Botany Notes Plus One PDF - Biological Classification

PLUS ONE BOTANY SHORT NOTE CONTENTS 1. Biological Classification 2. Plant Kingdom 3. Morphology of Flowering Plants 4. Anatomy of Flowering Plants 5. Cell : The Unit of Life 6. Cell Cycle and Cell Division 7. Photosynthesis in Higher Plants 8. Respira...

PLUS ONE BOTANY SHORT NOTE CONTENTS 1. Biological Classification 2. Plant Kingdom 3. Morphology of Flowering Plants 4. Anatomy of Flowering Plants 5. Cell : The Unit of Life 6. Cell Cycle and Cell Division 7. Photosynthesis in Higher Plants 8. Respiration in Plants 9. Plant Growth and Development By Nandini. K. N, HSST (jr) Botany, NHSS Kolathur, Malappuram (dt) Downloaded from hssreporter.com  BIOLOGICAL CLASSIFICATION 1. Who made the first attempt of classification? :- Aristotle. 2. How did Aristotle classified plants? :- Aristotle classified plants into herbs, shrubs & trees on the basis of morphology. 3. How did Aristotle classified animals? :- Aristotle classified animals as with red blood & without red blood. 4. Father of taxonomy :- Carolus Linnaeus. 5. Two kingdom classification :- Proposed by Carolus Linnaeus. He divided all living organisms into two kingdom – Kingdom Plantae & kingdom Animalia 6. Drawbacks of Two kingdom classification :-  Did not distinguish between Eukaryotes & Prokaryotes  Did not distinguish between Unicellular & Multicellular organisms.  There is no differentiation between Autotrophic & heterotrophic organisms  Large number of organisms did not fall under either category.  Similar organisms are placed under different groups  Dissimilar organisms are placed under same group 7. Five kingdom classification :- Proposed by R.H. Whittakker (1969). It include Monera, Protista, Fungi, Plantae & Animalia 8. What are the criteria for 5 kingdom classification ? :-  Cell structure  Body organisation  Mode of nutrition  Reproduction  Phylogenetic relationship 9. General characters of kingdom Monera :-  Prokaryotic (Well defined nucleus & membrane bound cell organells are absent)  Non cellulosic cell wall , composed of polysaccharide & aminoacids,  Unicellular organisms  Mode of nutrition :- Autotrophic (chemosynthetic / photosynthetic) and Heterotrophic (saprophytic/parasitic)  Members :- Bacteria & Mycoplasma 10. Bacteria :-  Sole member of kingdom monera.  Most abundant microorganism, occur almost everywhere.  They live in extreme habitats.  Their structure is very simple , but complex in behaviour.  They show most extensive metabolic diversity. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 2 Downloaded from hssreporter.com   Some are autotrophic (prepare their own food) & others are heterotrophic (require ready made food)  reproduction :-  Mainly by fission.  Under unfavourable conditio conditions they produce spores.  Sexual reproduction by a primitive type of DNA transfer from one bacterium to other 11. Classification of bacteria on the basis of their shape ::-  Coccus – Spherical  Bacillus – rod shaped  Vibrium – comma shaped  Spirillum – spiral shape shaped  12. Archebacteria:- Survive in extreme condition because they have different cellwall structure.  Halophiles :- Bacteria live in extreme salty areas.  Thermoacidophiles ::- live in hot springs.  Methanogens :- live in marshy areas areas.. They are present in the gut of several ruminant animals (cow, buffaloes etc) & produce methane ((biogas biogas) from dung. 13. Eubacteria (True bacteria) ::- They have rigid cell wall. If motile, flagellum present.  Cyanobacteria (Blue green algae) ::- eg., Nostoc, Anabaena  Unicellular  colonial / filamentous  Fresh water/ Marine / Terrestrial  Photosynthetic (prepare food using light energy)  Colonies are covered by mucilaginous sheath  Can fix atmospheric nitrogen in specialized cell called heterocyst  Algal bloom bloom:- Overproduction roduction of cyanobacteria. It leads to water pollution.  Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 3 Downloaded from hssreporter.com   Chemosynthetic bacteria :- Prepare food using chemical energy released through oxidation. They have major role in recycling of minerals. eg., sulphur bacteria, phosphorous bacteria  Heterotrophic bacteria :- Most abundant in nature. Important decomposers.  Uses :- Making curd from milk, production of antibiotics, recycling of minerals  Some are pathogens (organisms which cause diseases).  Example for bacterial diseases :- Cholera, typhoid, tetanus, pneumonia, citrus canker (in plant) 14. Mycoplasma :-  Smallest living organism.  can survive without oxygen.  They lack cell wall.  Pathogenic 15. General characters of kingdom Protista :-  Eukaryotic (Well defined nucleus & membrane bound cell organells are present)  Unicellular  Aquatic  Form a link with plants, animals & fungi  Cell wall present in some protistans  Mode of nutrition :- Photosynthetic and heterotrophic  Reproduce sexually & asexually by a process involving cell fusion & zygote formation. 16. Classification of kingdom Protista :-  Chrysophytes :-  Includes Diatoms & Golden algae (Desmids)  Aquatic (freshwater as well as Marine water)  Photosynthetic  Planktons (microscopic , free floating organisms)  Diatoms :-  Chief producers in ocean.  Cell walls are embedded with silica, thus walls are indestructible.  Cell wall form 2 thin overlapping shell, which fit together as a soap box.  Diatomaceous earth :- Accumulation of cell wall deposits of diatoms , over billions of years, on their habitat. Being gritty, soil is used in polishing, filtration of oils & syrups. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 4 Downloaded from hssreporter.com  Dinoflagellate :-  Aquatic ( Marine)  Photosynthetic  Appear yellow, green, brown, blue or red depending on the main pigment present in their cell wall.  Cell wall has stiff cellulose plate on the outer surface  Twowo flagella – one lies longitudinally & other transversely in the furrow between wall plates  Red tide :-- rapid multiplication of red dinoflagellate (eg., Gonyaulax) make the sea appear red. Toxin released by large number of red dinoflagellate may even kilkill fish & other marine animals.   Euglenoids :-  Aquatic (freshwater)  Photosynthetic in the presence of sunlight. If there is a lack of sunlight , they behave like heterotrophs (by predating small organisms)  Instead of cell wall, a protein rich layer called pellicle present, which makes their body flexible.  2 flagella – one short & one long.  Pigments are identified to those present in higher plants.  Slime moulds :-  Saprophytic ( liv live & take food from dead organic matter)  Body move along decaying twigs & leaves.  Under suitable condition, they form an aggregation called plasmodium which may grow & spread over several feet.  During unfavourable condition, Plasmodium differentiate & form fruiting bodies which bear spores at their tip.  Spores :– possess true wall. Spores are extremely resistant & survive for many years (even under unfavourable situations). Dispersed by air currents  Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 5 Downloaded from hssreporter.com   Protozoans :- primitive relatives of animals.  Heterotroph – predator or parasites (live & take food from living organisms).  4 major groups :-  Amoeboid protozoans :-eg., Amoeba , Entamoeba  Grow in fresh water, sea water, or moist soil. Some are parasites.  Move & capture prey by putting out pseudopodia  Marine forms have silica shells on their surface.  Flagellated protozoan :- Free living or parasitic protozoans having flagella. eg., Trypanosoma causing sleeping sickness.  Ciliated protozoan :- eg., Paramoecium.  Aquatic  They have thousands of cilia  They have a cavity (gullet) that opens to outside of cell surface.  Water with food enter into the gullet due to the Co- ordinated movement of rows of cilia   Sporozoans :- They have infectious spore like stage in their life cycle. eg., Plasmodium (malarial partasite) 17. General characters of kingom Fungi :-  Fungi are cosmopolitan and occur in air, water, soil, plants &animals. Grow in warm &humid places  Multicellular, filamentous. Exception – Yeast (unicellular)  Hyphae (fungal body)- long slender thread like structures.  Mycelium – Network of hyphae.  Coenocytic hyphae (Aseptate hyphae) – hyphae are continuous tubes with multinucleated cytoplasm.  Septate hyphae – hyphae having septa /cross walls.  Cell wall – composed of chitin &polysaccharides.  Saprophytic fungi – heterotrophic , live and absorb nutrients from dead substrates.  Parasitic fungi – Live and absorb nutrients from living plants &animals.  Lichen -Symbiotic association between algae and fungus. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 6 Downloaded from hssreporter.com   Mycorrhiza –Symbiotic association between fungus and roots of higher plants like pinus. 18. Uses of fungi :-  Edible. eg., Mushroom  Used to make bread & beer. eg., Yeast ( unicellular fungus)  Source of Antibiotics. eg., Penicillium 19. Disadvantages of fungi :-  Create harm by spoiling food , destroying timber etc.  Pathogens (disease causing organism). eg., Puccinia (cause wheat rust) , Ustilago (cause smut disease) , Asperegillus (cause Aspergillosis in man) Candida (cause candidiasis in man) etc. 20. Reproduction of fungi :-  Vegetative reproduction - By fragmentation ,fission and budding.  Asexual reproduction – by spores (conidia, sporangiospores or zoospores)  Sexual reproduction:-  Plasmogamy – Fusion of protoplasms between two non-motile or motile gametes.  Karyogamy – Fusion of nuclei.  Meiosis - Zygote undergoes meiosis to form haploid spores. Spores germinate.  Dikaryophase – Phase between plasmogamy and karyogamy. Dikaryotic stage (n+n ie., 2 nuclei per cell). Such condition is called Dikaryon. This stage occur in Ascomycetes &Basidiomycete. Later parental nuclei fuse and cell become diploid.  Sexual spores – Oospores , Ascospores and Basidiospores. 21. Classification of kingdom Fungi :-  Phycomycete :- eg., Mucor, Rhizopus (bread mould) , Albugo (parasite on mustard)  Found in aquatic habitat, decaying wood, moist & damp places, as obligate parasites in plants.  Mycelium is aseptate & coenocytic.  Asexual reproduction :- by zoospores (motile) or by aplanospore (non motile). Spores are endogenously produced in sporangium.  Sexual reproduction :- 2 gametes fused to form zygospore. These gametes are similar in morphology (Isogamous) or dissimilar (Anisogamous or Oogamous) Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 7 Downloaded from hssreporter.com   Mucor.  Ascomycete (Sac fungi) :-  They are saprophytes, decomposers, parasites or coprophilous (growing on dung.  Mycelium is branched & septate.  Asexual reproduction :- Conidia (asexual spore) produced exogenously on special mycelium called Conidiophores. Conidia germinate to produce mycelium.  Sexual reproduction :- Ascospores (sexual spores) produced endogenously in sac like asci (singular ascus). Asci are arranged in fruiting bodies called Ascocarp.  eg., Penicillium, Yeast, Aspergillus, Claviceps, Neurospora (used in biochemical & genetic work), Morels & tuffles (edible)  Aspergillus  Basidiomycete (bracket fungi) :-  Grow in soil, on log and tree stumps and as parasite.  Mycelium is branched & septate.  Asexual reproduction – generally not found.  Vegetative reproduction :- fragmentation  Sexual reproduction :-4 Basidiospores (sexual spore) are produced exogenously on basidium. Basidias are arranged in a fruiting body called Basidiocarp  eg., Agaricus (Mushroom), Ustilago (smut fungus), Puccinia (rust fungus)  Agaricus.  Deuteromycete (Imperfect fungi) :-  Mycelium is septate & branched.  Sexual phase is unknown, so they are called imperfect fungi.  Asexual reproduction :- by conidia  Vegetative reproduction :- fragmentation  Majority are decomposers of litter & help in mineral cycling.  eg., Alternaria, Colletotrichum, Trichoderma Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 8 Downloaded from hssreporter.com 22. General characters of kingdom Plantae :-  Eukaryotic, Multicellular, photosynthetic organisms.  Cell wall is made up of cellulose  Some are partially heterotrophic – Insectivorous plants (Bladder wort & venus fly trap) and parasites (cuscuta)  Alternation of generation :- Diploid sporophytic phase in the life cycle alternate with haploid gametophytic phase 23. General characters of kingdom Animalia :-  Eukaryotic, Multicellular, heterotrophic organisms.  Lack cell wall  Mode of nutrition – holozoic (by ingestion of food)  Digest food in an internal cavity & food reserve as glycogen or fat.  Show elaborate sensory & neuromotor mechanism. Most of them are capable of locomotion.  Follow a definite growth pattern, grow into adult, have definite shape & size.  Sexual reproduction – by copulation of male & female followed by embryological development. 24. Virus :-  Non-cellular organisms having an inert crystalline structure outside the living cell.  Biological puzzle -Viruses are neither living nor non-living. They are dead in open environment but when they infect a cell, they take over the machinery of host cell to replicate ,killing the host.  Virus is a nucleoprotein. Virus contain genetic material (DNA /RNA ) and protein coat (capsid made of small subunits called capsomeres).  Genetic material is infectious.  Viruses that infect plants have single stranded RNA. Viruses that infect animals have either single / double stranded RNA or double stranded DNA.  They are Obligate parasite  virus means venom or poisonous fluid  Scientists & their contributions :-  D.J.Iwanowsky –(1892) – Recognised certain microbes ,smaller than bacteria ( passed through bacteria proof filters) ,which cause tobacco mosaic disease  M.W.Beijerineck (1898) – demonstrated that extract of infected plant of tobacco can cause infection in healthy plants and named the new pathogen ‘Virus’. The fluid (extract) is called Contagium vivum fluidum /infectious living fluid. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 9 Downloaded from hssreporter.com   W.M.Stanley (1935)- showed that viruses could be crystallized and crystals consists of proteins. 25. Bacteriophage – Viruses that infect bacteria. They have double stranded DNA as genetic material. 26. Diseases caused by Virus – common cold, fever, covid19, mumps, small pox, herpes, influenza , AIDS etc. 27. Plant diseases – Tobacco mosaic disease , Leaf rolling and curling , Yellowing and vein clearing, Dwarfing and stunted growth etc. 28. Viroids :-  T.O. Diener discovered in 1971.  Smaller than virus.  Cause potato spindle tuber disease.  Lack protein coat.  Found to be a free RNA  RNA was of low molecular weight 29. Prions :-  Similar in size to virus  Consist of abnormally folded protein which can cause infectious neurological diseases.  Disease caused by prions are bovine spongiform encephalopathy (BSE) ,commonly called mad cow disease in cattle and its analogous variant Cr-Jacob disease (CJD) in humans. 30. Lichens :-  Symbiotic association between algae & fungi.  Algal component is phycobiont & fungal component is Mycobiont  Algae prepare food for fungus and fungus give shelter & absorb water & minerals for algae.  Economic importance :- Lichens are Pollution indicators. They do not grow in polluted areas. PLANT KINGDOM 1. Artificial system of classification :- Gave equal weightage to vegetative & sexual characters. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 10 Downloaded from hssreporter.com 2. Natural system of classification :- Consider both external & internal characters like ultra structure, anatomy, embryology, and phytochemistry. eg., Benthem & Hooker classification 3. Phylogenetic classification :- Based on evolutionary relationships between various organisms. 4. Numerical taxonomy :- Use computer by assigning code for each character & analyzing the features. Each character is given equal importance. 5. Cytotaxonamy :- Based on cytological informations like chromosome number, structure etc. 6. Chemotaxonamy :- Use chemical constituents of the plant to resolve confusions. 7. General characters of Algae :-  Aquatic ( fresh water & marine water)  Autotrophic & photosynthetic (prepare their- own food using light energy)  Chlorophyll-bearing  Thalloid ( plant body is Thallus)  They occur in moist stones, soils &wood  Association with fungi – Lichen  Association with animals eg., on sloth bear  Form & size is highly variable (colonial form – Volvox, filamentous form – Ulothrix & Spirogyra, branched forms reach a height of 100 metres – Kelps)  Reproduction :-  Vegetative reproduction –Fragmentation.  Asexual reproduction – By Spores (eg., Zoospores – Flagellated /motile spore)  Sexual reproduction –By fusion of two gametes.  Isogamous – Both the gametes are similar in size (flagellated/motile in Ulothrix & non –flagellated / non-motile in Spirogyra)  Anisogamous – Gametes are dissimilar in size eg., species of Udorina  Oogamous – Large non-motile female gamete fused with small motile male gamete eg., Volvox & Fucus. 8. Economic importance of Algae / Uses of Algae:-  Half of the total CO2 fixation on earth through photosynthesis (Producers which form the basis of food cycles of aquatic animals)  Increase the level of dissolved O2 in water  Edible / Used as food (eg., 70 species of marine algae such as Porphyra, Laminaria & Sargassum) Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 11 Downloaded from hssreporter.com   Produce large amounts of hydrocolloids (water holding substances) which are used commercially. eg., algin (brown algae) & carrageen (red algae)  Agar obtained from Gelidium & Gracillaria – Used to grow microbes & in the preparation of ice-creams and jellies.  Chlorella, Unicellular green algae rich in proteins - Used as food supplements by Space travellers. 9. Divisions of algae & their main characteristics:-  Chlorophyceae :-  Common name – Green algae  Unicellular, colonial or filamentous plant body  Major pigments – Chlorophyll a & chlorophyll b. So grass green in colour.  chloroplast may be discoid, cup shaped, plate like, reticulate, spiral / ribbon shaped in different species.  Pyrenoids – Storage bodies located in the chloroplast. Contain proteins besides starch.  Reserve food material –Starch.  Some algae store food in the form of oil droplets.  Rigid cell wall – Inner layer of cellulose & outer layer of pectose.  Zoospores have 2-8 equal ,Apical flagella  eg., Chlamydomonas, Volvox, Ulothrix, Spirogyra, Chara  Phaeophyceae :-  Common name :- Brown algae  They range from simple, branched, filamentous forms (Ectocarpus) to profusely branched forms as Kelps (reach a height of 100m).  Major pigments :- Chlorophyll a, Chlorophyll c, Fucoxanthine.  Vary in colour from olive green to various shades of brown depending upon the amount of the xanthophyll pigment.  Reserve food material :- Laminarin or Mannitol  Cellulosic cell wall covered by gelatinous coating called algin.  In addition to plastids, protoplast contain centrally located vacuole & nucleus.  Plant body contain root like holdfast, stem like stipe & leaf like frond  Gametes & zoospores are pear shaped & bear 2 unequal , laterally attached flagella.  eg., Ectocarpus, Kelps, Dictyota, Laminaria, Sargassum, Fucus  Rhodophyceae :-  Common name – Red algae. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 12 Downloaded from hssreporter.com   Most of them are multicellular. Some of them have complex body organisations  Major pigments – Chlorophyll a, Chlorophyll d, Phycoerythrin  Reserve food material :- Floridian starch (similar to amylopectin & glycogen )  Majority are marine with greater concentrations found in warmer areas.  They occur in both well lighted regions close to the surface of water & also at great depths in oceans where relatively little light penetrates.  Non motile spores & non motile gametes are present ( flagella absent)  Cell wall made up of cellulose, pectin & poly sulphate esters  Oogamous type of sexual reproduction. Show complex post fertilisation developments.  eg., Polysiphonia, Porphyra, Gracillaria, Gelidium 10. General characters of Bryophytes :-  Found in damp, humid and shaded localities.  Thallus - plant body - Prostrate /erect.  Attached to the substratum by unicellular /multicellular rhizoids.  Lack true root, stem or leaves 11. Lifecycle of bryophytes :-  Main plant body /dominant phase in the life cycle –Gametophyte (haploid ) which produce gametes  Antheridium (multicellular male sex organ) which produce biflagellate Antherozoid /male gamete.  Archegonium - (multicellular female sex organ, flask- shaped) which produce single egg/ female gamete.  Antherozoid , released into water, come in contact with archegonium & fuses with egg to form diploid zygote.  Zygote develops into Sporophyte – Multicellular plant body, but it is not free living (attached to photosynthetic and multicellular gametophyte).  Some cells of sporophyte undergo meiosis to produce haploid spores.  Spores germinate to produce gametophyte Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 13 Downloaded from hssreporter.com 12. Bryophytes are called Amphibians of plant kingdom Why ? :- They live in soil but water is essential for sexual reproduction. 13. Economic importance of Bryophytes / Uses of Bryophytes :-  Food for herbaceous mammals, birds & other animals.  Sphagnum provide peat – Used as fuel.  As packing material for trans - shipment of living material (because of their capacity to hold water)  Pioneer community in xerarch succession along with lichen (first organism which colonise on rock)  Prevent soil erosion. 14. Classification of bryophytes :-  Liverworts :-eg., Marchantia, Riccia  Thallus is dorsiventral & closely appressed to the substrate.  Leafy members have tiny leaf like structures in 2 rows on the stem like structure.  Asexual reproduction :-  By fragmentation of thallus  By the formation of gemmae ( green multicellular asexual buds). Gemmae develop in small receptacles called gemma cups located on the thalli.  Sexual reproduction :-  Sex organs are produced either on same thalli (homothallic) or on different thalli (heterothallic)  Sporophyte is differentiated into foot seta & capsule  After meiosis, spores are produced within the capsule.  Spores germinate to form gametophyte  Mosses :- eg., Funaria, Polytrichum, Sphagnum.  Gametophyte consists of 2 stages.  Protonema stage (first stage) – Develops directly from a spore. Creeping, green, branched & filamentous stage.  Leafy stage (second stage) :-  Develops from the secondary protonema as a lateral bud. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 14 Downloaded from hssreporter.com   Consists of upright, slender axis bearing spirally arranged leaves.  Attached to the soil through multicellular rhizoids.  This stage bears sex organs  Reproduction :-  Vegetative reproduction :- by fragmentation & budding.  Sexual reproduction :-  Sex organs are produced at the apex of leafy stage.  After fertilisation zygote develops into sporophyte , consisting of a foot, seta & capsule.  Sporophyte in mosses is more elaborate than that in liverworts.  Have an elaborate mechanism of spore dispersal. 15. General characters of pteridophytes :-  Found in cool, damp, shady places. Some may flourish well in sandy soil.  First land plants.  Possess vascular tissues (xylem & phloem)  Possess true root, stem & leaves. 16. Life cycle of pteridophytes :-  Main plant body is diploid sporophyte.  Leaves are small (microphylls) as in selaginella or large (macrophylls) as in ferns.  Sporophylls :- Spore bearing leaves (fertile leaves)  Cone/ strobili :- Compact structures formed by the aggregation of sporophylls. Found in Selaginella, Equisetum etc  Sporangias (structure within which spores are produced) are seen on the lowerside of sporophylls.  After meiosis, spores are produced in sporangia.  Spores germinate & form small, multicellular, free living, photosynthetic ,thalloid gametophytes called Prothallus (they require cool, damp, shady places to grow)  Prothallus bear male sex organ (Antheridia) & female sex organ (Archegonia)  Antherozoids / male gametes are released from antheridium  water is essential for the transfer of male gamete to the mouth of archegonium (egg /female gamete is present in the archegonium) Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 15 Downloaded from hssreporter.com   Fusion of male gamete & female gamete (egg) leades to the formation of diploid zygote  Zygote develops into multicellular, sporophyte. 17. Economic importance / uses of pteridophytes :-  Used for medicinal purposes  Used as soil-binders  Grown as ornamentals. 18. Homospory :- Production of morphologically similar spores. Such plants are called homosporous. eg., Psilotum 19. Heterospory :- Production of 2 types of spores , large spores (macrospores/megaspores) and smallspores (microspores). Such plants are heterosporous. Megaspores germinate & give rise to female gametophyte. Microspores germinate & give rise to male gametophyte eg., Selaginella, Salvinia. 20. Precursor of seed habit :-  Female gametophytes are retained on parent sporophyte for variable periods.  Development of zygotes into young embryos takes place within the female gametophytes.  This event is an important step in evolution. 21. Which pteridophytes show precursor of seed habit? :- Heterosporous pteridophytes like Selaginella & Salvinia. 22. Classification of pteridophytes :- 4 classes. Psilopsida (eg., Psilotum), Lycopsida ( eg., Selaginella, Lycopodium), Sphenopsida (Equisetum) and Pteropsida (Dryopteris, Pteris, Adiantum) 23. General characters of Gymnosperms :-  Plants with naked seeds/ Seeds are not covered (Ovules are not enclosed by any ovary wall & remain exposed, both before & after fertilisation).  Include medium sized trees or tall trees and shrubs.One of the tallest tree :- giant red wood tree (sequoia)  Roots :- generally tap root.  Mycorrhiza – Symbiotic association of fungus & roots of pinus  Coralloid root :- Association between roots of cycas & nitrogen fixing cyanobacteria.  Stem:- Unbranched in cycas. Branched in Pinus & Cedrus  Leaves :- Simple / compound.  In cycas , pinnate leaves persist for a few years.  In conifers, needle like leaves reduce the surface area  Leaves are well adapted to withstand extremes of temperature, humidity & wind. Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 16 Downloaded from hssreporter.com   Thick cuticle & sunken stomata also help to reduce water loss.  Main plant body is diploid sporophyte.  Cone :- reproductive structure.  Gymnosperms are heterosporous (produce microspores & megaspores)  tree Male & female cone may be borne on same tree (in pinus) or on different trees (in cycas)  Male & female gametophytes do not have an independent free living existence  cycas pinus ginkgo 24. Life cycle of gymnosperms ::-  Development of male gametophyte: gametophyte:-  Male cone – male reproductive structure, an aggregation of microsporophylls porophylls.  Microsporophylls bear microsporangium,, which produce microspores.  Microspores develops into male gametophyte ((pollengrain pollengrain)  Development of female gametophyte ::-  Female cone :- female reproductive structure, an aggregation of megasporophylls megasporophylls.  Megasporophylls bear megasporangium /ovule.  Megasporangium contain a tissue called nucellus.. One cell of nucellus differentiated into megasporemother cell, which undergo meiosis to form 4 megaspores megaspores.  Out of these 4 megaspores , one mega spore develops into multicellular female gametophyte.  Female gametophyte bears 2 or more archegonia that contain egg / female gamete.  Female gametophyte retained within the megasporangium / ovule.  Pollination :-  Pollengrains / male gametophyte released from micr microsporangium. osporangium.  carried in air currents  come in contact with opening of the ovule & discharge their content (male gamete) near the mouth of archegonia.  Fertilisation :- Male gamete & egg fused to form diploid zygote.  Post fertilization changes ::- Zygote te develops into embryo & the ovules into seeds. 25. General characters of Angiosperms ::- Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 17 Downloaded from hssreporter.com   Seeds are enclosed in fruits.  Reproductive organ – Flower  Large group of plants occurring in wide range of habitats  Smallest angiosperm – Wolffia  Tallest angiosperm – Eucalyptus (over 100 metres)  Classified into Dicotyledons & Monocotyledons. MORPHOLOGY OF FLOWERING PLANTS 1. Root :-Underground non-green part.Arised from radicle 2. Taproot system :- Primary root & its branches(network like arrangement) eg., Dicot plants 3. Fibrous root system :- Short lived primary root replaced by large number of roots. (roots arised from base of the stem). Eg., Monocot 4. Adventitious root system:- Arised from any part other than radicle. eg., Banyan tree, betle, pepper etc 5. Functions of root - (1)Absorption of water & minerals. (2) Anchorage 6. Regions of root :-  Root cap – Thimble-like structure which cover the root tip. It Protects the root tip  Region of Meristemmatic activity – Small, thin walled cells with dense protoplasm. They divide repeatedly.  Region of elongation – Undergo rapid elongation & enlargement. Responsible for growth in length.  Root hair – Fine, delicate ,thread-like structures present on epidermis. They absorb water & minerals.  Region of maturation – Region just above the region of elongation. Root hairs & lateral branches are arised from this region. Mature tissues perform specific functions 7. Stem :- Aerial , green part which bear branches, leaves, flowers & fruits. Stem bears Buds, Axillary /Terminal 8. Nodes – Region where leaves are born Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 18 Downloaded from hssreporter.com 9. Internodes – Portion between two nodes. 10. Leaf :- Lateral, green flattened structure born on stem. Develops at node & bear Bud (Axillary bud later develops to branch) in its axil. Originate from shoot apical meristem & arranged in an Acropetal order 11. Function of leaf :- Photosynthesis. 12. Parts of leaf :-  Leaf base – Attach leaf to stem. It bear two lateral leaf like structures (Stipule). Sheathing leaf base - Leaf base expands into a sheath covering the stem partially /wholly eg., Monocots. Pulvinous leaf base – Swollen leaf base eg., Pea plants.  Petiole Stalk of leaf which hold lamina to light & allow lamina to flutter in the wind.  Lamina / Leaf blade – green expanded part with Veins ( It provide rigidity to lamina & channels of transport of water, minerals and food) & Veinlets. Middle prominent vein is Midrib. 13. Venation :- Arrangement of veins on lamina 14. Reticulate venation :- Veins & Veinlets are arranged in the form of a network. eg., Dicot plants 15. Parallel venation :- Veins are arranged parallel to one another. eg., Monocot plants. 16. Types of Leaf :-  Simple leaf :- Lamina is entire, or when inscise, inscisions do not touch the midrib. eg., china rose  Compound leaf :- Inscisions of the lamina reach up to the midrib. Lamina divided into leaflets. A bud is present in the axil of petiole in both simple & compound leaves, but not in the axil of leaflets of compound leaf. (a) Pinnately compound leaf :- Number of leaflets are arranged on a common axis called rachis. eg., Tamarind, curry leaf, neem etc (b) Palmately compound leaf :- Leaflets are attached at a common point ie., at the tip of petiole. eg., Silk cotton, loovalam. 17. Phyllotaxy :- Arrangement of leaves on stem or branch a. Alternate :- Single leaf from each node in alternate manner. eg., china rose,mustard, sunflower etc. b. Opposite :- Two leaves from each node & lie opposite to each other. eg., Guava, calotropis , ixora etc c. Whorled :- More than two leaves from one node & form a whorl. eg., Alstonia, Allamanda etc 18. Inflorescence :- arrangement of flowers on floral axis Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 19 Downloaded from hssreporter.com  a. Racemose :- Peduncle (main axis ) continues to grow (unlimited growth). Flowers borne laterally in an Acropetal succession. eg.,Crotalaria b. Cymose :- Main axis terminates in a flower (limited growth). Flowers borne in a Basipetal succession. eg., Jasmine 19. Reproductive Part in Angiosperm :- Flower 20. Flower is a modified shoot. Justify ? :- Shoot apical meristem changes to floral meristem. Internodes do not elongate. Axis gets condensed. Apex produce floral whorls laterally at successive nodes instead of leaves. When a shoot tip transforms into a flower, it is always Solitary. 21. Pedicel :- Stalk of the flower 22. Thalamus/ Receptacle :- Swollen tip of pedicel from which floral whorls arises 23. Bisexual flower :- Flower has both androecium & gynoecium. eg., Ixora 24. Unisexual flower :- Flower having either androecium /gynoecium eg., Cucumber 25. Actinomorphic symmetry :- Flower can be divide into two equal parts in any radial plane passing through the centre eg., Mustard, Datura, Chilli, Shoe flower etc 26. Zygomorphic symmetry :- Flower can be divided into two equal parts only in one plane eg., Pea Gulmohur, Bean, Cassia etc 27. Asymmetric :- Flower cannot be divided int two equal parts by any vertical plane passing through the centre. eg., Canna 28. Trimerous flower :- Floral whorls are 3 /multiples of 3 in number 29. Tetramerous flower :- Floral whorls are 4 /multiples of 4 in number 30. Pentamerous flower :-Floral whorls are 5 /multiples of 5 in number 31. Bract :- Reduced leaf found at the base of the pedicel ( flower with bract – Bracteate. Flower without bract – Ebracteate) 32. Non essential whorles :- Parts of flower which are not essential for reproduction  Calyx :- Outer, green whorl. Its members are Sepals. It Protect flower in the bud stage. May be Gamosepalous (united sepals) or polysepalous (free sepals.)  Corolla :- Second whorl. Members are petals (brightly coloured to attract insects for pollination) gamopetalous (united petals).polypetalous (petals free). Shape of corolla may be varied.  Perianth – Undifferentiated calyx and corolla. Members are Tepals. 33. Essential whorles :- Parts of flower which are essential for reproduction. a) Androecium :- Male reproductive organ. Composed of stamens (consists of filament & anther).Anther is bilobed & each lobe has two chambers (pollen sacs) in which pollen grains are produced). Length of the filament in a flower may be varied eg., Salvia & Mustard.  Polyandrous :- Stamens remain free.  Monoadelphous :- Stamens are united to form single bundle eg., Shoe flower Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 20 Downloaded from hssreporter.com   Diadelphous ::- Stamens are united to form 2 bundles eg., Pea, Crotalaria  Polyadelphous ::- Stamens are united to form more than 2 bundles eg., Citrus  Staminode :- Sterile stamen  Epipetalous :-- Stamens are attached to petals eg., Brinjal  Epiphyllous :-- Stamens are attached to perianth eg., Lilly b) Gynoecium :-Female Female reproductive organ. Basic unit is carpel. Carpel consists of 3 parts (Ovary (enlarged basal part), Style (elongated tube) & Stigma (Receptive surface for pollen grain). Ovary bear ovules ovules.. Ovules are attached to flattened, cushion like Placenta Placenta.  Monocarpellary ovary :- one carpel present  Multicarpellary ovary :- Presence of more than 1 carpel.  Apocarpous ovary ::- Ovary with free carpels eg., lotus, rose  Syncarpous ovary ::- ovary with united carpels eg., Mustard & tomato). 34. Aestivation :- Arrangement of sepal / petals in floral bud with respect to other members of same whorl. (1) Valvate aestivation ::- Sepals /Petals in a whorl just touch one another without overlapping eg.,Ca eg.,Calotropis. (2) Twisted aestivation ::- Regular overlapping eg., Shoe flower, ladies finger, cotton etc (3) Imbricate aestivation ::- Irregular overlapping eg., cassia, gulmohur etc (4) Vexillary aestivation ::- 5 petals. 1 large standard petal overlap 2 wing petals which in turn overlap 2 unite keel petals. eg., Pea, Beans 35. Placentation :- Arrangement of ovules within the ovary  Marginal placentation ::- Placenta forms a ridge along the ventral suture of the ovary, ovules are borne on this ridge forming ttwo wo rows eg., Pea  Axile placentation ::- Ovules on central axis of syncarpous ovary, septa present eg., china rose, tomato, lemon Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 21 Downloaded from hssreporter.com   Parietal placentation :- Ovules Develop on inner wall of ovar y. eg., mustard, Argemone.  Freecentral placentation :- Ovules on central axis, septa absent eg., Dianthus &Primrose  Basal placentation :- Single ovule at the base of the ovary eg., Sunflower, Marigold 36. Hypogynous flower :- Gynoecium occupies the highest position, other parts are situated below it. Ovary superior. eg.,Mustard, shoe flower, Brinjal etc. 37. Epigynous flower :- Margin of thalamus grows upward enclosing the ovary completely & fused with ovary. other parts arise above the ovary. Inferior ovary. eg., Guava, Cucumber, ray florets of sunflower, Ixora etc. 38. Perigynous flower :- Gynoecium situated in the centre. Other parts are located on the rim of thalamus almost at the same level. Half inferior ovary eg., Pea, Plum, Rose,Peach , Clitorea, Crotalaria etc 39. Fruit :- Ripened ovary (Ovary is developed into fruit after fertilization)  Fruit wall:- Pericarp  Fleshy fruit :- Pericarp is thick & fleshy. Pericarp is differentiated into outer Epicarp , middle Mesocarp and inner Endocarp. In mango, mesocarp is fleshy. In coconut, mesocarp is fibrous.  Dry fruit :- Pericarp is dry. eg., Cashew Nuts , Dates, Raisins etc  In mango & coconut, fruit is known as Drupe 40. Seed :- Ovule developed into seed after fertilization Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 22 Downloaded from hssreporter.com   Seed coat - Outermost covering of seed. It has two layers, outer testa, & inner tegmen.  Hilum :- Scar on the seed coat through which seeds were attached to fruits.  Micropyle :- Small pore just above the hilum.  Embryo – Zygote developed into embryo. Consists of embryonal axis & cotyledon.  Cotyledon :- first formed leaf. Fleshy & reserve food material ( give food to developing seedling). Dicot seed contain 2 cotyledon & Monocot seed contain 1 cotyledon.  Radicle:- Part of embryo that develops into root  Plumule :- Part of embryo that develops into shoot  Endosperm :- Nutritive tissue for embryo.  Endospermous / Albuminous seed :- Seeds which store their food in endosperm. eg., castor, rice, coconut , etc.  Non-endospermous / Exalbuminous :- Endosperm is not present in mature seeds. Store their food in cotyledons. eg., bean, pea, gram, Orchid etc 41. Structure of Monocot seed :-  Aleuron layer- Proteinaceous outer covering of endosperm that separates the embryo  Scutellum- Large & shield shaped cotyledon  Embryonal axis contain Plumule & Radicle  Coleoptile –protective sheath covering of plumule  Coleorhiza- Protective sheath covering of radicle 42. Vegetative characters of Solanaceae (Potato family) :-  Habit – herbs, shrubs, rearly trees  Stem – herbaceous, rearly woody, aerial, erect, cylindrical , branched, solid,/hollow, underground stem in potato  Leaves – simple, alternate, rearly pinnately compound, exstipulate, reticulate venation 43. Floral characters of Solanaceae :-  Inflorescence – Solitary or cymose  Flower – Bisexual, actinomorphic  Calyx – 5 sepals, gamosepalous, valvate aestivation  Corolla – 5 petals, gamopetalous, valvate aestivation  Androecium – 5 stamens, epipetalous Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 23 Downloaded from hssreporter.com   Gynoecium – bicarpellary, syncarpous, superior ovary, bilocular, swollen placentation with many ovules.  Fruits – berry / capsules  Seed – Many, ndospermous 44. Floral diagram & Floral formula – Solanaceae :- 45. Solanaceae – Economic importance ::-  Edible :- Potato, Brinjal  Spice :- Chilly  Fumigatory :- Tobacco (dried leaves of Nicotiana tabacum)  Medicine :- Atropa belladonna, whithania somnifera (Aswagandha)  Ornamentals :- Petunia Prepared by Nandini. K.N, NHSS Kolathur, Malappuram. For MBTA Page 24 Downloaded from hssreporter.com  ANATOMY OF FLOWERING PLANTS 1. Epidermal Tissue System ::- Outermost covering of the whole plant body.It consists of Epidermis, Stomata, Trichome , hair & cuticle.  Epidermis :-  Outermost layer.  Elongated compactly arranged cells , forms a continuous layer.  Single layered parenchymatous cells with small amount of cytoplasm & large vacuole.  Function :-- Protection  Cuticle :- Waxy thick layer which cove coverr epidermis. It prevents the loss of water. Absent in roots.  Stomata :- Pores present in epidermis of leaves & young stems.  Stoma /Stomatal pore is surrounded by Guard cells ( in dicot bean shaped guard cells & in monocots dumb-bell shaped guard cells are present).  Outer walls of guard cells are thin & the inner walls are highly thickened.  Guard cells possess chloroplast & it regulate opening and closing of stomata.  Guard cells are surrounded by Subsidiary cells (specialised epidermal cells) whic whichh are specialised in shape and size.  Stomatal pore, guard cells & subsidiary cells together known as Stomatal apparatus.  Function –Removal Removal of excess water through transpiration & Exchange of gases.  Dicot and Monocot stomata.  Root hair :- Unicellular elongations of epidermal cells. Absorb water & minerals from the soil.  Trichomes / Stem hair :- Multicellular, branched / unbranched & soft / stiff. May be secretory. Prevent water loss due to transpiration. 2. Ground Tissue System :- All tissues except epid epidermis ermis & vascular bundles. Consists of simple tissues. Cortex, pericycle, medullary ray , pith & mesophyll in leaf constitute ground tissue system. 3. Vascular Tissue System :-- Xylem & Phloem together constitute Vascular bundles. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 25 Downloaded from hssreporter.com  a) Conjoint vascular bundle :- Xylem & Phloem are in the same bundle on the same radius. Phloem located on the outer side of Xylem eg., Stem.  Open vascular bundle – Cambium present in between Xylem & Phloem ( So able to form secondary xylem & phloem) eg., Dicot stem.  Closed vascular bundle – Cambium absent ( do not form secondary xylem & phloem) eg., Monocot stem. b) Radial vascular bundle :- Xylem & Phloem occur in separate bundles on different radius. eg., Root. 4. Dicot Root :-  Ouermost layer is Epiblema (Epidermis) Unicellular root hairs arise from epidermal cells.  Cortex – Several layers of thin walled parenchymatous cells with intercellular space below the epidermis.  Endodermis :-  Innermost layer of cortex. Single layer of barrel- shaped cells without intercellular space.  Casparian thickening :- Waxy material Suberin is deposited on the walls of endodermis.So endodermis is impermeable to water.  Pericycle – Few layers of thick walled parenchymatous cells , next to endodermis. Initiation of lateral roots & vascular cambium takes place in these cells.  Pith – Small / inconspicuous  Conjunctive tissue – Parenchymatous cells between the xylem & phloem.  Radial vascular bundle – 2-4 xylem & phloem bundles. Exarch xylem.  Stele – All tissues on the innerside of the endodermis such as pericycle, vascular bundles & pith. 5. Monocot Root :- It has outer Epidermis, Cortex, Endodermis, Pericycle, Radial vascular bundles , conjunctive tissue & pith similar to dicot root 6. Difference between Dicot & Monocot root Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 26 Downloaded from hssreporter.com  Dicot root Monocot root In the cortex Air cavity absent. Air cavity present in the cortex 2-4 Xylem & Phloem bundles More than six (polyarch) xylem & phloem bundles. Small pith Large & well developed pith Polygonal shaped xylem Round shaped xylem Undergo secondary growth Do not undergo secondary growth 7. Dicot stem :-  Epidermis – Outermost protective layer ,covered with a thin layer of cuticle , may bear Trichomes & few stomata.  Cortex – Several layers between epidermis & pericycle. It consists of 3 sub- zones.  Hypodermis – Few layers of collenchymatous cells just below the epidermis, which provide mechanical strength to young stem.  Cortex -Rounded thin walled parenchymatous cells with intercellular space.  Endodermis – Innermost layer of cortex. Cells are rich in starch grains , So the layer is Starch sheath.  Pericycle – Innerside of the endodermis and above the phloem in the form of semi – lunar patches of sclerenchyma (Bundle cap).  Medullary ray – Few layers of radially placed parenchymatous cells in between vascular bundles.  Vascular bundle - Conjoint, open with endarch xylem.  Pith – Large number of rounded parenchymatous cells with large intercellular spaces, occupies the central portion of the stem. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 27 Downloaded from hssreporter.com  8. Monocot Stem :-  It has Epidermis & Sclrenchymatous Hypodermis.  Numerous vascular bundles (Conjoint, closed, endarch xylem).  Peripheral vascular bundles are smaller than centrally located ones.  Phloem parenchyma absent.  Water containing cavities are present within the vascular bundle. 9. Difference between Dicot & Monocot stem Dicot stem Monocot stem Collenchymatous hypodermis Sclerenchymatous hypodermis Differentiated cortex Undifferentiated cortex Bundle cap present Bundle sheath present Limited number of vascular bundles Numerous Vascular bundles Vascular bundles arranged in the form of a ring Scattered vascular bundles Open vascular bundle ( cambium present) Closed vascular bundles ( Cambium absent) Well developed pith Pith absent Undergo secondary growth Do not undergo secondary growth Protoxylem lacunae (water containing cavity) Protoxylem lacunae (water containing absent cavity) present Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 28 Downloaded from hssreporter.com  10. Difference between Root & Stem Stem Root Conjoint vascular bundle Radial vascular bundle Endarch xylem Exarch xylem Multicellular hair (Trichome) Unicellular root hair Cuticle present Cuticle absent 11. Dorsiventral (Dicotyledonous) Leaf :- 3 main parts. Epidermis, Mesophyll & Vascular bundle.  Epidermis -Cover both upper ( adaxial) & lower ( abaxial) surface.  Cuticle – Covers the upper & lower epidermis.  Lower epidermis bears more stomata.  Mesophyll –Tissue ( parenchymatous cells) between the upper & lower epidermis. It possess chloroplast & carry out photosynthesis. It has 2 types of cells.  Palisade parenchyma – Elongated cells placed below the upper epidermis, arranged vertically & parallel to each other.  Spongy parenchyma – Oval /round & loosely arranged parenchymatous cells below the palisade parenchyma & extends to lower epidermis. Intercellular spaces & air cavities are present.  Vascular bundles – Present in the veins & midrib. Vascular bundles are surrounded by a layer of thick walled bundle sheath cells. 12. Isobilateral (Monocotyledonous) Leaf :-  3 main parts. Epidermis, Mesophyll & Vascular bundle.  Stomata are equally distributed on both upper & lower epidermis  Mesophyll is not differentiated into palisade & spongy parenchyma  Bulliform cells –Large, empty, colourless cells occur in the upper epidermis of many grasses. When they absorb water & are turgid, leaf surface is exposed. When they are flaccid due to water stress, they make the leaves curl inwards to minimize water loss. 13. Anatomical difference between dicot & monocot leaf Dicot leaf Monocot leaf Mesophyll is differentiated into Mesophyll is not differentiated into palisade & spongy parenchyma palisade & spongy parenchyma Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 29 Downloaded from hssreporter.com  Bulliform cells absent Bulliform cells present lower epidermis has more Equal distribution of stomata on both number of stomata upper & lower epidermis. Guard cells of stomata are bean Guard cells are dumbbell shaped. shaped Dicot leaf Monocot leaf CELL : THE UNIT OF LIFE 1. Cell :- fundamental structura structural & functional unit of all living organisms. 2. Cell theory :- All living organisms are composed of cells & products of cells. All cells arise from pre-existing cells. 3. Who discovered the cell? ::- Robert Hook 4. Who first saw & described a living cell? ::- Anton Von Leeuwenhoek 5. Who discovered nucleus? ::-Robert Brown 6. Who discovered that all plants are made of cells? ::- Matthias Schleiden (1838) 7. Who discovered that all animals are made of cells ? ::- Theodore Schwann (1839).He Studied animal cells & reported the presence of plasma membrane. He observed that cell wall is the unique character of plant cell. 8. Who proposed the cell theory? ::- Schleiden & Schwann. 9. Who modified & give final shape for the cell theory ? :- Rudolf Virchow (1855). He explained that cells divide & new cells are formed from pre-existing existing cells (Omnis cellula - e cellula) 10. Who proposed the fluid mosaic model of plasma membrane ? ::- Singer & Nicholson (1972) 11. Who discovered golgi apparatus ? ::- Camillo Golgi (1898) 12. Who discovered ribosome ribosomes ? :- George Palade (1953) 13. Who coined the name ‘chromatin’ ::- Flemming 14. Single membrane bound vesicles ::- Vacoule, Lysosome, Endoplasmic reticulum, Golgicomplex, Microbodies 15. Double membrane bound vesicles ::- Chloroplast, Mitochondria, Nucleus 16. Non membranee bound vesicle ::- Ribosome Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 30 Downloaded from hssreporter.com 17. Endomembrane system :- Group of membraneous organelles having co-ordinate function. They include –Endoplasmic reticulum, Golgi complex, Lysosome, Vacoule 18. Prokaryotic cells:-  There is no well defined nucleus & cell organelles.  Genetic material :- Naked DNA (Nuclear membrane absent)  Plasmid :-  Small, circular, self replicating extra chromosomal DNA present in prokaryotic cell.  provide resistance to antibiotics.  also used as a vector in genetic engineering processes.  cell envelope :-  chemically complex three layerd structure.  Glycocalyx :- outer layer. It may be a Slime layer (loose sheath) or Capsule (tough outer coat)  cell wall :-Middle layer. Determines the shape of the cell & provides a strong structural support to prevent the bacterium from bursting  Plasma membrane. :- Inner layer. Selectively permeable. Structurally similar to Eukaryotic plasma membrane.  Function :- Protection.  Gram staining :-  Christian Gram developed a technique of staining bacteria  Gram positive bacteria :- Bacteria which take up & retain stain after washing.  Gram negative bacteria :- They do not retain stain after washing.  Mycoplasma lack cell wall.  Cytoplasm – Fluid matrix filling the cell.  Ribosome :-  70S type - made of two subunits , Large subunit 50S & Small subunit 30S).  Polyribosomes / Polysome – Several ribosomes may attach to a single mRNA & form a chain  Function – Protein synthesis.  Mesosome :-  Membraneous extensions of plasma membrane ( Infoldings of cell membrane).  They are in the form of Vesicles, tubules & lamellae.  Functions of mesosome :-  Respiration  Secretion Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 31 Downloaded from hssreporter.com   Cell wall formation, DNA replication & distribution to daughter cells  To increase the surface area of the plasma membrane  Inclusion bodies :-  Reserve materials are stored in the cytoplasm.  Not covered by any membrane (lie free in the cytoplasm).  eg., phosphate granules, cyanophycean granules & glycogen granules.  Flagella :-  Thin filamentous extensions from cell wall.  Help in locomotion.  Composed of three parts – filament (longest portion & extends the cell surface to outside) , hook & basal body  Bacteria show a range in the number & arrangement of flagella.  Pili :- Surface outgrowth. Elongated tubular structures made of a special protein. Longer than fimbriae.  Fimbriae :- Small bristle like fibres sprouting out of the cell. Help to attach the bacteria to rocks in streams & also to the host tissues.  Prokaryotic organisms are bacteria, blue-green algae, & mycoplasma ( PPLO /Pleuro Pneumonia Like Organisms).  Prokaryotes are smaller & multiply more rapidly than Eukaryotes.  Prokaryotes vary in shape & size.Four basic shapes of bacteria are bacillus ( rod like), coccus ( Spherical) , vibrio ( comma shaped) & spirillum ( Spiral). 19. Eukaryotic Cell –well defined nucleus, nuclear membrane , cell organelles, cystoskeltal structures are present. They include Protists, Fungi, Plants & Animals. 20. Difference between plant & animal cells :-  Plant cells possess cell wall, plastids & large central vacuole, which are absent in animal cells.  Animal cells have centrioles, which are absent in plant cells. 21. Cell Membrane:-  Cell membrane is mainly composed of Lipids ( arranged in a bilayer) , Proteins & Carbohydrates.  Lipids are arranged with the Polar head ( hydrophilic) towards the outerside & non-polar tail /hydrophobic tail towards the inner part. Non-polar tail is thus protected from aquous environment. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 32 Downloaded from hssreporter.com   Membrane contain phospholipids & cholesterol. Lipid component mainly consists of phosphoglycerides.  Ratio of protein & lipids varies in different cell types. eg., in man, membrane of RBC has approximately 52% protein & 40% lipids.  Membrane proteins are of two types Integral proteins ( Partially /totally buried in the membrane) & Peripheral proteins ( lie on the surface of the membrane).  According to fluid mosaic model, quasi fluid nature of lipid enables lateral movement of proteins within the overall bilayer. This ability to move within the membrane is measured as its Fluidity.  Functions of cell membrane :-  Transport of molecules across it ( Membrane is selectively permeable / transport some molecules across it).  Cell growth  Formation of intercellular junctions  Secretion  Endocytosis  Cell division.  Passive transport – Movement of molecules across the membrane without using energy.  Diffusion – Movement of molecules ( liquid, solid / gas) from higher concentration to lower concentration. Neutral solutes may move across the membrane by simple diffusion.  Osmosis –Movement of water by diffusion through cell membrane.  Polar molecule ( water soluble substances) cannot pass through non - polar lipid bilayer. So Polar molecules require a Carrier protein of the membrane to facilitate their transport.  Active transport – Movement of molecules across the membrane using energy ( Against the concentration gradient , i.e. from lower to higher concentration.) eg., Na+ K+ Pump. 22. Cell wall :-  Outer covering for the plasma membrane of fungi & plants.  Most of the Plant cell wall is made up of cellulose, hemicelluloses, pectins & proteins. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 33 Downloaded from hssreporter.com   Algal cell wall is made up of cellulose, galactans, mannans & minerals like calcium carbonate.  Primary wall (cell wall of young plant cell) is capable of growth. As the cell matures,primary wall gradually diminishes & the secondary wall is formed on the innerside of cell.  Middle lamella :- A layer which holds/ glue neighbouring cells together (Cementing material between two cells). Made up of Calcium pectate  Plasmodesmata ::- A channel across the cell wall , which connect the cytoplasm of neighbouring cells.  Functions of cell wall :-  Give shape to the cell  Protects the cell from mechanical damage & infection.  Helps in cellcell-to-cell interaction & provides barrier to undesirable macromolecules 23. Endoplasmic reticulum :--  Network or reticulum of tiny tubular structures scattered in the cytoplasm.  Divides the intracellular space into two distinct compartments. Luminal (inside ER) & Extra luminal (cytoplasm) compartments.  Rough endoplasmic reticulum (RER (RER) :-  Endoplasmic reticulum bearing ribosomes on their surface.  They are extensive & continuous with the outer membrane of the nucleus.  Function – Protein synthesis & Secretion  Smooth endoplasmic reticulum (SER) :-  Endoplasm Endoplasmic reticulum without ribosomes.  Function ::- Synthesis of lipid (In animal cells, steroidal hormones are synthesized in SER) 24. Golgi apparatus :-  Located in the cytoplasm next to ER & near the nucleus  Made up of Cisternae (flat, disc shaped sac) with distinct convex cis/ forming face & concave trans/ maturing face. These two faces are entirely different but interconnected.  Function of golgi apparatus ::- Packaging & secretion Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 34 Downloaded from hssreporter.com   Golgi apparatus is the important site of formation of glycoproteins & glycolipids. 25. How the golgi apparatus remains in close association with the endoplasmic reticulum? :- :  Materials to be packaged in the form of vesicles from the ER fuse with cis face of golgi apparatus & move towar towards maturing face.  A number of proteins synthesized by RER are modified in the cisternae of the golgi apparatus before they are released from its trans face 26. Lysosomes :-  Membrane bound vesicular structures  Formed by the process of packaging in golgi aapparatus.  Suicidal bag :-Lysosomes Lysosomes are rich in almost all hydrolytic enzymes (optimally active at the acidic pH). These hese enzymes can digest their own cell, causing the cell to die. 27. Vacoules :-  Membrane bound space found in cytoplasm.  It contains water, sap sap,, excretory products & other materials not useful for the cell.  Vacoule is bounded by single membrane called tonoplast.  Tonoplast facilitate transport of ions against concentration gradient into the vacuole (concentration is higher in vacuole than in the cytoplasm)  In plant cells, vacuole occupies 90% of the volume of cell.  Contractilele vacuole in amoeba- important for excretion.  Food vacuoles in protists – formed by engulfing the food materials. 28. Mitochondria / Power houses of cell  Double membrane bound ccell ell organelle. Outer & Inner membrane divide its lumen into outer and inner compartments.  Matrix ( Inner compartment) - Space enclosed by inner membrane. Matrix possesses Single circular DNA , Few RNA molecules , Ribosomes (70S) & components required for protein synthesis.  Peri mitochondrial space (Outer compartment) – Space between outer & inner membrane.  Cristae – Infoldings of inner membrane towards matrix. It Increase the surface area. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 35 Downloaded from hssreporter.com   Sites of Aerobic Respiration – Produce cellular energy in the form of ATP. So they are called Power houses of cell.  Unless specifically stained, mitochondria are not easily visible under microscope.  Number per cell is varied depending on the physiological activity of cell. Shape & size also varied. 29. Plastids :-  Found in plants & in Euglenoids. Large organelle, so easily observed under the microscope. Bear some specific pigments, which impart specific colours.  Chromoplast - Coloured plastids. Fat soluble Carotenoid pigments like Carotene, Xanthophylls etc are present. They give Yellow, Orange / Red colour.  Leucoplast – Colourless plastid with stored nutrients. They are Amyloplast (store carbohydrate / Starch eg., potato), Elaioplast ( Store oil & fat) , Aleuroplast ( store proteins.  Chloroplast :-  Green plastids which contain green pigment Chlorophyll.  Found in the mesophyll cells of leaf.  Lens shaped, oval, spherical, discoid or ribbon like organelles having variable length.  Number varies from 1 per cell ( Chlamydomonas) to 20 -30 per cell in mesophyll.  Function :- Photosynthesis. 30. Structure of chloroplast :-  Double membrane bound cell organelle. Smooth Outer & Inner membrane Present.  Peri plastidal space – Space between Outer & inner membrane.  Stroma – Inner part of chloroplast. Stroma contains enzymes for photosynthesis & protein synthesis. It contain Small, double stranded circular DNAS & Ribosomes (70S)  Thylakoids – Flattened membraneous sacs present in stroma. Thylakoid membrane encloses a space called lumen. Chlorophyll pigments are present in the thylakoids.  Grana – Group of thylakoids ( thylakoids are arranged in stacks like piles of coins)  Stroma lamella – Flat membraneous tubules connecting the thylakoids of grana. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 36 Downloaded from hssreporter.com 31. Ribosomes  Granular structures.  Composed of ribonucleic acid (RNA).  Not surrounded by any membrane.  Each ribosome has two subunits. ( Larger & Smaller).  Eukaryotic ribosomes are 80S. Here Larger subunit is 60S & smaller subunit 40S.  Prokaryotic ribosomes are 70S. Here Larger subunit is 50S & smaller subunit 30S.  ‘S’ ( Svedberg’s unit) – Sedimentation coefficient, a measure of density & size. 32. Cytoskelton :-  Elaborate network of filamentous proteinaceous structures present in the cytoplasm. eg., Microtubules  Functions :- Mechanical support, motility, maintenance of the shape of the cell. 33. Cilia & Flagella :-  Both are hair like outgrowths of the cell membrane. Help in locomotion.  They emerge from centriole-like structure called basal bodies  Cilia – small. More in number. Work like oars, causing the movement of either the cell or surrounding fluid.  Flagella – Long. Less in number. Responsible for cell movement. Prokaryotic & eukaryotic flagellas are structurally different.  Structure of cilia & flagella:-  Covered with plasma membrane  Has a central core called axoneme.  Axoneme possesses microtubules – 9 pair of doublets of peripheral microtubules & a pair of centrally located microtubules (9+2 arrangement)  Central tubules are connected by bridges & enclosed by central sheath  Central sheath is connected to each peripheral doublet by radial spoke (9 radial spokes present)  Peripheral doublets are interconnected by linkers Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 37 Downloaded from hssreporter.com 34. Centrosome :-  Organ which contain 2 cylindrical centrioles  Centrioles are surrounded by amorphous pericentriolar materials. materials  Centrioles in a centrosome lie perpendicular to each other. 35. Structure of centriole :-  Made up of 9 periph peripheral eral triplet tubulins. Adjascent triplets are linked.  Central part is proteinaceous hub.  Hub is connected with peripheral tubules by radial spoke.  Functions of centrioles ::- They form the basal body of cilia , flagella and spindle fibres 36. Nucleus :-  Doublee membrane bound cell organelle  Outer membrane remains continuous with the endoplasmic reticulum and also bears ribosomes on it.  Nuclear pore – Minute pores present in nuclear envelope, formed by the fusion of its two membrane. Through nuclear pores R RNA NA & protein molecules move in both directions between the nucleus & cytoplasm.  Peri nuclear space – Space between outer & inner nuclar membrane (10 -15nm). It forms a barrier between the materials present inside the nucleus & that of cytoplasm.  Nucleoplasm – Nuclear matrix which contain Chromain & Nucleolus.  Nucleoli – Spherical structures. Not a membrane bound structure. Content is continuous with the rest of nucleoplasm. Site for active ribosomal RNA (rRNA) synthesis.  Chromatin – Highly extended & elaborate nucleo protein fibres present in the interphase nucleus.  Chromatin contains DNA , histone proteins, non non-histone histone proteins & RNA.  A single human cell has approximately 2m long thread of DNA distributed among its 46 chromosomes.  Chromosome – (visible only in dividing cells). It has a primary constriction (Centromere) on the sides of which disc shaped structures called Kinetochores are present. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 38 Downloaded from hssreporter.com   Centromere holds 2 chromatids of a chromosome. A few chromosomes have non- staining secondary constrictions , this gives the appearance of a small fragment called Satellite Satellite. 37. Chromosomes :-  Metacentric :- Middle Centromere. 2 equal arms.  Sub-metacentric metacentric ::- Centromere slightly tly away from the middle. one shorter arm & one longer arm.  Acrocentric :- Centromere is close to its end. one extremely short & one very long arm.  Telocentric :- Terminal centromere 38. Microbodies :- Membrane bound minute vesicles that contain various enzymes. They are present in both plant & animal cells. CELL CYCLE AND CELL DIVISION 1. Cell cycle – The sequence of events by which a cell duplicates its genome, synthesizes sy the other constituents of the cell and eventually divides into two daughter cells. 2. Phases of cell cycle :-  Human cell divide once in every 24 hours. This duration of cell cycle vary from organism to organism (Yeast divides in 90 minute).  Cell cycle cle divided into 2 phases. Interphase & M phase /Mitosis phase.  M Phase :- Cell division takes place. Starts with nuclear division ( karyokinesis karyokinesis) & ends with division of cytoplasm (cytokinesis). (cytokinesis) Lasts for only about an hour in hhuman cell.  Interphase :-- Resting phase during which cell is preparing for growth. lasts 95% duration of cell cycle. In human cell 23 hour. It is divided into 3 phases  G1 phase ::- Post mitotic gap phase. Cell is metabolically active & Continuously grows. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 39 Downloaded from hssreporter.com   S phase :- Synthesis phase. DNA synthesis / DNA replication takes place.  G2 phase :- Pre mitotic gap phase. Proteins are synthesized & the cell grows.  In animal cells, During S phase, DNA replication begins in the nucleus & Centriole duplicates in the cytoplasm.  In animal cells, Mitotic division is only seen in diploid vegetative cells. But in plants Mitosis takes place in both haploid and diploid cells 3. G0 (Quiscent stage) :-  Some cells that do not divide further exit G1 phase to G0 phase (inactive stage).  Cells remain metabolically active but no longer proliferate unless called on to do so. eg., Heart cell in adult, Neurons etc. 4. Mitosis -:-  Seen in vegetative cells.  Parent cell divides into two daughter cells.  No change in chromosome number ( Equational division). 5. Significance of mitosis:-  Cell growth  Cell repair  Maintenance of nucleo- cytoplasmic ratio.  Regeneration 6. Stages of Mitosis :- Karyokinesis include 4 stages  Prophase :-  Chromatin reticulum condenses to form Chromosomes.  Nuclear membrane & Nucleolus disappear.  Metaphase :-  Chromosomes are arranged at equatorial plane.  Spindle fibres from opposite poles attach to the kinetochore of centromere.  Anaphase :-  Centromere split.  Chromatids move towards opposite poles.  Telophase :-  Chromosomes decondenses to form chromatin reticulum. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 40 Downloaded from hssreporter.com   Nuclear membrane & Nucleolus reappear. 7. Cytokinesis :-  Division of cytoplasm.  In animal cell, a furrow appeared in the plasma membrane gradually deepens & joins in the centre  In plant cell, a cell-plate is formed at the centre & grows outward to meet the existing lateral wall. 8. Meiosis :-  Seen in reproductive cells.  Parent cell divides into 4 daughter cells.  Chromosome number reduced to half.  Leads to the formation of haploid gametes.  Involves 2 sequential cycles of division, Meiosis Ι & Meiosis ΙΙ. 9. Significance of Meiosis :-  Maintain chromosome number  create variation.  Formation of gametes in sexually reproducing organisms. 10. Meiosis Ι (Reduction division) :-  Prophase Ι – Longer & more complex phase. Subdivided into 5 phases. First two stages of prophase Ι are short lived.  Leptotene :- Chromosomes become visible under light microscope.  Zygotene :-  Homologous chromosomes starts pairing.  Synapsis / Synaptonemal complex formation.  Bivalent /Tetrad formation.  Pachytene :-  Appearance of recombination nodules.  Crossing over /Exchange of genetic material takes place between non - sister chromatids of homologous chromosomes.  Recombinase enzyme - mediated process.  Diplotene :-  Dissolution of synaptonemal complex Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 41 Downloaded from hssreporter.com   Separation of homologous chromosomes (except at the site of crossovers ie. at Chiasmata).  In Oocytes of some vertebrates, diplotene can last for months / years.  Diakinesis :-  Terminalisation of Chiasmata.  Nuclear membrane & Nucleolus disappears.  Metaphase Ι :-  Homologous chromosomes are arranged at equatorial plane.  Spindle fibres ffrom rom opposite poles attach to kinetochore of centromere.  Anaphase Ι :-  Homologous chromosomes separate ( Sister chromatids remain associated with their centromere).  Separated homo homologous logous chromosomes move towards opposite poles.  Telophase Ι :-  Nuclear membrane & Nucleolus reappear.  Cytokinesis follows & this is Dyad of cells. 11. Meiosis ΙΙ ( Equational division) :- Resemble mitosis.  Prophase ΙΙ  Chromosomes become compact  Nuclear membrane & Nucleolus disappear.  Metaphase ΙΙ  Chromosomes arranged at equatorial plane.  Spindle fibres from opposite poles attach to the kinetochore of centromere.  Anaphase ΙΙ  Centromere split.  Chromatids move towards opposite poles.  Telophase ΙΙ  Nuclear membrane & Nucleolus reappear.  Chromosomes decondenses to form chromatin reticulum.  Cytokinesis follows leads to the formation of 4 cells / Tetrads. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 42 Downloaded from hssreporter.com  12. Distinguish Anaphase of mitosis from Anaphase Ι of meiosis ? :-  Anaphase of mitosis – Centromere split & chromatids move towards opposite poles  Anaphase Ι of meiosis – Homologous chromosomes separate & move towards opposite poles PHOTOSYNTHESIS IN HIGHER PLANTS 1. Photosynthesis :- Process in which green plants prepare food using CO 2 and H2O in the presence of sunlight and chlorophyll pigment. 6 CO2 +12 H2O → C6H12O6 + 6 H2O +6 O2 2. Variegated leaf experiment :-  Starch test in a variegated leaf or leaf that was partially covered with black paper and one that was exposed to light.  Inference – Chlorophyll pigment is necessary for photosynthesis 3. Half leaf experiment :-  A part of a leaf is enclosed in a test tube containing some KOH soaked cotton (that absorbs CO2)  Other half is exposed to air  Setup is placed in light for some time.  Starch test – exposed part of leaf tested positive & portion that was in the tube tested negative.  Inference - CO2 is essential for photosynthesis. 4. Early experiments :- Scientist Inference of experiment Joseph priestley Plants restore to the air that was spoiled by breathing rat & burning candle Jan Ingenhousz Plants use light to produce oxygen Julius von sachs Starch/glucose is produced on green parts of the plant T.W.Engelmann Most of the photosynthesis takes place in the red & blue regions of spectrum Cornelius Van Niel Plants release oxygen as a result of splitting of water molecules. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 43 Downloaded from hssreporter.com 5. Site of photosynthesis ::- Chloroplast. There is a clear division of labour within the chloroplast. 6. Site of light reaction :-- Thylakoid. Chlorophyll pigment present in thylakoid trap light energy and produce ATP & NADPH. 7. Site of dark reaction :-- Stroma. Enzymatic reactions synthesize glucose which in turn forms starch. 8. Pigments :- Substanceses that have an ability to absorb light, at specific wavelengths. 9. Leaf pigments can be separated by :- Paper Chromatography. 10. Pigments involved in Photosynthesis :- Colour in the leaves is due to 4 pigments.  Chlorophyll a (bright or blue green in the chr chromatogram) omatogram) is the major pigment responsible for trapping light.  Accessory pigments - Chlorophyll b (yellow green), Xanthophylls (yellow), and Carotenoids (yellow to yellow yellow-orange). 11. Role of accessory pigments ::-  They absorb light and transfer the energy tto chlorophyll a.  Protect chlorophyll a from photo - oxidation 12. Action spectrum indicates overall rate of photosynthesis at each wavelength of light 13. Absorption spectrum indicates the wavelengths of light absorbed by each pigment. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 44 Downloaded from hssreporter.com  Action spectrum superimposed on absorption spectrum. 14. Light Reaction / Photochemical phase include :-  light absorption  water splitting  oxygen release  formation of ATP & NADPH.  Several protein complexes are involved in this process 15. Light harvesting complex / Antennae :-  Pigment-Protein complex that absorb light energy.  All the pigments except one molecule of chlorophyll a is a light harvesting complex.  They are made up of hundreds of pigment molecules bound to the protein within the Photosystem Ι & Photosystem ΙΙ. 16. Photosystem :-  Structural & Functional units for photosynthesis.  Photosystem has a reaction centre & light harvesting complex (which Use light energy to transfer electrons across thylakoid membrane and the electrons are used to produce ATP & NADPH). 17. Photosystem Ι (PS Ι) :- Reaction centre (Chlorophyll a)– P700 has an absorption maximum at 700nm 18. Photosystem ΙΙ (PS ΙΙ) :- Reaction centre ( chlorophyll a)- P680 has an absorption maximum at 680nm. 19. Electron Transport / Photophosphorylation :- Synthesis of ATP from ADP & inorganic phosphate (Pi) in the presence of light. 20. Cyclic photophosphorylation -  In PS Ι , reaction centre absorb 700nm wavelength of red light.  Electrons become excited and jump into an orbit farther from the atomic nucleus.  These electrons are picked up by an electron acceptor.  Excited electrons cycled back to the PS Ι through an electron transport system consisting of cytochromes.  Cyclic flow results in the synthesis of ATP. Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 45 Downloaded from hssreporter.com   Possible location is stroma lamella, because stroma lamella membrane lack PS ΙΙ and NADP reductase enzyme. 21. Non-cyclic cyclic photophosphorylation :-  In PSΙΙ , reaction centre absorb 680nm wavelength of red light.  Electrons become excited and jump into an orbit farther from the atomic nucleus.  These electrons are picked up by an electron acceptor.  Down hill movement of electrons through an electron transport system consisting of cytochromes and reach PS Ι ( ATP is formed during this transport). trans  Electrons in the PS Ι are also excited when they receive red light of 700nm wavelength and are transferred to another acceptor molecule.  Again downhill movement of electrons (results esults in the synthesis of NADPH). NADPH  Electrons needed to replace those remo removed from PS Ι are provided by PS ΙΙ. 22. Difference between Cyclic and Non Non-cyclic Photophosphorylation :- Cycic photophosphorylation Non-cyclic cyclic photophosphorylation Only PS Ι is functional Ps Ι and PS ΙΙ are functional Electrons from PS Ι are cycled back Electrons are not cycled back ATP is synthesized ATP & NADPH are synthesized Photolysis of water absent Photolysis of water present Location- Stroma lamella Location -Thylakoid membrane Found in bacterial cell Found in green plants Prepared by Nandini. K. N, NHSS Kolathur, Malappuram (dt). Page 46 Downloaded from hssreporter.com 23. Photolysis of water :-  Splitting of water in the presence of light.  Water splitting complex (located on the inner side of the Thylakoid membrane) is associated with PS ΙΙ.  The electrons moved from PS ΙΙ during non- cyclic photophospohorylation is replaced by electrons available due to splitting of water.  Creates Oxygen.  2H2O → 4H+ + O2 + 4 e- 24. Chemiosmotic Hypothesis ( Explain the mechanism of ATP synthesis) :-  Required components :- Proton gradient, Proton pump, ATP synthase enzyme.  Energy is used to pump protons across a membrane , to create a gradient or a high comcentration of protons within the thylakoid lumen.  Diffusion of protons from lumen to stroma through the channel of ATP synthase enzyme, release energy to produce ATP. 25. Protons in the stroma decreases in number and there is an accumulation of protons in the lumen / a proton gradient is established across the membrane due to three reasons. What are they? 1) Photolysis of water takes place on the innerside of the thylakoid membrane. 2) As electron transfer through photosystems , Protons are transported across the membrane into the thylakoid lumen. (Primary electron acceptor transfer its electron to H carrier. H carrier remove proton from stroma and transfer electron to electron carrier. During this transport , proton is released into lumen) 3) Protons necessary for the reduction of NADP + to NADPH +H+ is removed from stroma. 26. Location of NADP reductase enzyme :- stroma side of the thylakoid membrane 27. ATP synthase enzyme :- consists of 2 parts.  CF0 - embedded in the thylakoid membrane & forms a trans membrane channel that carries out facilitated diffusion of protons across the membrane.  CF1 – Protrudes on the outer surface of the thylakoid membrane on the side that faces the stroma. 28. ATP synthesis :-  Proton gradient across the thylakoid membrane is broken down due to the movement of protons from lumen to stroma through transm