BRILLIANT PUBLIC SCHOOL, SITAMARHI (Affiliated up to +2 level to C.B.S.E., New Delhi) Affiliation No

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1 BRILLIANT PUBLIC SCHOOL, SITAMARHI (Affiliated up t +2 level t C.B.S.E., New Delhi) Affiliatin N XI-Bilgy Chapter Ntes Sessin : Office: Rajpatti, Dumra Rad, Sitamarhi(Bihar), Pin Website: brilliantpublic@yah.cm Ph , Mbile: ,

2 Cntents 1. The Living Wrld Bilgical Classificatin Plant Kingdm Animal Kingdm Mrphlgy f Flwering Plants Anatmy f Flwering Plants Structural Organisatin in Animals Cell: The Unit f Life Bimlecules Cell Cycle and Cell Divisin Transprt in Plants Mineral Nutritin Phtsynthesis in Higher Plants Respiratin in Plants Plant Grwth and Develpment Digestin and Absrptin Breathing and Exchange f Gases Bdy Fluids and Circulatin Excretry Prducts and Their Eliminatin Lcmtin and Mvement Neural Cntrl and Crdinatin Chemical Crdinatin and Integratin

3 1. The Living Wrld POINTS TO REMEMBER: Characteristics f Living Organisms : Grwth, reprductin, metablism, cellular rganizatin, cnsciusness (ability t sense envirnment), self-replicating and self regulatin. Reprductin and grwth are NOT defining prperties. Metablism, cellular rganizatin and cnsciusness are defining prperties. Bidiversity : Term used t refer t the number f varieties f plant and animals n earth. Nmenclature: standardize the naming f living rganism such that a particular rganism is knwn by the name all ver the wrld. Identificatin: nmenclature r naming is nly pssible when the rganism is described crrectly and we knwn t what rganism the name is attached t. Need fr classificatin: T rganize the vast number f plants and animals int categries that culd be named, remembered, studied and understd. Rules fr Nmenclature: Latinized names are used, written in italics First wrd represents the genus, secnd wrd is species name. Printed in italics; if handwritten then underline separately. First wrd starts with capital letter while species name written in small letter. ICBN: Internatinal Cde f Btanical Nmenclature (fr giving scientific name t plants.) ICZN: Internatinal Cde f Zlgical Nmenclature (fr giving scientific name t animals.) Taxnmy: Study f principles and prcedures f classificatin. Binmial Nmenclature: Given by Carlus Linnaeus. Each scientific name has tw cmpnents - Generic name + Specific epithet. Systematics: It deals with classificatin f rganisms based n their diversities and relatinships amng them. Term was prpsed by Carlus Linnaeus wh wrte Systema Naturae. Taxnmic Hierarchy: Arrangement f varius steps (categries r taxa Species Genus Family Order Class Phylum (fr animals) /Divisin (fr plants) Kingdm Species: All the members that can interbreed amng themselves and can prduce fertile ffsprings are the members f same species. This is the bi-lgical cncept f species prpsed by Mayer. Three Dmains f Life: Prpsed by Carl Wese in 1990 wh als prpsed the six kingdm classificatin fr living rganisms. The three D-mains are Archaea, Eubacteria and Eukarya. 1

4 Herbarium: Strehuse f dried, pressed and preserved plant specimen n sheets. Btanical Garden: Cllectin f living plants fr reference. Taxnmical aids: Zlgical Park (Places where wild animals are kept in prtected envirnment.) Keys (Used fr identificatin f plant and animals n the basis f similarities and dissimilarities.) Fauna: (Index t animal species fund in a particular area) Flra (Index t plant species fund in a particular area.) Manuals (Prvide infrmatin fr identificatin f name f species in an area.) Mngraph (Cntain infrmatin n ne taxn.) 2

5 2. Bilgical Classificatin POINTS TO REMEMBER : SYSTEMS OF CLASSIFICATION : Earliest Classificatin was given by Aristtle. Divided plants int herbs, shrubs and trees. Animals int thse with RBC s and thse wh d nt have it. Tw kingdm classificatin : Given by Carlus Linnaeus Plant kingdm and Animal kingdm. Five kingdm classificatin : By R. H. Whittaker. Mnera, Prtista, Fungi, Plantae and Animalia are the five kingdms. Kingdm Mnera : Bacteria : Have bacteria a sle member. Bacteria can have shapes like: Cccus (spherical), Bacillus (rd-shaped), Vibri cmma shaped) and sprillum (spiral shaped). Bacteria fund almst everywhere and can be Phtsynthetic auttrphs, Chemsynthetic auttrphs r Hetertrphs. Archaebacteria : Differs frm bacteria having different cell wall structure. They live in mst harsh habitats Halphiles (salt-lving) Thermphiles (in ht springs) Acidphiles (high acidic cnditin) Methangen (marshy area) Methangen are als fund in the gut f ruminant and prduces bigas. Eubacteria : Called true bacteria having a rigid cell wall, and if mtile a flagellum. They als knwn as blue green algae r Cyanbacteria. Cyanbacteria are phtsynthetic auttrphs. Unicellular, clnial r filamentus, marine and terrestrial algae. Clnies are surrunded by gelatinus sheath. Sme f these can fix atmspheric nitrgen by specialized cells called hetercyst, e.g. Nstc and Anabaena. Chemsynthetic auttrphs: Oxidize varius inrganic substances like nitrates/nitrites, ammnia and use released energy fr their ATP prductin. Hetertrphic bacteria: Mstly decmpser Helpful in making curd frm milk Prduce antibitics 3

6 Symbitically assciated with leguminus plant and fix nitrgen. Sme are pathgen causing diseases like chlera, typhid, and tetanus. Bacteria reprduce mainly by fissin, als prduce spre in unfavrable cnditin. Reprduce sexually by transfer f DNA frm ne bacteria t ther, the prcess called cnjugatin. Mycplasma : Cmpletely lack cell wall. Smallest living cells. Can survive withut xygen. Pathgenic in animals and plants. Kingdm Prtista : All are unicellular and eukarytic. Mstly aquatic, can live in mist places. Frms a link between plants, animals and fungi. The cell cntain nucleus and membrane bund rganelles. Chrysphytes : Includes diatms and glden algae (desmids) Fund in freshwater r marine water. Mstly planktnic ( passive swimmer) Phtsynthetic. Cell walls verlap t fit tgether like a sap bx. Cell wall cntains silica hence indestructible. Their accumulatin frms Diatmaceus Earth. Used in plishing, filtratin f ils and syrups. Diatms are the chief prducers in the ceans. Dinflagellates : Marine, phtsynthetic. Cell wall has stiff cellulse plates. Appears yellw, green, brwn, blue r red depending n the pigments. Have tw flagella ne lngitudinal and ther transversely in a furrw between wall plates. Red Dinflagellates (Gnyaulax) frm red tides. Euglenids : Mstly fresh water frm fund in stagnant water. Instead f cell wall they have prtein rich layer pellicle which makes bdy flexible. They have tw flagella ne shrt and ne lng Phtsynthetic in presence f sunlight but becme hetertrphs if they d nt get sunlight. e.g. Euglena Slime Mulds : Saprphytic Prtists Frm aggregates t frm plasmdium grw n decaying twigs and leaves. 4

7 Plasmdium frms fruiting bdies bearing spres at their tips. Spres have true walls which are extremely resistant and survive fr many years. Prtzans : All prtzans are hetertrphs and live as predatrs r parasites. Believed t be primitive relatives f animals. These are divided int fur majr grups n the basis f lcmtery rganelle they have. Amebid prtzans : Mve and Catch prey using pseudpdia, e.g., Ameba. Many frms have silica shells n their surface. Sme f them are parasitic e.g. Entameba. Flagellated prtzans : Either free living r parasitic. They have flagella. Cause disease like sleeping sickness e.g., Trypansme. Ciliated prtzans : These are aquatic, actively mving rganisms due t presence f thusands f cilia. e.g., Paramecium. They have a cavity called gullet that pens t utside the cell. Sprzans : Lack any lcmtery rganelle. All members are parasitic. Have infective spre like stage in life cycle, e.g., Plasmdium which causes Malaria. KINGDOM FUNGI : With the exceptin f yeasts which are unicellular all thers are multicellular and filamentus. Cnsists f lng slender thread like structure called hypha. Nn chlrphyllus Netwrk f hyphae called mycelium. Uninucleated r multinucleated (cencytic) Cell wall made f cmplex plysaccharide called chitin. Grw in warm and humid places. Saprphytic, parasitic, symbitic (Lichen) Reprduce asexually by spres cnidia sprangispres r zspres. Sexual reprductin is by spres, ascspres and basidispres. Sexual cycle invlves the fllwing thee steps: Plasmgamy: fusin f prtplasms between tw mtile r nn-mtile gametes. Karygamy: fusin f tw nuclei Meisis: zygte underges meisis resulting haplid spres. e.g., Puccinia (rust causing), Penicillium. 5

8 CLASSES OF FUNGI - Phycmycetes : Fund in aquatic habitat, n decaying wd in mist and damp places. Sme f them are bligate parasite n plants. Mycelium is aseptate and cencytic Asexual reprductin by zspres (mtile) r by aplanspres (nnmtile). Spres are prduced endgenusly in sprangium. Zygspre prduced by fusin f gametes. e.g., Rhizpus, Albug. Ascmycetes : Cmmnly knwn as sac fungi. Unicellular (yeasts) r multicellular (e.g. Penicillium) Saprphytic, decmpsers, parasitic r cprphilus. Mycelium branched and septate. Asexual spres are called cnidia prduced exgenusly n the cnidiphres. Cnidia n germinatin prduce mycelium. Sexual spres are called ascspres prduced endgenusly in ascus prduced inside fruiting bdy calledasccarp. e.g., Aspergillus, Neurspra. (iii) Basidimycetes Cmmn knwn frms called mushrms, bracket fungi r puffballs. Mycelium septate and branched. Asexual spres generally are nt fund. Vegetative reprductin by fragmentatin. Sexual reprductin by fusin f vegetative r smatic cells f different strains t frm basidium prduced in basidicarp. Basidium prduces fur basidispres after meisis. e.g., Agaricus, Ustilag. Deutermycetes : Called as Fungi Imperfecti as sexual frm (perfect stage) is nt knwn fr them. Once sexual frm is discvered the member is mved t Ascmycetes r Basidimycetes. Mycelium is septate and branched. Are saprphytic, parasitic r decmpsers. Viruses : e.g., Alternaria, Cllettrichum. They did nt find a place in classificatin. Take ver the machinery f hst cell n entering it but as such they have inert crystalline structure. S, difficult t call them living r nn-living. Pasteur gave the term Virus i.e., pisnus fluid. D. J. Ivanwsky (1892) fund ut that certain micrbes caused Tbacc Msaic Disease in tbacc plant. 6

9 M. W. Beijerinek (1898) called fluid as Cntagium vivum fluidum as extracts f infected plants f tbacc culd cause infectin in healthy plants. W. M. Stanely (1935) shwed viruses culd be crystallised t frm crystals f prtein which are inert utside their specific hst. Structure f Virus : Its a nucleprtein made up f prtein called Capsid. Capsid is made up f capsmeres arranged in helical r plygemetric frms. Have either DNA r RNA as genetic material which may be single r duble stranded. Usually plant viruses have single stranded RNA; bacteriphages have duble stranded DNA and animal viruses have single r duble stranded RNA r duble stranded DNA. Diseases caused : Mumps, Small px, AIDS etc. Virids : Infectius agent, free RNA (lack prtein cat) RNA has lw mlecular weight. Causes ptat spindle tuber disease. Discvered by T. O. Diener in 1971 Lichens : Symbitic assciatin between algal cmpnent (Phycbint) and fungal cmpnent (Mycbint). Algae prvide fd. Fungi prvide shelter and absrb nutrients fr alga. Gd pllutin indicatrs as they d nt grw in plluted areas. 7

10 3. Plant Kingdm POINTS TO REMEMBER : CLASSIFICATION : Artificial System f Classificatin : Used superficial mrphlgical characters. Based n a few characteristics like habit, clrs, number and shape f leaf. Mainly based n vegetative characters. Such system develped by Linnaeus. Natural System f Classificatin : Based n natural affinities amng rganisms Included external as well as internal features like anatmy, embrylgy and phytchemistry. Develped by Gerge Bentham and J. D. Hker Phylgenetic System f Classificatin : Based n evlutinary relatinships between the varius rganisms. Organism belngs t same taxa have a cmmn ancestrs. Develped by Hutchinsn. Numerical Taxnmy : Carried ut using cmputers Based n all bservable characteristics Data prcessed after assigning number and cdes t all the characters. Cyttaxnmy : Based n cytlgical infrmatin. Gives imprtance t chrmsme number, structure and behaviur. Chemtaxnmy : Based n chemical cnstituents f the plants. ALGAE : Chlrphyll bearing, simple, thallid, auttrphic and mstly aquatic rganisms. Mist stne, sils and wd are the ther habitat. The size ranges frm micrscpic unicellular frms like Chlamydmnas, t clnial frms like Vlvx and t filamentus frms like Ulthrix and Spirgyra. A few marine frms such as kelps, frm massive plant bdies. Reprduce vegetatively by fragmentatin. Reprduce asexually mstly by prducing mtile spre called zspres. Reprduce sexually by prducing gametes. 8

11 Isgamus: bth gametes are same size and mtile Anisgamus: bth gametes are dissimilar in size but mtile. Ogamus: male gamete is smaller but mtile, female gamete is large and nn- mtile. Imprtance f Algae : At least half f the ttal carbn dixide fixatin n earth carried ut by them. Increase xygen level in the envirnment. Many species like Laminaria, Sargassum etc. are used as fd. Agar btained frm Gelidium and Gracilaria is used in ice-creams and jellies and als used t culture bacteria. Algin btained frm brwn algae and carrageen frm red algae used cmmercially. Chlrella and Spirullina are unicellular algae, rich in prtein and used as fd supplement even by space travelers. Algae divided int 3 classes : Chlrphyceae : Cmmnly knwn as Green algae. Main pigment is chlrphyll a and b. Unicellular, clnial r filamentus. Cell wall has inner layer f cellulse and uter layer f pectse. Have pyrenid as the strage bdy fr starch and prteins. e.g., Chlamydmnas, Vlvx, Spirgyra. Phaephyceae : Cmmnly knwn as Brwn algae and mainly fund in marine habitat. They pssess chlrphyll a, c, cartenid, xanthphylls and fucxanthin. Cell wall has cellulse and lignin r gelatinus cating f algin. Has mannitl and laminarin as reserve fd material. Bdy divisible int hldfast, stipe and frnd. Reprduce asexually by biflagellate pear-shaped zspres. e.g., Ectcarpus, Fucus, Laminaria. Rhdphyceae : Cmmnly knwn as red algae. Red clr is due t predminance f red pigment r-phycerythrin in their bdy alng with chlrphyll a, d. Fund n surface as well as great depths in ceans. Cell wall made f cellulse, pectin and plysulphate esters. Reserve fd material is flridean starch similar t amylpectin and glycgen in structure. Reprduce asexually by nn mtile spres and sexually by nn mtile gametes (Ogamus type) e.g., Plysiphnia, Prphyra, Gelidium. BRYOPHYTES : Amphibians f plant kingdm Occur in damp, humid places. 9

12 Lack true rts, stem r leaves. Plant bdy attached t the sil by unicellular r multicellular rhizids. Main plant bdy is haplid (n), r gametphytic. REPRODUCTION IN BRYOPHYTES : Vegetative reprductin by fragmentatin. Asexual reprductin by gemmae frmed in gemma cups. Sexual reprductin : Main plant bdy is gametphyte. The sex rgans in bryphytes are multicellular. Male sex rgan is called antheridium which prduces biflagellate antherzids as male gamete. Female sex rgan is archegnium is flask shaped and prduces a single egg. Fertilizatin takes place in water results in frmatin f zygte. The zygte develped int a multicellular bdy called sprphyte which remains parasitic n female gametphyte. The sprphyte differentiated int ft, seta and capsule. Sme cells f the capsule underg meitic divisin t prduce haplid spres. These spres germinated int an independent gametphyte. Mss gametphyte cnsists f tw stages First stage is called prtnema stage which develped frm the spre and is creeping, green, branched. Secnd stage is leafy stage which develped frm the prtnema stage as a lateral bud. They cnsist f upright, slender axes bearing spirally arranged leaves. Ecnmic Imprtance : Fd fr herbaceus animals. Sphagnum in frm f peat is used as fuel and als used fr trans-shipment f living material as it has water hlding capacity, prevent sil ersin, alng with lichens are first clnizers n barren rcks. They decmpse rcks making substrate fr the grwth f higher plant. PTERIDOPHYTES : First terrestrial plant pssesses vascular tissue like xylem and phlem. The plant bdy differentiated int true rt, stem and leaf. The main plant bdy is sprphytic. Leaves may be small (micrphyll) as in Selaginella r large (macrphyll) as in ferns. Sprangia having spres are subtended by leaf-like appendages called sprphylls. (Sprphylls may be arranged t frm strbili r cnes.) In Sprangia, the spre mther cells give rise t spres after meisis. Spres germinate t frm haplid gametphytic structure called prthallus which is free living, small, multicellular and phtsynthetic. Prthallus bears antheridia and archegnia which bear antherzids and egg cell respectively which n fertilizatin frm zygte. Zygte develped int multicellular, well differentiated sprphyte. Mst f pteridphytes prduce similar kinds f spres hence called hmsprus. Genera like Selaginella and Salvinia which prduce tw kind f spres, macr (large) and small (micr) spres are knwn as hetersprus. Micrspre and macrspre germinate and gives rise t male and female gametphyte respectively. 10

13 The female gametphytes in these plants are retained n the parent sprphyte fr variable perid. The develpment f zygte int yung embry takes place within the female gametphytes. This events is a precursr t the seed habits cnsidered an imprtant steps in evlutin Pteridphytes further classified int fur classes: Psilpsida (Psiltum), Lycpsida (Selaginella), Sphenpsida (Equisetum) and Pterpsida (Pteris). GYMNOSPERMS : Have naked seeds as the vules are nt enclsed by any vary wall and remain expsed bth befre and after fertilizatin. Gymnsperm includes medium-sized trees r tall trees and shrub. Rt is generally tap rt. May be assciated with myrrhiza. Stem is branched (Pinus), r unbranched (Cycas). Leaves may be simple r cmpund. REPRODUCTIONS : Gymnsperms are hetersprus. They prduce haplid micrspres and megaspres. Male strbili r cne has micrsprphylls which bear micrsprangia having micrspres which develp int reduced gametphyte called pllen grain. Female cne r strbili has megasprphylls which bear megasprngia having megaspres which are enclsed within the megasprangium (Nucellus). One megaspre develps int female gametphyte bearing tw r mrearchegnia. Pllen grains carried in air currents reach vules, frm pllen tube which reach archegnia and release male gametes which fertilize egg cell and frm zygte which prduce embrys. Ovules develp int seeds which are nt cvered. ANGIOSPERMS : Called flwering plants and have seeds enclsed in fruits. Divided int tw classes Dictyledns (have tw ctyledns) and Mnctyledns (have ne ctyledn). Smallest angisperm: Wlfia (micrscpic). Large tree: Eucalyptus ver 100 meters. Reprductive rgans develped in flwers. Male sex rgans in a flwer are called stamens. Stamen has filament and anther. Anthers n meisis prduce pllen grains. Pllen grains have tw male gametes. Female sex rgans are pistil. Pistil has stigma, style and vary. Ovary has ne r many vule in which female gametphyte (embry sac) develps by meisis. Embry sac has 7 cells and 8 nuclei. One egg cell, 2 synergids, 3 antipdal and ne central cell having tw plar nuclei. Pllen grain is carried by wind; water etc. reaches t stigma and prduces pllen tube which enters embry sac. Duble fertilizatin: Syngamy: One male gamete fuses with egg cell t frm zygte which develps int embry. Triple fusin: Other male gamete fuses with secndary nucleus (frmed by fusin f tw plar nuclei) which frms triplid primary endsperm nucleus (PEN). PEN develps int endsperm which nurishes the develping embry. Ovules develp int seeds and varies int fruits. Alternatin f generatin: Haplid gametphytic and spre prducing sprphytic generatin alternate with each ther in this prcess. Haplntic: Gametphytic phase dminant. e.g., Chlamydmnas Diplntic: Sprphytic phase dminant. e.g., Angisperms and Gymnsperms 11

14 Hapl-Diplntic: Intermediate like stage where gametphytic and sprphytic stage partially dminates at different stages. e.g., Bryphytes and Pteridphytes. Exceptins: Ectcarpus, Plysiphnia are Hapl-diplntic algae. Fucus is diplntic alga. 12

15 4. Animal Kingdm POINTS TO REMEMBER : Levels f rganizatin : Cellular level Tissue level Organ level Organ system level Circulatry System : Open type: Bld pumped ut thrugh heart. Cells and tissues are directly bathed in it. Clsed type: Bld is circulated thrugh vessels. Symmetry : Asymmetrical: Cannt be divided int equal halves thrugh median plane. e.g., Spnges. Radial symmetry: Any plane passing thrugh central axis can divide rganism int equal halves. e.g., Hydra. Bilateral symmetry: Only ne plane can divide the rganism int equal halves. e.g., Annelids and Arthrpds. CLASSIFICATION ON BASIS OF GERMINAL LAYERS : Diplblastic: Cells arranged in tw embrynic layers i.e. external ectderm and internal endderm. (Mesglea may be present in between ectderm and endderm) e.g., Celenterates. (Cnidarians) Triplblastic: Three layers present in develping embry i.e., ectderm, endderm and mesderm. e.g., Chrdates. Celm (Bdy cavity which is lined by mesderm) Celmates: Have celm e.g., Annelids, Chrdates etc. Pseudcelmates: N true celm as mesderm is present in scattered puches between ectderm and endderm. e.g., Aschelminthes. Acelmates: Bdy cavity is absent. E.g. Platyhelminthes. Metamerism: If bdy is externally and internally divided int segments with serial repetitin f at least sme rgans then phenmenn is called metamerism. e.g., Earthwrm. Ntchrd: Rd-like structure f mesdermal rigin, frmed during embrynic develpment n the drsal side. e.g., Chrdates. PHYLUM PORIFERA : Als called spnges. Are usually marine and asymmetrical. Have cellular level f rganizatin. Fd gathering, respiratry exchange and remval f wastes ccur thrugh water canal system. Digestin intracellular. Ostia (minute pres n bdy), spngcel (bdy cavity) and sculum help in water transprt. They are lined bychancytes (cllar cells). Bdy wall has spicules and spngin fibers. Animals are hermaphrdite. Fertilizatin internal. 13

16 Develpment is indirect, with larval stage which metamrphses t adult. e.g., Sycn, Euspngia. PHYLUM COELENTERATA : Als called Cnidarians. Are usually marine and radially symmetrical. Sessile r free-swimming. Have tissue level f rganizatin Diplblastic. Presence f cnidblast, fr anchrage, defense and capture f prey. Central bdy cavity called gastr-vascular cavity r celenterne. Digestin extracellular and intracellular. Blind sac type bdy plan, with ne pening called hypstme. Bdy wall cmpsed f calcium carbnate. Exhibit tw bdy frms: plyp and medusa e.g., Hydra, Aurelia. Alternatin f generatin between bdy frms called Metagenesis ccurs in Obelia where Medusa sexually reprduced and plyp asexually reprduced. e.g., Physalia, Adamsia. PHYLUM CTENOPHORA : Als called as sea walnuts r cmb jellies. Are exclusively marine, radially symmetrical. Have tissue level rganisatin, are diplblastic. Digestin bth extra and intracellular. Bdy has eight external rws f ciliated cmb plates fr lcmtin. Shw Biluminescence (living rganism emit light). Sexes are nt separate i.e. hermaphrdite. Reprduce nly by sexual methds. External fertilizatin. Indirect develpment e.g., Ctenplana. Pleurbranchia PHYLUM PLATYHELMINTHES : Als called as flat wrms. Have drsventrally flattened bdy. Mstly endparasites in animals including human. Bilaterally symmetrical, Triplblastic Acelmate Organ level rganizatin. Absrb nutrients thrugh bdy surface. Parasite frms have hks and suckers. Flame cells help in smregulatin and excretin. Fertilizatin internal. Many larval stages. Planaria has high regeneratin capacity. e.g., Taenia, Fascila. 14

17 PHYLUM ASCHELMINTHES : Als called rund wrms. May be free living, parasitic, aquatic r terrestrial. Are bilaterally symmetrical, triplblastic, Pseudcelmates. Alimentary canal cmplete (has muscular pharynx), wastes remved thrugh excretry pre. Organ system level f rganizatin. Sexes separate i.e. diecius. Shws sexual dimrphism. Females lnger than males. Fertilisatin internal. Develpment direct r indirect. e.g., Ascaris, Wuchereria. PHYLUM ANNELIDA : Are aquatic r terrestrial, free-living r parasitic. Are bilaterally symmetrical, triplblastic, Organ-system level f rganizatin Metamerically segmented bdy. Have lngitudinal and circular muscles in bdy wall fr lcmtin. Aquatic annelid like Nereis has ar shaped parapdia fr mvement. Have nephridia fr smregulatin and excretin. Nervus system cnsists f paired ganglia cnnected by lateral nerves t a duble ventral nerve crd. Circulatry system is clsed type. Earthwrm (Pheretima) and Leech (Hirudinaria) which are hermaphrdites (i.e., mnecius). Nereis an aquatic frm is diecius. Fertilizatin is external Develpment is direct r indirect. PHYLUM ARTHROPODA : Largest phylum f Animalia includes insects. Are bilaterally symmetrical, triplblastic and rgan system level f rganizatin, celmate and segmented bdy. Bdy divisible int head, thrax, abdmen. Bdy cvered by a chitinus exskeletn. They have jinted appendages. Respiratin by gills, bk gills, lungs r tracheal system. Circulatin is pen type. Excretin thrugh malpighian tubules. Sensry rgans: Antennae, eyes; Organs f balance: Statcysts. Mstly diecius. Fertilisatin internal. Are mstly viparus. Develpment is indirect r direct. e.g., Apis, Bmbyx, Anpheles, Lcusta, Limulus. PHYLUM MOLLUSCA : 15

18 Secnd largest phylum f Animalia. Terrestrial r aquatic. Are bilaterally symmetrical, triplblastic and rgan system level f rganizatin, celmate. Bdy divisible int head, muscular ft and visceral hump and is cvered by a sft and spngy layer f skin calledmantle. Unsegmented bdy. Bdy is cvered by calcareus shell. Respiratin and excretin by feather like gills (ctenedium) in mantle cavity. Head has sensry tentacles. Radula-file like rasping rgan fr feeding. Usually diecius, diecius, have indirect develpment. e.g., Pila, Pinctada, Octpus. PHYLUM ECHINODERMATA : Are spiny bdied rganisms. Endskeletn f calcareus ssicles. Are exclusively marine. Radially symmetrical in adult but bilaterally symmetrical in larval stage. Organ system level f rganizatin. Triplblastic and eucelmate. Digestive system cmplete. Muth ventral, Anus n drsal side. Fd gathering, respiratin, lcmtin carried ut by water vascular system. Excretry system is absent. Diecius i.e. sexes are separate. Fertilizatin external. Develpment indirect (free swimming larva) e.g., Asterias, Cucumaria. PHYLUM HEMICHORDATA : Have small wrm-like marine animals. Was earlier placed as sub-phylum f Phylum Chrdata. Bilaterally symmetrical, triplblastic and celmate. Bdy cylindrical, has prbscis, cllar and trunk. Circulatin is pen type. Respiratin by gills Excretin by prbscis gland. Sexes separate, external fertilizatin, indirect develpment. e.g., Balanglssus PHYLUM CHORDATA : Presence f Ntchrd (between gut and nerve crd) Have drsal hllw nerve chrd. Have paired pharyngeal gill slits. Heart is ventral. Pst anal tail present. Bilaterally symmetrical, triplblastic, and celmate with rgan system level f rganizatin. Circulatin is clsed type. 16

19 SUB-PHYLA UROCHORDATA : Ntchrd present nly in tail f larval stage. e.g., Ascidia, Salpa, Dlilium. SUB-PHYLA CEPHALOCHORDATA : Ntchrd extends frm head t tail. e.g., Amphixus. SUB-PHYLA VERTEBRATA : Have ntchrd nly during embrynic perid. Ntchrd gets replaced by bny r cartilaginus vertebral clumn. Have ventral muscular heart with tw, three r fur chambered. Paired appendages which may be fins r limbs. Kidneys fr excretin and smregulatin. Divisin Agnatha (lack jaws) - Class: Cyclstmata : Have sucking and circular muth withut jaws. Live as ectparasites n sme fishes. Devid f scales, n paired fins. Cranium and vertebral clumn is cartilaginus. Marine habit but migrates t fresh water fr spawning and die after spawning. Larva returns t cean after metamrphsis. e.g., Petrmyzn. Divisin Gnathstmata (Bear Jaws) - SUPER-CLASS: PISCES - Class 1: Chndrichthyes : Have cartilaginus endskeletn. Muth ventrally lcated. Ntchrd persists thrughut life. Gill slits are separate and withut perculum. Skin has placid scales. Jaw cntains teeth, which are mdified placid scales. Mstly predaceus. Swim bladder absent. Heart is tw chambered. (ne auricle and ne ventricle) Sme f them cntain electric rgans ( e.g. Trped) Sme pssesses pisn sting. ( e.g. Trygn) Pikiltherm r cld blded. Diecius. Sexually dimrphic, male s pelvic fin bears claspers. Fertilizatin internal. 17

20 Many f them viviparus. e.g., Trped, Trygn, Sclidn. Class 2 : Osteichthyes : Includes bth marine and fresh water fishes. Bny endskeletn. Muth is usually terminal. Fur pairs f gill slits cvered by perculum. Skin has cyclid/ctenid scales. Air bladder is present fr buyancy. Heart is tw chambered. Cld blded animals. Diecius. Sexually mnmrphic. Fertilizatin external. Mstly viparus Develpment is indirect. e.g., Hippcampus, Labe, Catla, Betta. SUPER CLASS: TETRAPODA - Class-1: Amphibia Can live in aquatic as well as terrestrial habitats. Mst f them have tw pairs f limbs. Bdy divisible int head and trunk. Skin mist, withut scales. Tympanum represents ear. Claca is the cmmn chamber where alimentary, urinary and reprductive tracts pen. Respiratin by gills, lungs r skin. Heart is 3-chambered.( tw auricle and ne ventricle) Cld blded animals. Sexes separate. Fertilizatin is external and requires water. Oviparus. Indirect develpment. e.g., Buf, Rana, Hyla. Class - 2: Reptilia Creeping r crawling mde f lcmtin. Bdy has dry and crnified skin and epidermal scales r scutes. Tympanum represents ear. Limbs when present are tw pairs. Mstly three chambered heart but 4-chambered in crcdiles. 18

21 Snakes and lizards shed scales as skin cast. Pikiltherm. Sexes are separate. Fertilizatin internal. Oviparus. Direct develpment. e.g., Testud, Naja, Vipera, Caltes. Class - 3: Aves Presence f feathers and mst cay fly except flightless bird like strich. Jaw mdified t beak withut teeth. Frelimbs are mdified int wings. Hind limbs have scales. N glands n skin except il gland at base f tail. Endskeletn bny with air cavities (pneumatic) and hllw bnes t assist in flight. Digestive tract has additinal chambers like crp and gizzard. Heart is fur chambered. Hmithermus r warm blded, able t maintain cnstant temperature. Air sacs are cnnected t lungs t supplement respiratin. Oviparus. Direct develpment. e.g., Clumba, Struthi, Crvus. Class- 4: Mammalia Have mammary glands t nurish yung nes by secreting milk. Have tw pairs f limbs. Skin has hairs. External ears r pinna present. Different types f teeth in jaw. Heart is fur chambered. Hmithermus. Respiratin by lungs. Sexes separate, fertilizatin internal. Viviparus r viparus. Direct develpment. e.g., Rattus, Canis Elephas, Equus. Oviparus mammal is Ornithrhynchus.'' 19

22 5. Mrphlgy f Flwering Plants POINTS TO REMEMBER : Mrphlgy: The study f varius external features f the rganism is knwn as mrphlgy. Adaptatin: Any alteratin in the structure r functin f an rganism r any f its part that results frm natural selectin and by which the rganism becmes better fitted t survive and multiply in its envirnment. The Rt: The rt is undergrund part f the plant and develps frm elngatin f radicle f the embry. Varius types f rt : Tap rt: Originated frm the radicle. Persistent in dict plant. E.g. gram, pea, mang Fibrus rt Originates frm the base f the stem. Large number f rts replaces the primary rt. This type f rt fund in mnct plant. E.g. wheat, paddy, grass. Adventitius rt Rts develped frm any part f the plant ther than radicle. Fund in grass, Mnstera and the banyan tree. Functin f rt : Absrptin f water and mineral frm sil Anchrage f the plant bdy String reserve fd material. Synthesis f plant grwth regulatrs. Regins f rt : Rt Cap : The rt is cvered at the apex by the thimble-like structure which prtects the tender apical part. Regin f meristematic activity : Cells f this regin have the capability t divide. The cells f this regin are very small, thin-walled and with dense prtplasm. Regin f elngatin : Cells f this regin are elngated and enlarged. Regin f Maturatin : This regin has differentiated int matured cells. Sme f the epidermal cells f this regin frm thread-like rt hairs, which absrbs water and minerals frm the sil. Mdificatins f Rt : Rts are mdified fr supprt, strage f fd, respiratin. Fr supprt : Prp rts in banyan tree, stilt rts in maize and sugarcane. Fr respiratin: pneumatphres in Rhizphra (Mangrve). Fr strage f fd: Fusifrm (radish), Napifrm (turnip), Cnical (carrt). 20

23 The Stem : Stem is the aerial part f the plant and develps frm plumule f the embry. It bears ndes and interndes. Bears bud, may be axillary r terminal Main functin is t spreading branches bearing leaves, flwer and fruits. Mdificatins f Stem : Fr fd strage: Rhizme (ginger), Tuber (ptat), Bulb (nin), Crm and Clcasia). Fr supprt: Stem tendrils f watermeln, grapevine, and cucumber. Fr prtectin: Axillary buds f stem f citrus, Bugainvillea get mdified int pinted thrns. They prtect the plants frm animals. Fr vegetative prpagatin: Undergrund stems f grass, strawberry, lateral branches f mint and jasmine. Fr assimilatin f fd: Flattened stem f puntia cntains chlrphyll and perfrms phtsynthesis. The Leaf : Develped frm sht apical meristem, flattened, green structure. Manufacture the fd by phtsynthesis. It has bud in axil. A typical leaf has leaf base, petile and lamina. Leaf attached t the stem by leaf base. May bear tw small leaves like structure called stipules. Leaf base may swllen t frm pulvinus. The structure that hlds the leaf called petile. The green expanded part f the leaf is called lamina r leaf blade. Venatin : The arrangement f veins and the veinlets in the lamina f leaf is termed as venatin. Veinlets frm a netwrk reticulate venatin. (dict leaf) Vein runs parallel t each ther parallel venatin. (mnct leaf) Types f leaf : A leaf is said t be simple, when its lamina is entire r when incised, the incisins d nt tuch the midrib. When the incisins f the lamina reach up t the midrib breaking it int a number f leaflets, the leaf is called cmpund. Bud present in the axil f petile in bth simple and cmpund leaf. Bud never present in the axil f the leaflets f cmpund leaf. Pinnately cmpund leaf: number f leaflets present in a cmmn axis called rachis, which represents the midrib f leaf. Palmately cmpund leaves: leaflets are attached t the cmmn pint i.e. at the tp f the petile. Phylltaxy : It is the pattern f arrangement f leaves n the stem f branch. Alternate : a single leaf arises frm each nde Oppsite : a pair f leaves arise at each nde and lie ppsite t each ther. Whrled : mre than tw leaves arise at a nde and frm a whrl. 21

24 Mdificatins f leaves : leaves are ften mdified t perfrm functins ther than phtsynthesis. Mdified t tendril fr climbing as in peas. Mdified t spines fr defense as in cacti. Fleshy leaves f nin stre fd. In Australian acacia, the leaves are small the shrt-lived. The petiles expanded, becme green and synthesize fd. In insectivrus plant leaves are mdified t trap insects e.g. pitcher plant, Venus fly trap. THE INFLORESCENCE : The arrangement f flwers n the flral axis f stem. A flwer is a mdified sht Apical meristem changes t flral meristem. Interndes d nt elngate and the axis gets cndensed. The apex prduces different kinds f flral appendages laterally at successive ndes instead f leaves. Racemse : the main axis cntinues t grw; the flwers are brne laterally in an acrpetal successin. Cymse : the main axis terminates in flwer, hence limited t grw. The flwers are brne in a basipetal rder. THE FLOWER : Atypical flwer has fur different kinds f whrls arranged successively n the swllen end f the stalk r pedicel called thalamus r receptacle. The fur whrls are:- Calyx, crlla, Andrecium and Gynecium. Calyx and crlla are accessry rgans. Andrecium and Gynecium are reprductive rgans. In flwer like lily, the calyx and crlla are indistinct and are called perianth. Bisexual: flwer having bth Andrecium and Gynecium. Unisexual: flwer having either stamens r carpel. Symmetry : Actinmrphic: radially symmetrical. Zygmrphic: bilaterally symmetrical. Asymmetrical: when a flwer cannt be divided int tw equal half in any plane. Pattern f flwer : A flwer may be trimerus, tetramerus r pentamerus when the flral appendages are in multiple f 3, 4 r 5 respectively. Reduced leaf fund at the base f the pedicel are called bract. Flwers which bears bract are said t be bracteates. Flwers withut bract are said t be ebracteate. Psitin f flral parts n thalamus : Hypgynus : Gynecium ccupies the highest psitin. Other whrls are present belw the Gynecium. Ovary is said t be superir. E.g. mustard, China rse and brinjal. Epigynus : 22

25 The thalamus enclses the vary. Thalamus fused with vary. The ther whrl arises abve the vary. Ovary is inferir. E.g. guava, cucumber, ray flrets f sunflwer. Perigynus : Ovary is said t be half inferir. The Gynecium situated in the centre. Other whrls lcated n the rim f the thalamus almst at the same level. E.g. plum, Rse, peach. Parts f a flwer : Calyx : It is the utermst whrl Each member called sepals. Sepals are green leaf like prtect the flwer in the bud stage. Gamsepalus: sepals are united. Plysepalus: sepals are free. Crlla : It is the secnd whrl f a flwer. Each member called petal. Usually brightly clred t attract insect fr pllinatin. Plypetalus: petals are free. Gampetalus: petals are united r fused. Aestivatin : the mde f arrangement f sepals r petals in the flral bud with respect t the ther members f the same whrl is knwn as aestivatin. Valvate : sepals r petals in a whrl just tuch ne anther at the margin, withut verlapping. E.g. Caltrpis. Twisted : ne margin f the appendage verlaps that f the next ne and s n. E.g. china rse. Imbricate : the margin f sepals r petals verlap ne anther but nt in any particular directin as in Cassia and gulmhur. Vexillary : The large petal (standard) verlaps the tw lateral petals (wings) which in turn verlap the tw smallest anterir petals (keel). Andrecium : It is the male sex rgan f the flwer. Cmpsed f stamens. Each stamen cnsists f a stalk r filament and an anther. Each anther is usually bilbed and each lbe has tw chambers, pllen sac. Pllen grains are prduced inside the pllen sacs. A sterile stamen is called staminde. Epipetalus: stamens attached t the petals. E.g. brinjal. Epiphyllus: stamens attached t the perianth. E.g. lily. Plyandrus: stamens are free. Mnadelphus: stamens united int ne bunch r ne bundle e.g. China rse. Diadelphus: stamens fused t frm tw bundles as in pea. Plyadelphus: stamens fused t frm mre than tw bundles as in citrus. 23

26 Gynecium : It is the female reprductive part f the flwer. Members are called carpel. Each carpel has three parts namely stigma, style and vary. Ovary is the enlarged basal part n which lies the elngated tube, the style. The stigma usually at the tip f the style. Stigma is the receptive surface fr pllen grain. Each vary bears ne r mre vules. Ovule attached t a flattened cushin-like placenta in the vary. When mre than ne carpel is present they may be:- Apcarpus: all carpels are free. E.g. rse, ltus Syncarpus: carpels fused. E.g. Tmat mustard. After fertilizatin:- Ovules develp int seed. Ovary develped int fruit. Placentatin : arrangement f vules within the vary is knwn as Placentatin. Marginal: Placenta frms a ridge alng the ventral suture f vary. Axile: Margins f carpels fuse t frm central axis. Parietal: Ovules develp n inner wall f vary. Free central: Ovules brne n central axis, lacking septa. Basal: Placenta develps at the base f vary. THE FRUIT : It is the ripened r matured vary after fertilizatin. Parthencarpic fruits develped frm the vary withut fertilizatin. Generally fruits cnsist f a wall r pericarp and seeds. Pericarp may be dry r fleshy. Pericarp differentiated int Outer epicarp. Middle mescarp. Inner endcarp. Fruit develped frm mncarpellary superir vary and are ne seeded. Such fruit is said t be drupe as in mang and ccnut. Edible part f the mang is mescarp. Mescarp f ccnut is fibrus. THE SEED : After fertilizatin vules develped int seed. A seed is made f seed cat and embry. The embry is made up f A radicle An embrynal axis One r tw ctyledns. Structure f dictylednus seed : 24

27 Outer mst cvering f seed is seed cat. Seed cat has Outer testa Inner tegmen. The hilum is a scar n the seed cat, the pint f attachment f develping seed with the fruit. Abve the hilum is a small pre called the micrpyle. Embry present inside the seed cat, cnsists f - An embrynal axis. Tw ctyledns Ctyledns are fleshy and stre reserve fd. At the tw end f embrynal axis are present the radicle and the plumule. In sme seed endsperm stre the reserve fd as in castr. Mature seed withut endsperm called nn-albuminus seed r nn-endspermus as in bean, gram and pea. Structure f mnctylednus Seed : Generally mnctylednus seeds are endspermic, rchids are nn-endspermic. In seeds f cereals such as maize, the seed cat is fused with the fruit wall. The uter cvering f separates the embry by a prteinus layer called aleurne layer. Embry is small and lcated ne side f the endsperm and cnsists f One large shield shaped ctyledn knwn as scutellum. A shrt axis with radicle and plumule. Plumule cvered by a sheath called cleptile. Radicle cvered by a sheath called clerhiza. 25

28 6. Anatmy f Flwering Plants POINTS TO REMEMBER : Study f internal structure f plant is called anatmy. In plants cells are the basic unit. Cells rganized int tissues and tissues rganized int rgans. THE TISSUES : A grup f cells having cmmn rigin and perfrm ne functin. Plant tissues are classified int tw types:- Meristematic tissue. Permanent tissue Meristematic tissues : Grwth in plants is restricted t specific regins with active cell divisin called meristems. Different types f meristems are:- Apical meristem: Occurs in the sht and rt tips. Primary meristem Increase the length f plant Intercalary meristem : Present in-between mature tissues. Primary meristem Occurs in grasses and regenerate parts remved by grazing. Lateral meristem: Occurs in the mature regins f rts and shts. Als knwn as secndary meristem. Respnsible fr prducing secndary tissues. Fascicular vascular cambium, interfascicular cambium and crk cambium are example f lateral meristem. Axillary bud : During frmatin f leaves and elngatin f stem, sme cells left behind frm sht apical meristem, cnstitute the axillary bud. Present in the axils f leaves and are capable fr frming a branch r a flwer. Permanent tissues : Cells prduced frm primary r secndary meristem stp dividing and differentiated structurally and functinally, termed as permanent cells. 26

29 A grup f permanent cell cnstitutes the permanent tissues. Permanent tissues having similar in structure and functin are called simple tissues. Permanent tissues having many different types f cells are called cmplex tissues. Simple tissues : Simple tissues made f nly ne type f cells. Parenchyma : Frms majr cmpnent within rgans. Cells are isdiametric. Thin cell wall made f cellulse. Cells may be spherical, val, rund, plygnal r elngated shape. Cells are clsely packed r have small intercellular space. Perfrm varius functins such as phtsynthesis, strage, secretin. Cllenchyma : Fund either in hmgeneus layer f in patches. Cell wall thickened in the crner due t depsitin f cellulse, hemicellulses and pectin. Cells are val, spherical r plygnal in shape Often cntain chlrplasts. N intercellular spaces. Prvide mechanical supprt t the grwing part f the plant such as yung stem and petile f a leaf. Sclerenchyma : Cnsists f lng, narrw cells Cell wall is thick and lignified. Cell wall with few r numerus pits. Cells are usually dead and withut prtplast. Prvides mechanical supprt t the rgans. Sclerenchymas are f tw types n the basis f rigin, frm, structure. Fibres : Thick walled Elngated and pinted cells Generally ccurs in grup in varius parts f the plant. Sclereids : Spherical, val r cylindrical in shape. Highly thickened dead cells with very narrw cavities (lumen). Cmmnly fund in fruit walls f nuts; pulp f guava, pear and sapta; seed cats f legumes and leaves f tea. Cmplex tissues : Made f mre than ne type f cells and these wrk tgether as a unit. 27

30 Xylem and phlem cnstitute the cmplex tissues in plants. Xylem : Functins as cnducting tissues fr water and minerals frm rts t stem and leaves. Prvides mechanical supprt t the plant. It cnsists f fur different kinds f elements:- Tracheids Vessels Xylem fibres and Xylem parenchyma. Tracheids : Elngated r tube like cells. Thick and lignified walls and tapering ends. Cells are dead and withut prtplasm. Inner layers f cell walls have thickenings which vary in frms. Vessels. Is a lng cylindrical tube-like structure made up f many cells called vessel members. Each with lignified walls and a large central cavity. Cells are devid f prtplasm. Vessel members are intercnnected thrugh perfratins in their cmmn walls. Presences f vessels are the characteristics f the angisperm. Xylem fibres : Have highly thickened walls and bliterated central lumen. Either septate r aseptate. Xylem Parenchyma : Cells are living and thin-walled. Cell walls are made up f cellulse. They stred fd materials in the frm f starch r fat. Als stre materials like tannins. The radial cnductin f water takes place by the ray parenchymatus cells. The primary xylem is f tw types Prtxylem Metaxylem. 28

31 The first frmed xylem elements are called prtxylem. The later frmed primary xylem is called metaxylem. Endarch: the prtxylem lies twards pith and metaxylem twards the periphery f the rgan ( in stem) Exarch: in rt the prtxylem lies twards periphery and metaxylem lies twards the centre. Phlem : Transprts fd materials usually frm leaves t ther part f plant. It is cmpsed f fur elements:- Sieve tube elements. Cmpanin cells. Phlem parenchyma. Phlem fibres. Sieve tube elements : Lng tube like structure arranged lngitudinally Assciated with cmpanin cells. End walls are perfrated t frm sieve plates. A mature sieve element pssesses peripheral cytplasm and a large vacule but lacks nucleus. The functin f sieve elements cntrlled by nucleus f cmpanin cells. Cmpanin cells : Specialized parenchymatus cells. Clsely assciated with sieve tube elements. Cnnected with sieve tube element by pit field. Helps in maintaining pressure gradient in the sieve tubes. Phlem parenchyma : Made up f elngated tapering cylindrical cells Have dense cytplasm and nucleus. Cell wall made f cellulse and has pits thrugh plasmdesmatal cnnectins exist between the cells. Stre fd materials and ther substances like resins and latex and mucilages. It is absent in mnctyledns. Phlem fibres : Als knwn as bast fibres. Made f sclerenchymatus cells. Absent in primary phlem but present in secndary phlem. Much elngated, unbranched and have pinted, needle like apices. Cell wall is quite thick. On maturity lse their prtplasm and becme dead. Phlem fibres f jute, flax and hemp are used cmmercially. 29

32 The first frmed primary phlem cnsists f narrw sieve tubes and referred as prtphlem. The later frmed phlem has bigger sieve tubes and is referred t as metaphlem. THE TISSUE SYSTEM : On the basis f their structure and lcatin there are three types f tissue systems. Epidermal tissue system. Grund r fundamental tissue system. Vascular r cnducting tissue system. Epidermal tissue system : Frms the utermst cvering f the whle plant bdy and cmprises: Epidermal cells. Stmata Epidermal appendages like trichmes and hairs. Epidermis cnsists f single layer parenchymatus cells. Cells are elngated, cmpactly arranged, which frm cntinuus layer. Epidermis is usually single layered. Outside the epidermis cvered with waxy thick layer called cuticle. Cuticle absent in epidermis f rt. Stmata are the structure present in the epidermis f leaf. Stmata regulate the prcess f transpiratin and gaseus exchange. Stmata : Each stma cmpsed f tw bean shaped cell called guard cells. In grasses the guard cells are dumb-bell shaped. Outer wall f guard cell is thin and inner wall is thick. Guard cell pssesses chlrplast and regulates the pening and clsing f stmata. Epidermal cells in the vicinity f guard cell called subsidiary cells. Stmatal aperture, guard cells and subsidiary cells tgether called stmatal apparatus. The rt hairs are unicellular elngatins f the epidermal cells and help absrb water and mineral frm the sil. Trichmes : On stem the epidermal hairs are called trichmes. Trichmes are usually multicellular. May be branched r unbranched and sft r stiff. Smetimes secretry. Trichmes help in preventing water lss due t transpiratin. The grund tissue system : All the tissues except epidermis and vascular bundles cnstitute the grund tissue. 30

33 It cnsists f simple tissues such as parenchyma, cllenchyma, Sclerenchyma. Parenchymatus cells are present in crtex, pericycle, pith and medullary rays. In leaves, the grund tissue cnsists f thin-walled chlrplast cntaining cells called mesphyll. The vascular tissue system : Vascular system cnsists f cmplex tissues xylem and phlem. Xylem and phlem tgether cnstitute the vascular bundle. In dict presence f cambium between xylem and phlem called pen vascular bundle. Vascular bundle withut cambium is said t be clsed vascular bundle. Radial vascular bundle: xylem and phlem arranged alternate manner n the different radii. Cnjint vascular bundle: xylem and phlem are situated at the same radius f vascular bundle. ANATOMY OF DICORYLEDONOUS AND MONOCOTYLEDONOUS PLANTS :- Dictylednus Rt : The utermst layer is epidermis. Presence f unicellular rt hairs in epidermis. The crtex cnstitutes many layer thin-walled parenchyma cells with intercellular spaces. The innermst layer f crtex is enddermis. Enddermis cnsists f single layered barrel-shaped cells withut intercellular spaces. Presence f casparian strip in the enddermis. Next t enddermis there is few layer parenchymatus cells frm pericycle. Initiatin f lateral rt and vascular cambium during secndary grwth takes place frm the cells f pericycle. The parenchymatus cells present in-between xylem and phlem is called cnjuctive tissue. The number f xylem and phlem bundle is three r fur. All the tissues n the inner side f enddermis such as pericycle, vascular bundles and pith cnstitute the stele. Mnctylednus Rt : Mnct rt have similar tissues as in dict except :- It cntains mre than six xylem bundles called plyarch. Pith is large and well develped. D nt underg any secndary grwth. Dictylednus Stem : Outermst layer is epidermis. Epidermis cvered with thin layer f cuticle and has trichmes and few stmata. The cells arranged in multiple layers in-between epidermis and pericycle cnstitute the crtex. Crtex has three sub-znes : Hypdermis: a few layers f cllenchymatus cells belw epidermis. Crtical layers: cnsists f runded thin walled parenchymatus cells with intercellular spaces. Enddermis: it is the innermst layer f crtex. Cells are rich in starch grains and are referred t as starch sheath. 31

34 Pericycle : present n the inner side f the enddermis and abve the phlem in the frm f semi-lunar patches f Sclerenchyma. Medullary rays: a few layers f radially placed parenchymatus cells present in between vascular bundles. A large number f vascular bundles arranged in a ring. Each vascular bundle is cnjint, pen and endarch prtxylem. The central prtin f stem cnstitutes the pith. Mnctylednus Stem : It has similar tissues with the dict stem except in fllwing Sclerenchymatus hypdermis. Vascular bundles are scattered in the grund tissue. Each vascular bundle is cvered by bundle sheath cells. Vascular bundles are cnjint and clsed. Peripheral vascular bundles are smaller than central ne. Phlem parenchyma is absent. Water cntaining cavities are present within the vascular bundles. Drsiventral (Dictylednus) Leaf : Vertical sectin f a Drsiventral leaf shws three main parts: Epidermis. Mesphyll cells. Vascular systems. Epidermis cvers bth upper (adaxial) and lwer (abaxial) surface f the leaf has a cnspicuus cuticle. Abaxial surface has mre stmata than the adaxial epidermis. Tissue between upper and lwer epidermis called mesphyll. Mesphyll cells are tw types: Palisade parenchyma Spngy parenchyma Adaxially placed palisade parenchyma is made up f elngated cells arranged vertically, parallel t each ther. Spngy parenchyma: val r rund and lsely arranged cells belw the palisade parenchyma. Vascular bundles are seen in the midrib and veins. The vascular bundles are surrunded by a layer f thick walled bundle sheath cells. Isbilateral (Mnctylednus) leaf : It is similar with Drsiventral leaf in many respect except Stmata are equally distributed n upper and lwer epidermis. Mesphyll cells are nt differentiated int palisade and spngy. 32

35 In grasses, certain adaxial epidermal cells alng the veins mdified themselves int large, empty, clurless cells called bullifrm cells. Causes rlling f leaves t reduce transpiratin during water stress. Mnctylednus Rt : Mnct rt have similar tissues as in dict except :- It cntains mre than six xylem bundles called plyarch. Pith is large and well develped. D nt underg any secndary grwth. Dictylednus Stem : Outermst layer is epidermis. Epidermis cvered with thin layer f cuticle and has trichmes and few stmata. The cells arranged in multiple layers in-between epidermis and pericycle cnstitute the crtex. Crtex has three sub-znes : Hypdermis: a few layers f cllenchymatus cells belw epidermis. Crtical layers: cnsists f runded thin walled parenchymatus cells with intercellular spaces. Enddermis: it is the innermst layer f crtex. Cells are rich in starch grains and are referred t as starch sheath. Pericycle : present n the inner side f the enddermis and abve the phlem in the frm f semi-lunar patches f Sclerenchyma. Medullary rays: a few layers f radially placed parenchymatus cells present in between vascular bundles. A large number f vascular bundles arranged in a ring. Each vascular bundle is cnjint, pen and endarch prtxylem. The central prtin f stem cnstitutes the pith. Mnctylednus Stem : It has similar tissues with the dict stem except in fllwing Sclerenchymatus hypdermis. Vascular bundles are scattered in the grund tissue. Each vascular bundle is cvered by bundle sheath cells. Vascular bundles are cnjint and clsed. Peripheral vascular bundles are smaller than central ne. Phlem parenchyma is absent. Water cntaining cavities are present within the vascular bundles. Drsiventral (Dictylednus) Leaf : Vertical sectin f a Drsiventral leaf shws three main parts: Epidermis. Mesphyll cells. Vascular systems. 33

36 Epidermis cvers bth upper (adaxial) and lwer (abaxial) surface f the leaf has a cnspicuus cuticle. Abaxial surface has mre stmata than the adaxial epidermis. Tissue between upper and lwer epidermis called mesphyll. Mesphyll cells are tw types: Palisade parenchyma Spngy parenchyma Adaxially placed palisade parenchyma is made up f elngated cells arranged vertically, parallel t each ther. Spngy parenchyma: val r rund and lsely arranged cells belw the palisade parenchyma. Vascular bundles are seen in the midrib and veins. The vascular bundles are surrunded by a layer f thick walled bundle sheath cells. Isbilateral (Mnctylednus) leaf : It is similar with Drsiventral leaf in many respect except Stmata are equally distributed n upper and lwer epidermis. Mesphyll cells are nt differentiated int palisade and spngy. In grasses, certain adaxial epidermal cells alng the veins mdified themselves int large, empty, clurless cells called bullifrm cells. Causes rlling f leaves t reduce transpiratin during water stress. 34

37 7. Structural Organisatin in Animals POINTS TO REMEMBER : Tissue : A grup f similar cells alng with intercellular substances which perfrm a specific functin. ANIMAL TISSUES : Animal tissues are classified int fur types: Epithelial tissues. Cnnective tissues. Muscular tissues. Neural tissues. Epithelial tissues : These tissues cmmnly called epithelium. Has free surface, which faces either a bdy fluid r the utside envirnment. Cells are cmpactly packed with little intercellular matrix. There are tw types f epithelial tissues: Simple epithelium. Cmpund r stratified epithelium. Simple epithelium is cmpsed f a single layer f cells and functins as a lining fr bdy cavities, ducts and tubes. The cmpund epithelium cnsists f tw r mre cell layers and has prtective functin as it des in ur skin. Simple epithelium, n the basis f mdificatin, divided int three types: Squamus Cubidal Clumnar. Squamus epithelium : Made f single thin layer f flattened cells with irregular bundaries. Fund in the wall f bld vessels and air sacs f lungs. Functins as diffusin bundary. Cubidal epithelium : Cmpsed f a single layer cube like cells. Fund in ducts f glands and tubular part f nephrns in kidneys. Main functin is secretin and absrptin. Clumnar epithelium : Cmpsed f a single layer f tall and slender cells. Their nuclei lcated at the base. 35

38 Free surface may have micrvilli. Fund in the lining f stmach and intestine Helps in absrptin and secretin. Ciliated epithelium : It is a mdified Cubidal r clumnar epithelium. Cell bears cilia n their free surfaces. Fund in the inner surface f hllw rgans like brnchiles and fallpian tubes. Their functin is t mve particles r mucus in a specific directin ver the epithelium. Glandular epithelium : It is a mdified Cubidal r clumnar epithelium. Get specialized fr secretin. Simple glands having unicellular and islated cells f alimentary canal. Multicellular glands: cnsisting f cluster f cells, as in salivary gland. Excrine gland: the secretry prduct transprted t a pint by means f a duct. These glands secrete mucus, saliva, ear wax, milk, digestive enzymes etc Endcrine gland: cmmnly called as ductless gland, because the secretry prducts directly pured int bld. The glands secretes hrmne. Cmpund epithelium : Made f mre than ne layer f cells. Limited rle in absrptin and secretin. Main functin is t prvide prtectin against chemical and mechanical stresses. They cver the dry surface f skin, mist surface f buccal cavity, pharynx, inner lining f duct f salivary gland and pancreatic duct. Cell junctin : Cells f the epithelium are held tgether with little intercellular matrix. Cell junctin prvide structural and functinal link between the cells Tight junctin: help t stp substances frm leaking acrss a tissue. Adhering junctins: perfrm cementing t keep neighbring cells tgether. Gap junctins: facilitate the cells t cmmunicating the cytplasm f adjining cells, fr rapid transfer f ins, small mlecules. Cnnective tissues : Mst abundant and widely distributed tissues. Special functin f linking and supprting ther tissues/rgans f the bdy. Cnnective tissues include cartilage, bne, adipse, and bld. In all cnnective tissue except bld, the cells secrete fibres f prteins called cllagen and elastin. The fibre prvides strength, elasticity and flexibility t the tissue. Presence f grund substance r matrix in between the cells, mdified plysaccharides. Lse cnnective tissue : Has cells and fibres lsely arranged in a semislid grund substance. 36

39 Arelar tissue : Arelar tissue is ne example f lse cnnective tissue. Present beneath the skin. It supprts the framewrk fr epithelium. It cntains cell like fibrblasts (secretes fibres), macrphages and mast cells. Adipse tissue: Anther type f lse cnnective tissues. Lcated mstly beneath the skin. Cells f this tissue specialized t stre fats called adipcytes. Dense cnnective tissue : Fibres and fibrblasts are cmpactly packed. Dense regular tissues : Orientatin f fibres shws a regular pattern. The cllagen fibres are present in rws between many parallel bundles f fibres. Tendns: jints muscles t bne. Ligaments: jins bne t bne are the examples. Dense irregular tissues: Fibrblasts and many fibres are riented differently. This tissue present in skin. Specialized cnnective tissues : Cartilage bne and bld are the special cnnective tissues. Cartilage: Intercellular material f cartilage is slid. Chndrcytes are the cells f cartilage. Pliable and resists cmpressin. Cells are enclsed in small cavities within the matrix. Mst f the cartilage f the embry replaced by bnes in adult. Cartilage present in nse tips, ear pinna, between adjacent vertebrae. Bnes: Have hard and nn pliable matrix r grund substance. The matrix is rich in calcium salts and cllagen fibers which give the bne its strength. Prvides the structural frame f human bdy. Supprt and prtect the sft tissues and rgans. The bne cells called Ostecytes are present in fluid filled cavity called lacunae. Sustain bdy weight. 37

40 Attached with skeletal muscles meant fr lcmtin. Bne marrw is the site f prductin f Red bld cells. Muscular tissues: Each muscle is made f many lng, cylindrical fibres arranged in parallel arrays. Each fibre cmpsed f numerus fine fibrils, called myfibrils. Muscle fibres cntracts in respnse t stimulus. Muscle plays a great rle in mvement and lcmtin. Skeletal muscle: Clsed attached t the skeletn r bne and cartilage. Muscle cells are unbranched and multinucleated. A number f muscle fibres are bundled tgether in parallel fashin. A sheath f tugh cnnective tissues enclses several bundles f muscle fibres. Smth muscle : The smth muscle fibres tapers r pinted at bth ends D nt shw crss striatin. Cell junctins hld them tgether. They are bundled tgether in a cnnective tissue sheath. Present in wall f bld vessels, stmach and intestine. They are invluntary in nature. Cardiac muscles: Cntractile muscular tissue present in heart. Cell junctins fuse the plasma membranes f cardiac muscles cells and make them stick tgether. Cmmunicatin junctin r intercalated discs at sme fusin pints allw the cells t cntract as a unit. Muscle cells are branched and Uninucleated. Neural tissues: Neural tissues exert greatest cntrl ver bdy s respnse t changing cnditin. Neurns are the units f nervus tissues. Neurglial cells nn-cnducting and prtects and supprt neurns. Neurglia makes up mre than ne-half the vlume f neural tissue. Electrical impulse is cnducted thrugh the plasma membrane f neurn. EARTHWORM : Mrphlgy : Earthwrm has lng cylindrical bdy. The bdy divided int mre than 100 equal segments called metamere. Mid-drsal dark line indicates the drsal bld vessel. The ventral surface is distinguished by genital penings. Anterir end cnsists f the muth and prstmium. 38

41 The first segment is called peristmium, which cntain the muth. In matured wrm, segments are cvered by dark band f glandular tissue called clitellum. Bdy divisible int: Preclitellar. Clitellar. Pstclitellar External apertures: Fur pairs f spermathecal aperture 5th 9th segments. A female genital aperture- 14th segment. A pair f male genital apertures in 18th segment. Numerus nephridial pres n the skin f each segment. There are rw f S- shaped Setae in each segment except 1st and last segment. Setae have principal rle in lcmtin. ANATOMY : Bdy wall : Bdy wall externally cvered by thin nn-cellular cuticle. Bdy wall cntains epidermis belw cuticle. Epidermis is made f single layer f clumnar epithelium with secretry glands. Tw layers f muscles (circular and lngitudinal). Digestive system: Alimentary canal is a straight tube between 1st and last segment. Muth present in the 1st segment. Muth pens int buccal cavity 1-3 segments. Buccal cavity leads int muscular pharynx in 4th segment. Narrw esphagus at 5-7 segments. Muscular gizzard in 8-9 segments helps in grinding f ingested fd. Stmach extended frm 9-14 segments. Calciferus gland present in the stmach, neutralize the acidic nature f humic acid present in the humus. Intestine starts frm 15th segment and cntinues till last segment. A pair f Intestinal caecae present in the 26th segment. Presence f internal median fld f drsal wall f intestine called typhlsle between segments. Typhlsle increases the surface area fr absrptin. Intestine pens t utside by means f anus. Bld vascular system : Bld vascular system is clsed type. Bld vascular system cnsists f: Bld vessels 39

42 Capillaries Heart. Bld glands present n 4th, 5th and 6th segments. Bld glands prduce bld cells and haemglbin. Haemglbin disslved in plasma instead f embedded in crpuscles. Bld cells are Phagcytic in nature. Respiratin: Earthwrm lack specialized breathing devices. Gaseus exchange takes place thrugh mist surface f skin. Transprt f respiratry gases takes place in haemglbin. Excretry system: Excretry rgans are segmentally arranged ciled tubules called nephridia. There are three types f nephridia: Septal nephridia: Present n bth side f intersegmental septa f segment 15 t last segment. They pened int the intestine. Integumentary nephridia. Attached t the lining f the bdy wall frm 3th t last segment. Opened int the bdy surface. Pharyngeal nephridia: Present in three pairs in 4th, 5th and 6th segment. Nephridia regulate the vlume and cmpsitin f bdy fluids. A nephridium starts with a ciliated funnel like structure called nephrstme, cnnected with a tubular part. Nervus system : Represented by ganglia arranged segmentally n the ventral paired nerve crd. Nerve crd in the anterir regin (3rd and 4th segments) bifurcates, laterally encircling the pharynx and jins the cerebral ganglia drsally t frm nerve ring. Segmental ganglia give rise t nerve fibres t the bdy rgans. 40

43 Sensry rgans : Pssesses light and tuch sensitive rgans (receptr cells) Have specialized chemreceptr, which reacts t chemical stimuli. Sense rgans lcated in the anterir part f the bdy. Reprductive system : Earthwrm is hermaphrdite Tw pairs f testes present in the 10th and 11th segments. Their vasa deferentia run upt 18th segment and jins with prstatic duct. Tw pairs f accessry glands present ne pair each in the 17th and 19th segment. The prstrate and spermatic duct (vasa dererentia) pens t exterir by a pair f male genital pre n the ventr-lateral side f the 18th segment. Fur pairs f spermathecae are lcated in 6th 9th segments. They receive and stre spermatza during cpulatin. One pair f varies is attached at the inter-segmental septum f 12th and 13th segment. Ovarian funnel cntinued as viduct, jin tgether and pen by a single female genital aperture n the 14th segment. Mutual exchange f sperm ccurs between tw wrms during mating. Mature sperms and egg cells and nutritive fluid are depsited in the ccns prduced by gland cells f clitellum. Fertilizatin takes place inside the ccn which depsited in sil, After three weeks each ccn prduces tw t twenty baby wrms. Develpment is direct withut larval stage. COCKROACH : Mrphlgy : Adults cckrach Periplaneta americana are abut cm lng with wings that extended beynd the tip f the abdmen. Segmented bdy distinguished int head, thrax and abdmen. Entire bdy is cvered by external chitinus exskeletn. Each segment has hardened plates called sclerites (drsaltergites, ventral sternites). Successive sclerites are jined by flexible articular membrane (arthrdial membrane) Head : Head is frmed by fusin f six segments, with flexible neck. The head bears a pair f cmpund eye, a pair f antennae. Antennae have sensry receptrs. Head bears appendages meant fr biting and chewing types f muth parts. The muth parts cnsists f: A labrum (upper lip) A pair f mandibles. A pair f maxillae A labium (lwer lip) A median flexible lbe acting as tngue (hyppharynx). Thrax : Thrax cnsists f three parts prthrax, mesthrax and metathrax. 41

44 Each thracic segment bears a pair f walking legs. First pair f wings arises frm mesthrax and secnd pair frm metathrax. The hind wings are transparent, membranus meant fr flying. Abdmen : The abdmen cnsists f 10 segments. In female the 7th segment is bat shaped and alng with 9th and 10th segment it frms the brad r genital puch. Genital puch cntains female gnpre, spermathecal pres and cllateral glands. In male the genital puch bunded drsally by 9th and 10th terga and ventrally by the 9th sternum. Male bears a pair f anal style, absent in female. Anal cerci present in bth sexes in 10th segment. ANATOMY : Digestive system : Alimentary canal divided int three regins; fregut, midgut and hindgut. The muth pens int shrt pharynx leading t esphagus. Oesphagus pens int a sac like crp, which stre fd. Crp is fllwed by gizzard r prventriculus. Gizzard cntains chitinus teeth fr grinding the fd. The entire fre gut is lined by cuticle. A ring f 6-8 blind tubules called hepatic r gastric caecae present at the junctin f fregut and midgut, which secretes digestive juices. Midgut is lng tube like structure. At the junctin f midgut and hindgut, anther ring f yellw clured thin filamentus Malpighian tubulesare present. Malpighian tubules are meant fr excretin frm haemlymph. The hindgut is brader and differentiated int ileum, cln and rectum. Bld vascular system: Bld vascular system is pen type. Bld vessels are prly develped and pen int space called haemcel. Visceral rgans lcated in the haemcel and bathed in bld called haemlymph. The haemlymph cmpsed f clurless plasma and haemcytes. Heart is elngated multichambered, funnel shaped with stia. Bld enter int the heart thrugh stia and is pumped anterirly int the sinuses. The haemcel differentiated int three sinuses; Pericardial sinus. Perivisceral sinus. Perineural sinus. Respiratry system : The respiratry system cnsists f a netwrk f trachea. Trachea pens t utside by 10 pairs f small hles called spiracles n lateral side f the bdy. Trachea gives rise t branching tubes called tracheal tubes which subdivided int tracheles. Opening f spiracles regulated by valves. Mvement f air takes place by diffusin and directly t the bdy cell. 42

45 Excretin: Excretin is perfrmed by malpighian tubules. Each tubule is lined by glandular and ciliated cells. They absrb nitrgenus wastes frm the haemcel and cnverted int uric acid and pured int the hindgut. Hence cckrach is urictelic in nature. Nephrcytes and uricse glands als assist in excretin. Nervus system: Cnsists f a series f segmentally arranged ganglia jined by paired lngitudinal duble ventral nerve crd. Three ganglia lie in thrax and six in the abdmen. Head cntain a bit f nervus system. The brain is represented by supra-esphageal ganglin which innervates the cmpund eye and antennae. The sense rgans are antennae, eyes maxillary palps, labial palps, anal cerci etc. Each cmpund eye cnsists f abut 2000 hexagnal mmatidia. Each mmatidium frms a part f the image, called msaic visin. Reprductive system : Cckraches are diecius and sex rgans are well develped. Male reprductive system cnsists f a pair f testes lying ne n each in 4th and 6th segments. Vas deferens arises frm each testis, pens int ejaculatry duct thrugh seminal vesicle. Ejaculatry duct pens int the male gnpre situated ventral t anus. Accessry reprductive gland called mushrm gland present n 6th-7th segment. External genitalia represented by male gnpphysis r phallmere. Sperms are srted in the seminal vesicles and are glued tgether in the frm f bundles called spermatphreswhich are discharged during cpulatin. The female reprductive system cnsists f tw large varies present in 2nd 6th abdminal segments. Each vary is frmed a grup f eight varian tubules r variles, cntaining chain f develping va. Oviduct f each vary fused t frm single median viduct r vagina, which pens int genital chamber. A pair f spermatheca is present in the 6th segment which pens int genital chamber. Sperms are transferred thrugh spermatphres. The fertilized eggs are encased in capsules called thecae. Otheca is dark reddish t blackish brwn capsule abut 3/8 lng. On average, female prduce 9-10 thecae, each cntaining eggs. Develpment is purmetablus i.e develpment thrugh nymphal stages. The nymph grws by mlting abut 13 times t reach the adult frm. FROG : Frg belngs t class Amphibia. Mst cmmn species in India is Rana tigrina. They are cld blded animal; the bdy temperature varies accrding t envirnmental temperature. They have ability t change the bdy clur accrding t the envirnment. They underg hibernatin (summer sleep) and aestivatin (winter sleep). Mrphlgy : The skin is smth and mist, slippery due t mucus. 43

46 Drsal bdy is live green with dark irregular spts. Ventral side f the bdy is unifrmly pale yellw clured. The frg never drinks water and absrb it thrugh skin (hygrscpic). Bdy divisible int head and trunk. Neck is absent. On either side f the eyes a membranus tympanum (represents the external ear), t receive the sund waves. Frelimbs and hind limbs helps in swimming, leaping and burrwing. Fre limb have fur digit and hind limb strnger and has five digits. Frg exhibit sexual dimrphism. Male frg distinguished frm female frg: Having sund prducing vcal sac. Cpulatry pad r amplexury pad n the first digit f the fre limb. Anatmy : Digestive system : Digestive system cnsists f alimentary canal and digestive glands. Alimentary canal is shrt because frgs are carnivrus. Muth pens int buccal cavity that leads int esphagus thrugh pharynx. Oesphagus is a shrt tube that pens int the stmach, which inturn cntinues as the intestine, rectum and finally pens utside by the claca. Liver secrete bile that stred in the gall bladder. Pancreas a digestive gland prduces pancreatic juice cntaining digestive enzymes. Fd is captured by bilbed tngue. Digestin f fd takes place by the actin f HCl and gastric juice secreted frm the walls f the stmach. Partially digested fd in the stmach is called chyme. Chyme passed frm stmach t intestine, the dudenum. The dudenum receives the bile frm gall bladder and pancreatic juice frm pancreas thrugh a cmmn bile duct. Bile emulsifies fat and pancreatic juices digest carbhydrates and prteins. Final digestin takes place in intestine. Digested fd is absrbed by intestinal villi and micrvilli. The undigested fd remved t utside thrugh claca. Respiratry system : In water frg respire thrugh skin (cutaneus respiratin) Exchange f respiratry gases takes place thrugh diffusin. In land it respires thrugh buccal cavity, skin and lungs. Respiratin by lungs is called pulmnary respiratin. During aestivatin and hibernatin it respires thrugh skin. Circulatry system : The bld vascular system includes heart, bld vessel and bld. The lymphatic system includes lymph, lymph ndes and lymphatic vessels. Heart is three chambered with tw atria and ne ventricle. Heart is cvered by a membrane called pericardium. A triangular sinus vensus pens int right atrium. It receives the dexygenated bld thrugh vena cava. The ventricle pens int cnus atrerisus n the ventral side f the heart. Frm the cnus atrerisus the bld circulated t different part f the bdy by arterial system. Bld cllected frm the bdy t the heart by venus system. 44

47 Special venus cnnectin between liver and intestine is called hepatic prtal system. Venus cnnectin between lwer part f the bdy and kidney is called renal prtal system. The bld is cmpsed f plasma and cells. The bld cells are; erythrcytes (RBC), leuccytes (WBC) and Thrmbcytes (Platelets). RBC is nucleated and cntains hemglbin. The lymph differs frm in, it lack prteins and RBC. Excretry system : The excretry system cnsists f a pair f kidneys, ureters, claca and urinary bladder. Each kidney cmpsed f several uriniferus tubules r nephrns. The ureter arises frm the kidney act as uringenital duct which pens int claca in male. In female the ureters and viduct pen separately int the claca. Thin walled urinary bladder lcated ventral t rectum, pens t the claca. The frg excretes nitrgenus waste in the frm f urea, hence uretelic. Cntrl and crdinatin system : It includes bth nervus and endcrine system. Chemical crdinatin is carried ut by hrmnes secreted by endcrine glands. Endcrine glands fund in frg are pituitary, thyrid, parathyrid, thymus, pineal bdy, pancreas, adrenal and gnads. The nervus system rganized int; Central nervus system- brain and spinal crd. Peripheral nervus system cranial and spinal nerves. Autnmic nervus system sympathetic and parasympathetic. There are 10 pairs f cranial nerves arises frm the brain. Brain is enclsed in side the cranium. The brain differentiated int; fre brain, mid brain and hind brain. Fre brain includes; Paired lfactry lbe. Paired cerebral hemisphere Unpaired diencephaln. The mid brain is characterized by a pair f ptic lbes. Hind brain cnsists f cerebellum and medulla blngata. Medulla blngata passes thrugh framen f magnum and cntinues as spinal crd which runs inside the vertebral clumn. Sense rgans: Frg has different types f sense rgans; Organs f tuch (sensry papillae) Taste (taste buds) Smell (nasal epithelium) Visin (eye) Hearing (tympanum with internal ear) 45

48 Eye is well rganized inside the rbit f the skull. Ear is an rgan fr hearing and equilibrium (balancing). Male reprductive system: Cnsists f a pair f yellwish vid testes, attached t the upper part f kidneys, by mesrchium. Vasa efferentia are in number arises frm the testes. They enter int the kidney and pens int Bidder s canal. Bidder s canal cmmunicates with the uringenital duct that cmes ut f the kidneys and pens int the claca. The claca is a small median chamber that is used t pass faecal matter, urine and sperms t the exterir. Female reprductive system: Includes a pair f varies present near the kidneys. A pair f viduct arising frm varies pens int the claca separately. A mature female lays 2500 t 3000 va at a time. Fertilizatin is external i.e. in water Develpment is indirect invlved a larval stage called tadple larva. Tadple larva metamrphses int adult frg. 46

49 8. Cell: The Unit f Life POINTS TO REMEMBER : CELL THEORY : Schieiden and Schwann tgether frmulated the cell thery. They prpsed that the bdy f animal and plant are cmpsed f cells and prduct f cells. Rudlf Virchw (1855) he mdified and gives the final shape t thecell thery. All living rganisms are cmpsed f cells and prducts f cells. All cells arise frm pre-existing cells. PROKARYOTIC CELLS : Represented by bacteria, blue-green algae, mycplasma and PPLO. Smaller and multiply mre rapidly than eukarytic cells. Fur basic shape f bacteria are Bacillus (rd like) Cccus (spherical) Vibri (cmma shaped) Sprillum (spiral) All prkarytes have a cell wall surrunds the plasma membrane. There is n well defined nucleus. Chrmsme is single and circular, nt envelped by nuclear membrane. Presence f many small, circular, extra chrmsmal and self replicable DNA called plasmid. Plasmid prvides unique characteristic t the bacteria. One f the characteristic is antibitic resistant. N membrane bund cell rganelles. A specialized differentiated frm f cell membrane called messme is present. Cell envelpe and its Mdificatins : Mst prkarytic cell have characteristic cmplex cell envelpe. The cell envelps cnsists f tightly bund three layer structure; The utermst glyccalyx. Middle cell wall Inner plasma membrane. Accrding t the nature f the cell wall and behavir twards the stain develped by Gram, bacteria are Gram psitiver Gram negative. Glyccalyx may fr a lse sheath called slime layer. Glyccalyx may be thick and tugh called the capsule. The cell wall determines the shape f the cell, strng structural supprt t prevent the bacterium frm bursting and cllapsing. Plasma membrane is semi-permeable in nature and interacts with utside wrld. A special membranus structure is the messme which is frmed by extensins f plasma membrane int the cell. 47

50 These extensins are in the frm f vesicles, tubules and lamellae. They help in cell wall frmatin, DNA replicatin and distributin t the daughter cell. They als help in respiratin and secretin. Sme bacteria have filamentus extensins called flagella. Bacterial flagellum has three parts filament, hk and basal bdy. Pili are elngated tubular structures made f a special prtein. Fimbriae are small bristle like fibres spruting ut f the cell. Play rle in adhesin. Ribsme and inclusin bdies : Ribsmes are assciated with the plasma membrane f the cell. Each ribsme (70 S) has tw sub units; smaller (30 S ) and large (50 S). Ribsmes are the site f prtein synthesis. Several ribsmes attached t a single mrna t frm a chain called plyribsme r plysme. Reserve materials are stred in the frm f inclusin bdies. Phsphate granules, cyanphycean granules and glycgen granules are the inclusin bdies. EUKARYOTIC CELL : Eukarytes include all the Prtists, plants, animals and fungi. Extensive cmpartmentalizatin due t membrane bund cell rganelles. Pssess an rganized nucleus with nuclear envelpe. Have a variety f cmplex lcmtry and cytskeletal structure. Genetic materials are rganized int chrmsmes. The plant cell pssess cell walls, plastids and a large central vacule, which are absent in animal cell. Animal cells have centriles which absent in plant cells. Cell membrane : The cell membrane cmpsed f lipids that arranged in bilayer. Lipids are arranged within the membrane with the hydrphilic plar head twards the uter sides and thehydrphbic tails twards the inner part. Nn plar tail f saturated hydrcarbns is prtected frm the aqueus envirnment. The lipid cmpnent f the membrane mainly cnsists f phphglycerides. Cell membrane als pssesses prtein and carbhydrates. Rati f prtein and lipids varies frm cell t cell. Human erythrcyte plasma membrane cntains 52 % prtein and 40 % lipids. Membrane prtein may be integral r peripheral. Peripheral prtein lie n the surface and integral prteins are partially r ttally buried in the membrane. The imprved mdel f the structure f plasma membrane was prpsed by singer and Niclsn (1972) widely accepted as fluid msaic mdel. Accrding t this the quasi fluid nature f lipid enables the lateral mvement f prteins within the verall bilayer. Functin : Passive transprt. Simple diffusin 48

51 Facilitated diffusin. Active transprt. Phagcytsis Excytsis. Pincytsis. Cell wall : A nn-living rigid structure called cell wall present utside the plasma membrane f plant and fungal cell. Algae have a cell wall made f cellulse, galactans, mannans and minerals like calcium carbnate. Plant cell wall cnsists f cellulse, hemicellulses, pectins and prteins. The cell wall f yung plant is called primary cell wall. On maturity secndary cell wall frmed inner t it. The middle lamella is a layer f calcium pectate which hlds r glues the neighbring cells. The cell wall and middle lamella may traversed by plasmdesmata; the cytplasmic cnnectin between tw adjacent cell. The endmembrane system : Endplasmic reticulum : Netwrk r reticulum f tiny tubular structures scattered in the cytplasm, called endplasmic reticulum. It divides the intracellular space int tw distinct cmpartments: Luminal (inside the ER) Extra luminal (cytplasm). The ER shws ribsmes attached t their uter surface called Rugh Endplasmic reticulum (RER). Endplasmic reticulum withut ribsme called SER (smth endplasmic reticulum) Functin: RER present in the cell actively invlved in prtein synthesis. SER is the site fr synthesis f lipid, glycgen and sterid hrmnes. Glgi apparatus: Camill Glgi (1898) first bserved this rganelle, and named after him. It cnsists f many flat, disc shaped sacs r cisternae. These are staked parallel t each ther. The Glgi cisternae are cncentrically arranged near the nucleus with distinct cnvex cisr the frming face and cncave transr the maturing face. Functin: Principally respnsible fr packing f materials t be delivered intra-cellular target r intercellular target. 49

52 Materials are packed in the frm f vesicles, frm the ER fuse with the cis face f the Glgi apparatus and mve twards the trans face. Imprtant site fr the frmatin f glycprtein and glyclipids. Lyssmes: Membrane bund vesicular structure. Frmed by Glgi bdy. Rich in all type hydrlytic enzymes, ptimally active in acidic ph. These enzymes are capable t digesting carbhydrates, prteins, lipids and nucleic acids. Vacules: The vacule is the membrane-bund space fund in the cytplasm. It cntains water, sap, excretry prduct. Vacule is bunded by a single membrane called tnplast. In plant cells the vacule can ccupy 90% f the vlume. Tnplast facilitates active transprt f material frm cytplasm int the vacule. In Ameba the cntractile vacule is imprtant fr excretin and smregulatin. In many prtists, fd vacules are frmed by engulfing the fd particles. Mitchndria: The number f mitchndria varies accrding t the physilgical activity f the cell. Each mitchndrin is a duble membrane bund structure with uter and inner membrane, dividing its lumen int tw aqueus cmpartments Outer cmpartment. Inner cmpartment. The inner cmpartment is called the matrix. The inner membrane frms a number f infldings called the cristae twards the matrix. The cristae increase the surface area. Tw membranes have their wn specific enzymes assciated with the mitchndrial functin. Mitchndria are the site f aerbic respiratin. They prduce cellular energy in the frm f ATP, hence called pwer huse f the cell. The matrix als pssess single circular DNA mlecule and a few RNA mlecules, ribsmes (70S), they synthesize their wn prtein. Mitchndria divide by fissin. Plastids : Plastids are fund in all plant cells and in Euglenids. They bear sme specific pigment, impart specific clur t the plants. Based n the type f pigments plastids can be classified int Chlrplast. Chrmplast Leucplast. 50

53 The chlrplasts cntain chlrphyll and cartenid pigments, traps slar energy fr phtsynthesis. In the chrmplasts fat sluble cartenid pigments like cartene, xanthphylls are present. The leucplasts are clurless plastids f varied shapes and size with stred nutrients. Amylplast - stre carbhydrates. Elaiplasts stre ils and fats. Aleurplast stre prteins and minerals. Chlrplasts are fund in the mesphyll cells f the leaves. These are val, spherical, discid r even ribbn like rganelles. Chlrplast is a duble membrane rganelle. The space limited by inner membrane is called strma. A number f rganized flattened membranus sacs called thylakid are present in the strma. Thylakids are arranged like stakes f cins t frm grana. There are flat membranus tubules called the strma lamellae cnnecting the thylakids f the different grana. They thylakids enclse a space called lumen. Chlrphyll pigments are lcated in the thylakids. Chlrplast cntains enzymes required fr the synthesis f carbhydrates and prteins. Strma cntains small circular DNA and ribsmes. Ribsmes : Ribsmes are granular structure first bserved by Gerge Palade (1953). Cmpsed f ribnucleic acid (RNA) and prteins. Nn-membranus cell rganelles. Eukarytic ribsmes are 80S while the prkarytic ribsmes are 70S. S stands fr sedimentatin cefficient; measure f density and size. Bth 70S and 80S ribsmes cnsists f tw subunits. Primary functin is prtein synthesis hence called prtein factry f the cell. Cytskeletn : An elabrate netwrk f filamentus prteinaceus structures present in the cytplasm is cllectively knwn ascytskeletn. Cytskeletn invlved in many functin such as mechanical supprt, mtility, maintenance f the shape f the cell. Cilia and Flagella : Cilia and flagella are hair-like utgrwths f the cell membrane. Cilia are small help in the mvement f cell r surrunding fluid. Flagella are lnger and respnsible fr cell mvement. Cilia and flagella cvered by plasma membrane. Their cre called axneme, pssess a number micrtubules running parallel t the lng axis. The axneme usually has nine pairs f dublets f radially arranged peripheral micrtubules and a pair f centrally lcated micrtubules. The central tubules are cnnected by bridges and are als enclsed by a central sheath, which is cnnected t ne f the tubules f each peripheral dublet by radial spke. The peripheral dublets are als intercnnected by linkers. 51

54 Bth cilia and flagella emerge frm centriles-like structure called basal bdies. Centrsme and centriles : Centrsme is an rganelle usually cntaining tw cylindrical structures called centriles. They are surrunded by amrphus pericentrilar materials. Bth centriles in a Centrsme lie perpendicular t each ther. Each centrile has an rganizatin like the cartwheel. They are made f nine evenly spaced peripheral fibrils f tubulin. Each f the peripheral fibril is a triplet. The adjacent triplets are als linked t each thers. The central part f the centrile is called hub. The hub cnnected t peripheral triplets by radial spkes. The centrile frms the basal bdy fr cilia, flagella and frm spindle fibres during cell divisin. Nucleus : Nucleus as a cell rganelle was first described by Rbert Brwn in Materials inside the nucleus was stained by Flemming and named as chrmatin. The interphase nucleus has highly extended and elabrates nucleprtein fibres called chrmatin. The nucleus als cntains nuclear matrix and ne r tw spherical bdies called nucleli. Nuclear envelpe cnsists f tw membranes with perinuclear space (10-50 nm). The uter membrane remains cntinuus with endplasmic reticulum. Presence f nuclear pre due t fusin f tw membranes. Nuclear pres allw the mvement f RNA and prtein in bth directins. The nuclear matrix r nucleplasm cntains nuclelus and chrmatin. Nuclelus is the site fr active ribsmal RNA synthesis. During cell divisin the chrmatins cndensed t frm chrmsmes. Chrmatin cntains DNA and sme basic prteins called histnes, nn-histne prteins and sme RNA. A single human cell cntains apprximately tw meter lng thread f DNA in 46 chrmsmes. Each chrmsme essentially has a primary cnstrictin r the centrmere. On each side f centrmere there is disc shaped structures called kinetchres. Based n the psitin f the centrmere chrmsmes are classified int fur types:- Metacentric: centrmere at the middle with tw equal arms. Sub-Metacentric: ne shrt arm and ne lng arm. Acrcentric: with extremely shrt arm and a very lng arm. Telcentric: with terminal centrmere. A few chrmsmes have nn-staining cnstrictins at a cnstant lcatin. This gives the appearance f a small fragment called the satellite. 52

55 9. Bimlecules POINTS TO REMEMBER : Bimlecules: All the carbn cmpunds that we get frm living tissues. Macrmlecules: Mlecules which have mlecular weights less than ne thusand daltn. Amin acids: Organic cmpunds cntaining an amin grup and ne carbxyl grup (acid grup) and bth these grups are attached t the same carbn atm called α carbn. Twenty types f amin acids ccur in prteins. Based n number f amin and carbxyl grups, amin acids can be: Acidic: e.g. Glutamic acid Basic: e.g. Arginine and lysine Neutral: e.g. valine, alanine. Armatic amin acids are tyrsine, phenylalanine, and tryptphan. Amin acids are inizable int zwitterinic frm. Lipids : Water insluble, cntaining C, H, O. They culd be simple fatty acids. A fatty acid has a carbxyl grup attached t an R grup. The R grup may be a methyl grup (-CH3) r ethyl (-C2H5) r higher number f-ch2 grup (1 carbn t 19 carbn). E.g. palmitic acid with 19 carbns, arachidnic acid has 20 carbns. Fatty acids culd be saturated (withut duble bnd) r unsaturated (with ne mre (c=c) duble bnd. Anther example f lipid is glycerl which is trihydrxy prpane. Many lipids may have bth glycerl and fatty acids. Fatty acids esterified with glycerl t frm mn, di r triglycerides. These are als called fats and ils based n the melting pints. Oils have lw melting pints (e.g. gingely il). Phsphlipids are cmpund lipids with phsphrus and a phsphrylated rganic cmpund. They are fund in the cell membrane. e.g., Lecithin. Nitrgen bases : Carbn cmpunds with hetercyclic rings. Purine: Adenine, Guanine. Pyrimidine: Cytsine, Uracil, Thymine. Nucleside: Nitrgenus base + Sugar e.g., Adensine, guansine, thymidine Uridine and cytidine Nucletide: Nitrgenus base + Sugar + Phsphate grup. e.g., Adenylic acid, thymidylic acid, guanylic acid, uridylic acid and cytidylic acid. Nucleic acid: Plymer f nucletides - DNA and RNA. PRIMARY AND SECONDARY METABOLITES : Primary metablites : Have identified functin. Play knwn rles in physilgical functin. Carbhydrates, amin acids, fats and ils, nitrgen bases are the example f primary metablites. 53

56 Secndary metablites : Have n definite functin. Have n direct rle in nrmal physilgy. Alkalid, favnides, rubber, essential ils, antibitics, clured pigments. Scents, gums, spices are sme example. Bimacrmlecules : Bimlecules with mlecular weights in the range f ten thusand daltns and abve; fund in acid insluble fractin. Lipids are nt strictly macrmlecules as their mlecular weights d nt exceed 800 Da but frm a part f the acid insluble pl. Prteins : Are plymers f amin acids linked by peptide bnd. Is a heterplymer nt hmplymer. Essential amin acids: thse can t be synthesized in ur bdy, have t be supplied thrugh ur diet. Nn-essential amin acids: ur bdy can synthesize it frm ther surces. Cllagen is the mst abundant prtein in animal. Ribulse bisphsphate Carbxylase-Oxygenase (RUBISCO) is mst abundant prtein in the whle bisphere. POLYSACCHARIDES : Acid sluble pillet als has plysaccharides as anther class f macrmlecules. Plysaccharides are the lng chain f sugars. Cellulse is hmplymer cntaining nly glucse units. Starch is a variant f hmplymer f glucse which stre energy. Glycgen is anther hmplymer fund in animal. Inulin is a plymer f fructse. In a plysaccharide chain the right end is called reducing end and left end is nn-reducing end. Starch frm helical secndary structure. Starch can hld Idine (I2) mlecule in its helical prtin hence gives blue clur. Cellulse dse nt cntain cmplex helices and hence cannt hld Idine (I2) and nt give blue clur. Cmplex sugars have amin-sugar as building blcks. (Glucsamine, N-acetyl galactsamine.) Exskeletn f arthrpds made f cmplex sugar called chitin. Cmplex plysaccharides are heterplymer. STRUCTURE OF PROTEINS : Primary structure: Is fund in the frm f linear sequence f amin acids. First amin acid is called N-terminal amin acid and last amin acid is called C-terminal amin acid. Secndary structure: Plypeptide chain underges flding r ciling which is stabilized by hydrgen bnding. Right handed helices are bserved. e.g., fibrus prtein in hair nails. Tertiary structure: Lng prtein chain is flded upn itself like a hllw wlen ball. Gives a 3-dimensinal view f prtein, e.g., mysin. Quaternary structure: Tw r mre plypeptides with their flding and ciling are arranged with respect t each ther. e.g., Human haemglbin mlecule has 4 peptide chains - 2α and 2β subunits. 54

57 NATURE OF BOND LINKING MONOMERS IN A POLYMER : Peptide bndb : Frmed between the carbxyl (-COOH) grup f ne amin acid and the amin (-NH2) grup f the next amin acid with the eliminatin f water miety. Glycsidic bndb : Individual mnsaccharides linked with each ther t frm plysaccharides. This bnd is als frmed by dehydratin. Frmed between tw carbn atms f tw adjacent mnsaccharides. Phsphdiester bndbb : In a nucleic acid a phsphate miety links the 3 -carbn f ne sugar ne nucletide t the 5 -carbn f the sugar f the succeeding nucletide. The bnd between the phsphate and hydrxyl grup f sugar is an ester bnd. There is ne such ester bnd n either side, it is called Phsphdiester bnd. Anablic pathways: Lead t frmatin f mre cmplex mlecules frm a simpler mlecules with the cnsumptin f energy. e.g., Prtein frm amin acids. Catablic pathway: Lead t frmatin f simpler mlecule frm a cmplex mlecule. e.g., Glucse Lactic Acid. ENZYMES : Are bicatalysts. Almst all enzymes are prteins. Ribzyme - Nucleic acids that behave like enzymes. Has primary, secndary and tertiary structure. Active site f an enzyme is a crevice r pcket int which substrate fits. Enzymes get damaged at high temperatures. Enzymes islated frm thermphilic rganisms (live under high temperatures) are thermstable. Enzymes accelerate the reactins many flds. Enzymes lwer the activatin energy f reactins. The chemicals n which the enzyme acts called substrates. Enzyme cnverts substrates int prducts. Nature f enzyme actin : The substrate binds t the active site f the enzyme, fitting int the active site. The binding f the substrate induces the enzymes t alter its shape, fitting mre tightly arund the substrate. Active site nw breaks the chemical bnd f the substrate and enzyme-prduct cmplex is frmed. The enzyme releases the prduct. Factrs affecting enzyme activity : Temperature : Shw highest activity at ptimum temperature. Activity declines abve and belw the ptimum value. 55

58 ph : Enzymes functin in a narrw range f ph. Highest activity at ptimum ph. Cncentratin f substrate : The velcity f enzymatic reactin rises with increase in substrate cncentratin till it reaches maximum velcity (V max). Further increase f substrate des nt increase the rate f reactin as n free enzyme mlecules are available t find with additinal substrate. Enzyme inhibitin: When the binding f a chemical shuts ff enzyme activity, the prcess is called inhibitin and chemical is called inhibitr. Cmpetitive inhibitin: Inhibitr clsely resembles the substrate in its mlecular structure and inhibits the enzyme activity. E.g., inhibitin f succinic dehydrgenase by malnate. Classificatin f enzymes : Oxidreductase/dehydrgenases: Catalyse xidreductin between 2 substrates. Transferases: Catalyse transfer f a grup between a pair f substrates. Hydrlases: Catalyse hydrlysis f ester, ether, peptide, glycsidic, C-C, P-N bnds. Lyases: Catalyse remval f grups frm substrates by mechanisms ther than hydrlysis leaving a duble bnd in the prduct. Ismerases: Catalyse inter-cnversin f ptical, gemetric r psitinal ismers. Ligases: Catalyse linking tgether f 2 cmpunds. Cfactrs : Nn-prtein cnstituents fund t the enzyme t make it catalytically active. Prtein prtin f enzyme is called apenzyme. Prsthetic grups: Are rganic cmpunds tightly bund t apenzyme. E.g., haem in perxydase and catalase. C-enzymes: Organic cmpunds which lsely bind with enzyme. E.g., NAD, NADP. Metal ins: Required fr enzyme activity. Frm crdinatin bnd with side chains at active site and with substrate. E.g., zinc is a c-factr fr enzyme enters stmach? 56

59 10. Cell Cycle and Cell Divisin POINTS TO REMEMBER : Cell cycle : The sequence f events by which a cell duplicates its genme, synthesis the ther cnstituents f the cell and eventually divides int tw daughter cells. Phases f cell cycle : Interphase : G1 Phase: Cell metablically active and grws cntinuusly. S Phase: DNA synthesis ccurs, DNA cntent increases frm 2C t 4C.but the number f chrmsmes remains sme (2N). G2 Phase: Prteins are synthesized in preparatin fr mitsis while cell grwth cntinues. M Phase (Mitsis Phase): Starts with nuclear divisin, crrespnding t separatin f daughter chrmsmes (karykinesis) and usually ends with divisin f cytplasm (cytkinesis). Quiescent stage (G0): Cells that d nt divide and exit G1 phase t enter an inactive stage called G0. Cells at this stage remain metablically active but d nt prliferate. MITOSIS : Prphase : Replicated chrmsmes, each cnsisting f 2 chrmatids, cndense and becme visible. Micrtubules are assembled int mittic spindle. Nuclelus and nuclear envelpe disappear. Centrile mves t ppsite ples. Metaphase : Spindle fibres attached t kinetchres (small disc-shaped structures at the surface f centrmers) f chrmsmes. Chrmsmes line up at the equatr f the spindle t frm metaphase plate. Anaphase : Centrmeres split and chrmatids separate. Chrmatids mve t ppsite ples. Telphase : Chrmsmes cluster at ppsite ples. Nuclear envelpe assembles arund chrmsme cluster. Nuclelus, Glgi cmplex, ER refrm. 57

60 Cytkinesis : Is the divisin f prtplast f a cell int tw daughter cells after Karykinesis (nuclear divisin). Animal cytkinesis : Appearance f furrw in plasma membrane which deepens and jins in the centre dividing cell cytplasm int tw. Plant cytkinesis : Frmatin f new cell wall begins with the frmatin f a simple precursr cell plate which represents the middle lamella between the walls f tw adjacent cells. Significance f Mitsis : Grwth additin f cells. Maintenance f surface/vlume rati. Maintenance f chrmsme number. Regeneratin. Reprductin in unicellular rganism. Repair and wund healing. MEIOSIS : Specialized kind f cell divisin that reduces the chrmsme number by half, resulting in frmatin f 4 haplid daughter cells. Occurs during gametgenesis in plants and animals. Invlves tw sequential cycles f nuclear and cell divisin called Meisis I and Meisis II. Interphase ccurs prir t meisis which is similar t interphase f mitsis except the S phase is prlnged. 4 haplid daughter cells are frmed. Meisis I - Prphase I : Subdivided int 5 phases. Lepttene : Chrmsmes make their as single stranded structures. Cmpactin f chrmsmes cntinues. Zygtene : Hmlgus chrmsmes start pairing and this prcess f assciatin is called synapsis. Chrmsmal synapsis is accmpanied by frmatin f synaptnemal cmplex. Cmplex frmed by a pair f synapsed hmlgus chrmsmes is called bivalent r tetrad. Pachytene : Crssing ver ccurs between nn-sister chrmatids f hmlgus chrmsmes. Dipltene : 58

61 Disslutin f synaptnemal cmplex ccurs and the recmbined chrmsmes separate frm each ther except at the sites f crssing ver. These X-shaped structures are called chaismata. Diakinesis : Terminalisatin f chaismata. Chrmsmes are fully cndensed and meitic spindles assembled. Nuclelus disappears and nuclear envelpe breaks dwn. Metaphase I : Bivalent chrmsmes align n the equatrial plate. Micrtubules frm ppsite ples f the spindle attach t the pair f hmlgus chrmsmes. Anaphase I: Hmlgus chrmsmes separate while chrmatids remain assciated at their centrmeres. Telphase I : Nuclear membrane and nuclelus reappear. Cytkinesis fllws (diad f cells). Interkinesis : Stage between tw meitic divisins. (Meisis I and meisis II) Meisis II - Prphase II Nuclear membrane disappears. Chrmsmes becme cmpact. Metaphase II Chrmsmes align at the equatr. Micrtubules frm ppsite ples f spindle get attached t kinetchres f sister chrmatids. Anaphase II Simultaneus splitting f the centrmere f each chrmsme, allwing them t mve twards ppsite ples f the cell. Telphase II Tw grups f chrmsmes get enclsed by a nuclear envelpe. Cytkinesis fllws resulting in the frmatin f tetrad f cells i.e., 4 haplid cells. Significance f Meisis Frmatin f gametes: In sexually reprducing rganisms. Genetic variability 59

62 Maintenance f chrmsmal number: By reducing the chrmsme number in gametes. Chrmsmal number is restred by fertilisatin f gametes. 60

63 11. Transprt in Plants POINTS TO REMEMBER : Translcatin : Transprt f substances in plants ver lnger distances thrugh the vascular tissue (Xylem and Phlem) is called translcatin. Means f transprt : The transprt f material int and ut f the cells is carried ut by a number f methds. These are diffusin, facilitated diffusin and active transprt. Diffusin : Diffusin ccurs frm regin f higher cncentratin t regin f lwer cncentratin acrss the permeable membrane. It is passive and slw prcess. N energy expenditure takes place. Facilitated diffusin : The diffusin f hydrphilic substances alng the cncentratin gradient thrugh fixed membrane transprt prtein withut invlving energy expenditure is called facilitated diffusin. Fr this the membrane pssesses aquarprins and in channels. N energy is utilized in this prcess. Methds f Facilitated Diffusin : Sme carrier r transprt prteins allw diffusin nly if tw types f mlecules mves tgether. Symprt: bth mlecules crss the membrane in the same directin. Antiprt: bth mlecule mves in ppsite directin. Uniprt: ne type f mlecule mves acrss the cell membrane. Active transprt : Active transprt is carried by the mvable carrier prteins (pumps) f membrane. Active transprt uses energy t pump mlecules against a cncentratin gradient frm a lw cncentratin t high cncentratin (uphill-transprt). It is faster than passive transprt. Water ptential : Water mlecule pssesses kinetic energy. The greater the cncentratin f water in a system, the greater is its kinetic energy r water ptential. Pure water has the highest water ptential. Water always mves frm higher water ptential t lwer water ptential. Water ptential is dented by Ψw (Psi) and measured in Pascals (Pa). The water ptential f a cell is affected by slute ptential (Ψs) and pressure ptential (Ψp). Ψ w = Ψ s + Ψ p Water ptential f pure water at standard temperature which is nt under any pressure is taken t be zer (by cnventin). Osmsis : 61

64 Osmsis is mvement f slvent r water mlecules frm the regin f their higher diffusin pressure r free energy t the regin f their lwer diffusin pressure r free energy acrss a semi-permeable membrane. Water mlecules mve frm higher water ptential t lwer water ptential until equilibrium is reached. Plasmlysis : Prcess f shrinkage f prtplasm in a cell due t exsmsis in hypertnic slutin. Turgr pressure: a plant cell placed in hyptnic slutin, water enters int it due endsmsis and the cytplasm exert pressure against the cell wall called turgr pressure. Imbibitin: Imbibitin is the phenmenn f adsrptin f water r any ther liquid by the slid particles f a substance withut frming a slutin. Sme examples f Imbibitin : If a dry piece f wd is placed in water, it swells and increases in its vlume. If dry gum r pieces f agar-agar are placed in water, they swell and their vlume increases. When seeds are placed in water they swell up. Lng distance transprt f water : Mass flw: Mass flw is the mvement f substances (water, minerals and fd) in bulk frm ne pint t anther as a result f pressure differences between tw pints. Translcatin: the bulk mvement f substance thrugh the cnducting r vascular tissue is called translcatin. Hw d plants absrb water? Transprt f water in plants: Water is absrbed by rt hairs, then water mves upt xylem by tw pathways applast and symplast pathway. Applast pathway : Mvement f water takes place exclusively thrugh the intercellular spaces and the walls f the cells. Mvement thrugh the applast des nt invlve crssing the cell membrane. Mvement depends n the gradient. The applast des nt prvide any barrier t water mvement. Water mvement is trugh mass flw. Symplast pathway : System f intercnnected prtplasts. Neighbring cells are cnnected thrugh cytplasmic strands that extend thrugh plasmdesmata. Water enters int the cytplasm by crssing the plasma membrane. Intercellular mvement is thrugh the plasmdesmata. Casparian strip : enddermis is impervius t water because f a band f suberised matrix called casparian strip. 62

65 Water mvement up a plant : Rt pressure : A hydrstatic pressure existing in rts which push the water up in xylem vessels. Guttatin : The water lss in its liquid phase at night and early mrning thrugh special penings f vein near the tip f leaves. Transpiratin pull : The transprt f water t the tps f trees ccurs thrugh xylem vessels. The frces f adhesin and chesin maintain thin and unbrken clumns f water in the capillaries f xylem vessels thrugh which it travels upward. Water is mainly pulled by transpiratin frm leaves. (Chesin-tensin-transpiratin pull Mdel) Transpiratin : The lss f water thrugh stmata f leaves and ther aerial parts f plants in frm f water vapur. Transpiratin driven ascent f xylem sap depends n the fllwing physical prperties f water: Chesin : mutual attractin between water mlecules. Adhesin : attractin f water mlecules t plar surface(such as the surface f tracheary elements) Surface tensin : water mlecules are attracted t each ther in the liquid phase mre than t water in the gas phase. Rle f transpiratin : Creates transpiratin pull fr absrptin and transprt f plants. Supplies water fr phtsynthesis. Transprts minerals frm the sil t all parts f the plants. Cls leaf surfaces, smetimes 10 t 15 degrees, by evaprative cling. Maintains the shape and structure f the plants be keeping cells turgid. Factrs affecting transpiratin : Temperature, light, humidity, wind speed, number and distributin f stmata, water status f plant. Uptake and transprt f mineral nutrients : Ins are absrbed by the rts by passive and active transprt. The active uptake f ins requires ATP energy. Specific prteins in membranes f rt hair cells actively pump ins frm the sil int the cytplasm f epidermal cells and then xylem. The further transprt f ins t all parts f the plant is carried thrugh the transpiratin stream. The Pressure r Mass Flw Hypthesis : The glucse is prepared at the surce by the prcess f phtsynthesis and is cnverted t sucrse (sugar). This sugar is then mved int sieve tube cells by active transprt. It prduces hypertnic cnditin in phlem. Water in the adjacent xylem mves int phlem by smsis. Due t smtic (turgr) pressure, the phlem sap mves t the areas f lwer pressure. At the sink, smtic pressure is decreased. 63

66 The incming sugar is actively transprted ut f the phlem and remved as cmplex carbhydrates (sucrse). As the sugar is remved, the smtic pressure decreases, the water mves ut f the phlem and returns t the xylem. 64

67 12. Mineral Nutritin POINTS TO REMEMBER : Auttrphs : An rganism that synthesize its required nutrients frm simple and inrganic substances. Hetertrphs : An rganism that cannt synthesize its wn nutrients and depend n thers. Essential Mineral elements : Mre than sixty elements fund in different plants. Sme plant accumulates selenium, sme ther gld. Criteria fr Essentiality : Element abslutely necessary fr nrmal grwth and reprductin. In the absence f the element the plant can nt cmplete their life cycle. Rle f the element can nt be replaced by any ther elements. The element must be directly invlved in the metablism f plant. Macrnutrients : are generally present in the plants tissues in large amunt (in excess f 10 mmle Kg -1 f dry matter). Micrnutrients : r trace elements are needed in very small amunts (less than 10 mmle Kg -1 f dry matter) Fur grup f essential elements : As cmpnents f bimlecules and frms structural elements f cells (e.g. carbn, hydrgen, xygen and nitrgen) As cmpnents f energy-related chemical cmpunds in plants. (magnesium in chlrphyll and phsphrus in ATP) Element that activate r inhibit enzymes (Mg 2+, Zn 2+ ) Alter the smtic ptential f a cell. (K + ) Rle f macr and micr-nutrients : Nitrgen : Absrbed in the frm f NO2 - r NH4 + Required by meristematic tissue and metablically active tissue. Cnstituent f prteins, nucleic acids, vitamins and hrmnes. Phsphrus : Absrbed in the frm f H2PO4- r HPO4 2-. Cnstituents f cell membrane certain prteins, all nucleic acids and required in phsphrylatin reactin. Ptassium : Absrbed as ptassium in (K + ) Required in meristematic tissues. Maintain catin and anin balance in cell. Opening and clsing f stmata. Activatin f enzyme. 65

68 Maintenance f turgidity f cells. Calcium : Absrbed in the frm f calcium ins (Ca 2+ ). Required by meristematic and differentiating tissues. Used in synthesis f cell wall particularly as calcium pectate in middle lamella. Required during frmatin f mittic spindle. Invlved in nrmal functining f cell membrane. Activate certain enzyme. Imprtant rle in regulating metablic activity. Magnesium : Absrbed in the frm f Mg 2+. Activates enzymes f respiratin, phtsynthesis. Invlved in the synthesis f DNA and RNA. Cnstituent f the ring structure f chlrphyll. Maintain ribsme structure. Sulphur : Absrbed in the frm f sulphate SO4 2-. Present in tw amin acids cystine and methinine Main cnstituent f several cenzyme, vitamins and ferredxin. Irn : Obtained in the frm f ferric ins (Fe 3+ ). Required in larger amunt in cmparisn t ther elements. Cnstituent f prteins invlved in the transfer f electrn like ferredxin and cytchrmes. Activates catalase enzyme. Essential fr frmatin f chlrphyll. Manganese : Absrbed in the frm f manganus ins (Mn 2+ ). Activates many enzymes f phtsynthesis, respiratin and nitrgen metablism. Phtlysis f water and evlutin f xygen during light reactin. Zinc : Obtained in the frm f Zn 2+. Activates enzymes like carbxylase. Required in synthesis f auxin. Cupper : Absrbed in the frm f cupric ins (Cu 2+ ). Essential fr verall metablism. 66

69 Assciated with enzyme invlved in redx reactins. Brn : Absrbed in the frm f BO3 3- r B4O7 2-. Required in uptake and utilizatin f Ca 2+. Pllen germinatin. Cell elngatin. Cell differentiatin. Carbhydrate translcatin. Mlybdenum : Obtained in the frm f mlybdate ins (MO2 2- ). Cmpnent f enzyme like nitrgenase and nitrate reductase. Required in nitrgen metablism. Chlrine : Absrbed in the frm f chlride anin (Cl - ). Alng with Na + and K + it determines the slute cncentratin. Maintain anin catin balance f the cell. Essential fr phtlysis f water during light reactin f phtsynthesis. Deficiency symptms f essential elements : Critical cncentratin: the cncentratin f the essential element belw which plant grwth is retarded. The element is said t be deficient when present belw the critical cncentratin. Fr the elements that are actively mbilized within the plant that shw the deficiency symptms in the lder tissues. (nitrgen, ptassium and magnesium) The deficiency symptms tend t appear first in the yung tissues whenever the elements are relatively immbile and are nt transprted ut f the mature rgans.(sulphur and calcium) Deficiency symptm includes chlrsis, necrsis, and stunted grwth, premature fall f leaves and buds, and inhibitin f cell divisin. Chlrsis: is the lss f chlrphyll. Necrsis: death f cells and tissues. Txicity f Micrnutrients : Micrnutrient required in lw amunt. Mderate decrease causes the deficiency symptms. Mderate increase causes txicity. Any mineral in cncentratin in tissues that reduces the dry weight f the tissues by 10 percent is cnsidered txic. Nitrgen cycle : Nitrgen fixatin: cnversin f mlecular nitrgen int ammnia. Bilgical nitrgen fixatin: Cnversin f atmspheric int rganic cmpunds by living rganisms. Ammnificatin: decmpsitin f rganic nitrgen f dead plants and animals int ammnia is called Ammnificatin. (Nitrmnasbacteria) 67

70 Nitrificatin. Ammnia xidized int nitrite by NitrsmnasandNitrcccus bacteria. The nitrite further xidized t nitrate with the help f Nitrbacter. These steps are called nitrificatin. Assimilatin: Nitrates absrbed by plant frm sil and transprted t the leaves. In the leaves nitrates reduced t frm ammnia that finally frms the amine grup f amin acids. Denitrificatin: Nitrate in the sil is als reduced t mlecular nitrgen. This prcess is carried by bacteria likepseudmnas and Thibacillus. Bilgical nitrgen fixatin : Reductin f nitrgen t ammnia by living rganisms is called bilgical nitrgen fixatin. The enzyme nitrgenase which catalyses the prcess are present in prkarytes, called nitrgen fixer. Nitrgen fixing micrbes culd be free-living r symbitic. Free-living nitrgen fixing aerbic micrbes are Aztbacter and Beijernickia. Free-living nitrgen fixing anaerbic micrbes are Rhdspirilium. A number f cyanbacteria like Anabaena and Nstc are free-living nitrgen fixer. Symbitic nitrgen fixatin : Best example f symbitic nitrgen fixatin is bserved in legume-rhizbium bacteria. Rhizbium frm rt ndules in leguminus plants. Frankia als prduces nitrgen-fixing ndules n the rts f nn-leguminus plants (e.g. Alnus). Bth Rhizbium and Frankia are free living in sil, but as symbint, can fix atmspheric nitrgen. The rt ndules cntain pink clured pigment cntains a prtein called leg-haemglbin. Ndule frmatin : Ndule frmatin invlves a sequence f multiple interactins between Rhizbium and rts f the hst plant. Rhizbia multiply and clnize the surrundings f rts and get attached t the epidermal and rt hair cells. An infectin thread is prduced carrying the bacteria int the crtex f rt. Bacteria released frm the thread int the cells which differentiated int special nitrgen fixing cells. Ndule develps vascular cnnectin fr exchange f nutrients. The ndule cntains an enzyme called nitrgenase. Nitrgenase is a M-Fe prtein and catalyses the cnversin f atmspheric nitrgen t ammnia. Nitrgenase is highly sensitive t mlecular xygen; it requires anaerbic cnditin. Ndule cntains a special prtein called leg-haemglbin. Leg-haemglbin acts as xygen scavenger and prvides anaerbic cnditin t the bacteria inside the ndules; prtect the enzyme nitrgenase frm xidatin. Ammnia synthesis by nitrgenase is energetically expensive prcess; 8 ATP required synthesizing each mlecule f NH3. Fate f ammnia : At physilgical ph, the ammnia is prtnated t frm NH4+. Mst f plant assimilated nitrate and ammnium ins. 68

71 Reductive aminatin: the ammnia reacts with α-ketglutaric acid and frms Glutamic acid. Transaminatin: it invlves the transfer f amin grup frm ne amin acid t the ket grup f a ket acid. Glutamic acid is the main amin acid frm which by the prcess f transaminatin ther amin acids are synthesized. Tw imprtant amides asparagines and glutamine fund in the prtein f plant. They are frmed frm tw amin acids namely aspartic acid and Glutamic acid respectively. 69

72 13. Phtsynthesis in Higher Plants POINTS TO REMEMBER : Phtsynthesis: Phtsynthesis is an enzyme regulated anablic prcess f manufacture f rganic cmpunds inside the chlrphyll cntaining cells frm carbn dixide and water with the help f sunlight as a surce f energy. Histrical Perspective : Jseph Priestley (1770) : Shwed that plants have the ability t take up CO2 frm atmsphere and release O2. Jan Ingenhusz (1779) : Release f O2 by plants was pssible nly in sunlight and nly by the green parts f plants. Thedre de Saussure (1804) : Water is an essential requirement fr phtsynthesis t ccur. Julius Vn Sachs (1854) : Green parts in plant prduce glucse which is stred as starch. T. W. Engelmann (1888) : The effect f different wavelength f light n phtsynthesis and pltted the first actin spectrum f phtsynthesis. C. B. Van Niel (1931) : Phtsynthesis is essentially a light dependent reactin in which hydrgen frm an xidisable cmpund reduces CO2 t frm sugar. He gave a simplified chemical equatin f phtsynthesis. Hill (1937) : Evlutin f xygen ccurs in light reactin. Calvin ( ) : Traced the pathway f carbn fixatin. Hatch and Slack (1965) : Discvered C4 pathway f CO2 fixatin. Site fr phtsynthesis : Phtsynthesis takes place nly in green parts f the plant, mstly in leaves. Within a leaf, phtsynthesis ccurs in mesphyll cells which cntain the chlrplasts. Chlrplasts are the actual sites fr phtsynthesis. The thylakids in chlrplast cntain mst f pigments required fr capturing slar energy t initiate phtsynthesis. The membrane system (grana) is respnsible fr trapping the light energy and fr the synthesis f ATP and NADPH. Bisynthetic phase (dark reactin) is carried in strma. Pigments invlved in phtsynthesis: Chlrphyll a : (Bright r blue green in chrmatgraph). Majr pigment, act as reactin centre, invlved in trapping and cnverting light int chemical energy. Chlrphyll b : (Yellw green) Xanthphylls : (Yellw) Cartenid : (Yellw t yellw-range) In the blue and red regins f spectrum shws higher rate f phtsynthesis. What is light reactin? Light reactins r the Phtchemical phase includes light absrptin, splitting f water, evlutin f xygen and frmatin f high energy cmpund like ATP and NADPH. Light Harvesting Cmplexes (LHC) : The light harvesting cmplexes are made up f hundreds f pigment mlecules bund t prtein within the phtsystem I (PSI) and phtsystem II (PSII). Each phtsystem has all the pigments except ne mlecule f chlrphyll a frming a light harvesting system (antennae). The reactin centre (chlrphyll a) is different in bth the phtsystems. 70

73 Phtsystem I (PSI) : Chlrphyll a has an absrptin peak at 700 nm (P700). Phtsystem II (PSII) : Chlrphyll a has absrptin peak at 680 nm (P680). Prcess f phtsynthesis : It includes tw phases - Phtchemical phase and bisynthetic phase. Phtchemical phase (Light reactin) : This phase includes - light absrptin, splitting f water, xygen release and frmatin f ATP and NADPH. Bisynthetic phase (Dark reactin) : It is light independent phase, synthesis f fd material (sugars). The electrn transprt : In phtsystem centre chlrphyll a absrbs 680 nm wavelength f red light causing electrns t becme excited and release tw electrns frm the atmic nucleus. These electrns are accepted by primary electrn acceptr i.e. ferredxin. The electrn frm the ferredxin passed t electrn transprt system cnsisting cytchrmes. The electrn mved in dwn hill in terms f redx ptential by xidatin-reductin reactins. Finally the electrn reached phtsystem-i. Simultaneusly electrn released frm phtsystem-i is accepted by electrn acceptr. Electrn hle created in PS-I is filled up by the electrn frm PS-II. Electrn frm PS-I passed dwn hill and reduce NADP int NADPH + + H +. Phtlysis f water : PS-II lse electrns cntinuusly, filled up by electrns released due t phtlysis f water. Water is split int H +, (O) and electrns in presence f light and Mn 2+ and Cl -. This als creates O2 the bi-prduct f phtsynthesis. Phtlysis takes place in the vicinity f the PS-II. 2H2O 4H + + O2 + 4e -. Phtphsphrylatin : The prcess f frmatin f high-energy chemicals (ATP and NADPH). Nn Cyclic phtphsphrylatin : Tw phtsystems wrk in series First PSII and then PSI. These tw phtsystems are cnnected thrugh an electrn transprt chain (Z. Scheme). ATP and NADPH + H + are synthesized by this prcess. PSI and PSII are fund in lamellae f grana, hence this prcess is carried here. Cyclic phtphsphrylatin : Only PS-I wrks, the electrn circulates within the phtsystem. It happens in the strma lamellae (pssible lcatin) because in this regin PS-II and NADP reductase enzyme are absent. Hence nly ATP mlecules are synthesized. Chemismtic Hypthesis : Chemismtic hypthesis explain the mechanism f ATP synthesis in chlrplast. 71

74 In phtsynthesis, ATP synthesis is linked t develpment f a prtn gradient acrss a membrane. The prtns that are prduced by the splitting f water are accumulated inside f membrane f thylakids (in lumen). As the electrn mves thrugh the phtsystem, prtns are transprted acrss the membrane. NADP reductase enzyme is lcated n the strma side f the membrane, alng with electrns frm the acceptr it remves H+ frm the strma during reductin f NADPH + H +. This creates prtn gradients acrss the thylakid membrane as well as a measurable decrease in ph in the lumen. ATPase has a channel that allws diffusin f prtns back t strma acrss the membrane. This releases energy t activate ATPase enzyme that catalyses the frmatin f ATP. Bisynthetic phase in C3 plants : ATP and NADH, the prducts f light reactin are used in synthesis f fd. The first CO2 fixatin prduct in C3 plant is 3-phsphglyceric acid r PGA. In sme ther plants the first stable prduct is an rganic acid called xalacetic acid a 4-C cmpund hence is called C4 plants. The Calvin cycle : The CO2 acceptr mlecule is RuBP (Ribulse bisphsphate). The cyclic path f sugar frmatin is called Calvin cycle n the name f Melvin Calvin, the discverer f this pathway. Calvin cycle prceeds in three stages: Carbxylatin : Carbxylatin is the fixatin f CO2 int a stable rganic intermediate. CO2 cmbines with Ribulse 1, 5 bisphsphate t frm 3 PGA in the presence f RuBisC enzyme. Reductin : These are a series f reactins that lead t the frmatin f glucse. 2 mlecules f ATP fr phsphrylatin and tw f NADPH fr reductin per CO2 mlecule fixed. The fixatin f six mlecules f CO2 and 6 turns f the cycle are required fr the frmatin f ne mlecule f glucse. Regeneratin : Regeneratin f the CO2 acceptr mlecule RuBP is crucial if the cycle is t cntinue uninterrupted. Regeneratin steps required ne ATP fr phsphrylatin t frm RuBP. Hence fr every CO2 mlecule entering the Calvin cycle, 3 mlecules f ATP and 2 mlecules f NADPH are required. The C4 pathway : Plants that are adapted t dry trpical regins have the C4 pathway. C4 xalacetic acid is the first CO2 fixatin prduct. These plants have special type f leaf anatmy, they tlerate higher temperatures. The leaf has tw types f cells: mesphyll cells and Bundle sheath cells (Kranz anatmy). 72

75 Initially CO2 is taken up by phsphenl pyruvate (PEP) in mesphyll cells and changed t xalacetic acid (OAA) in the presence f PEP carbxylase. Oxalacetate is reduced t malate/asparate that reaches int bundle sheath cells. In the bundle sheath cells these C4 acids are brken dwn t release CO2 and a 3-carbn mlecule i.e. pyruvic acid. The CO2 released in the bundle sheath cell enters the C3 cycle because these cells are rich in enzyme Ribulse bisphsphate carbxylase-xygenase (RuBisCO). The pyruvate frmed in the bundle sheath cell transprted back t the mesphyll cell, get phsphrylated t frm phsphenl pyruvate. Phtrespiratin: The light induced respiratin (evlutin f CO2) in green plants is called phtrespiratin. Active site f RuBisCO has active site fr bth O2 and CO2. In C3 plants sme O2 binds with RuBisC and hence CO2 fixatin is decreased. In this prcess RuBP instead f being cnverted t 2 mlecules f PGA, binds with O2 t frm ne mlecule f PGA and phsphglyclate. In the phtrespiratry pathway there is neither synthesis f sugar, nr f ATP. Rather it results in the release f CO2with utilizatin f ATP. In the phtrespiratry pathway there is n synthesis f ATP r NADPH. Therefre phtrespiratin is a wasteful prcess. In C4 plant phtrespiratin des nt ccur: RuBisCO enzyme is present in the bundle sheath cells. Primary carbxylatin is takes place in the mesphyll cell by PEP carbxylase. CO2 supplied t bundle sheath cell by C4 acid intermediate. Hence C4 plants are phtsynthetically mre efficient than C3 plant. Law f Limiting Factrs : If a chemical prcess is affected by mre than ne factr, then its rate will be determined by the factr which is nearest t its minimal value. It is the factr which directly affects the prcess if its quantity is changed. 73

76 14. Respiratin in Plants POINTS TO REMEMBER : The breaking f C-C bnds f cmplex cmpunds thrugh xidatin within the cells, leading t release f cnsiderable amunt f energy is called respiratin. The cmpund that xidized during this prcess is knwn asrespiratry substrates. In the prcess f respiratin the energy is released in a series f slw step-wise reactins cntrlled by enzymes and is trapped in the frm f ATP. ATP acts as the energy currency f the cell. Glyclysis : The term has riginated frm the Greek wrd, glycs =glucse, lysis = splitting r breakdwn means breakdwn f glucse mlecule. It is als called Embeden-Meyerhf-Paranus pathway. (EMP pathway) It is cmmn in bth aerbic and anaerbic respiratin. It takes place utside the mitchndria, in the cytplasm. One mlecule f glucse (Hexse sugar) ultimately prduces tw mlecules f pyruvic acid thrugh glyclysis. Glucse and fructse are phsphrylated t give rise t glucse-6-phsphate, catalyzed by hexkinase. This phsphrylated frm f glucse is then ismerizes t prduce fructse-6-phsphate. ATP utilized at tw steps: First in the cnversin f glucse int glucse-6-phsphate Secnd in fructse-6-phsphate fructse 1, 6-diphsphate. The fructse-1, 6-diphsphate is split int dihydrxyacetne phsphate and 3-phsphglyceraldehyde (DPGA). In ne step where NADH + H + is frmed frm NAD + ; this is when 3-phsphgleceraldehyde (PGAL) is cnverted int 1, 3-bisphphglyceric acid (DPGA). The cnversin f 1, 3-bisphphglyceric acid int 3-phsphglyceric acid is als an energy yielding prcess; this energy is trapped by the frmatin f ATP. Anther ATP synthesized when phsphenlpyruvate is cnverted int pyruvic acid. During this prcess 4 mlecules f ATP are prduced while 2 mlecules f ATP are utilized. Thus net gain f ATP is f 2 mlecules. FERMENTATION : There are three majr ways in which different cells handle pyruvic acid prduced by glyclysis: Lactic acid fermentatin. Alchlic fermentatin. Aerbic respiratin. Alchlic fermentatin : The incmplete xidatin f glucse t achieved under anaerbic cnditins by sets f reactins where pyruvic acid is cnverted int CO2 and ethanl. 74

77 The enzyme pyruvic acid decarbxylase and alchl dehydrgenase catalyze these reactins. NADH + H + is rexidised int NAD +. Lactic acid fermentatin: Pyruvic acid cnverted int lactic acid. It takes place in the muscle in anaerbic cnditins. The reactin catalysed by lactate dehydrgenase. NADH + H + is rexidised int NAD +. Aerbic respiratin: Pyruvic acid enters int the mitchndria. Cmplete xidatin f pyruvate by the stepwise remval f all the hydrgen atms, leaving three mlecules f CO2. The passing n the electrns remved as part f the hydrgen atms t mlecular xygen (O2) with simultaneus synthesis f ATP. AEROBIC RESPIRATION: The verall mechanism f aerbic respiratin can be studied under the fllwing steps : Glyclysis (EMP pathway) Oxidative Decarbxylatin Krebs s cycle (TCA-cycle) Oxidative phsphrylatin Oxidative decarbxylatin: Pyruvic acid frmed in the cytplasm enters int mitchndria. Pyruvic acid is cnverted int Acetyl CA in presence f pyruvate dehydrgenase cmplex. The pyruvate dehydrgenase catalyses the reactin require several cenzymes, including NAD + and Cenzyme A. During this prcess tw mlecules f NADH are prduced frm metablism f tw mlecules f pyruvic acids (prduced frm ne glucse mlecule during glyclysis). The Acetyl CA (2c) enters int a cyclic pathway, tricarbxylic acid cycle. Tri Carbxylic Acid Cycle (Krebs cycle) r Citric acid Cycle : This cycle starts with cndensatin f acetyl grup with xalacetic acid and water t yield citric acid. This reactin is catalysed by citrate synthase. Citrate is ismerised t frm iscitrate. It is fllwed by tw successive steps f decarbxylatin, leading t frmatin f α-ketglutaric acid and then succinyl-ca. In the remaining steps the succinyl CA xidized int xalacetic acid. During cnversin f succinyl CA t succinic acid there is synthesis f ne GTP mlecule. In a cupled reactin GTP cnverted t GDP with simultaneus synthesis f ATP frm ADP. During Krebs cycle there prductin f : 2 mlecule f CO2 3 NADH2 1 FADH2 75

78 1 GTP. During the whle prcess f xidatin f glucse prduce: CO2 10 NADH2 2 FADH2 2 GTP.( 2 ATP) Electrn transprt system and xidative phsphrylatin : The metablic pathway, thrugh which the electrn passes frm ne carrier t anther, is called Electrn transprt system. it is present in the inner mitchndrial membrane. ETS cmprises f the fllwing: Cmplex I NADH Dehydrgenase. Cmplex II succinate dehydrgenase. Cmplex III cytchrmes bc1 Cmplex IV Cytchrmes a-a3 (cytchrmes c xidase). Cmplex V ATP synthase. NADH2 prduced in the citric acid cycle xidized by NADH Dehydrgenase, and electrns are then transferred t ubiquinne lcated in the inner membrane. FADH2 is xidized by succinate dehydrgenase and transferred electrns t ubiquinne. The reduced ubiquinne is then xidized with transfer f electrns t cytchrme c via cytchrmes bc1 cmplex. Cytchrme c is small prtein attached t the uter surface f the inner membrane and acts as a mbile carrier fr transfer electrns frm cmplex III and cmplex IV. When electrns transferred frm ne carrier t anther via cmplex I t IV in the electrn transprt chain, they are cupled t ATP synthase fr the synthesis f ATP frm ADP and Pi. One mlecule f NADH2 gives rise t 3 ATP. One mlecule f FADH2 gives rise t 2ATP. Oxygen plays a vital rle in remving electrns and hydrgen in finally prductin f H2O. Phsphrylatin in presence f xygen is called xidative phsphrylatin. Ttal ATP Prductin - Prcess Ttal ATP prduced : Glyclysis 2ATP + 2NADH2 (6ATP) = 8ATP Oxidative decarbxylatin 2NADH2 (6ATP) = 6ATP Krebs s Cycle 2GTP (2ATP) + 6NADH2 (18ATP) + 2FADH2 (4ATP) = 24 ATP Energy prductin in prkarytes during aerbic respiratin = 38 ATP Energy prductin in eukarytes during aerbic respiratin = 38 2 = 36 ATP (2ATP are used up in transprting 2 mlecule f pyruvic acid in mitchndria.) Abbreviatins : ATP Adensine tri phsphate ADP Adensine di phsphate 76

79 NAD Nictinamide Adenine dinucletide NADP Nictinamide Adenine dinucletide Phsphate NADH Reduced Nictinamide Adenine dinucletide PGA Phsphglyceric acid PGAL Phsph glyceraldehyde FAD Flavin adenine dinucletide ETS Electrn transprt system ETC Electrn transprt chain TCA Tricarbxylic acid OAA Oxal acetic acid FMN Flavin mn nucletide PPP Pentse phsphate pathway 77

80 15. Plant Grwth and Develpment POINTS TO REMEMBER : Grwth : An irreversible permanent increase in size f an rgan r its parts r even f an individual cell. Grwth is accmpanied by metablic prcess that ccurs at the expense f energy. Plant grwth is generally is indeterminate : Plants retain the capacity f unlimited grwth thrughut their life. This ability is due t the presence f meristems at certain lcatins in their bdy. The cells f such meristems have capacity t divide and self-perpetuate. The prduct eventually lses the capacity t divide and differentiated. Apical meristems respnsible fr primary grwth f the plants and principally cntribute t the elngatin f the plants alng their axis. The lateral meristem, vascular cambium and crk cambium appears later and respnsible fr the increase in the girth. Phases f grwth : The perid f grwth is generally divided int three phases Meristematic. Elngatin. Maturatin. Rt apex and sht apex represent the meristematic phase f grwth. The cells f this regin are rich in prtplasm, pssesses large cnspicuus nuclei. Their cell walls are primary in nature, thin and cellulsic with abundant plasmdesmatal cnnectin. The cells prximal t that regin are the phase f elngatin. Increased vaculatin, cell enlargement and new cell wall depsitin are the characteristic f the cells in this phase. Further away frm the zne f elngatin is the phase f maturatin. The cells f this zne attain their maximal size in terms f wall thickening and prtplasmic mdificatins. Cnditin f grwth : Water, xygen and nutrients as very essential element fr grwth. Turgidity f cells helps in extensin grwth. Water als prvides the medium fr enzymatic activities needed fr grwth. Oxygen helps in releasing metablic energy essential fr grwth activities. Nutrients are required by plants fr synthesis f prtplasm and act as surce f energy. Differentiatin, dedifferentiatin and redifferentiatin : The cells derived frm rt apical and sht apical meristems and cambium differentiate and mature t perfrm specific functins. 78

81 This act f maturatin is termed as differentiatin. During differentiatin majr changes takes place in their cell wall and prtplasm. Differentiated tracheary element cells lse their prtplasm, develp a very strng, elastic ligncellulsic secndary cell walls. The living differentiated cells, that by nw have lst the capacity t divide can regain the capacity f divisin under certain cnditin is dedifferentiatin. Develpment f interfascicular cambium and crk cambium frm fully differentiated parenchymatus cells is the example f dedifferentiatin. Cells prduced by the dedifferentiated tissues again lse the capacity t divide and mature t perfrm specific functin is called redifferentiatin. PLANT GROWTH REGULATORS : Characteristics : The plant grwth regulatrs are small, simple mlecules f diverse chemical cmpsitin. They culd be: Indle cmpunds (indle-3-acetic acid, IAA); adenine derivatives (N6-furfurylamin purine, kinetin) derivatives f cartenids (abscisic acid,aba) terpenes (gibberellic acid, GA2) Gases (ethylene, C2H4) One grup f PGRs are invlved in grwth prmting activities such as cell divisin, cell enlargement, pattern frmatin, trpic grwth, flwering, fruiting and seed germinatin. These are called plant grwth prmters, e.g. auxin, gibberellins and cytkinin. Anther grup f PGRs play imprtant rle in plant respnses twards t wunds and stresses f bitic and abitic rigin. They invlved in inhibitry respnses like drmancy and abscissin, e.g. abscisic acid. Discvery f plant grwth regulatrs : Auxin was islated by F.W. Went frm tips f at seedlings. The bakane (flish seedling) a disease f rice seedlings, was caused by a fungal pathgen Gibberalla fujikuri. E. Kursawa reprted the appearance f the symptm f the disease in uninfected rice seedlings when treated with sterile filtrate f the fungus. The active substance was later identified as Gibberellic acid. Skg and Miller identified and crystallized the cytkinesis prmting active substance that they termed as kinetin. 79

82 During mid 1960s three different kinds f inhibitrs purified, i.e. inhibitr-b abscissin II and drmin. Later all the three prved t be chemically identical and named as Abscisic acid (ABA). Cusinsdiscvered a gaseus PGR called ethylene frm ripened range. Physilgical effect f plant grwth regulatrs : Auxin : The term auxin is applied t indle-3-acetic acid Generally prduced by grwing apices f the stems and rts. IAA and IBA have been islated frm plants. NAA and 2, 4-D (2, 4-dichlrphenxyacetic acid) are synthetic auxin. Prmte rting in stem cutting. Prmte flwering. Inhibit fruit and leaf drp at early stages. Prmte abscissin f lder mature leaves and fruits. The grwing apical bud inhibit the grwth f lateral bud, the phenmenn is called apical dminance. Auxin induces parthencarpy. Used as herbicides. Cntrls xylem differentiatin. Prmte cell divisin. Gibberellins : Ability t cause an increase in length f axis is used t increase the length f grapes stalks. Gibberellins cause fruits like apple t elngate and imprve its shape. Delay senescence GA3 is used t speed up the malting prcess in brewing industry. Gibberellins prmte t increase length f stem in sugar cane. Prmte early seed prductin. Prmte blting (interndes elngatin) in beet, cabbages. Cytkinins : Cytkinins have specific effects n cytkinesis. Zeatin islated frm crn-kernels and ccnut milk. Prmte cell divisin. Help t prduce new leaves, chlrplast in leaves, lateral sht grwth Prmte frmatin f adventitius sht. Cytkinins help t vercme apical dminance. Prmte nutrient mbilizatin. Delay senescence. Ethylene : 80

83 Ethylene is a simple gaseus PGR. Synthesized in the tissue underging senescence and ripening fruits. Prmte hrizntal grwth f seedling. Prmte swelling f axis and apical hk frmatin in dict seedlings. Prmte senescence and abscissin f plant rgans like leaf and flwer. Increase rate f respiratin during ripening f fruits, called respiratry climactic. Breaks seed and bud drmancy. Initiate germinatin. Prmte rapid interndes elngatin. Prmte rt grwth and rt hair frmatin. Used t initiate flwering and fr synchrnizing fruit-set. Induce flwering in mang. The surce f ethylene is ethephn. Prmte female flwer in cucumbers thereby increasing the yield. Abscisic acid : Regulates abscissin and drmancy. Acts as general plant grwth inhibitr and an inhibitr f plant metablism. Inhibit seed germinatin. Stimulates the clsure f stmata and increases the tlerance f plants t varius kinds f stresses, hence called asstress hrmne. Imprtant rle in seed develpment, maturatin and drmancy. Inducing drmancy, ABA helps seeds t withstand desiccatin and ther factrs unfavurable fr grwth. Acts as antagnist t Gas. PHOTOPERIODISM : Sme plants require a peridic expsure t light t induce flwering. Respnse f plants in terms f day/night in relatin t flwering is called phtperidism. Lng day plant: plant requires the expsure t light fr a perid exceeding critical perid. Shrt day plant: plant requires the expsure t light fr a perid less than critical perid. Day neutral plant: there is n such crrelatin between expsure t light duratin and inductin f flwering respnse. The site f perceptin f light/dark duratin is the leaves. VERNALISATION : Vernalisatin: There are plants fr which flwering is either quantitatively r qualitatively dependent n expsure t lw temperature. It prevents preccius reprductive develpment late in the grwing seasn. Vernalisatin refers t the prmtin f flwering by a perid f lw temperature. 81

84 16. Digestin and Absrptin POINTS TO REMEMBER : Digestin : enzymatic cnversin f cmplex fd substances t simple absrbable frms in the alimentary canal. DIGESTIVE SYSTEM : Includes: Alimentary canal Digestive glands r assciated glands. Alimentary canal : The alimentary canal begins with muth and ends with anus. Muth leads t buccal cavity r ral cavity. Oral cavity has teeth and muscular tngue. Each tth embedded in a scket f jaw bne: such attachment called thecdnt. Diphydnt : human has tw sets f teeth in their life time: Milk teeth r deciduus teeth Permanent teeth. Heterdnt : teeth are f unequal shape and size. Incisr (I) Canine (C) Premlar (PM) Mlar (M). Dental frmula : arrangement f teeth in each half f the upper jaw and lwer jaw. Dental frmula f human adult is The hard chewing surface f the teeth made up f enamel. The tngue is a freely mvable muscular rgan attached t the flr f the ral cavity by the frenulum. The upper surface f tngue has small prjectins called papillae, sme f which bears taste buds. The ral cavity leads int a shrt pharynx which serves as a cmmn passage fr fd and air. Oesphagus and the trachea pen int the pharynx. Opening f wind pipe r trachea called glttis, and that f esphagus is called gullet. The cartilaginus epiglttis prevents the entry f fd int the glttis during swallwing. Oesphagus cnnects pharynx with stmach. Opening f esphagus is regulated by gastr-esphageal sphincter. 82

85 The stmach has three parts: Cardiac: int which esphagus pens. Fundus: air filled prtin f stmach. Pylric: prtin pens int the small intestine. Small intestine distinguished int three parts: Dudenum: U shaped first part. Jejunum: lnger, ciled middle prtin. Ileum: highly ciled psterir part. The pening f stmach int the dudenum is guarded by pylric sphincter. Large intestine cnsists f three parts: Caecum Cln Rectum. Caecum is a small blind sac which hsts sme symbitic micr-rganisms. Caecum has a finger-like blind tubular prjectin called vermifrm appendix. The Caecum pens int cln, which has three distinct part Ascending cln Transverse cln Descending cln The descending cln pens int rectum which pens t ut thrugh anus. Histllgy f alimentary canal : Alimentary canal frm esphagus t rectum has fur layers. Sersa. Muscularis. Sub mucsa. Mucsa. Sersa is the utermst layer and is made up f a thin mesthelium with sme cnnective tissues. Muscularis is frmed by smth muscles arranged uter lngitudinal and inner circular layers. Sub-mucsa is frmed by lse cnnective tissues cntaining nerves, bld and lymph vessels. Mucsa is the innermst layer made f endthelium. Mucsa frms irregular flds (rugae) in the stmach and small finger like flding called villi in the small intestine. The cells lining the villi prduce numerus micrscpic prjectins called micrvilli giving a brush brder appearance. These mdificatins increase the surface area fr absrptin. 83

86 Villi are supplied with a netwrk f capillaries and a central lymphatic vessel called lacteal. Epithelial cells f mucsa cntain secretry cells which secretes digestive enzymes. Mucsa als frms glands in the stmach (gastric gland) Mucsa frms crypts in between the bases f villi in the intestine called Crypts f Lieberkuhn. Digestive glands : The digestive glands assciated with the alimentary canal includes Salivary gland Liver Pancreas. There are three pairs f salivary gland present in the buccal cavity. Partid gland (belw internal ear) Sub-maxillary / submandibular (belw lwer jaw) Sub-lingual (belw tngue) All salivary glands prduce saliva int the buccal cavity. Liver : Largest gland f the bdy weighing abut 1.2 t 1.5 kg in adult. Lcated belw diaphragm and has tw lbes. Structural and functinal unit f liver is the hepatic lbules. Hepatic lbules cnsist f hepatic cells arranged in the frm f crds. Each lbule is cvered by a thin cnnective tissue sheath called Glissn s capsule. The bile secreted by the hepatic cells passes thrugh the hepatic ducts and stred in the gall bladder in cncentrated frm. Bile frm the gall bladder is transprted by cystic duct. Cystic duct alng with hepatic duct frms the cmmn bile duct. Bile duct jined with pancreatic duct t frm hepat-pancreatic duct which pen int the dudenum. Hepat-pancreatic has a swelling prtin called ampulla f Vater; the pening is guarded by sphincter f Oddi. Pancreas : Pancreas is a cmpund myxcrine gland (bth excrine and endcrine) elngated rgan situated between the limbs f U shaped dudenum. The excrine aciner cells secrete pancreatic juice cntaining enzymes. The endcrine Islets f Langerhans secrete hrmnes like insulin and glucagn. DIGESTION OF FOOD : Digestin is accmplished by mechanical and chemical prcess. In the buccal cavity : Buccal cavity perfrms tw majr functins; 84

87 Masticatin f fd. Facilitatin f swallwing. The teeth and tngue with the help f saliva masticate and mix up the fd. The saliva cmpsed f ; Electrlytes (Na +, K +, Cl - HCO - 3) Enzyme- salivary amylase r ptyalin. Lyszyme. Abut 30% f starch is hydrlyzed int disaccharide (maltse) by salivary amylase in ptimum ph 6.8). Lyszyme acts as antibacterial agent preventing infectins. Mucus in the saliva helps in lubricating and adhering the masticated fd particle int a blus. The blus is then passed int esphagus thrugh pharynx by swallwing r deglutitin. By peristalsis the blus frm the esphagus passed int the stmach. In the stmach : The mucsa f stmach has gastric glands. Gastric glands have three majr types f cells namely Mucus neck cells secretes mucus. Peptic r chief r zymgen cells secretes prenzymes pepsingen. Parietal r xyntic cells secretes HCl and castles intrinsic factr (factr essential fr absrptin f vitamin B12) The stmach stres the fd fr 4-5 hurs. The fd mixed with the acidic gastric juice and frm chyme. Pepsingen cnverted int active pepsin in presence f HCl. Active pepsin cnverts prteins int prtese and peptnes (peptides). Mucus and bicarbnate ins play imprtant rle in lubricatin and prtectin f mucsal epithelium frm excriatin by HCl and active enzymes. HCl prvides the acidic ph f stmach (ph1.8) Rennin is an enzyme present in gastric juice helps in digestin f milk prteins. Small amunt f lipases are present in gastric juice helps in digestin f fats. In the intestine : Imprtant secretin added t the intestine during digestin: Bile juice. 85

88 Pancreatic juice. Intestinal juice r succus entericus. The pancreatic juice cntain fllwing enzymes: Trypsingen Chymtrypsingen Prcarbxypeptidase. Amylases Lipases Nucleases. Trypsingen is activated by an enzyme, enterkinase secreted by intestinal mucsa int active trypsin. Active trypsin activates ther enzymes in the pancreatic juice in the intestine. The bile released int the dudenum cntains Bile pigments (bilirubin and bili-verdin) Bile salts. (Bicarbnate, turchlate, glyclate) Chlesterl and Phsphlipids. Bile salt helps in emulsificatin f fat, i.e. breakdwn fats int small micelles. Bile als activates lipases. The intestinal mucsa cntains gblet cells which secrete mucus. The secretin f brush brder cells f intestinal mucsa and the gblet cells cnstitute the intestinal juice r succusentericus. The intestinal juice cntains variety f enzymes Disaccharidases (maltase, lactase and invertase) Dipeptidases. Lipases. Nuclesidases. Sub-mucsal glands (Brunner s glands) als secrete alkaline fluid t cunter act acidic chyme befre secretin f bile and pancreatic juice. 86

89 ABSORPTION OF DIGESTED PRODUCTS : Absrptin is the prcess by which the end prduct f digestin passes thrugh the intestinal mucsa int the bld r lymph. Absrptin is carried ut by passive, active r facilitated transprt mechanism. Glucse, amin acids and electrlytes are absrbed by simple diffusin int the bld in the cncentratin gradient. Fructse and sme amin acids absrbed with the help f carrier ins like Na+. This is called facilitated diffusin. Active transprt f digested fd and electrlytes takes place against the cncentratin gradients hence require energy. Absrptin f fatty acid and glycerl. Fatty acids and glycerl being insluble cannt be absrbed int bld. They are transprted int mucsal epithelium and triglycerides are frmed. Triglycerides are cvered by a prtein cat t frm small fat glbules called chylmicrn, which are incrprated int the lacteal in the villi. These lymphatic vessels ultimately release the absrbed substances int the bld stream later n. Assimilatin and egestin : The absrbed substances finally reach the tissues which utilize them fr their activities. This prcess is calledassimilatin. The digestive wastes, slidified int cherent faeces in the rectum and remved t utside peridically by the prcess called defaecatin. DISORDERS OF DIGESTIVE SYSTEM : Jaundice : 87

90 Affected rgan is the liver. Skin and eyes turn yellw due t depsitin f bile pigments. Vmiting : Ejectin f stmach cntents thrugh the muth. It is cntrlled by the vmit centre in the medulla blngata. A feeling f nausea precedes vmiting. Diarrahea : Abnrmal frequency f bwel mvement and increased liquidity f the faecal discharge. It reduces the absrptin f fd. Cnstipatin : The faeces are retained in the rectum as the bwel mvements ccurs irregularly. Indigestin : The fd is nt prperly digested leading t a feeling f fullness. Causes are inadequate enzymes secretin, anxiety, fd pisning, ver eating and spicy fd. 88

91 17. Breathing and Exchange f Gases POINTS TO REMEMBER : Breathing: (External respiratin) the prcess f exchange f O2 frm the atmsphere with CO2 prduced by the cells. RESPIRATORY ORGANS : Direct respiratin by diffusin frm the envirnment spnges, celenterates, flat wrms etc. Cutaneus r by skin earthwrm. Tracheal system insects. Gills aquatic arthrpds mllusks Lungs terrestrial frms. HUMAN RESPIRATORY SYSTEM: External nstril pens int the nasal chamber thrugh nasal passage. The nasal chamber pens int the naspharynx. Naspharynx pens thrugh glttis f the larynx int the trachea. Larynx is a cartilaginus bx which prduce sund hence called sund bx. Cartilaginus epiglttis cvers the glttis during swallwing t prevent entry f fd int trachea. Trachea is a straight tube extending up t themed-thracic cavity, which divides int right and left primary brnchi at the level f 5th thracic vertebra. Each brnchus underges repeated divisins t frm the secndary and tertiary brnchi and brnchiles ending up in very thin terminal brnchiles. Trachea, primary, secndary and tertiary brnchi and initial brnchiles are supprted by cartilaginus rings. Each terminal brnchile gives rise t a number f very thin, irregular-walled and vascularised bags like structures called alveli. The branching netwrk f brnchi, brnchiles and alveli cmprises the lungs. There are tw lungs which are cvered by a duble layered pleura, with pleural fluid in them. Lungs are situated in the thracic chamber which is anatmically a air tight chamber. The thracic chamber is frmed Drsally by vertebral clumn. Ventrally by sternum. Laterally by ribs. On the lwer side by dme shaped diaphragm. Respiratin invlves in fllwing steps Breathing r pulmnary ventilatin by which atmspheric air is drawn in and CO2 rich alvelar air is released ut. Diffusin f gases (O2 and CO2) acrss alvelar membrane. Transprt f respiratry gases by bld. Diffusin f O2 and CO2 between bld and tissues. Utilizatin f O2 by the cells fr catablic reactins and resultant release f CO2. MECHANISM OF BREATHING : 89

92 Inspiratin : Intake f atmspheric air int the lungs. It ccurs if the pressure within the lungs (intra-pulmnary pressure) is lwer than the atmspheric pressure. Cntractin f diaphragm which increases the vlume f thracic chamber in the anterir psterir axis. The cntractin f external intercstals muscles lifts up the ribs and the sternum causing an increase in the vlume f thracic chamber in the drs ventral axis. It causes an increase in pulmnary vlume decrease the intra-pulmnary pressure t less than the atmspheric pressure. It frces the air ut side t mve in t the lungs, i.e, inspiratin. Expiratin : Relaxatin f diaphragm and inter-cstal muscles returns the diaphragm and sternum t their nrmal psitins and reduce the thracic and pulmnary vlume. It increases in intrapulmnary pressure slightly abve the atmspheric pressure. It causes the expulsin f air frm the lungs, i.e, expiratin. A healthy man breathes times/minutes. The vlume f air invlved in breathing is estimated by spirmeter. Respiratry Vlumes and Capacities : Tidal vlume: vlume f air inspired r expired during a nrmal breathing. It is abut 500 ml. Inspiratry reserve vlume: Additinal vlume f air, a persn inspire by a frceful inspiratin. It is abut ml. Expiratry reserve vlume: Additinal vlume f air, a persn expires by a frceful expiratin. It is abut ml. Residual vlume: Vlume f air remaining in the lungs even after a frceful expiratin. It is abut 1200 ml. Inspiratry capacity: it includes tidal vlume and Inspiratry reserve vlume. Expiratry capacity: it includes tidal vlume and expiratry reserve vlume. Functinal residual capacity: This includes ERV+RV. Vital capacity: IRV + TV + ERV. Ttal lung capacity: RV + IRV + TV + ERV EXCHANGE OF GASES : Alveli are the primary site f exchange f respiratry gases. Exchange f gases als takes place between bld and tissues. Exchange f O2 and CO2 take place in the pressure gradient, by simple diffusin. Pressure cntributed by an individual gas in a mixture f gases is called the partial pressure and is represented by po2 fr xygen and pco2 fr carbn dixide. Diffusin f O2 po2 in alvelar air = 104 mm Hg. po2 in venus bld = 40 mm Hg. O2 diffuses frm alveli t venus bld. Diffusin f CO2 pco2 is venus bld = 45 mm Hg. 90

93 pco2 is alvelar air = 40 mm Hg CO2 diffuses frm venus bld t alveli. Slubility f CO2 is times higher than that f O2; the amunt f CO2 that can diffuse thrugh the diffusin membrane per unit difference in partial pressure is much higher cmpared t that f O2. Respiratry membrane is frmed by; Thin Squamus epithelium f the alveli. Endthelium f alvelar capillaries Basement membrane between them. TRANSPORT OF GASES : Bld is the medium f transprt f O2 and CO2. Abut 97 per cent f O2 is transprted by RBCs in the bld. 3 per cent f O2 is transprted in the plasma in disslved state per cent f CO2 transprted in the RBC in the frm f carbamin-haemglbin. 70 percent CO2 carried as bicarbnate in in plasma. 7 percent CO2 transprted in disslved state in plasm. Transprt f Oxygen : Haemglbin is red clured pigment present in the RBC. O2binds with hemglbin reversibly t frm xy-hemglbin. Each haemglbin can binds maximum with fur O2 mlecules. Binding f Oxygen with haemglbin is primarily related with partial pressure f O2. Partial pressure f CO2, hydrgen in cncentratin (ph) and temperature are the factrs that influence this binding. A sigmid curve is btained when percentage f saturatin f hemglbin with O2 is pltted against the partial pressure f O2 (po2). This curve is called xygen dissciatin curve. Cnditin favurable fr binding f Hemglbin with O2 at alvelar level; High po2 Lw H + in cncentratin. Lw temperature. Cnditin favurable fr dissciatin f HbO2 int Hb and O2 at tissue level; Lw po2 High H + in cncentratin. High temperature. Every 100 ml f xygenated bld can deliver arund 5 ml f O2 t the tissues under nrmal physilgical cnditins. Transprt f Carbn dixide: percent f CO2 is carried ut in the RBC by binding with the free amin grup f haemblbin by frmatin f carbaminhaemglbin. 91

94 When pco2 is high and po2 is lw as in the tissues, mre binding f CO2 ccurs whereas, when the pco2 is lw and po2 is high as in the alveli, dissciatin f CO2 frm carbamin-haemglbin takes place. 70 per cent f CO2 transprted in the frm f HCO3- in the plasma. CO2 frm the tissue diffused int the plasma and alng with the water it frms carbnic acid which dissciated int HCO3- and H +. This reactin is catalysed by an enzyme called carbnic anhydrase present in the plasma membrane f RBC and plasma. REGULATION OF RESPIRATION : Specialized centre present in the medulla regin f the brain called respiratry rhythm centre is primarily respnsible fr regulatin f breathing. Pneumtaxis centre f pns regin f brain has mderate regulatin. Neural signal frm this centre can reduce the duratin f inspiratin and alter the rate f respiratin. Chemsensitive area adjacent t rhythm centre is sensitive t CO2 and H + in. Receptrs assciated with artic arch and cartid artery als can recgnize changes in the CO2 and H + cncentratin and send necessary signals t the rhythm centre fr remedial actins. DISORDERS OF REPIRATORY SYSTEM : Asthma : is a difficulty in breathing causing wheezing due t inflammatin f brnchi and brnchiles. Emphysema : a chrnic disrder in which alvelar walls are damaged due t which respiratry surface is decreased. It caused due t smking. 92

95 18. Bdy Fluids and Circulatin POINTS TO REMEMBER : Bld: A special cnnective tissue that circulates in principal vascular system f man and ther vertebrates cnsisting f fluid matrix, plasma and frmed elements. Plasma : The liquid part f bld r lymph which is straw clured, viscus fluid cnstituting nearly 55 per cent f bld percent f plasma is water and 6-8% prteins. Fibringen, glbulin and albumins are the majr prtein fund in plasma. Fibringen is required in bld cltting r cagulatin f bld. Glbulins invlved in defense mechanism f the bdy. Albumin helps in smtic balance f bld. Plasma als cntains small amunts f minerals, glucse, amin acids, lipids etc. Plasma withut the cltting factrs is called serum. Frmed elements : Erythrcytes : Als knwn as RBC (red bld cells) is the mst abundant f all the cells f bld millin RBC fund per mm-3 f the bld. Prduced frm the red bne marrw in the adult. RBCs devid f nucleus in mst f mammals. Bicncave in shape Red in clr due presence f cmplex cnjugated prtein called haemglbin gm f haemglbin present per 100 ml f bld in a healthy adult. RBCs have average life span f 120 days after which is destryed in the spleen. Spleen is cmmnly knwn as the graveyard f RBCs. Leukcytes : Als knwn as white bld cells (WBC). They are clrless due t lack f haemglbin. They are nucleated and relatively lesser in number which averages mm-3 f bld. We have tw main categry f WBC; Granulcytes Neutrphils Basphils Esinphils Agranulcytes. Lymphcytes Mncytes. 93

96 Neutrphils (60-65%) f the ttal WBCs are phgcytic in nature. Basphils (0.5-1 %), secretes histamine, sertnin and heparin and als invlved in inflammatry reactins. Esinphils (2-3 %) resist infectin and als assciated with allergic reactin. Lymphcytes (T cells and B cells) cnstitute percent and invlved in the immune respnse f the bdy. Mncytes (10-15%), becmes macrphages. Thrmbcytes : Als knwn as bld platelets. Prduced frm fragmentatin f megakarycytes. Bld nrmally cntain 1, 500, 00 3, 500, 00 platelets mm-3. Invlved in releasing thrmbplastin required t initiate bld cagulatin. BLOOD GROUPS : Tw bld gruping mechanisms ABO and Rh system. ABO gruping : ABO gruping is based n the presence r absence f tw surface antigens n the RBCs namely A and B. Plasma f different individuals cntains tw natural antibdies, anti A and B. In a mismatched transfusin the antigen f the dnr reacts with antibdy f the recipient t cause a reactin calledclumping f agglutinatin. Persn with bld grup O has n antigen hence can dnate bld anybdy, called universal dnr. Persn with bld grup AB has n antibdy in his plasma hence can receive bld frm anybdy, called universal recipient. Rh gruping : Anther antigen, the Rh antigen similar t ne present in Rhesus mnkeys (hence Rh), is als bserved n the surface f RBCs n majrity (nearly 80 %). Persn with Rh antigen is said t be Rh psitive (Rh+). Persn withut Rh antigen is said t be Rh negative (Rh-). Persn with Rh- bld transfused with Rh+ bld, frms anti Rh antibdy and destry the Rh+ RBCs. A special case f Rh incmpatibility (mismatching) has been bserved between the Rh- blds f pregnant mther with the Rh+ bld f the fetus. During parturitin the Rh+ fetal bld mixed with the Rh- maternal bld, hence anti Rh antibdy frmed in mthers bld. In successive pregnancy the anti Rh antibdy frm mther s bld leaks int the fetal bld and destry the Rh+ RBCs. 94