characteristic features, , , , , Live in damp and shady habitats, found to grow during rainy season on damp soil,, rocks, walls, etc. Sporophyte is dependent on gametophyte for nourishment, The dominant phase or plant body is free living gametophyte., Roots are absent but contain rhizoids, Vegetative reproduction is by fragmentation, tubers, gemmae, buds etc. sex organs are, multicellular and jacketed. The male sex organ is called antheridium. They produce, biflagellate antherozoids. The female sex organ called archegonium is flask-shaped, and produces a single egg., , Economic importance, , , , , , Some mosses provide food for herbaceous animals, Peat moss Sphagnum provide peat that have long been used as fuel,packing materials, for transhipment of living materials, Mosses along with lichens are the first organism to colonise on rocks, Prevent soil erosion, , Bryophytes are classified into1. Liverworts., , Vijayabheri, Malappuram Dist. Panchayat Project

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18, , , , , , , , The plant body of a liverwort is thalloid, e.g., Marchantia. The thallus is dorsiventral, and closely appressed to the substrate., Asexual reproduction in liverworts takes place by fragmentation, or by the formation, of specialised structures called gemmae., Gemmae are green, multicellular, asexual buds, which develops in small receptacles, called gemma cups. The gemmae becomes detached from the parent body and, germinate to form new individuals, During sexual reproduction, male and female sex organs are produced either on the, same or on different thalli. The sporophyte is differentiated into a foot, seta and, capsule. Spores produced within the capsule germinate to form, free-living gametophytes., 2. Mosses, , , , , , , , The gametophyte consists of two stages- the first stage is protonema stage, which, develops directly from spores. It is creeping, green and frequently filamentous. The, second stage is the leafy stage, which develops from secondary protonema as lateral, bud having upright, slender axes bearing spirally arranged leaves., Vegetative reproduction is by the fragmentation and budding in secondary protonema., In sexual reproduction, the sex organs antheridia and archegonia are produced at the, apex of the leafy shoots., Sporophytes in mosses are more developed and consist of foot, seta and, capsule.Common examples are Funaria, Polytrichum, Sphagnum etc., , PTERIDOPHYTES, , , , , , , , , , , They are seedless vascular plants that have sporophytic plant body and inconspicuous, gametophyte. Sporophytic plant body is differentiated into true stem, roots and leaves., Vascular tissue are present but vessels are absent from xylem and companion cells, and sieve tube are absent., Sporophytes bear sporangia that are subtend by leaf like appendages called, sporophylls. In some plants (Selaginella) compact structure called strobili or cone is, formed., Sporangia produce spores by meiosis in spore mother cells. Spores germinate to, produce multicellular thalloid, prothallus., Gametophyte bears male and female sex organ called antheridia and archegonia., Water is required for fertilisation of male and female gametes., Most of Pteridophytes produce spores of similar kind (homosporous) but in, Selginella and Salvinia, spores are of two kinds (heterosporous) larger called, megaspore that produce female gametophyte and smaller microspore that produce, male gametes., Heterospory is a precursor to seed habit:The development of zygote into young, embryos takes place within the female gametophyte which is retained on the parent, sporophyte.This event is a precursor to seed habit., , GYMNOSPERMS:, , , Gymnosperms are those plants in which the ovules are not enclosed inside the ovary, wall and remain exposed before and after fertilisation., , Vijayabheri, Malappuram Dist. Panchayat Project

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19, , , , , , , , , , , , They are perennial and woody, forming either bushes or trees. Some are very large, (Sequoia sempervirens) and others are very small (Zamia pygmia)., Stem may be unbranched(Cycas) or branched(Pinus). Root is taproot. Leaves may be, simple or compound., Roots of Pinus have fungal association to form mycorhiza, Cycas have small specilised roots called coralloid root which are associated with, nitogen fixing cyanobacteria., Leaves of gymnosperms are well adapted to withstand extreme environmental, conditions.Eg.Needle leaves reduce surface area,sunken stomata,thick cuticle, They are heterosporous, produce haploid microspore and megaspore in male and, female Strobili respectively., Male and female gametophytes do not have independent free-living existence., Pollination occurs through air and zygote develops into embryo and ovules into seeds., These seeds are naked., Example- Pines, Cycus, Cedrus, Ginkgo, etc., , ANGIOSPERMS, , , , , , , , Pollen grain and ovules are developed in specialized structure called flower. Seeds are, enclosed inside the fruits., Size varies from almost microscopic Wolfia (0.1cm)to tall tree Eucalyptus (more than, 100m, The male sex organs in a flower is the stamen. It contains pollen grain., The female sex organs in a flower is the pistil or the carpel. Pistil consists of an ovary, enclosing one or many ovules. Within ovules are present highly reduced female, gametophytes termed embryo-sacs., Each embryo-sac has a three-celled egg apparatus – one egg cell and two synergids,, three antipodal cells and two polar nuclei. The polar nuclei eventually fuse to produce, a diploid secondary nucleus., , Angiosperms are further classified into:, , , , Monocotyledons, Dicotyledons, , 1., 2., 3., 4., 5., 6., , Monocotyledons, Single cotyledons., Parallel venation., Fibrous root system., Closed vascular bundle., More number of vascular bundles., Banana, wheat, rice., , , , 1., 2., 3., 4., 5., 6., , Dicotyledons, Two cotyledons., Reticulate venation., Tap root system., Open vascular bundle., Less number of vascular bundles., Gram, mango, apple., , Double fertilisation- Each pollen grain produce two male gametes. One gametes fuse, with egg to form embryo. This is called Syngamy. Other gametes fuse with two polar, nuclei to form endosperm, triple fusion. Since fertilisation takes place twice, it is, called double fertilisation., , Vijayabheri, Malappuram Dist. Panchayat Project

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20, , Alternation of generation, Different plant groups complete their life cycles in different patterns. Angiosperms complete, their life cycle in two phases- a diploid sporophytes and haploid gametophyte. The two, follows each other. This phenomenon is called alternation of generation., Haplontic- Saprophytic generation is represented by only the one-celled zygote. Meiosis in, zygote results into haploid spores to form gametophytes, which is the dominant vegetative, phase. Example- Volvox, Spirogyra etc., Diplontic- Diploid sporophytes is dominant, independent, photosynthetic plants. The, gametophyte is represented by single to few celled. All seed bearing plants fall under this, category., Haplo-diplontic- Both phases are multicellular and intermediate condition is present. It is, present in Bryophytes and Pteridophytes., , CHAPTER: 3 MORPHOLOGY OF FLOWERING PLANTS, ROOT (Underground non-green part), Arised from radicle, , Taproot system, , Arised from any part other than radicle, , Fibrous root system, , Adventitious root system, , Primary root & its, , Short lived primary root, , eg., Banyan tree,, , branches (network, , replaced by large number, , beetle, pepper etc, , like arrangement), , of roots. (roots arised, , eg., Dicot plants, , from base of the stem)., Eg., Monocot plants, , Regions of root, 1. Root cap – Thimble-like structure which cover the root tip . It Protects the root tip, 2. Region of Meristemmatic activity – Small, thin walled cells with dense protoplasm., They divide repeatedly., 3. Region of elongation – Undergo rapid elongation & enlargement. Responsible for, growth in length., 4. Root hair – Fine, delicate ,thread-like structures present on epidermis. They absorb, water & minerals., , Vijayabheri, Malappuram Dist. Panchayat Project

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21, , 5. Region of maturation – Region just above the region of elongation. Root hairs &, lateral branches are arised from this region. Mature tissues perform specific, functions, , Modifications of Root, , (Roots change their shape & structure to perform special, , functions), , , , , , Modification for Storage -eg., Carrot, Beetroot, Radish, Sweet potato , Mango ginger, , Asparagus etc., Modification for Climbing - eg., betle, pepper, etc, Modification for Support – (1) Prop root (Pillar like roots from branches) eg.,, Banyan tree. (2) Stilt root (Roots from lower nodes) eg., Maize & Sugarcane., Modification for Respiration - Pneumatophores (Roots grow vertically upwards to, get Oxygen). eg., Rhizophora (growing in marshy areas), , STEM, , , , , , , Aerial , green part which bear branches, leaves, flowers & fruits., Nodes – Region where leaves are born, Internodes – Portion between two nodes., Stem bears Buds, Axillary /Terminal, Underground parts are not always root. Potato, Ginger etc are Unerground Stems, which store food. Nodes & Internodes are present in them., , Modification of Stem –(Stem modified to perform special functions), , , , Under ground Stem modification for Storage & Vegetative reproduction –eg.,, Potato, Ginger, Yam, Onion, Colochasia, Tamarind etc., Sub aerial Stem modification for Vegetative reproduction :1. Runner eg., Grass, Strawberry, Oxalis etc (have long Internodes. leaves &, roots arised from nodes)., 2. Stolon –eg., Mint, Jasmine etc ( Lateral branch from base of main stem grow, aerially for sometime & arch downwards to touch the soil)., 3. Offset –eg., Pistia, Eichhornia etc (Short internode. Rosette of leaves & tuft, of roots arised from node).

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22, , , , , , 4. Sucker – eg., Banana, Pineapple, Chrysanthemum etc (lateral branch from, underground &basal part of stem grow horizontally & then come out to grow, vertically upward), Modification for Photosynthesis – eg., Opuntia (flattened stem) , Euphorbia (fleshy, cylindrical stem), Modification for Climbing – eg., Tendril (Slender ,spirally coiled structure develop, from axillary buds) in Cucumber, Bittergourd, Pumpkin,Watermelon, Grapevines etc., Modification for Protection – eg., Thorns (Woody, straight&pointed structure, develop from Axillary bud) in Citrus, Bougainvilla etc., , LEAF, , , , , , Lateral, green flattened structure born on stem, Develops at node & bear Bud (Axillary bud later develops to branch) in its axil., Originate from shoot apical meristem & arranged in an Acropetal order, Function – Photosynthesis., , Parts of leaf, , , , , , Leaf base – Attach leaf to stem. It bear two lateral leaf like structures (Stipule)., Sheathing leaf base - Leaf base expands into a sheath covering the stem partially, /wholly eg., Monocots. Pulvinous leaf base – Swollen leaf base eg., Pea plants., Petiole Stalk of leaf which hold lamina to light & allow lamina to flutter in the wind., Lamina / Leaf blade – green expanded part with Veins ( It provide rigidity to lamina, & channels of transport of water, minerals and food) & Veinlets. Middle prominent, vein is Midrib., , Venation (Arrangement of veins on lamina), Reticulate venation, Veins & Veinlets, , are arranged in the, , form of a network. eg., Dicot plants, , Parallel venation, Veins are arranged parallel to one another., eg., Monocot plants.

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23, , Types of Leaf, , Simple leaf, Lamina, , is, , entire,, , Compound leaf, or, , when, , inscise,, , inscisions do not touch the midrib. eg.,, , Inscisions of the lamina reach up to the, midrib. Lamina divided into leaflets., , china rose, , Pinnately compound leaf, Number of leaflets, , are, , arranged on a, , Palmately compound leaf, Leaflets are attached at a common, , common axis called rachis. eg., Tamarind,, , point ie.,, , at the tip of petiole. eg.,, , curry leaf, neem etc, , Silk cotton, Tapioca, , A bud is present in the axil of petiole in both simple & compound leaves, but not in the axil, of leaflets of compound leaf., , Phyllotaxy ( Arrangement of leaves on stem or branch), Alternate, Single leaf from each node in, , Two leaves from each node, , More than two leaves from one, , alternate manner. eg., china, Opposite, rose,mustard, sunflower etc., , & lie opposite to each other., Whorle ,, eg., Guava, calotropis, , node, , &, , form, , a whorl., , Alstonia, Allamanda etc, , ixora etc, , Modification of leaf, , , , , , , Modification for storage – Scale leaves – Fleshy leaves of onion & garlic., Modification for climbing – Tendrils – Spirally coiled structure. eg., Pea, Gloriosa, Modification for defence & to reduce transpiration - Spine leaf - eg., Cactus, Modification for photosynthesis – Phyllode –eg., In Acacia, leaves are small &, short lived. So Petiole expand, become green to perform photosynthesis., Modification to catch insects - eg., Pitcher plant , venus-fly-trap ., , Vijayabheri, Malappuram Dist. Panchayat Project, , eg.,

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24, , INFLORESCENCE (arrangement of flowers on floral axis), Racemose, , Cymose, , Peduncle (main axis ) continues to grow, (unlimited growth). Flowers borne laterally, in an Acropetal succession. eg.,Crotalaria, , Main axis terminates in a flower, (limited growth). Flowers borne in, a Basipetal succession. eg.,, Jasmine, , FLOWER – Reproductive Part in Angiosperm, Flower is a modified shoot – Shoot apical meristem changes to floral meristem. Internodes, do not elongate. Axis gets condensed. Apex produce floral whorls laterally at successive, nodes instead of leaves. When a shoot tip transforms into a flower, it is always Solitary., Pedicel, , Stalk of flower, , Thalamus/ Receptacle, , Swollen tip of pedicel from which floral whorls arises., , Bisexual flower, , Flower has both androecium & gynoecium. eg., Ixora, , Unisexual flower, , Flower having either androecium /gynoecium eg., Cucumber, , Actinomorphic symmetry, , Flower can be divide into two equal parts in any radial plane passing, through the centre eg., Mustard, Datura, Chilli, Shoe flower etc, , Zygomorphic symmetry, , Flower can be divided into two equal parts only in one plane eg., Pea, Gulmohur, Bean, Cassia etc, , Asymmetric, , Flower cannot be divided int two equal parts by any vertical plane, passing through the centre . eg., Canna, , Trimerous flower, , Floral whorls are 3 /multiples of 3 in number, , Tetramerous, , Floral whorls are 4 /multiples of 4 in number, , Pentamerous, , Floral whorls are 5 /multiples of 5 in number, , Bract, , Reduced leaf found at the base of the pedicel ( flower with bract –, Bracteate. Flower without bract – Ebracteate), , Aestivation, , Arrangement of sepal / petals in floral bud with respect to other, members of same whorl., , Placentation, , Arrangement of ovules within the ovary, , Epipetalous, , Stamens are attached to petals eg., Brinjal, , Epiphyllous, , Stamens are attached to perianth eg., Lilly, , Vijayabheri, Malappuram Dist. Panchayat Project

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25, , Monoadelphous, , Stamens are united to form single bundle eg., Shoe flower, , Diadelphous, , Stamens are united to form 2 bundles eg., Pea, Crotalaria, , Polyadelphous, , Stamens are united to form more than 2 bundles eg., Citrus, , Staminode, , Sterile stamen, , Parts of flower, , , Calyx - Outer, green whorl. Its members are Sepals.. It Protect flower in the bud stage., May be Gamosepalous (united sepals) or polysepalous (free sepals.), , , , Corolla _ Second whorl. Members are petals (brightly coloured to attract insects for, , , , pollination) gamopetalous (united petals) .polypetalous (petals free). Shape of corolla may, be varied., Perianth – Undifferentiated calyx and corolla. Members are Tepals.., , Androecium _Male reproductive organ. Composed of stamens (consists of filament, , , , & anther).Anther, er is bilobed & each lobe has two chambers (pollen_sacs in which pollen, grains are produced). Stamens in a flower may either remain free (Polyandrous, (Polyandrous) or united ., Length of the filament in a flower may be varied eg., Salvia & Mustard., Fem reproductive organ. Basic unit is carpel. Carpel consists of 3, Gynoecium – Female, , , , parts (Ovary (enlarged basal part), Style (elongated tube) & Stigma (Receptive surface for, pollen grain). Ovary bear ovules. Ovules are attached to flattened, cushion like Placenta., Ovary may be Monocarpellary ( one carpel) or Multicarpellary ( more than 1 carpel)., Carpels may be Apocarpous (free carpels eg., lotus, rose )or Syncarpous ( united carpels, eg., Mustard & tomato). Later Ovules develop into seeds and Ovary into Fruit., Aestivation, , Valvate, , Twisted, , Sepals /Petals in a, , Regular, , whorl just touch one, , eg.,, , another without, , ladies finger, cotton, , overlapping, , overlapping, , Shoe, , flower,, , Imbricate, , Vexillary, , Irregular, overlapping, , 5 petals. 1 large standard, eg.,, , cassia, gulmohur etc, , petal, , overlap 2 wing, , petals, , which, , overlap, , 2, , in, , turn, , unite, , keel

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26, , Placentation, , Marginal, Placenta forms a ridge, along the ventral, suture of the ovary,, ovules are borne on, this ridge forming two, rowseg., Pea, , Axile, Ovules on, central axis of, syncarpous, ovary, septa, present eg.,, china rose,, tomato, lemon, , Parietal, Ovules, Develop on, inner wall, of ovary., eg.,, mustard,, Argemone., , Freecentral, Ovules on, central axis,, septa absent, eg.,, Dianthus, &Primrose, , Basal, Single ovule at the, base of the ovary, eg., Sunflower,, Marigold, , Flower, , Perigynous, , Hypogynous, Epigynous, Gynoecium occupies the, highest, , position,, , other, , parts are situated below it., Ovary, , superior., , Gynoecium situated in the, , Margin of thalamus grows upward, , centre., , Other, , enclosing the ovary completely &, , located, , on, , fused with ovary. other parts arise, , thalamus almost at the same, , above the ovary . Inferior ovary., , level. Half inferior ovary, , eg., Guava, Cucumber, ray florets, , eg., Pea, Plum, Rose,Peach ,, , of sunflower, Ixora etc., , the, , parts, rim, , are, of

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27, , Fruit, , , , , , , Ovary is developed into fruit after fertilization, Pericarp- Fruit wall., Fleshy fruit – Pericarp is thick & fleshy. Pericarp is differentiated into outer Epicarp, , middle Mesocarp and inner Endocarp. In mango, mesocarp is fleshy. In coconut,, mesocarp is fibrous., In mango & coconut, fruit is known as Drupe, , Seed, , , , , , , , , , , , Ovule developed into seed after fertilization., Seed coat - Outermost covering of seed. It has two layers, outer testa, & inner, tegmen., Hilum – Scar on the seed coat through which seeds were attached to fruits., Micropyle – Small pore just above the hilum., Embryo – Zygote developed into embryo. Consists of embryonal axis &, cotyledon., Cotyledon first formed leaf. Fleshy & reserve food material ( give food to, developing seedling), Radicle- Part of embryo that develops into root, Plumule – Part of embryo that develops into shoot, Endosperm – Nutritive tissue for embryo., Dicot seeds contain two cotyledons & monocot seeds contain one cotyledon, Seed, , Endospermous / Albuminous, Seeds, , which, , endosperm., ,orchids etc., , store, , their, , food, , Non-endospermous / Exalbuminous, in, , Endosperm is not present in mature seeds. Store, , eg., castor, rice, coconut, , their food in cotyledons. eg., bean, pea, gram,, etc, , Monocot seed, , , , , Most of the monocot seeds are endospermic, but orchid is non-endospermic., In the seeds of cereals like maize, membraneous seed coat fused with fruit wall.

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30, , Economic importance, , , , , Edible – onion, garlic, asparagus etc., Ornamentals- Tulip, gloriosa etc, Medicine- Aloe (kattarvazha), Colchicum. Autumnale (produce Colchicine), , CHAPTER 4: ANATOMY OF FLOWERING PLANTS, origin and common function. Based on the, Tissues - Group of cells having common origin, dividing capacity, they are classified into two Meristematic Tissues, , and, , Permanent, , tissues Meristems- Actively dividing cells. Based on the position, they are divi, divided into 3., Apical, intercalary & lateral meristems., 1. Apical meristem,  Occur at the tip of root & shoot,  Primary meristem (produce primary tissues),  Appear early in the life of a plant,  Function – Growth in length.,  Axillary buds - Left out cells of shoot apical meristem (during the formation of, leaf & elongation of stem). They are present in the axils of leaves & are capable of, forming a branch / Flower., 2. Intercalary meristem,  Occurs between permanent tissues (mature tissues),  Occur in grasses (nodes of monocot plants) and regenerate parts removed by th, the, grazing herbivores,  Primary meristem (produce primary tissues),  Appear early in life of a plant., 3. Lateral meristem,  Occurs in the mature regions of root and shoot.,  Cylindrical meristems,  Secondary meristem (produce secondary tissues)

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31, , , , , , Appear later in the life of plant than primary meristem., Function –Secondary thickening (increase in girth / Produce woody axis), eg., Vascular cambium & Cork cambium., , Permanent tissues – Structurally & functionally specialized cells lose the ability to divide., Permanent tissues are classified into two. Simple Tissues (made up of only one type of cells), and Complex Tissues (Made of more than one type of cells & these work together as a unit)., , Simple Tissue, 1. Parenchyma,  Generally isodiametric in shape. They may be spherical, oval, round,, polygonal or elongated in shape.,  Thin cellulosic cell wall,  They may either be closely packed or have small intercellular spaces.,  Perform various functions like photosynthesis, storage & secretion, 2. Collenchyma,  Cells thickened at the corners due to the deposition of cellulose,, hemicelluloses & pectin.,  Oval, spherical or polygonal in shape,  Intercellular space absent,  Cells assimilate food when they contain chloroplast,  Provide mechanical support to growing parts of the plant such as young stem, & petiole of a leaf, 3. Sclerenchyma,  Cell walls are thickened due to the deposition of lignin,  Dead cells without protoplasts,  On the basis of variation in form, structure, origin & development, sclerenchyma may be either fibres or sclereids.,  Fibres- Thick walled, elongated & pointed cells generally occurring in groups,  Sclereids – Spherical, oval or cylindrical ,highly thickened dead cells with, very narrow cavities . Found in the fruit walls of nut, pulp of fruits (like, guava, pear, & sapota ), Seed coat of legumes and leaves of tea.

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32, , Parenchyma, , Collenchyma, , Sclerenchyma – fibre & sclereid, , Complex Tissues, 1. Xylem,  Conducting tissue for water & minerals ( from root to stem & leaves),  Provide mechanical strength to plant parts.,  Composed of 4 types of cells, (a) Tracheids -Elongated, Elongated /tube like cells. Thick & lignified walls (Inner, layers of cell walls have thickenings) . Tapering ends. Dead & without, protoplasm., (b) Vessels – Long Cylindrical tube, tube-like, like structure made up of many cells, called vessel members ( each with lignified walls & large central cavity)., Dead cells without protoplasm. Vessel members are interconnected, through, hrough Perforations in their common walls., (c) Xylem fibres – Sclerenchyma fibres .Dead cells. Highly thickened walls., Obliterate central lumen. Septate /Aseptate., (d) Xylem parenchyma - Living thin walled cells with cellulosic cell wall., Store food materials in the form of starch / fat and other substances like, tannins. Radial conduction occur through Ray parenchymatous cells.,  Gymnosperms lack Xylem vessels ( vessel is a characteristic feature of, Angiosperm).,  In flowering plants (Angiosperms), Tracheids & vessels, vessels are main transporting, elements.,  Protoxylem – First formed primary xylem. Small vessels,  Metaxylem – Later formed primary xylem. Large vessels,  Endarch xylem – Protoxlem lies towards the centre & Metaxylem towards, Periphery eg., Stem.,  Exarch xylem – Protoxylem, Protoxylem lies towards periphery & metaxylem towards, centre eg., Root., 2. Phloem,  Transport food materials ( usually from leaves to other parts),  Composed of 4 type of cells., (1) Sieve tube elements – Living ,long tube- like structures. Arranged, longitudinally. Associated with companion cells. End walls are perforated

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33, , in a sieve like manner & form sieve plates. Mature sieve element, possesses peripheral cytoplasm & large vacuole. Nucleus absent., Functions of sieve tubes are controlled by nucleus of companion cells., (2) Companion cells – Specialised parenchymatous cells. Connected with, sieve tube elements by Pit fields present between their common wall., Dense cytoplasm & nucleus present. Helps in maintaining the pressure, gradient in the sieve tubes., (3) Phloem parenchyma - Living parenchymatous cells. Elongated, cylindrical, with dense cytoplasm & nucleus. Cellulosic cell wall. Cells, are connected with each other through plasmodesmata. Store food &, other substances like resins, latex & mucilage. Absent in Monocots., (4) Phloem fibres (bast fibres) – Sclerenchymatous fibres. Absent in, primary phloem .Present in secondary phloem. Dead, Lignified, elongated, , branched cells with pointed (needle like) end walls. Provide mechanical, strength. Phloem fibres of jute, flax & hemp are used commercially.,  Gymnosperms have albuminous cells & sieve cells ( Sieve tubes &, companion cells are absent in gymnosperm).,  Protophloem – First formed primary phloem with narrow sieve tubes.,  Metaphloem – Later formed Primary phloem with bigger sieve tubes., , Xylem- trachieds & vessels, , Phloem, , Epidermal Tissue System, , , , , , , Outermost covering of the whole plant body .It consists of Epidermis, Stomata,, Trichome , hair & cuticle., Epidermis – Outermost layer. Elongated compactly arranged cells , forms a, continuous layer. Single layered parenchymatous cells with small amount of, cytoplasm & large vacuole. Function :- Protection, Cuticle – Waxy thick layer which cover epidermis. It prevents the loss of water., Absent in roots., Stomata – Pores present in epidermis of leaves & young stems. Stoma /Stomatal, pore is surrounded by Guard cells ( in dicot bean shaped guard cells & in monocots, dumb-bell shaped guard cells are present) .Outer walls of guard cells are thin & the, inner walls are highly thickened. Guard cells possess chloroplast & it regulate, opening and closing of stomata. Guard cells are surrounded by Subsidiary cells, (specialised epidermal cells) which are specialised in shape and size. Stomatal pore,, guard cells & subsidiary cells together known as Stomatal apparatus. Function –, Removal of excess water through transpiration & Exchange of gases.

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34, , Dicot, , , , , and, , Monocot, , stomata., , Root hair – Unicellular elongations of epidermal cells. Absorb water & minerals, from the soil., Trichomes / Stem hair – Multicellular, branched / unbranched & soft / stiff. May be, secretory. Prevent water loss due to transpiration., trans, , Ground Tissue system, , , , , All tissues except epidermis & vascular bundles., Consists of simple tissues, Cortex, pericycle, medullary ray , pith & mesophyll in leaf constitute ground tissue, system., , Vascular Tissue System, , (Xylem & Phloem together constitute Vascular bundles.), , Conjoint vascular bundle :- Xylem & Phloem are in the same bundle on the same radius., Phloem located on the outer side of Xylem eg., Stem., , , , Open vascular bundle – Cambium present in between Xylem & Phloem ( So able to, form secondary xylem & phloem) eg., Dicot stem., Closed vascular bundle – Cambium absent ( do not form secondary xylem &, phloem) eg., Monocot stem., , Radial vascular bundle :- Xylem & Phloem occur in separate bundles on different radius., eg., Root., , Conjoint closed., , Conjoint open., , Radial., , Dicot Root, , , , Ouermost layer is Epiblema (Epidermis) Unicellular root hairs arise, rise from, epidermal cells., Cortex – Several layers of thin walled parenchymatous cells with intercellular space, below the epidermis.

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35, , , , , , , , , , Endodermis – Innermost layer of cortex. Single layer of barrel- shaped cells without, intercellular space. Waxy material Suberin is deposited on the walls of endodermis, (Casparian thickening) .So endodermis is impermeable to water., Pericycle – Few layers of thick walled parenchymatous cells , next to endodermis., Initiation of lateral roots & vascular cambium takes place in these cells., Pith – Small / inconspicuous, Conjunctive tissue – Parenchymatous cells between the xylem & phloem., Radial vascular bundle – 2-4 xylem & phloem bundles. Exarch xylem., Stele – All tissues on the innerside of the endodermis such as pericycle, vascular, bundles & pith., , Monocot Root, , -It has outer Epidermis, Cortex, Endodermis, Pericycle, Radial vascular, , bundles , conjunctive tissue & pith similar to dicot root, , Difference between Dicot & Monocot root, Dicot root, In the cortex Air cavity absent., , Monocot root, Air cavity present in the cortex, , 2-4 Xylem & Phloem bundles, , More than six (polyarch) xylem & phloem bundles., , Small pith, , Large & well developed pith, , Polygonal shaped xylem, , Round shaped xylem, , Undergo secondary growth, , Do not undergo secondary growth, , Dicot stem, , , , Epidermis – Outermost protective layer ,covered with a thin layer of cuticle , may, bear Trichomes & few stomata., Cortex – Several layers between epidermis & pericycle. It consists of 3 sub-zones.

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36, , , , , , , 1. Hypodermis – Few layers of collenchymatous cells just below the epidermis,, which provide mechanical strength to young stem., 2. Rounded thin walled parenchymatous cortical cells with intercellular space., 3. Endodermis – Innermost layer of cortex. Cells are rich in starch grains , So the, layer is Starch sheath., Pericycle – Innerside of the endodermis and above the phloem in the form of semi –, lunar patches of sclerenchyma (Bundle cap)., Medullary ray – Few layers of radially placed parenchymatous cells in between, vascular bundles., Conjoint, open vascular bundle with endarch xylem., Pith – Large number of rounded parenchymatous cells with large intercellular spaces,, occupies the central portion of the stem., , Monocot Stem –, , , , , , , It has Epidermis & Sclrenchymatous Hypodermis., Numerous vascular bundles (Conjoint, closed, endarch xylem)., Peripheral vascular bundles are smaller than centrally located ones., Phloem parenchyma absent., Water containing cavities are present within the vascular bundle., , Difference between Dicot & Monocot stem, Dicot stem, , Monocot stem, , Collenchymatous hypodermis, , Sclerenchymatous hypodermis, , Differentiated cortex, , Undifferentiated cortex, , Bundle cap present, , Bundle sheath present

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37, , Limited number of vascular bundles, , Numerous Vascular bundles, , Vascular bundles arranged in the form of a ring, , Scattered vascular bundles, , Open vascular bundle ( cambium present), , Closed vascular bundles ( Cambium absent), , Well developed pith, , Pith absent, , Undergo secondary growth, , Do not undergo secondary growth, , Protoxylem lacunae (water containing cavity) Protoxylem, absent, , lacunae (water containing, , cavity) present, , Difference between Root & Stem, Stem, , Root, , Conjoint vascular bundle, , Radial vascular bundle, , Endarch xylem, , Exarch xylem, , Multicellular hair (Trichome), , Unicellular root hair, , Cuticle present, , Cuticle absent, , Dorsiventral (Dicotyledonous) Leaf, , , , , , , , , 3 main parts. Epidermis, Mesophyll & Vascular bundle., Epidermis -Cover both upper ( adaxial) & lower ( abaxial) surface., Cuticle – Covers the upper & lower epidermis., Lower epidermis bears more stomata., Mesophyll –Tissue ( parenchymatous cells) between the upper & lower epidermis. It, possess chloroplast & carry out photosynthesis. It has 2 types of cells., 1) Palisade pa*renchyma – Elongated cells placed below the upper epidermis,, arranged vertically & parallel to each other., 2) Spongy parenchyma – Oval /round & loosely arranged parenchymatous cells, below the palisade parenchyma & extends to lower epidermis. Intercellular spaces, & air cavities are present., Vascular bundles – Present in the veins & midrib. Vascular bundles are surrounded, by a layer of thick walled bundle sheath cells., , Isobilateral (Monocotyledonous) Leaf, , , , , , 3 main parts. Epidermis, Mesophyll & Vascular bundle., Stomata are equally distributed on both upper & lower epidermis, Mesophyll is not differentiated into palisade & spongy parenchyma, Bulliform cells –Large, empty, colourless cells occur in the upper epidermis of many, grasses. When they absorb water & are turgid, leaf surface is exposed. When they are, flaccid due to water stress, they make the leaves curl inwards to minimize water loss., , Vijayabheri, Malappuram Dist. Panchayat Project

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38, , Anatomical difference between dicot & monocot leaf, Dicot leaf, , Monocot leaf, , Mesophyll is differentiated into Mesophyll is not differentiated into, palisadee & spongy parenchyma, , palisade & spongy parenchyma, , Bulliform cells absent, , Bulliform cells present, , lower epidermis, , has more Equal distribution of stomata on both, , number of stomata, , upper & lower epidermis., , Guard cells of stomata are bean Guard cells are dumbbell shaped., shaped, , Dicot leaf, , Monocot leaf, , Secondary Growth, , , , , , , Increase in thickness exhibited by most of the dicot plants., Tissue involved in secondary growth – lateral meristems ( Vascular cambium & Cork, cambium), Vascular cambium –Meristemmatic, Meristemmatic layer responsible for cutting off vascular tissues., Cork cambium – Meristemmatic layer responsible for formation of periderm., Stele- central part of root & stem consisting of pith, vascular bundles, medullary, rays & pericycle., , Stelar Secondary Thickening (by the activity of vascular cambium), , , , , , , , Intrafascicular cambium –cambium, cambium present between primary xylem & primary, phloem, Cells of medullary rays, adjoining intrafascicular cambium become meristemmatic to, form Interfascicular cambium., Intra fascicular cambium & interfascicular cambium join together to form Vascular, cambium., Vascular cambium cut off new cells towards inner & outersides. Inner cells mature, into secondary xylem & outer cells mature into secondary phloem., Cambium is more active towards innerside. So the amount of secondary xylem is, more than the secondary phloem., Primary & secondary phloems get gradually crushed, crushed due to the continued formation, & accumulation of secondary xylem.

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39, , , , Secondary medullary rays – At some places , cambium forms a narrow band of, parenchyma which passes through secondary xylem & phloem in the radial directions., , Spring wood / Early wood, , Autumn wood / Late wood, , Xylem/ Wood formed during spring season, , Xylem/ Wood formed during winter season, , Cambium is more active & produce large Cambium is less active & produce fewer xylem, number of xylem, , having, , vessels with that have narrow vessels., , wider cavities., Lighter in colour, , Dark in colour, , Lower density, , Higher density, , , , Annual ring- The alternation of spring wood & autumn wood in a concentric circle, on the trunk. Annual rings in a cut stem give an estimate of the age of tree., , Heart wood, , , , , , , Older,harder,dead central wood (xylem) of trees, Secondary xylem is dark brown in colour due to the deposition of resins, tannins, oils,, gums, aromatic substances & essential oils., Deposition of organic compounds make it hard, durable & resistant to the attack of, micro organisms &insects., Dead elements with lignified walls., Give mechanical support to stem, , Sap wood, , , , , soft outer layers of recently formed secondary xylem between heart wood & bark, Lighter in colour, Involved in the conduction of water & minerals., , Extrastelar Secondary Thickening (by the activity of cork cambium), , , Due to the activity of vascular cambium, outer cortical & epidermal cells get broken, and need to be replaced.

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40, , , , , , , , , , , , , Some cortical cells become meristemmati, meristemmatic to form Cork cambium (Phellogen) ., Phellogen is a couple of layers thick. Made of narrow ,thinwalled, rectangular cells., Cork cambium cut off cells on both sides. Outer cells differentiates into Cork, (Phellum)) & inner cells differentiates into Secondary cortex (Phelloderm, (Phelloderm)., Phellogen, phellum & phelloderm are collectively known as Periderm., Cork is impermeable to water due to suberin deposition in the cell walls., Ceils of secondary cortex are parenchymatous., Bark- All tissues exterior to vascul, vascular, ar cambium (Periderm & secondary phloem)., phloem), Early/ soft bark – Bark formed early in the season., Late/ hard bark- Bark formed towards the end of the season., Complementary cells- loosely arranged parenchymatous cells, which are cuts off by, phellogen towards outerside, uterside instead of cork cell at certain regions., Lenticels- Lens shaped opening found on the epidermis of woody trees, through, which gas exchange takes place., , Secondary Thickening In Root, , , , , , , , , Vascular cambium, um is completely secondary in origin., Tissue located just below the phloem bundles & portion of pericycle just above the, protoxylem become meristemmatic. They join together to form wavy vascular, cambium., Vascular cambium cut cells towards innerside & oute, outerside., rside. Inner cells mature into, secondary xylem & outer cells mature into secondary phloem., Cambium is more active towards innerside. So more secondary xylem is formed., Due to the continuous activity, activity,, wavy vascular cambium becomes circular., Primary & secondary phloem get gradually crushed.

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41, , CHAPTER 5: CELL-THE, CELL, UNIT OF LIFE, , , , , Cell is the structural and functional unit of life, The study of structure of cell and its organelles is called cytology., Cell was discovered by Robert Hooke., , CELL THEORY, , , , , M.J Schlieden said; the body of all plants are made up of cells., Theoder Shwann said; the body of all animals are made up of cells, Rudolph Virschow said; new cells are formed from pre-existing cells, (omniscellula -e cellula) these three constitute the cell theory., , PROKARYOTIC CELLS-Eg:, CELLS, Bacteria, Cyanobacteria, Mycoplasma, sma (PPL, (PPLO)., Bacteria can be divided into 2 groups based on their cell envelope differennces and, response to gram staining methods, thods, Gram staining, Christian gram developed a technique of staining bacteria called gram staining., Gram positive: The bacteria which take up and retain stain after the washing., Gram negative: They do not retain stain after washing., Addition to cell wall in some bacteria, bacte there is another layer –glycocalyx-It, It may be a, slime layer (loose sheath) or ca, apsule. (tough outer coat), , Mesosomes:- They are invaginations of palsma membrane. They help in respiration and, secretion., Ribosomes: The only cell organelle, nelle in prokaryotic cell, c ,70S ribosomes are seen in bacteria, Plasmids: They are extra chromosomal circular DNA present in, bacteria, Flagella: they help in locomotion. Flagellum has three parts, 1. filament, 2. hook, 3. basal body, some outgrowths are also seen on the body of bacteria. They are pili and fimbriae., fimbriae Pili are, longer the fimbria, Pili are elongated tubular structures. While fimbriae are bristle like, which help to at, attach, two bacterial cells together during, ing reproduction. Some reserve food materials in fo, form of, inclusion bodies are also present, sent in bacteria, EUKARYOTIC CELLS, 1.Cell membrane, Singer and Nicholson proposed fluid mosiac model of plasma membrane.

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42, , According to them cell membrane is made up of lipid bilayer and protein According, to Fluid Mosaic Model, Phosphoglycerides are in form two layers-bilayer. Into this, bilayer proteins are arranged in a Mosaic (scattered) manner. Some proteins are seen, completely inside the bilayer-Intrinsic (Integral) proteins and some outside the, bilayer-Extrinsic proteins and some are partially in and out., Function:,  Cell membrane protect the cells, helping transport of materials across, it-passive transport, (without energy), active transport(with energy) and osmosis.,  Due to the fluid nature, plasma membrane can help in cell growth,, formation of inter cellular junctions,secretion, endocytosis, cell, division etc, , 2. CELL WALL,  It forms the outer covering for the, plasma membrane of fungi and plants,  It is a non living rigid structure,  It has primary wall, secondary wall, and middle lamella,  Middle lamella is a layer mainly of, calcium pectate which holds the, neighbouring cells together,  The adjacent cells are connected, through fine strands of cytoplasm through, fine pores called plasmodesmata, , 3.ENDOMEMBRANE SYSTEM, It is a group of membranous organelles having co ordinate function., They include, 1. Endoplasmic reticulum, 2. Golgi bodies, 3. Lysosomes, 4. Vacuoles

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43, , i).ENDOPLASMIC RETICULUM, , , , , , , , , , Two types of ER are there Rough ER and smooth ER., In rough ER the ribosomes are attached onthe surface of ER., Protein synthesis and secretion are the functions of RER, In smooth ER, ribosomes are absent on it., The function is lipid synthesis., ii). GOLGI APPARATUS, First observed by Camillo Golgi., Golgi bodies are made up of Cisternae,Tubules and Vesicles, Functions:, Packaging of materials, It is the important site of formation of glycoproteins and Glycolipid, , 3., , Endoplasmic reticulum, , Golgi bodies, , iii).LYSOSOME,  Other wise called as suicidal bags.they contain hydrolytic, enzymes,  Function: Intra cellular and extra cellular digestion, iv).VACOULES,  They are membrane bound space in cytoplasmit contain water,sap, etc,  Its membrane is called tonoplast, a single layer membrane, Functions: Contractile vacuole helps in excretion( Eg: Amoeba), Food vacuoles are formed by engulfing the food particles.( Eg: in, Protists)

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44, , 4.MITOCHONDRIA, , , , , Discovered by Kolliker, Responsible for respiration, Otherwise called powerhouses of cell; because they, produce, store and supply energy, , , , They are double layered, outer and inner membrane, in between outer and inner membrane is a space,, peri-mitochondrial space, , , , , , , Inner membrane show several infoldings called cristae, On cristae and inner side of the inner membrane tennis racquet like structures, seen called asoxysomes, There is a fluid inside the mitochondria called matrix, They are semi autonomous; they contain DNA, RNA and 70S ribosomes., 5. PLASTIDS, Classification: Plastids are grouped into three, , 1.Chloroplast ( green plastids), 2.Chromoplast (are coloured other than green), 3.Leucoplast (are colourless plastids), Leucoplasts are divided into 3, Amyloplast [ store starch], Elaioplast [ store lipid and oil], Aleuroplast [ store protein ], Chloroplast,  Double membraneous ; outer and inner membrane,  A space in between outer and inner membrane called, peri plastidal space, , , , , Fluid inside chloroplast called stroma, Membraneous structures inside it termed as lamella, Or thylakoids, Thylakoids seen as stack; then this stack is known as, grana., , , , , Some thylakoids connect adjacent grana; termed as stroma lamella, They are semiautonomous ;they contain DNA and 70 S ribosomes., , , , , , , 6. RIBOSOME, Non-membrane covered structures., First observed by George Palade, Seen in both prokaryotic and eukaryotic cell., Each made of a large sub-unit and small sub unit.

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45, , , , , , , , , , , , , , Sub units are made up of ribonucleoproteins, (RNA + proteins)., In eukaryotic cells ribosomes seen in cytoplasm are 80S type, and those in mitochondria and chloroplasts – 70S type., ‘S’-is Svedberg unit – sedimentation co -efficient – indirectly, related to density and size., 80S = 60S + 40S, 70S = 50S + 30S, , 7. CILIA AND FLAGELLA, Cilia and flagella are hair like outgrowths of cell, membrane., Cilia are small and more in number while flagella are, longer less in number Both help in locomotion, Both flagellum and cilia has a central core called, axoneme this axoneme is made up of microtubules, Microtubules are in 9+2 condition, 9 peripheral doublet tubules and two central singlet tubules, From peripheral to central radial spokes are seen, , , , , , , , , , , , , , , , , , , 8. CENTROSOME AND CENTRIOLES, Centrosome is an organ which contain two cylindrical centrioles, Both centrioles in a centrosome is perpendicular to each other, Centrioles are made up of nine triplet tubulins, Central part is proteinaceous, Spokes are there in between peripheral tubulins and spoke, Centrioles form the basal body of cilia ,flagella and spindle fibers, , 9. NUCLEUS, It was first described by Robert Brown, Each nucleus has an envelope; it is double membraneous, [outer and inner membrane]in between outer and, inner membrane there is space called perinuclear space, Some pores are there for the nuclear envelope called, Nuclear Pore., Nucleus is filled with a fluid called Nucleoplasm, Nucleus show a spherical structure called Nucleolus., Chromatin threads seen inside the nucleus. They later form chromosomes during cell, division, Chromatin contain DNA,RNA, histone proteins and non histone proteins.

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46, , Chromosome, , , , Every chromosome has a primary constriction called centromere, On either side of the centromere there is disc shaped structures, called, kinetochore, , Types of chromosome, 1. Metacentric: Centromere is seen at the centre of chromosome, 2. Sub metacentric: Centromere is seen nearer to the centre, 3. Acrocentric: Centromere towards apex, 4. Telocentric: Centromere is terminal in position, , satellite chromosome: in some chromosomes a secondary constriction is seen. This gives, the appearance, ofa small fragment . It is the satellite., 10. Micrbodies: The membrane bound small vesicles present in animal, and plant cell is called, microbodies.They contain various enzymes., 11. Cytoskeleton : An elaborate network of filamentous , proteinaceous, structures present in the, ytoplasm is collectively called as the cytoskeleton. Cytoskeletal structures are, Microfilaments and Microtubules., , CHAPTER 6: CELL CYCLE AND CELL DIVISION, Cell cycle: The sequence of events by which a cell duplicates its genome, synthesis the other, constituents of the cell and eventually divides into two daughter cells.

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47, , Phases of cell cycle :, 1. Interphase :, a) G1 Phase: Cell metabolically active and grows continuously., b) S Phase:: DNA synthesis occurs, DNA content increases from, 2C to 4C.but the number of chromosomes remains some (2n)., (2n, c) G2 Phase: Proteins are synthesized in preparation for mitosis, while cell growth continues., 2. M Phase (Mitosis Phase):, Phase): Starts with nuclear division, corresponding to separation, of daughter chromosomes (karyokinesis) and usually ends with division of cytoplasm, (cytokinesis)., Quiescent stage (G0): Cells that do not divide and exit G1 phase, pha to, enter an inactive stage called G0. Cells at this stage remain metabolically, active but do not proliferate., , MITOSIS, 1. Prophase :, , , , , , Chromatin network condenses to form chromosomes, Each chromosomes consisting of 2 chromatids attached at, centromere, Microtubules are assembled into mitotic spindle., Nucleolus and nuclear envelope starts to disappear., , 2. Metaphase :, , , Spindle fibres attached to kinetochores (small disc-shaped, disc, structures, attached surface of centromers) of chromosomes., , , , Chromosomes, es line up at the equator of the spindle to form, metaphase plate., , 3. Anaphase :, , , , Centromeres split and chromatids separate., Chromatids move to opposite poles., , 4. Telophase :, , , , , Chromosomes cluster at opposite poles., Nuclear envelope assembles around chromosome cluster., Nucleolus, Golgi complex, ER reform, , Cytokinesis : Is the division of protoplast of a cell into two daughter

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48, , cells after Karyokinesis (nuclear division)., , , Animal cytokinesis : Appearance of cleavage 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., , Significance of Mitosis :, , , , , , , , Growth − addition of cells., Maintenance of surface/volume ratio., Maintenance of chromosome number., Regeneration,, Repair and wound healing., Reproduction in unicellular organism., , MEIOSIS, , , , , , Specialized kind of cell division that reduces the chromosome number by half,, resulting in formation of 4 haploid daughter cells., Occurs during gametogenesis in plants and animals.It takes place in reproductive, cells, Involves two cycles of nuclear and cell division called Meiosis I and Meiosis II., Interphase occurs prior to meiosis which is similar to interphase of mitosis except the, 4 haploid daughter cells are formed., Meiosis I, , I., , , , , , , Prophase I : Subdivided into 5 phases., a) Leptotene :, Chromatin network condensed to form single, strandedand thread like chromosomes., b) Zygotene :, Homologous chromosomes start pairing and this process of association is called, synapsis., Chromosomal synapsis is accompanied by formation of synaptonemal complex., Chromosome pairs of zygotene is called bivalent, c) Pachytene :

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49, , , , , , , , , , II, , e) Diakinesis :, Terminalisation of chaismata., Chromosomes are fully condensed and meiotic spindles assembled., Nucleolus and nuclear envelope disappears., Metaphase I :, , , , , III, , Bivalent chromosomes align on the equatorial plate., Microtubules from opposite poles of the spindle attach to the pair of homologous, chromosomes., , Anaphase I:, , , , IV, , Each chromosomes split longitudinally in to 2 sister chromatids. The bivalent become, tetrad with 4 chromatids., Recombination nodules appear, these are the site at which crossing over takes place, Crossing over occurs between non-sister chromatids of homologous chromosomes., d) Diplotene :, Dissolution of synaptonemal complex occurs and the recombined chromosomes, separate from each other except at the sites of crossing over. These X-shaped, structures are called chaismata., , Homologous chromosomes separate while chromatids remain associated at their, centromeres., The number of chromosomes move towards opposite poles is reduced to half, Telophase I :, , , , Nuclear membrane and nucleolus reappear., Cytokinesis follows 2 haploid daughter cells (dyad of cells)., , Interkinesis : Stage between two meiotic divisions. (Meiosis I and meiosis II), Meiosis II, It is similar to Mitosis and is also called equational division, I, Prophase II,  Nuclear membrane disappears.,  Chromosomes become compact., II, , Metaphase II

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50, , , , III, , IV, , , , , 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., Telophase II, The chromosomes in the respective poles uncoil and form the chromatin network, 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,  Formation of gametes: In sexually reproducing organisms.,  Genetic variability,  Maintenance of chromosomal number: By reducing the chromosome number in, gametes.,  Chromosomal number is restored by fertilisation of gametes., , CHAPTER : 7 TRANSPORT IN PLANTS, , CHAPTER : 7 TRANSPORT IN PLANTS, Transport of substances over along distance is through xylem and phloem. it is called, translocation. Transport of substances in xylem is unidirectional that means from root to, stem., Means of transprot, Diffusion, ,  Diffusion is a passive process, i.e here no energy is used.

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51, ,  Diffusion is the movement of substances from region of higher concentration to the, region of lower concentration., A pressure formed in the substances due to the diffusion is called diffusion, pressure.(D.P), Eg.spreading of a drop of ink in water, Diffusion rates are affected by, a) The gradient of concentration, b) The permeability of the membrane., c) Temperature, d) Pressure, , Facilitated diffusion, The diffusion take place with the help of proteins is called facilitated diffusion., Reason for facilitated diffusion., , Substances with hydrophilic moiety, find difficult to pass through the membrane., Their movement has to be facilitated., Such substances are moved by the help of proteins present tin the membrane., The diffusion rate depends on the size of substances., The smaller substances move faster., , In facilitated diffusion there is, no, , expenditure, , of, , energy., , The diffusion of substance across the membrane also, , Facilitated diffusion is very, , depends on solubility of it in lipids., , specific[ selective. ], , Lipid soluble substances move faster., Porins:-, ,  They are the proteins that form huge pores in the outer, membranes of the plastids, mitochondria and some, bacteria.,  Aquaporins are the water channels made up of eight, different types of aquaporins.

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52, , Passive symport and antiports, Uniport, , only one molecule is transported, through protein, , Antiport, , Two molecules move in opposite, directions, , Symport, , Two, , molecules move, , in, , same, , direction, , Active transport, This type of transport uses energy. It is carried out by membrane proteins. It takes, place against the concentration gradient., Comparison of different transport, Property, , Simple diffusion, , Facilitated diffusion Active transport, , Requires special membrane proteins, , No, , Yes, , Yes, , Highly selective, , No, , Yes, , Yes, , Transport saturates, , No, , Yes, , Yes, , Uphill transport, , No, , No, , Yes, , Require ATP, , No, , No, , Yes, , Water potential, This is the chemical potential of water. It is denoted by the symbol ψw., , The water potential of pure water is the maximum, it is 0., If solute is added it is decreased to negative value., Solute potential ( ψs ). and pressure potential (ψp). are thetwo components of ψw., , ψw. = ψs+ ψp, , ψs will be negative, , OSMOSIS,  Osmosis is the simple diffusion across a semi permeable membrane.,  Here water move from a region of high water potential to a region of lower water, potential.,  As a result of osmosis a pressure is exerted, is called osmotic pressure.,  If we give a pressure against the osmotic pressure the process of osmosis will stop.,  If we increase such pressure again; the osmosis takes place in reverse direction.

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53, ,  This is called reverse osmosis., osmosis,  The reverse osmosis is used for the purification of water., Osmosis are of two types.; endosmosis and exosmosis., exosmosis, Difference between endosmosis and exosmosis, , Endosmosis, , Exosmosis, , endosmosis takes place , when a, , exosmosis takes place , when a cell, , cell is placed in hypotonic, , is placed inhyper, inhypertonic solution, , solution, , Hypotonic, , solution, , During endosmosis water move During exosmosis water move out, , means, , the, , solution, , into the cell, , of the cell, , with, , comparatively, , After endosmosis cell become, , During exosmosis cell, , Turgid, , flaccid, , become, , Plasmolysis, , less concentration, , Hypertonic, , solution, , When water move out of the cell the cell (by exosmosis) membrane shrinks and, detaches from the cell wall. This process is called plasmolysis., Water lost from cytoplasm first and then from vacuole during, plasmolysis., By endosmosis the cytoplasm exerts a pressure, pr, against the cell, wall, is called turgor pressure., Imbibition, , Here water is absorbed by the solids colloids, colloid and result in the, increase in volume., Eg. Absorb water by dry seeds, dry wood., , The prerequisite for the imbibition are:, 1. water potential gradient, dient between the absorbent and the liquid imbibed, 2. affinity between the adsorbent and liquid, water absorption, water from soil is absorbed by the root hair. Then from there it is moved deeper through two, pathway., a) apoplast pathway, b) symplast pathway

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54, , Apoplast: here water moves through inter cellular spaces and cell wall., Symplast: here water move by crossing the cell membrane, and through the plasmodesmata., , Water movement in roots, , , , Root hair to cortex, , , , cortex to endodermis (apoplast way), , , , Then to xylem, , Endodermis,is impervious to water because of, casparian strip.(they are the, , band of, , suberisedmatrix in endodermal cells), , Mycorrhiza,  is a symbiotic association of a fungus with a root system.,  Thefungus increase the surface areato absorb mineral ions and water from the soil.,  The roots provide sugars and N-containing compounds to the fungus, Water movement up a plant, , Can be explained by various theories., 1. Root pressure theory, Root pressure is the pressure developed inside the root due to the accumulation of water., This pressure helps in the upward movement., Guttation, , , Ii is the process take place by the phenomenon of root pressure., , , , Guttation is the water loss from plants in the form of liquid. It takes place at the, openings of veins of leaf blade and leaf tip., , , , It occurs in herbs, and takes place in night., , 2. Transpiration pull theory, , Transpiration is a water loss process in plants. Transpiration takes place through, stomata and cuticle. Transpired water is in the form of vapour., When transpiration take place in leaves a pull is occurred, that pull affects at the root, xylem. So that pull result in the absorption of water and upward movement of water., It is because of the presence of continuous column of water in the xylem from leaf to, root.

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55, , The continuous column of water is maintained by the two special properties of water;, cohesion and adhesion, Adhesion, , Cohesion, , is the affinity between similar molecules., Here water molecules show affinity, between them., , is the affinity between the dissimilar, molecules. Here the affinity is, between, the water molecule and inner wall of, xylem., , Transpiration – merits, , 1. creates transpiration pull, 2. helps in the absorption and upward movement of water, 3. helps in the absorption and upward movement of minerals, 4. cools leaf surfaces, 5. maintains the structure and shape of plants by keeping cells turgid., Transpiration – demerits, , 1. leads to wilting and death of plant, Uptake of mineral ions, Minerals are absorbed and transported by both active and passive mode., Phloem transport, ,  The synthesisedfood from leaves is transported to different regions of the plant, through the phloem.,  Sometimes it is stored at some parts. That part is called sink.,  Form sink the food again move to different parts when it is required. So a sinkto, source transport is seen this time. So the phloem transport is a bidirectional one.,  But the xylem transport is unidirectional., Pressure flow hypothesis, ,  The glucose formed in the leaves then converted into sucrose and reach at companion, cell, and then into sieve tubes by active transport.,  This produce a hypertonic, condition inside the phloem.,  So water in the adjacent xylem, move into the phloem by osmosis.,  Then the phloem sap will move to, lower pressure area.

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56, , Girdling Experiment, , The experiment is used to identify the tissues through which, food is transported., On the trunk of a tree a ring of bark, up to a depth of the phloem layer, is removed., In the absence of downward movement of food,the portion of, the bark above the ring becomes swollen after few weeks., , CHAPTER 8: MINERAL NUTRITION, Mineral nutrition is the study of source, mode of absorption, distribution and metabolism of, various inorganic substances (minerals) by plants for their growth, development, structure,, physiology and reproduction., , Methods to study the Mineral Requirement of Plants, , , , , Hydroponics is the technique of growing plants in nutrient solution in complete, absence of soil. This method is used to determine the nutrients essential for plants., In this method plant is cultured in soil-free, defined mineral solution. These methods, require purified water and mineral nutrients., Essential elements are identified and their deficiency symptoms are discovered by, hydroponics methods. It is also used for commercial production of vegetables, like, tomato and cucumber., , Essential mineral nutrients- About 65 elements are found in different plants., Following criteria is used to determine the essentiality of an element., 1. Element must be absolutely necessary for the normal growth and reproduction to, complete their life cycle., 2. The requirement of element must be specific and not replaceable., 3. Element must be directly involved in the metabolism of plants., Macro and Micro nutrients- On the basis of diverse functions, essential elements are, divided into following categories, , , Macronutrients are present in plants tissues in larger quantity. C, H and O is obtained, from water and rest are absorbed from soil., Micronutrients or trace nutrients are required in very small quantity., , Role of Macro and Micro nutrients-

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57, , 1. Essential elements participate in various metabolic processes in plants such as, permeability of cell membrane, maintenance of osmotic potential, ETS. Etc., 2. Act as major constituents of macromolecules and co-enzymes., Various forms and function of essential nutrients1. Nitrogen- required by plants in greatest amount, it is absorbed by plants as NO2–,, NO3– and NH4+ . It is one of the major constituent of proteins, nucleic acids and, vitamins., 2. Phosphorus- Absorbed by plants from soil in the form of phosphate ions. It is the, constituent of cell membrane. All nucleic acids and nucleotides require phosphorus., 3. Potassium – absorbed as potassium ions (K+). Help to maintain cation-anion balance, in cells. It is involved in protein synthesis, opening and closing of stomata., 4. Calcium – absorbed by plants from soil in form of Calcium ions (Ca2+). Used in, synthesis of cell wall. It activates certain enzymes., 5. Magnesium- absorbed by plants in form of Mg2+ ions. It activates the enzymes for, respiration, photosynthesis, and involved in synthesis of DNA and RNA. It is, constituent of chlorophyll., 6. Sulphur- plants obtain sulphur in form of sulphate (SO42-). Present in amino acids, (cysteine, methionine) and is main constituent of coenzymes and vitamins., 7. Iron- obtained in the form of ferric iron (Fe3+). It is important constituent of protein, involved in transport system., 8. Manganese-absorbed in form of Mn2+ ions. Main function is splitting of water to, liberate Hydrogen and Oxygen during photosynthesis., 9. Zinc-obtained as Zn2+ ions. Activate enzymes like carboxylases. Needed in formation, of Auxin., 10. Copper –absorbed as cupric ions(Cu2+). Involved in various metabolic activities and, redox reactions., 11. Boron-absorbed as BO33- or B4O72- ions. Required for uptake of calcium, cell, elongation and pollen germination., 12. Chlorine – it is absorbed in form of Cl– ions. Determine the solute concentration and, splitting of water during photosynthesis., Deficiency Symptoms of Essential elements, , , , , , When supply of essential elements becomes limited, plant growth is retarded. The, concentration of essential elements below which plant growth is retarded is called, critical concentration., In absence of any particular element, plant shows certain morphological changes., These morphological changes are called deficiency symptoms., The parts of plant that show deficiency symptoms depend upon mobility of elements, in the plants. Elements that are actively mobilized (N,Mg,K) show deficiency in older, regions. On the other hand, symptoms appear first in young region if the elements are, relatively immobile (Ca) and not transported out of mature tissues., Kinds of deficiency syndrome are as follows-, , Deficiency Disease, , Deficient elements, , Chlorosis, , N, K, Mg, S, Fe, MN, Zn, Mo, , Vijayabheri, Malappuram Dist. Panchayat Project

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58, , – It is the loss of chlorophyll leading to yellowing of leaves, Necrosis -Death of tissue (leaf)., , Ca, Mg, Cu, K., , Stunted plant growth, , Fe, K., , Premature fall of leaves and buds., , P, Mg, Cu, , Inhibition of cell division, , Low level of N, K, S, Mo., , , , , , , , , , , , Deficiency of any element may cause many symptoms or same symptoms may be, caused by different elements. To identify the deficient elements various symptoms are, compared with standard chart.Toxicity of micronutrients- in higher doses,, micronutrients become toxic. Any tissue concentration which reduces dry weight of, tissue by 10% is called toxic concentration. Critical toxic concentration is different for, different elements.Mechanism of absorption of elements, It takes place in two phases. In first phase, rapid intake of ions occurs in free space or, outer space of the cells, apoplast. In second phase, ions are taken slowly into inner, space, the symplast of the cells., Passive movement of ions in apoplast occurs through ion channels and transmembrane protein. On the other hand, movement of ions into symplast occurs by, expenditure of energy by active process., The movement of ion is called flux. The inward movement is called influx and, outward movement is called efflux., Translocation of solutes occur through xylem along with ascending stream of water, , Soil as reservoir of essential elements- most of the nutrients required for growth and, development is obtained from soil by roots. These minerals are formed by weathering of, rocks. Soil also harbours nitrogen fixing bacteria and other microbes, holds water and, supplies air to roots. Deficiency of essential elements affects the crop yield. So, fertilisers are, used to supplement these elements., , Metabolism of Nitrogen, , , , , , , , , , Nitrogen is the most prevalent element in living world along with C, H and O. It is the, main constituent of proteins, nucleic acids, fats, hormones, enzymes etc., The process of conversion of nitrogen to ammonia is called nitrogen fixation. In, nature lightening and ultraviolet radiation provide energy to convert atmospheric, nitrogen into nitrogen oxide ( No, NO2 and N2O)., Industrial combustion, forest fire and automobiles along with thermal power plants, produce nitrogen oxides., The decomposition of organic nitrogen of dead plants and animals into ammonia is, called ammonification., Ammonia is first oxidized to nitrite by bacteria Nitrosomonas or Nitrococcus which is, further oxidized to nitrate with help of bacteria Nitrobactor. These processes are, called nitrification., Nitrates formed is absorbed by plants and transported to leaves. Nitrates is converted, into free nitrogen by the process called denitrificaion by bacteria Pseudomonas and, Thiobacillus., , Vijayabheri, Malappuram Dist. Panchayat Project

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59, , , , Reduction of nitrogen to ammonia by living organism is called Biological Nitrogen, Fixation. The enzyme nitrogenase is present in prokaryotic organism called nitrogen, fixer., , , , Nitrogen fixing microbes may be symbiotic (Rhizobium) or free living (Nostoc,, Azotobactor, Anabaena)., Symbiotic biological nitrogen fixation includes legume-bacteria, legume bacteria relationship in which, rod shaped Rhizobium lives with symbiotic relation with nodules, nodules of Leguminous, plants., Central portion of nodule is pink or red due to presence of leguminous haemoglobin, or leg-haemoglobin., , , , , , Nodule formation involves sequence of interaction between root and Rhizobium as followsfollows, , Nodule formation involves a sequence of, of multiple interactions between Rhizobium and roots, of the host plant. Main stages in the nodule formation are:, (i) Rhizobia multiply and colonise the surrounding of roots and get attached to epidermal and, root hair cells, (ii)The root hair curl and the bacteria, cteria invade the root hair., (iii)An infection thread is produced carrying the bacteria into the inner cortex of the root, (iv)The bacteria get modified into rod-shaped, rod shaped bacteroids and cause inner cortical and, pericycle cells to divide. Division and growth of cortical and peri cycle cells lead to nodule, formation., (v) The nodule thus formed, establishes a direct vascular connection with the host for, exchange of nutrients, (vi)The nodule contains all the necessary biochemical components, such as the enzyme, nitrogenase, trogenase and leghaemoglobin. The enzyme nitrogenase catalyses the conversion of, atmospheric nitrogen to ammonia, the first stable product of nitrogen fixation., The reaction is as follows-

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60, , , , , , The enzyme nitrogenase is highly sensitive to molecular oxygen and needs anaerobic, condition. To protect this enzyme from oxygen, the nodules contain an oxygen, scavenger called leg-haemoglobin., The ammonia synthesized by nitrogenase enzyme require large amount of energy, (18ATP) for each NH3 produced.0, , Fate of ammonia- at physiological pH, ammonia is converted into ammonium ions (NH4+).It, is toxic for plants in larger concentration and ammonium ion is converted into amino acids by, two methods1. Reductive amination– in this process ammonia reacts with α-ketoglutaric acid to, form glutamic acid., 2. Transamination– it involves the transfer of amino group from amino acids to keto, group of keto acid. Glutamic acid is the main amino acid from which transfer of NH3, takes place and other amino acids are formed by transamination. The enzyme, transaminase catalyses all such reactions., Two important amides asparagine and glutamine found in plants as structural part of proteins., They are formed from aspartic acid and glutamic acid by addition of another amino group to, it, , CHAPTER 9: PHOTOSYNTHESIS IN HIGHER PLANTS, Half leaf experiment, , , Here a part of a leaf is enclosed in a test tube, containing some KOH soaked cotton (That absorbs, CO2),, , , , while the other half is exposed to air., , , , The setup is then placed in light for some time., , , , Starch is formed at exposed part while the part inside, the test tube does not produce starch., , , , This is because of absence of starch., , Early experiments relate with photosynthesis, , 1, , Scientist, , Inference of Experiment, , Joseph preistely, , Found that air is restored by mint plant inside the bell jar of his experiment [, by using candle, mint plant and mice], , 2, , Jan Ingenhouesz, , Found air restored in light only after repeating Preistly’s experiment

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61, , 3., , Julius Von sachs, , Found glucose is produced in some green bodies[chloroplasts] during the, process of photosynthesis, , 4., , T.W Engelmann, , Found that the places where aerobic bacteria is concentrated during his, cladophora experiment, , Photosynthesis is an oxidation reduction reaction; because here CO2 is reduced and, H2O, getsoxidised, In photosynthesis Glucose is the main product and O2is bye product, here solar energy converted into chemical energy, photosynthesis completes in two phases; light reaction and Dark reaction, Difference between light reaction and dark reaction, LIGHT REACTION, , DARK REACTION, , 1. Takes place in grana, , 1. Takes place in stroma, , 2. ATP and NADPH are formed, , 2. Glucose is formed, , 3. Light dependent phase, , 3. Light independent phase, , Photosynthetic pigments, , , , They are of different colours, , , , They absorb light, of specific wavelengths., , , , They are present in grana., , , , Chlorophyll a is the major pigment responsible, for trapping light,, , , , Chlorophyll b, xanthophylls and carotenoids,, , Photosynthetic pigments, Chlorophyll a, (bright, , or, , )chlorophyll b, (yellow green), , xanthophylls, (yellow), , absorb light and transfer the energy to chlorophyll a., , , The pigments other than chlorophyll a iscalled accessory pigments., The accessory pigments protect the chlorophyll a from photo oxidation, , Action spectrum and absorption spectrum, , Absorption spectrum: It is the graph showing the, , absorption of different wavelength of light by pigments., More absorption takes place blue and red light, , blue, , green

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62, , Action spectrum: graph showing the rate of photosynthesis in different wavelength of light ., , More photosynthesis takes place blue and red light., Light harvesting complexes(LHC), , , , The LHC are made up of hundreds of pigment molecules bound to proteins., , , , These pigments absorb light and transfer energy to chlorophyll a ;[ the reaction, centre]., , , , The other pigments(except chlorophyll a ) are called antenna pigments or accessory, pigments., ,  The LHC is the part of Photosystems.,  Two photosystems are there. Photosystem I and Photosystem II (PS I and PS II),  Both PS I and PS II show the reaction centre of chlorophyll a.,  The reaction centre of PS I absorb 700 nm wavelength of light,  The reaction centre of PS II absorb 680 nm wavelength of light, , Difference between cyclic photophosphorylation and noncyclic, photophosphorylation, Cyclic photophosphorylation, , Noncyclic photophosphorylation, , Only photosystem I is involved, , Both photosystem I and photosystem II are involved, , Electrons travel in cyclic manner, , Electrons travel in non cyclic manner, , Only ATP is synthesized, , ATP and NADPH are synthesised, , No photolysis of water, , Photolysis of water occur, , No oxygen evolution, , Oxygen evolution takes place, , It is predominant in bacteria, , Predominant in green plants

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63, , Cyclic photophosphorylation, , Noncyclic photophosphorylation, , Non cyclic is also called Z scheme, because of the shape of movement of electron, Phosphorylation, , It is the production of ATP from ADP., , Photolysis, , It is the splitting of water, i.e addition of inorganic phosphate with, , into H+, [O] and electrons, , ADP and the formation of ATP, How ATP is synthesised in grana?,  It can be explained by ChemiosmoticHypothesis .,  ATP synthesis takes place due to proton gradient, across a membrane.,  Inside the thylakoid lumen H+ ions are accumulated.,  Then they move to stroma ; across the membrane.,  Then the phosphorylation takes place., The concentration of H+ ions are increased inside the lumen, of thylakoid by following ways...., (a) Hydrogen ions that are produced by the splitting of, water accumulate within the lumen of the thylakoids., (b) As electrons move through the photosystems, protons are, transported to lumen from stroma., (c) The H+ ions are taken from stroma for reduction of NADP .( H+ ions decreases in stroma), DARK REACTION, , , The ATP and NADPH produced in light, reaction are used here and, the synthesis of glucose takes place, , , , This is the biosynthetic phase of, photosynthesis., , , , This process does not directly depend on, the presence of light., , Calvin cycle, , Three steps of Calvin cycle are: carboxylation,, reduction and regeneration.

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64, , 1. Carboxylation, , •, , RuBP (5 carbon compound) accept CO2 and, , two molecules of 3-PGA are formed., •, , It is catalysed by the enzyme RuBP carboxylase Oxygenase. (RuBisCO)., , 2. Reduction– These are a series of reactions that lead to the formation of glucose., , This steputilise 2 molecules of ATP for phosphorylation and two molecules of NADPH., 3. Regeneration– Regeneration of the RuBP (CO2 acceptor molecule ) . The regeneration, , steps require one ATP., To make one molecule of glucose 6 turns of the cycle are required., So in Calvin cycle 18 ATP and 12 NADPH are required for the synthesis of 1 glucose, molecule., Hatch and Slack Pathway (C4 Cycle), Plants that are adapted to dry tropical regions have the, C4 pathway to fix CO2, , , , The pathway completes in mesophyll and, bundle sheath cells., Pathway is traced out by Hatch and Slack, , PHOTORESPIRATION, , If the O2 concentration is more than that of, CO2the RuBP combines with O2 to form 1, molecule of 3PGA and one molecule, phosphoglycolate.[ It is common in C3, plants]., In the photorespiration there is no, synthesis of ATP or NADPH. Therefore,, photorespiration is a wasteful process., In C4 plants photorespiration does not occur., , Because the RuBisCO s seen in, bundlesheath cells; there is enough supply, of CO2.

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65, , Difference between C3 cycle and C4 cycle, C3 cycle, , C4 cycle, , Traced out by Melvin Calvin, , Traced out by Hatch and Slack, , Co2 acceptor is RuBp, , Co2 acceptor is PEP, , First stable compound is 3-PGA, , First stable compound is OAA, , RuBisCo is the carboxylation enzyme, , PEP Case is the carboxylation enzyme, , Leaves have no Kranz anatomy, , Leaves show Kranz anatomy, , Bundle sheath cells do not show chloroplasts Bundle sheath cells show chloroplasts, Only mesophyll cells involved, , Both mesophyll and Bundle sheath cells involved, , Optimum temperature is low, , Optimum temperature is high, , Photorespiration is high, , No Photorespiration, , Co2 compensation point is high, , Co2 compensation point is low, , Eg.wheat, rice, cotton, , Eg.sugarcane,sorghum,amaranthus, , Less efficient, , High efficient, , Factors affecting photosynthesis, , Internal factors, , External factors, , leaf number, leaf size, leaf age and orientation of, , sunlight, temperature, CO2 concentration and, , leaves, orientation of mesophyll cells,orientation, , water,, , of chloroplasts, , 1. Light: light affect in various ways, a) light quality: photosynthesis is maximum in red and blue light, b) light intensity: photosynthesis is maximum in intense light than dim light., c) duration: photosynthesis is maximum in intermittent light than continuous light., , Vijayabheri, Malappuram Dist. Panchayat Project

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66, , 2. Carbon dioxide Concentration, The concentration of CO2 is very low in the atmosphere (between 0.03 and 0.04 per cent)., Increase in concentration up to 0.05 per cent can cause an increase photosynthesis; beyond, this the levels can become damaging., 3. Temperature, The dark reactions being enzymatic are temperature controlled, the C4 plants respond to, higher temperatures and show higher rate of photosynthesis while C3 plants have a much, lower temperature optimum., 4.Water, Water is necessary for photosynthesis., Water stress causes the stomata to close hence reducing the CO2 availability., Blackman’s Law of Limiting Factors, This states that- 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., , CHAPTER: 10 RESPIRATION IN PLANTS, Respiration, , , , , , , During the process of respiration, glucose is oxidised, oxygen is utilised and carbon, dioxide, water and energy are released as products, C6H12O6 + 6O2® 6CO2 + 6H2O + Energy (glucose), This combustion reaction requires oxygen (aerobes). But some cells or many not, available (aneorbes). Some of these organisms are facultative anaerobes while in, others the requirement for anaerobic condition is obligate., In any case, all living organisms retain the enzymatic machinery to partially oxidise, glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is, called glycolysis., , Glycolysis (glycos: sugar, lysis: splitting), , , , , The scheme of glycolysis was given by Gustav Embden, Otto Meyerhof, and J., Parnas., It is often referred as EMP pathway., It occurs in the cytoplasm of the cell and is present in all living organisms., , Vijayabheri, Malappuram Dist. Panchayat Project

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67, , , , , In glycolysis glucose undergoes partial oxidation to form two molecules of pyruic, acid., In plants, this glucose is derived from sucrose, which is the end product of, photosynthesis, or from storage carbohydrates. Sucrose is converted into glucose and, fructose by the enzyme, invertase and these two monosaccharide readily enter the, glycolytic pathway., , Steps, (1) Glucose and fructose are phosphorylated to give rise to glucose-6- phosphate by the, enzyme hexokinase., ATP is utilised in this step., , (2) This glucose - 6- phosphate then isomerises to produce fructose- 6 - phosphate, , (3) The fructose - 6 - phosphate converted to fructose 1, 6, bisphosphate. ATP molecule is, utilized in this step., , (4) The fructose 1, 6 bisphosphate is split into dihydroxyacetone phosphate and 3phosphoglycer aldehyde (PGAL), , (5) Glyceraldehyde - 3- phosphate is converted to 1,3 bisphosphoglyceric acid (BPGA). In, this step NADH + H+ is formed from NAD+. Two redox equivalents are removed (in the form, of 2 hydrogen atoms) from PGAL and transferred to a molecule of NAD+

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68, , (6) 1,3 bisphosphoglyceric acid is converted to 3 phosphoglyceric acid. One molecule of, ATP is formed in this step., , (7) 3 - phosphoglyceric acid is converted to 2- phosphoglycerete., , (8) 2 phosphoglycerate converted to phosphoenol pyruvate by the elimination of water, molecule., , (9) Phosphoenol pyruvate is converted to pyruvate. ATP molecule is formed in this step., , (10) ATP is utilised at 2 steps first in the conversion of glucose into glucose-6 phophale and, second in the conversion of fructose 6 phosphate to fructose 1,6 bisphospate., , (11) When PGAL is converted to 1,3 biphosphoglycerate (BPGA), NADH + H+ is formed, from NAD+., , (12) Conversion of 1,3 bisphosphoglycerate to 3 phosphoglycerate and phosphoenol pyruvate, to pyruvate yield energy and is coupled with the formations of ATP.

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69, , , , , , There are 3 major ways in which different cells handle pyruvic acid produced by, glycolysis. These are lactic acid fermentation, alcoholic fermentation and aerobic, respiration., Fermentation is anaerobic respiration, whereas organisms adopt Krebs cycle which is, also called as aerobic respiration., , Fermentation, There are 3 major ways in which different cells handle pyruvic acid produced by glycolysis, (i) Alcoholic fermentation, (ii) Lactic acid fermentation, (iii) Aerobic respiration

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70, , (i) Alcoholic fermentation, , , , , , The incomplete oxidation of glucose is achieved under anaerobic conditions by set of, reactions where pyruvic acid is converted to CO2 and ethanol., o Eg:- yeast, The enzyme pyruvic acid decarboxylase and alcohol dehydrogenase catalyse these, reactions., NADH + H+ is reoxidised into NAD+, , (ii) Lactic acid fermentation, , , , , , Pyruvic acid converted into lactic acid, It takes place in the muscle in anaerobic conditions., The reaction catalysed by lactate dehydrogenase., NADH + H+ is reoxidised into NAD+, , (iii) Aerobic respiration, , , , In eukaryotes it takes place within the mitochondria, It leads to the complete oxidation of organic substances in the presence of oxygen,, and releases CO2, water and a large amount of energy present in the substrate., Aerobic Respiration, The mechanism of aerobic respiration can be studies under following steps., (i) Glycolysis, (ii) Oxidative decarboxylation, (iii) Kreb’s cycle(TCA - cycle), (iv) Oxidative phosphorylation

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71, , Oxidative decarboxylation, , , Pyruvate is transported from the cytoplasm into the mitochondria., (pyruvate is the final product of glycolysis), , , , Pyruvic acid is converted into a acetyl CoA in presence of pyruvate dehydrogenase., , , , During this process 2 molecules of NADH are produced from 2 molecules of pyrivic, acids (produced, from one glucose molecule during glycolysis),  The crucial events in aerobic respiration are:, (i) The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms,, leaving 3 molecules of CO2., (ii) The transport of the electrons removed as part of the hydrogen atoms to molecular O2, with simultaneous synthesis of ATP., , Tricarboxylic acid cycle (Krebs cycle or citric acid cycle), , , , , , , , , , , It starts with the condensation of acetyl group with oxaloacetic acid (OAA) and water, to yield citric acid. The reaction is catalysed by citrate synthase and the molecule of, CoA is released., Citrate is then isomerised to isocitrate., It is followed by 2 successive steps of decarboxylation, leading to the formation of µketoglutaric acid and then succinyl CoA., In the remaining steps the succinyl CoA oxidized into oxalo acetic acid (OAA)., During conversion of succinyl CoA to succunic acid there is synthesis of one GTP, molecule., In a coupled reaction GTP converted to GDP with simultaneous synthesis of ATP, from ADP

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72, , , , During Krebs cycle there production of 2 molecule of CO2, 3 (NADH+H+), 1 FADH2, and 1 GTP.,  There are 3 points in the TCA cycle, (i) NAD+ is reduced to NADH + H+, (ii) FAD+ is reduced to FADH2, (iii) The continued oxidation of acetyl CoA requires continued replenishment of, oxaloacetic acid & regeneration of NAD+ and FAD+ from NADH and FADH2, respectively., The summary equation for thus phase of respiration as follows, , During the whole process of oxidation of glucose produce”, CO2, 10 (NADH + H+), 2 FADH2, 2 GTP ( 2ATP)

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73, , Electron Transport system and oxidation phosphorylation, Electron transport system (ETS) is the metabolic pathway through which the electron passes, from one carrier to another. It is located in the inner mitochondrial membrane., , ETS comprises of the following, Complex I - NADH dehydrogenase, Complex II - Succinate dehydrogenase, Complex III - Cytochrome b - c1, Complex IV - Cytochrome c oxidase, Complex V - ATP synthase, , , , , , , , , , , , , NADH + H+ produced in the citric acid cycle is oxidized by NADH dehydrogenase, and electrons are then transferred to ubiquinone located in the inner membrane., Succinete is oxidized by succinate dehydrogenase and transferred electrons FADH2, and then to ubiquinone., The reduced ubiquinore is then oxidized with transfer of electrons to cytochrome b c1 complex., Cytochrome c is a small protein attached to the outer surface of the inner membrane, and acts as a mobile carrier for transfer electrons from complex III and complex IV., When electrons transferred from one carrier to another via complex I to IV in the, electron transport chain, they are coupled to ATP synthase for the synthesis of ATP, from ADP and Pi, One molecule of NADH + H+ gives rise to 3 ATP., One molecule of FADH2 gives rise to 2 ATP, Oxygen plays a vital role in removing electrons and hydrogen ion finally production, of H2O. Oxygen acts as the final hydrogen accepter., In photophosphorylation the light energy that is utilised for the production of proton, gradient required for phosphorylation. In respiration it the energy of oxidation reduction utilised for the same process. So it is called oxidative phosphorylation., , Vijayabheri, Malappuram Dist. Panchayat Project

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74, , Mechanism of membrane linked ATP synthesis, Explained by chemiosmotic hypothesis, , , , The energy released during the electron transport system is utilised in synthesising, ATP with the help of ATP synthase (complex v)., This complex consists of 2 major components, F1 and F0.

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75, , , , , , , The F1 headpiece is a peripheral membrane protein complex and contains the site for, synthesis of ATP from ADP and inorganic phosphate., F0 is an integral membrane protein complex that forms the channel through which, protons cross the inner membrane., The passage of protons through the channel is coupled to the catalytic site of the F1, component for the production of ATP., For each ATP produced, 3H+ passes through F0 from the intermembrane space to the, matrix down the electro chemical proton gradient., , The Respiratory Balance sheet, Total ATP production, There can be a net gain of 36 ATP molecule during aerobic respiration of one molecule of, glucose., , , , , , Glycolysis 2 ATP + 2NADH2 (6ATP) = 8ATP, Oxidative decarboxylation 2 NADH2 ( 6ATP) = 6ATP, Krebs cycle 2GTP (2ATP) + 6NADH2, o (18ATP) + 2 FADH2 (4ATP) = 24 ATP, Energy production during acrobic respiration = 38 ATP

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76, , AMPHIBOLIC PATHWAY, The respiration pathway is involved in both anabolism and catabolism. So the respiratory, pathway is an amphibolic pathway., , Respiratory Quotient (RQ), The ratio of the volume of CO2 evolved to the volume of O2 consumed in respiration is called, the respiratory quotient (RQ) or respiratory ratio., , The respiratory quotient depends upon the type of respiratory substrate used during, respiration., Carbohydrates RQ will be 1, , Fats RQ is less than 1, , When proteins are respiratory substrates the ratio would be about 0.9., , CHAPTER 11: PLANT GROWTH AND DEVELOPMENT,  Growth, , , , , Irreversible permanent increase in size of an organ / its parts /of an individual cell., Growth is accompanied by metabolic processes occur at the expense of energy., Plants can grow throughout their life due to the presence of meristem

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77, , , , , Open form of growth- Form of growth where new cells are always being added to, the plant body by the activity of meristem., Growth is measurable –Growth is measured by a variety of parameters like increase, in fresh weight, dry weight, length , area, volume & cell number. eg., one single root, apical meristem can give rise to more than 17,500 new cell/hour (increase in cell, number), Cells in a watermelon increase in size upto 3,50,000times, growth of pollen, tube is measured in terms of its length., Phases of growth, , Meristemmatic phase, Root & shoot apical meristem, represent this phase. Cells, divide constantly., , Elongation phase, Cells just next to, meristemmatic zone., Characteristics - Cell, enlargement, increased, vacoulation, new cell wall, deposition, , Maturation phase, Just next to elongation phase., Cells attain maximum size in, terms of wall thickening &, protoplasmic modifications, , , , , Growth rate- Increased growth/ unit time, Arithmetic growth curve - Following mitotic cell division, one daughter cell, continues to divide . The other daughter cell differentiates and matures. EquationLt=L0+rt. Lt - length at time t, L0 – length at time 0, r- growth rate, , , , Geometric growth curve –Following mitotic cell division, both the daughter cells, retain the ability to divide. Initial growth is slow (lag phase). Then growth increases, at exponential rate (log/ exponential phase) . After some time growth slows down, due to limited nutrient supply & leads to stationary phase. Sigmoid/ S-curve, obtained. Equation – w1= w0 ert. W1 – final size, w0 – initial size, r- growth rate, ttime, e – base of natural logarithms.

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78, , , , , , , , , , , , , Relative growth is the measure of the ability of the plant to produce new plant, material referred to as efficiency index., index Hence final size of w1 depends on the initial, size w0., Absolute growth rate –Measurement, Measurement & the comparison of total growth / unit time, Relative growth rate- Growth of given system / unit time expressed on a common, basis., Water, oxygen,, nutrients & optimum temperature are essential for growth., Environmental signals such as light & gravity also affect certain stages of growth., Differentiation- Cells mature to perform specific functions. Differentiated tissues lost, the capacity of division. eg. Formation of permanent tissues from meristem., Dedifferentiation – Living differentiated tissues (permanent tissues) regain the, capacity of division, n under certain conditions. eg., Formation of secondary meristems (, vascular cambium & Cork cambium) from differentiated parenchyma cells., Redifferentiation- Secondary meristem divide and produce secondary permanent, tissues which again lost their capacity of division & mature to perform specific, functions. eg., formation of secondary xylem & phloem and periderm formation., , Development - All changes from germination to senescence. Development=, , , , , , , , , Growth+differentiation, Plasicity – Ability of a plant to follow, follow different pathways in response to environment, to form different types of structures. eg., heterophylly in cotton, coriander & larkspur, , Development in plants is under the control of intrinsic (genetic factors & activity of, hormones) and extrinsic factors, factors ( light, temperature, water, oxygen, nutrition)., Plant Growth Regulators :Small simple molecules of diverse chemical composition., They could be Indole compounds (IAA), adenine derivatives (kinetin), derivatives of, carotenoids (ABA), terpenes (giber, (giberellic acid), or gas (ethylene)., Plant growth regulators are also known as Plant growth substances, Plant hormones, or Phytohormones.

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79, , , , , , , , , Plant growth promoters :- involved in growth promoting activities like cell division,, cell enlargement, tropic growth, flowering, fruiting ,seed formation etc. eg., auxin,, giberellin, cytokinin., Plant growth inhibitors :- important role in plant responses to wound & stresses. Also, involved in inhibiting activities like dormancy & abscission. eg., ABA & ethylene ., For every phase of growth, differentiation and development of plants, one or other, Phytohormones has some role to play. Such roles could be complementary, /antagonistic., Number of events in the life of a plant where more than 1 PGR interact to affect that, event. eg., dormancy in seeds / buds, abscission, senescence, apical dominance etc., , Physiological Effects Of Phytohormones,  Auxin, , , , , , , , , , Discovery- First persons associated with the discovery of auxins -Charles Darwin &, his son Francis Darwin . Auxin was isolated by F.W. Went from tips of coleoptiles, of oat seedlings., Auxin (from Greek ‘auxein’ : to grow) was First isolated from human urine., Produced by the growing apex of stem & root, from where they migrate to regions of, action., Natural auxins (derived from plants) :- IAA (indole-3-acetic acid) & IBA (indole, butyric acid), Synthetic auxin :- NAA ( Naphthalein acetic acid), & 2, 4-D (2,4dichlorophenoxyacetic acid), Physiological responses:1. Apical dominance - (Inhibition of growth of lateral bus by the terminal bud, due to the presence of auxin). When apical bud is removed (decapitation), lateral buds sprout & this is widely used in tea plantations and hedge making., 2. Initiate rooting in stem cutting., 3. Promote flowering in pineapple., 4. Prevent fruit & leaf drop at early stages but promote the abscission of older, mature leaves & fruits., 5. Induce Parthenocarpy. eg., in tomatoes., 6. Weedicide (2,4-D used to kill dicot weeds, & does not affect monocot plants), used to prepare weed-free lawns by gardners., 7. Auxin control xylem differentiation & helps in cell division, , Giberellin, , , , , Discovery – E. Kurosawa reported the symptoms of the ‘ bakane’ (foolish seedling), disease in uninfected rice seedling , when seedlings were treated with sterile filtrates, of Giberella. Fujikuroi ( a fungal pathogen) Active substance is later identified as, giberellic acid., More than 100 giberellins are reported from different organisms like fungi & higher, plants. All GAs are acid., , Vijayabheri, Malappuram Dist. Panchayat Project

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80, , , , Physiological responses :1. Promote Bolting (Internode elongation before flowering) in beet, cabbage etc., 2. Increase the length of stem & Increase the yield in sugarcane., 3. Speed up maturity period of juvenile conifers & leads to early seed, production, 4. Speed up malting process in brewing industry., 5. Delay senescence., 6. Increase the length of grapes stalks., , Cytokinin,  Discovery- Skoog & Miller identified and crystallized cytokinesis promoting active, , , , , substance ,kinetin, kinetin :- first cytokinin discovered from the autoclaved herring sperm DNA. Kinetin, does not occur naturally in plants., Zeatin :- Natural cytokinin present in corn-kernels and coconut milk., Physiological responses :1. Overcome apical dominance, 2. Shoot initiation, 3. Cell division & differentiation, 4. Promote nutrient mobilisation., 5. Delay senescence., 6. Produce new leaves & chloroplasts in leaves, , Ethylene :, , , , , Discovery- Cousins confirmed the release of volatile substance from ripened organs., Only gaseous hormone. Most widely used PGR in agriculture., Ethephon:- Aquous solution which is readily absorbed and transported within the, plant & release ethylene slowly, Physiological responses :1. Fruit ripening ., 2. Enhance Respiratory climactic (Rise in rate of respiration during ripening, of fruit )., 3. Breaks seed & bud dormancy (initiate germination in peanut seeds,, sprouting of potato tubers), 4. Initiate flowering & synchronise fruit set in pineapple., 5. Induce flowering in mango, 6. Promote female flowers in cucumbers & thus increase the yield., 7. Promote senescence & abscission of leaves , flowers & fruits., 8. Promote root &root hair formation, thus helping plants to increase, absorptive surface., 9. Promote rapid internode /petiole elongation in deep water rice plants (So, leaves & upper part of shoot remain above water), , Vijayabheri, Malappuram Dist. Panchayat Project

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81, , Abscisic acid (ABA), , , Discovery- Three independent researches reported the purification & chemical, characterization of three different kinds of inhibitors , inhibitor-B, abscission –ΙΙ &, domain. Later all three were proved to be chemically identical, named ABA, , Physiological responses :1. Stimulate the closure of stomata & increase the tolerance of plants to, various kinds of stresses. So ABA is called Stress hormone, 2. Promote Abscission ( leaf fall)., 3. Inhibit seed germination., 4. Induce dormancy (help seeds to withstand desiccation & other factors, unfavourable for growth), 5. ABA act as an Antagonist to giberellin (Action of ABA inhibit / limit the, action of giberellin), , Photoperiodism, , , , , , , Response of plants to Photoperiod (period of day / night) expressed in the form of, flowering., Site of perception of light / dark duration are the leaves . hormone responsible for, flowering, migrate from leaves to shoot apex to induce flowering only when the plants, are exposed to necessary photoperiod., Critical Photoperiod :- Length of day / light required to induce flowering, Classification of plants based on photoperiodism :1. Long day plant (LDP) which flower when they are exposed to photoperiod, longer than critical photoperiod (require more than 12 hous of light). eg.,, Spinach, radish, sugar beet, potato etc., 2. Short day plants (SDP) which flower only when day length is less than, critical period (require less than 12 hours of light). They requires a long, period of darkness. eg., Chrysanthemum, soyabean, sugarcane etc., 3. Day neutral plants (DNP) :- Exposure to light / Photoperiod does not affect, flowering. eg., Cucumber, Corn, Pea etc.

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82, , Vernalisation - Low temperature treatment for flowering., , , , , , Plants like Wheat, barley & rye have two kinds of varieties: Winter & Spring, varieties., Spring varieties planted in the spring and come to flower & produce grain before the, end of season, Winter varieties, planted in autumn, they germinate & over winter come out as, seedlings, resume growth in the spring & are harvested around mid-summer., Cold treatment stimulate photoperiodic flowering response in biennial plants like, Cabbage, Carrot, Sugarbeet etc., , ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------, , Vijayabheri, Malappuram Dist. Panchayat Project