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Subject : Biology Basic Terminology Cell :- The basic structural & functional unit of life is called cell. Tissue :- ‘A’ group of cells performing a particular function is called tissue. Organ :- A group of tissue performing a particular function is called organ. Organ System :- A group of organs performing a particular function is called organ system. Eukaryotic cell :- The cell in which nucleus is well organized as well as member bound cell organelles are present is called Eukaryotic cell. Prokaryotic Cell :- The cell in which nucleus is not well organized as well as membrane bound cell organelles are not present then it is called procariyotic cell. Nutrition :- The process in which nutrients are taken inside the body is called nutrition. Photosynthesis Hetrotroptric Chemosynthesis Saprophytic Parasite Holozoid Ectoparasite Endoparasite :- The parasite which is present outside the body of the host is called ectoparasite. Holozoic Nutrition :- The nutrition in which organisms shows tendency towards engulfing food material is called holozoic nutrition. HABITAT : Aquatic organisms :- The organisms which can survive only in water are called as aquatic organizations. Amphibian :- The organisms which can survive in water as well as on land are called amphibians. Terrestrial :- The organisms which can survive in water as well as on land are called amphibians. NUTRITION Autotropric Parasitic Nutrition :- The nutrition in which an organisms is dependent on another living organisms for is nutrition is called parasitic nutrition. Ectoparasite Autotrophic Nutrition (Self-dependent) :The nutrition in which organisms depend on itself for nutrition is called autotrophic nutrition. Chemosynthetic Nutrition :The type of nutrition in which organisms prepare its own food in presence of chemical is called chemosynthetic Nutrition. Photosynthetic Nutrition :- The type of nutrition in which organisms prepare its own food in presence of light is called photosynthetic nutrition. Hetrotrophic Nutrition :- The nutrition in which organisms are depends on another organisms is called heterotrophic nutrition. Saprophytic Nutrition :- The nutrition in which an organisms are dependent on the dead or decaying matter is called as saprophytic Nutrition. Arboreal :- The organisms which spends most of the life time over the trees are called arboreal organisms. Aerial :- The organisms which can fly in air are called aerial originations. Hydrophytes :- The plants which survives in water are called hydrophytes. Mesophytes :- The plants which survives in moderate conditions are called mesophytes. Xerophytes :- The plants which survives in high temperature and low rainfall in called as xerophytes. Reproduction :- The process of production of new individual from the pre-existing individuals is called as Reproduction. Types of Reproduction : Haploid : A cell having single set of chromosomes is called Haploid. It is represented by ‘n’. Diploid : A cell having two sets of chromosomes is called diploid (2n) Gamete : gamete. A sexually reproducing cell is called Sextual Reproduction : The reproduction in which hapliod male gamete unites with hapliod female gamete to form a diploid zygole is called as sexual reproduction. Asexual Reproduction :- The reproduction which does not involve union of opposite haploid gamete is called Asexctual Reproduction. Vegetative propogation / Reproduction : The formation of new plant from pre-existing plant body’s vegetative parts is called vegetative reproduction or vegetative propagation. Vegetative Part : The part of the plant body which does not produces either male or female gamete is called vegetative part. Reproductive part : The part which can produce either male or female gamete is called Reproductive part. Cell Division : The ability of a cell to divide into two is called cell division. Types of cell Division : A cell division can be differenciated into two types as 1) Mitosis. 2) Meiosis. Mitosis :- A type of cell division in which a mother cell divide into two daughter cells is called mitosis. Meiosis :- A type of cell division in which one mother cell divides into four daughter cells with the change in chromosome number is called meiosis. ================== Subject : Biology. Topic : DIVERSITY IN ORGANISMS 1. DIVERSITY IN LIVING ORGANISMS : Enormous variety of living organisms exist on the earth. There are about 5-30 milion species of plants and animals on earth. It is not possible for a human being to remember the characteristics of all these organisms without their systematic arrangement. 2. SYSTEMATICS : TAXONOMY, TAXONOMIC HIERARCHY AND BINOMIAL NOMENCLATURE. Systematics : “ Systematics is the scientific study of similarities and differences among different kinds of organisms and it also includes their identification, nomenclature and classification. Taxonomy : It is the branch of biology which deals with the collection, identification of plants and animals. Objectives of Systematics/ Taxonomy : i) To know various kinds of plants on the earth with their names, affinities, geographical distribution, habit, characteristics and their economic importance. ii) To have a reference system for all organisms with which the scientists can work. iii) To demonstrate the manifold diversities of organisms and their phylogenetic (evolutionary) relationship. iv) To ascertain nomenclature i.e, scientific name for every organism. Classification : The classification is based on similarities and dissimilarities among the organisms. Need of Classification : i) ii) iii) iv) The classification helps to explain unity in diversity of the organisms. It is gives specific and scientific names to the organisms which are accepted universally. It reveals the relationships among various group of organisms. The classification places an organism amongst those which have common characteristics. Taxonomic hierarchy [Gr. – Hierarchs = rank] The manner of scientific grouping of different taxonomic categories in a descending order on the basis of their ranks or positions in classification is called taxonomic hierarchy. i) Taxon :- Taxon a group of living organisms (pl. taxa) which is used to represent a concrete unit of classification. ii) Category :- A category is a rank of level in the hierarchial classification of organisms. Example : Method of classification of China rose and Cobra. Category Taxon Taxon Kingdom Plantae Animalia Division/Phylum Angiospermae Chordata Class Dicotyledonae Reptilia Sub-class Polypetalae Diapsida Series Thalamiflorae Order Malvales Squamata Family Malvaceae Elapidae Genus Hibiscus Naja Species Rosa-sinensis naja Hierarchy of taxonomic categories : Species : It is the basis unit in the system of classification. Members of a species show all the similar characters and are able to breed among themselves to produce their own kind. For Example, all the plants of potato (Solanum tuberosum) are grouped under the species tuberosum. Genus : (Pl. genera) – It is a group of closely related species. E.g rosa- sinensis, esculentus, canabinus etc. are different species under the genus Hibiscus. Family : A family represents a group of closely related genera. The genera like Hibiscus, Malva, Sida, Gossypium, Abutilon, etc. belong to the family Malvaceae. Order : It is a group of closely related families which resemble in major characters. Families Malvaceae, Tiliaceae, Sterculiaceae etc. belong to the order Malvales. Sub-Class : It is an assemblage of different orders having some similarities. The orders, Malvales, Ranales, Parietales etc. have free petals and hence grouped under the sub-class Polypetalae. Class : It is a group of related sub-classes. The class Dicotyledonae includes subclasses as Polypetalae and Gamopetalae. Division : The division is a category composed of related classes. Division angiospermae includes two classes-Dicotyledonae and Monocotyledonae. Sub Kingdom : Different divisions having similarities from sub-kingdom. some Division Angiospermae and Gymnospermae will form the sub kingdom Phanerogams or Spermatophyta. Kingdom : It is the highest taxonomic category composed of different sub Kingdoms. Sub-Kingdom Phanerogams and Cryptogams, form the Plant kingdom. Binomial Nomenclature : A system of nomenclature of plants and animals in which the scientific name consists of two words or parts or epithets is called binomial nomenclature. When a single species is described under different names by different authors, then these names are called synonyms. In such cases the name under which the species is first described is considered to be valid. These names are simple, meaningful, precise and standard as they are accepted universally Due to this system confusion and uncertain created by local or vernacular names is avoided. The binomials are easy to understand and remember. Indicate phylogeny (evolutionary history) of organisms and help to understand relationships between organisms, and groups of organisms. FIVE KINGDOM CLASSIFICATION : The five kingdoms are : 1. 2. 3. 4. 5. SYSTEM OF Kingdom Monera Kingdom Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia Kingdom : Monera The organisms included in this kingdom are microscopic and prokaryotic, having a primitive type of nucleus. The cells are without membrane bound cell organelles Rules of binomial nomenclature : The name of the organism is composed of two Latin or Latinised or Greek words. The generic name is a simple noun should come first and should begin with a small letter. These scientific names must be underlined separately if hand written and must be printed in italics. The generic as well as specific name should not have less than three letters and more than thirteen letters. Usually the name of the author, who names a plant or animal, is also written in full or in abbreviated form after the scientific name. E.g. Mangifera indica L. where L. stands for Linnaeus. Composition : The cell wall is rigid and composed of peptidoglycan Organisation : These organisms are unicellular as in eubacteria or filamentous as in cyanobacteria. Locomotion : These organisms are either motile (the locomotion is due to gliding movement or flagella. Cilia are absent or non-motile. Nutrition : The organisms exhibit different modes of nutrition like autotrophic, heterotrophic, parasitic or saprophytic. The autotrophs are either photoautotrophs e.g. cyanobacteria or chemoautotrophs e.g. Thiobacillus. Reproduction : The mode of reproduction in Monera is either asexual or with the help of fission or budding. (Sexual reproduction, mitosis and meiosis are absent) Example : - Archaebacteria e.g. – Methanobacillus, Thiobacillus, etc. - Eubacteria. e.g – Rhizobium, Clostridium - Cyanobacteria e.g. – Nostoc, Anabaena, etc. - Actinomycetes e.g. – Streptomyces, Mycobacterium, etc. Kingdom – Protista ( Protoctista) : Occurrence : Fungi like protists : They are saprophytic and lack cell wall e.g. Smile moulds. Kingdom - Fungi : It is a unique kingdom of heterotrophic organisms, showing extracelluar digestion. Organisation : The organisms are unicellular of multicellular and filamentous. Unicellular Organisms : They have a protoplast with many nuclei. e.g. Rhizopus. Multicelluar organisms consist of a body called mycelium in which a number of thread-like structures called hyphae are present. The hyphae may be with septa (septate) or without septa (aseptate). They may be uni or multi-nucleated. The nonseptate multinucleated hyphae are called coenocytic hyphae. These organisms are unicellular, eukaryotic and mostly aquatic. However, some are terrestrial. They are either motile or non-motile. The locomotory organs are cilia, flagella, pseudopodia, etc. Cell wall composition : The protists are with or without cell wall. If cell wall is present, it is composed of cellulose. Nutrition : They show either photosynthetic, holozoic, saprophytic or parasitic mode of nutrition. The reserve food material is in the form of glycogen or starch and fat. Cell wall Composition : The cell wall in fungi is composed of chitin or fungal cellulose. Nutrition : Reproduction : The reproduction is by asexual or sexual method. Reproduction : Reproduction is vegetative, asexual of sexual. (Example : Mucor, Rhizopus, Yeast, Penicillum, Agaricus, ect.) Asexual Reproduction : Asexual reproduction occurs by mitotic or amitotic cell division. Sexual reproduction is by fusion of male and female gametes forming zygote. The zygote directly develops into young individual without formation of embryo. Plant like protists : They are autotrophic (photosynthetic) have cellulosic cell wall and store reserve food as starch e.g. Dianoflagellates and Diatoms. Animal like protists : These are heterotrophic, ingest food, lack cell wall and store reserve food as glycogen.e.g Amoeba, Paramoecium. The fungi exhibit heterotrophic mode of nutrition. Most of the members are saprophytes. Some are parasites or predators and some are symbiotic Kingdom : Plantae The Kingdom Plantae includes multicellular, eukaryotic and autrophic organism Cell wall Composition : The cell wall of plant cells is composed of true cellulose. Photosynthetic pigments :- The members possess photosynthetic pigments. Reserve food material :- It is in the form of starch. Vascular tissues : Vascular tissues are absent in the lower plants (Algae and Bryophytes) but present in higher plants (Pteridophytes, Gymnosperms and Angiosperms) Reproduction : The plants reproduce by vegetative, asexual or sexual methods. Vegetative reproduction : Vegetative reproduction occurs with the help of vegetative parts. Asexual reproduction : Asexual reproduction with the help of spores. Sexual reproduction: Sexual reproduction takes place with the help of gametes. Example : - Algae e.g. - Spirogyra, Chara, etc. - Bryophytes e.g. - Riccia, Funaria, etc. - Pteridophytes e.g - Lycopodium, Nephrolepis, etc. - Gymnosperms e.g.- Cycas, Pinus, etc. - Angiosperms e.g. – Sunflower, Jowar, etc. Kingdom Animalia : Occurance : The animals are multicellular and eukaryotic and may be aquatic, terrestrial, amphibious or aerial. Locomotion : Majority of the animals are motile. However a few like sponges are sedentary. Cell Wall Composition : The animals cells do not possess cell wall, plastids and central vacuole. Nutrition : They are heterotrophic, mostly holozoic and some are parasitic. Advantages of S. Kingodom System : The fungi are separated from Plantae on the basis of their saprophytic mode of nutrition. Organisms with doubtful placement like Euglena get proper place in classification. During redistribution of the organisms among additional kingdom, the original subdivisions of old two-kingdom system are not disturbed. Drawbacks in five kingdom system. : Viruses do not find any place in fivekingdom dystem of classification. Kingdom Protista includes photosynthetic and non-photosynthetic organisms, as well as those with or without cell wall and it is difficult to imagine them together. LICHENS : The lichens are slow growing, long living organisms, occurring in wide variety of places. Composition : Lichens are formed by close association of two different partners (organisms) one of which is an algal component and the other is fungal component. The algal component is called phycobiont or photobiont and it mostly belongs to Chlorophyceae (green algae) or cyanobacteria (blue green algae). The fungal component is called mycobiont and it mostly belongs to Ascomycetes and rarely Basidiomycetes or Deuteromycetes. Habitat : The Lichens are distributed in wide variety of habitats. They grow on tree trunks, decaying logs, and on soil too. They are sensitive to air pollution and generally do not grow near the cities. They are thalloid, and the thallus is greenish or bluish green in colour. Some lichens have additional pigments such as yellow, orange, brown and black. Body structure : On the basis of fungal components the lichens are divided into three cagagories. Type of lichens : A) Ascolichens - In this category the fungal partner belong to Ascomycetes. B) Basidiolichens - Here the fungal partner belongs to Basidiomycetes. C) Deuterolichens – In this category the fungal partner belongs to Deuteromycetes. These are sterile lichens producing no spores. On the basis of external form, (thallus organization) the lichens are of three types asA) Crustose Lichens - These are thin and flat lichens occurring as crust on the bark or rock. e.g. Graphis. Leanora, Haematomma etc. B) Foliose Lichens - These are lobed and dorsiventrally flattened, leafy lichens. They are attached to substratum by hairy rhizoid like structures called rhizines e.g. Parmelia, Collema, Petligera. C) Fruticose Lichens - These lichens are commonly called shruby lichens. They have cylindrical, branched and erect or pendulous thallus which given them a shrub like appearance. They remain attached to the substratum by basal mucilaginous disc. e.g. Cladonia, Usnea, Alectoria. The lichens generally reproduce by vegetative, asexual and sexual methods. Economic Importance of Lichens. 1) Lichens as Food :-- Several lichens are used as food. The lichens contain as substance lichenin which is similar to carbohydrate e.g. Lecanora esculenta in Israel and Umbilicaria esculenta in Japan. Parmelia is used in curry powder as well as in making chocolates and pestries. Body Structure : Viruses show very simple structure i.e. a nucleic acid core surrounded by a protein coat (capsid) to form the nucleocapsid. They posses their own genetic material in the form of either DNA or RNA (but never both). They can be crystallized. They can be stored for long period. 2) Lichens as Fodder :-- Lichens form a favourite food for reindeers and cattles. Species of Cladonia, Citraia, Evernia, Parmelia are used as fodder. Reproduction : 3) Medicinal Uses :-- Usnic Acid obtained from the Usnea and Cladonia species is used as an antibiotic against Gram positive bacteria, Lobaria, Citraria species are, useful in respiratory disease like T. B., Peltigera is useful in hydrophobia, Parmelia is useful in epilepsy and Usnea species in urinary disease. Some lichens possess anticarcinogenic property. Types of viruses : (Classification of viruses) Viruses are classified into three groups on the basis of their hosts. 1) Plant viruses :- The viruses which attack and infect plants are called plant viruses. These viruses consists of ss.-RNA or ds-RNA. They show helical symmetry and are mostly rod-shaped or cylindrical. (e.g. : TMV) 2) Animal viruses :- The viruses which attack and infect animals are called animal viruses. The genetic material is either RNA or DNA. They show radial symmetry. These are mostly polyhedral in shape. (e.g. : Herpes) 3) Bacterial viruses or Bacteriophages :(Greek phagin=eater). The viruses which attack and infect the bacteria are called bacteriophages or bacterial viruses. The genetic matrial is DNA. They were discovered by Twort (1915). Felix d’ Herelle named them as bacteriophages. They are mostly tadpole shaped. 4) Industrial Uses of Lichens :-a) In Sweden na Russia, Lichens are used for production of alcohol. b) Lichens are used in the process of tanning and dying. c) In the litmus paper preparation which used as acid-base indicator extract of species of Rocella and Lasallia are used d) Orcein a biological stain is obtained from orchrolechia androgyna and O. tortaria. e) In Perfumery, species of Evernia and Ramalina are the sources of essential oils which are used in preparation of soaps and other cosmetics. Ecological Importance of Lichens : The lichens are the pioneers of vegetation on rocks. Lichens are the first plants to settle on barren rocks. Lichens bring about weathering of rocks by releasing carbonic and oxalic acids. Weathering of rocks leads to formation of soil and is called pedogenesis. VIRUSES AND VIROIDS : Viruses : Viruses are a cellular, highly infectious microorganisms which are considered to be on the threshold of life. Size : Their size ranges from 10nm to 2000nm Viruses do not grow, do not eat food or respire. They utilize the ribosomes and enzymes of the host cell for synthesis of protein during reproduction Economic Importance of viruses : The plant viruses and animal virues are of great economic importance as they cause various diseases in plants and animals. Plant diseases caused by viruses are like – 1) 2) 3) 4) 5) 6) 7) Little leaf of Brinjal Yellow vein mosaic of lady’s finger. Potato leaf roll Leaf curl of papaya Bunchy top of banana Grassy shoot of sugarcane Tabacco mosaic disease Common symptoms due to viral infection include – Local lesions clearing of veins, mosaic formation, chlorosis, necrosis, stunting and premature defoliation, ring spotting, etc. Animal diseases caused by viruses are like. Disease virus 1) Common cold - Rhino virus 2) Influenza - Orthomyxo viruses 3) Small pox - Variola virus 4) Mumps - Myxovirus parotiditis 5) Mealses - Morbilli virus 6) Poliomyelitis - Polio viruses 7) Yellow fever - Flavi virus 8) Swine flu - H1N1 virus 9) AIDS - Retro virus /HIV Viroids : These are very small, circular, single – stranded RNAs which are not complexed with any protein. (without protein coat) This RNA is either covalently closed circular RNA or single stranded linear RNA. These are mainly plant pathogens. The first viroid discovered was the potato spindle tuber viroid (PSTV) which causes a disease in potato. PSTV is composed of 359 nucleotides and thus has ten times less genetic material than the smallest known virus. The naked RNA molecule can replicate autonomously in plant cells. It can also disperse into the environment and produce disease. ******************* Subject : Biology. Topic : KINGDOM PLANTAE INTRODUCTION : On the earth there is a large number of living organisms, conmmonly known as plants, animals and microorganisms. All multicellular, eukaryotic organisms with photosynthetic mode of nutrition are included under kingdom Plantae. These are the main producers on land and in water. With the help of green pigments (chlorophylls) they synthesize carbohydrates and release oxygen in air. Thus they are the most essential biotic components of the ecosystem. Kingdom plantae is broadly classified into two sub-kingdoms. A) Cryptogamae B) Phanerogamae Cryptogamae : Cryptogams are spore producing plants, and do not produce seeds and flowers. They reproduce sexually by gametes but sex organs are concealed. Cryptogams include three major groups, namely (a) Algae (b) Bryophytes (c) Pteridophytes. Habitate : Algae are mostly aquatic, some being terrestrial also. A few alage grow on other plants. Aquatic algae grow in marine water or fresh water. Most of them are free living while some are symbiotic. Structure : The vegetative structure (thallus) of algae display variety in organization and size. Theymay be small, unicellular, microscopic like chlorella (non-motile), chlamydomonas (motile) or multicellular unbranched filamentous like Spirogyra, or branched filamentous like Chara or huge macroscopic such as sea weeds which measure more than 60 meters in length e.g. Sargassum. Cell Composition : The algal cell wall consists of two layers i.e. inner cellulosic and outer composed of pectin. The algae consist of various type of photosynthetic pigments. Chlorophyll-a (essential pigment) is present in all groups of algae. The accessory pigments present are chlorophyll-b, chlorophyll-c and chlorophylld, carotenes, xanthophylls and phycobilins. Phycobilins are of two types i.e, phycocyanins and phycoerythrins. The reserve food material is in the form of starch, laminarin-starch, mannitol or floridean-starch, etc. Reproduction : Algae reproduce by three different methods. Vegetative reproduction occurs by fragmentation (in filamentous forms) and cell division (in inicellular forms. Asexual reproduction occurs by the formation of various types of non- motile or motile spores. Sexual reproduction takes place by formation and fusion of gametes. Occurrence : The bryophytes are mostly terrestrial plants which depend of external water for fertilization and completion of their life cycle. Hence they are called amphibian plants. Habitat : The Bryophytes generally grow in shady and moist places such as moist walls, damp rocks, moist soil and on decaying logs. Body Structure : They show thalloid plant body which is not differentiated into root, stem and leaves as in liverworts. In mosses, thallus is foliose, i.e, it bears leaf-like structures. Rhizoids : In Bryophytes true roots are absent but rhizoids are present. Rhizoids are unicellular in liverworts while multicelluar in mosses. They absorb water and minerals and also help in fixation of thallus to the substratum. Vascular tissues : The vascular tissue are absent. However, a condicting strand of ew thick-walled cells is present in mosses. Leaves : Some bryophytes show leaf like structures (e.g. moss) but they are not true leaves. They do not produce flowers or seeds as well. Bryophytes show heteromorphic alternation of generations. In which the gametophyte is the dominant, green haploid and independent phase while sporophyte is diploid recessive and partially dependent on gametophyte. Reproduction : Bryophytes reproduce by vegetative means i.e, by special structures like tubers and gemmae while asexual reproduction takes place by spore formation Sexual reproduction occurs by formation of gametes. Examples : Liverworts e.g. - Raccia ; Marchantia Hornworts e.g. - Anthoceros Mosses - Funaria. e.g. Division : Pteridophyta (pteron – feather : phyton = plant) : The pterodophytes were the first vascular plants on the land and are hence considered as the first successful terrestrial plants. The Pteridohytes are also known s vascular cryptogams. Habitat : The Pteridophytes are terrestrial, small, either annual or perennial, and grow luxuriantly in moist and shady places. e.g. ferns. They may be aquatic (Azolla, Marsilea), xerophytic (Equisetum) epiphytic (Lycopodium) i.e. growing on large trunks of trees. Alo The pteridophytes show heteromorphic alternation of generation in which the sporophyte is diploid, dominant, autotrophic, independent and is differentiated into root, stem and leaves. Root Structure :The primary root is short-lived and is soon replaced by adventitious roots while the Leaves :The leaves may be scaly (Equisetim), simple and sessile (Lycopodium) or large and pinnately compound (Ferns). Vascular tissue. :In pteridophytes the xylem consists of only tracheids and phloem consists of sieve cells only. Secondary growth is not seen in Pteridophytes due to absence of cambium. Reproduction. :The sporophyte shows asexual reproduction and produces spores by meiosis from which the gametophyte develops. Gametophyte is haploid recessive but independent, and reproduces sexually. Product of sexual reproduction, i.e. zygote produces diploid sporophyte. Apogamy - It is the development of the sporophyte without the fusion of the male and female gametes. It arises directly from the gametophyte. Here the sporophyte is haploid. Apogamy It is the development of thegametophyte from any cell of the sporophyte other than the spores. Such a gametophyte is diploid in nature. Phanerogamae The members of Phanerogamae i.e, Phanerogams are commonly called seed plants. Which are further divided into two divisions name a) Gymnospermae b) Angiospermae. Gymnospermae : Gymnosperms are the plants with naked seeds. Most of the Gymnosperms are evergreen, perennial woody trees or shrubs. Vascular Tissue : They are vascular plants having xylem with tracheids and phloem with sieve cells. The Gymnosperms show heteromorphic alternation of generations. The sporophyte is diploid, dominant, autotrophic, independent while the gametophyte is haploid, recessive and dependent. (It is much reduced and exists within sporophyte.) stem may be aerial or underground. Vascular Tissue : They are vascular plants having xylem with tracheids and phloem with sieve cells. The Gymnosperms show heteromorphic alternation of generations. The sporophyte is diploid, dominant, autotrophic, independent while the gametophyte is haploid, recessive and dependent. (It is much reduced and exists within sporophyte. ) Morphology : The plant body i.e. sporophyte is differentiated into root, stem and leaves. The root system is well developed tap root system. Coralloid roots of Cycas show association with blue-green algae roots of Pinus show association with endophytic fungi called mycorrhizae. Stem : The gymnospermic stem is mostly erect, aerial, solid and cylindrical. In cycas it is usually unbranched, while in conifers it is branched. The leaves are dimorphic. The foliage leaves are green, simple, needle like or pinnately compound, where as scale leaves are small, membranous and brown. Secondary growth is seen in Gymnosperms due to presence of cambiu. Type of Spores :Gymnosperms are heterosporous. They produce microspores (pollen grains) in mocrosporangia and megaspores in megasporangia (ovules). The sporangia are borne on leafy structures called sporophylls which are often aggregated to form cones or strobili (sing-strobilus). Reproduction : The pollination in Gymnosperm is anemophilous (wind pollination) and direct as the pollen grains are received directly in the pollen chamber of the ovule. Fertilization is achieved through a pollen tube. This process is called siphonogamy. Vegetative reproduction takes place with the help of bulbils. Some Gymnosperms like Ginkgo biloba are called living follils. It is because the plant is found in living as well as follil form, and the number of fossil forms is much more thena the living forms. ANGIOSPERMS :- The Angiospermae is the most advanced division of the flowering plants. The Angiosperms are flowering plants in which seeds are enclosed within the fruit. Habitat : The Angiosperms is a group of highly evolved plants, primarily adapted to terrestrial habitat. They vary in size; e.g. Wolffia is the smallest angiosperm, 1mm in size and Eucalyptus grows to over 100 meters. Marphology : The plant body is differentiated into root, stem and leaves. It has flowers, fruits and seeds. Vascular tissue are well developed. Xylem shows vessels or tracheae while phloem has sieve tubes and companion cells. Angiosperms show heteromorphic alternation of generation in which the sporophyte is diploid, dominant, autotrophic and independent while the gametophytes (male or female) are recessive, haploid and delepndent on the sporophyte. (exist within sporophyte) Reproduction Asexual reproduction :Angosperms are heterosporous. Microspores (commonly called pollens) are formed in microsporangia. They develolop in highly specialized microsporophylls or stamens while megaspores are formed in megasporangia (or ovules) borne on highly specialized megasporophylls called carpels. Pollination :- In Angiosperms the pollination is indirect (pollen grains received on stigma) and may be self or cross. Sexual Reproduction :- These plants show double fertilization. One male gamete fuses with egg cell and another fuses with secondary nucleus, to form embryo and endosperm respectively. It occurs within the ovule, and ovule changes to seed. The ovqer simultaneously ripens into a fruit. Class dictyledonae : These plants have two cotyledons in their embryo. They have a tap root system and the stem is generally profusely branched. The leaves show reticulate venation while the flowers show tetra or pendamerous symmetry. The vascular bundles are conjoint, collateral and open. In dicots secondary growth is commonly found. Class Monocotyledonae : These plants have single cotyledon in their embryo. They have adventitious root system and the stem is rarely branched. The leaves generally have sheathing left base and parallel venation while the flowers are generally trimerous. The vascular bundles are conjoint, collateral and closed. In monocots, secondary growth is absent due to absence of cambium. (e.g. Zea mays (Maize) Sorghum vulgare. Jowar) Importance of Botanical Garderns :Botanical garders are important for They records of local flora and as basis for continued monographic work. That provide vacilities for collection of living plant material for studies. Botanical gardens also supply seeds and material for botanical investigations. The botanical gardens in addition to outdoor garden, may contain herbaria, green houses, research laboratory and library. Botanical Gardens of India : 1) The Indian Botanical Gardern, Kolkata. 2) Lioyd Botanical Garden, Darheeling. 3) National botanical Garden, Lucknow. 4) Botanical Garden of the Forest Research Institute, Dehradun. 5) Government Botanical Garden, Ootacamund. 6) The State Botanical Garden, Lalbagh, Mysore. 7) Botanical Garden, Saharanpur. Herbaria : The collection or deposition of dried plant material by using various techniques of preservation and their arrangement in the sequence of an accepted classification, forms herbaria. A herbarium technique involves collection, drying, poisoning, mounting, stitchning, labeling and deposition. Herbaria are associated with research institutes, scientific societies, botanic gardens, universities and colleges. Herbaria can be classified into three main categories such as – a) Regional herbaria b) Local herbaria and c) Herbaria of educational institutions including schools, colleges and universities. Importance of herbaria : The hyrbaria preserve national regional, local plant wealth. Help to carry out research programmes of fundamental or of applied value. It also facilitates exchange and loan of preserved plant material for various purpose like exhibitions, research etc. It fulfils public demand by supplying plant material and giving scientific information regarding plants by arranging training courses. =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= Metaphase : During metaphase, the condensation of chromosomes is completed and the thick chromosomes get organized along equational plane of the cell. This phase is characterized by formation of kinetic spindle. In animal cells the spindle fibres radiate as an aster from centriole and called astral rays. Hence it is called astral mitosis. In plant cells asters are absent and so it is called anastral mitosis. Anaphase : Centromeres divide into two, resulting in the separation of chromatids. Each separated chromatid is now called daughter chromosome The kinetic spindle now has four type of fibres made up of microtubules. They are 4) Telephase : At the poles, daughter chromosomes uncoil and undergo hydration to from chromatin network. The nuclear membrane begins to reappear around each group of aughter chromosomes and the daughter nuclei are formed. Cytokinesis : The division of cytoplasm of the mother cell is called cytokinesis. In animal cells it occurs by furrowing of plasma membrane that deepens and the daughter cells ar formed. This process is called cleavage. In plant cells it takes place formation and extension of cell plate, from centre to the periphery. MEIOSIS : Meiosis is a type of cell division, which involves halving of the chromosome number. Therefore, it is termed as reduction division. The meiotic division involves two successive divisions. a) Meiosis-I or reduction division b) Meiosis-II or equational division both of which have karyokinesis and cytokinesis phase. Karyokinesis includes four phase like mitosis. A) Meiosis – I or reduction division : Interphase : It is similar to that in mitosis. Karyokinesis : a) Prophase-I : It is furthet distinguished into five sub-stage viz, leptotene i) Leptotene or leptonema , ii) Zygotene or Zygonema, iii) Pachytene or Pachynema, iv) Diplotene, v) Diakinesis, i) ii) iii) iv) Leptotene or leptonema : During this phase the chromatin network condenses and resolves into long and thin, thread like chromosomes. Zygotene or Zygonema : It is a phase in which homologous chromosomes begin to pair lengthwise . Such a pairing of chromosomes is called synapsis. Pachytene or Pachynema : During this phase condensation of chrosomes progresses and they become short and thick. During this process crossing over i.e, exchange of genetic material between nonsister chromatids of homolgous chromosomes takes place. It result in genetic recombination of parental characters. The points where crossing over takes place are called chiasmata. Diplotene : The homologues now start repelling each other and begin to separate. However, at the points of crossing over, they remain attached and thus chiasmata can be seen. Nucleolus and nuclear membrane start disappearing. v) Diakinesis : During this phase chromosomes continue to condense and shorten. The chrasmata get shifted to the ends of chromatids called terminalisation. The nucleolus and nuclear membrane completely disappear and kinetic spindle become apparent. b) Metaphase – I The spindle formation is complete and the bivalents move and arrange themselves at the equatorial plane. c) Anaphase – The chromosomal fibres contract and pull the homologues and inter-chromosomal fibres appear and extend so that homologous chromosomes start moving towards opposite poles. A) Telophase-I : The chromosomes uncoil to form chromatin. The spindle fibres disappear. The nuclear membrane and nucleolus reappear forming two daughter nuclei. Cytokinesis – I Telophase-I is often followed by division of the cytoplasm. B) Meiosis – II : a) Prophase – II : During this phase the chromosomes with chromatids become distinct. The nucleoius and nuclear membrane disappear. b) Metaphase – II : During this phase spindle formation takes place and the chromosomes move towards equatorial plane. The chromosomes get connected to the respective poles by the chromosomal fibres. c) Anaphase II : The centromere of each chromosome divides and chromatids are separated. Each chromatid is now called daughter chromosome. Telophase II : The daughter chromosomes which have gathered at each pole start uncoiling . The nucleolus reappears and the nuclear membrane is formed around each group of chromosomes forming two daughter nuclei. Cytokinesis-II Telephose-II is followed by division of cytoplasm of each cell forming two daughter cells. At the end of meiosis-II four haploid daughter cells are thus formed. Subject : Biology Biochemistry of cell Introduction : Cell is a fundamental, structural and functional unit of an organism. One of the major attributes of a living cell is its ability to carry of metabolic activities. To know how a tiny cell can carry out the metabolic activities one has to understand the chemistry of various organic molecules, found in cells. The collection of various types of molecules in a cell is known as cellular pool. Metabolism, it indicates a variety of reactions carried out at cellular level. The metabolic reactions can be divided into two main categories such as i) Anabolic reactions- The reactions in which biosynthesis of a new cellular material takes place. ii) Catabolic reactions- The reactions in which a complex storage product is hydrolyzed and or broken down into smaller and simpler molecules. Both, anabolic and catabolic reactions catalyzed by biological catalysts called enzymes. BASIC CHEMICAL CONSTITUENTS OF CELL: Carbohydrates: Carbohydrates are the basic components food. Carbohydrates are compounds of carbon, hydrogen and oxygen atoms. The general formula is C H O for simple (C H O)n, for complex carbohydrates. Rhamnose (C H O) and digitoxose (C H O) are carbohydrates, but do not follow general formula of carbohydrates. Simple carbohydrates are commonly known as sugars. Complex carbohydrates like starch, cellulose, etc. Carbohydrate molecules are also characterized by the presence of either aldehyde (-CHO) or ketone (C=O) group and two or more hydroxyl (-OH) groups. Classification of carbohydrates The three types are1) Monosaccharides 2) Disaccharides and 3) Polysaccharides 1) Monosaccharides:- Monosaccharides are compounds, which cannot be further hydrolyzed into still smaller molecules. Monosaccharides are further classified aldoses and ketoses They consist of 3 to 6 carbon atoms. They are crystalline, soluble in water and sweet to taste. On the basis of number of carbon atoms the monosaccharides can be trioses, tetroses,pentoses, hexoses etc. 2) Desaccharides: Disaccharide is a carbohydrate made up of two monosaccharide units. These are soluble in water, sweet to taste and crystalline. The covalent bond that joins monosaccharide units is called glycosidic bond. The most familiar disaccharides are sucrose, lactose, maltose. 3) Polysaccharides: These are complex carbohydrates formed by the condensation of large number of monosaccharides. A single polysacchyaride may consist of thousands of units of monosaccharide may. These are amorphous, tasteless and insoluble in water. A polysaccharide may contain one type of monosaccharides (or homopolysaccharide) or different types of monosaccharides (heteropolysaccharide). The role of carbohydrates is (1) To provide energy for metabolism. (2) The monosaccharide like glucose is main substrate for synthesis of ATP. (3) In mammals, disaccyharide lactose present in the milk, provides energy to their babies. (4) The polysaccharedes serve as structural components of cell membrane and cell wall and also serve as reserved food material (starch). Proteins are long chain polymers of amino acids. Serve as an important structural constituent of cells. Most of the proteins are host species and show slight variations in each species. The differences among the species are due to differences in their protein components. All proteins consist of nitrogen in addition to the carbon, hydrogen and oxygen. Some protein molecules contain sulphur and other elements in addition to C, H, O, and N. In a long chain of amino acids forming a protein, the amino group (-NH) of one amino acid is linked to the carboxyl (-COOH) group of the other amino acid. Two amino acids are condensed by removal of a water molecule (OH from COOH and H from NH) to form a peptide linkage. The remainder of each amino acid after removal of a water molecule (H+ and OH-) is called residue. A molecule of a protein made up of two amino acid residues is called dipeptide, of three residues as residues as tripeptide and of many residues as polypeptide. Classification of proteins: 1) Simple proteins: These are composed of only amino acids or their derivatives. e.g. histones, zein from maize. 2) Conjugated proteins: These are simple proteins (amino acids) with some non protein part called prosthetic group. Proteins play important role as – Enzymes- Most of the enzymes are proteins ( all proteins are not enzymes) e.g. amylase. Hormones- Hormones like insulin, growth hormones, etc. are proteins. Structural Proteins- These proteins form parts of cells or tissues Contractile proteins- These proteins occur in muscles. e.g. Transport proteins- They are useful for transportation of certain materials e.g. Defensive Proteins- They are useful for protection of the body against diseases. e.g. Lipids: Lipids are a group of organic components having oily or greasy consistency. Lipids are a group of heterogenous compounds like fats, oils, steroids, waxes etc. Lipids are insoluble in water but freely soluble in organic or non-polar solvents benzene, chloroform, etc. Similar to carbohydrates lipids are composed of C, H, O atoms Compound lipids contain N, S and P in addition to C, H and O. Classification of lipids: Lipids are classified into 3 main types as1) Simple lipids 2) Compound lipids 3) Derived lipids 1) Simple lipids: These are esters of fatty acids with alcohol, Glycerol is a three-carbon alcohol with three –OH groups. Fatty acid is a long straight chain of carbon atoms with a carboxyl (-COOH) group at one end. Saturated fatty acids - These fatty acids do not have double bond between carbon atoms of its chain e.g. palmitic acid, stearic acid, etc. Unsaturated fatty acids – These fatty acids contain one or more double bonds between carbon atoms of its chain e.g. oleic acid, linoleic acid, Fats containing unsaturated fatty acids liquid at room temperature and are called oils. 2) Compound lipids: These lipids contain some additional elements or groups in addition to fatty acids and alcohol such as nitrogen, phosphorous, sulphur, protein, etc. 3) Derived lipids: These lipids are the hydrolytic products of lipids. They include – Steroids, waxes, carotenoids, essential oils, etc. a. Steroids: Steroids are structurally quite different from other lipids. Each molecule of steroid has carbon atom arranged in four interlocking rings. Some of the biologically important steroids are cholesterol, bile salts, male and female sex hormones b. Waxes: Plant waxes are esters of saturated fatty acids with long chain alcohols and ketone. These are secreted by epidermis and form a covering on stem, fruits and leaves. In animals, fur and feathers are wax. c. Carotenoids: Carotenoids are pigments composed of two, six-carbon rings with a highly unsaturated strait chain of hydrocarbons. For example, alpha and beta carotene, xanthophylls, etc. Role of lipids : 1) Lipids act as high energy reserve food material e.g. oil seeds store oils. 2) They are important components of cell membrane of eukaryotes e.g. 3) Some of the lipids act as components of some enzyme systems. 4) Subcutaneous tissue contains fat which acts as insulator for heat. 5) Wax provides water proofing and checks the rate of transpiration in plants. 6) Steroids like cholic acid are constituents of bile. 7) Cholesterol takes part in the synthesis of vitamin D and is precursor molecule of many sex hormones. From the chemical analysis of nucleus it is clear that it consists of two types of nucleic acids i.e. DNA (Deoxyribose nucleic acid) and RNA Nucleic acids are macromolecules composed of many small units or monomers called nucleotides. Each nucleotide is formed of three components i.e. a pentose (5c) sugar, a nitrogenous base and a phosphate (phosphoric acid). I) Sugar - It is a pentose (5c) sugar. The sugars can be one of the two types i.e. ribose sugar or deoxyribose sugar. II) Nitrogenous bases – Each nucleotide has one of the four types of nitrogenous bases out of which two are purines and remaining two are pyrimidines. Purine bases are double ring compounds III) further distinguished into adenine and guanine while pyrimidine bases are single ring compounds further distinguished into thymine, cytosine and uracil. Phosphoric acid – Phosphate is present in nucleic acid (H PO) DNA is double-stranded helix in which each strand is made up of thousands of deoxyribose nucleotides. The two strands of DNA molecule are antiparallel, complementary and are joined by weak Hbonds. There are two –H bonds between adenine and thymine while three-H bonds between guanine and cytosine. Total the number of purine bases is equal to that of purimidine bases. Thus purine: pyrimidine ratio is 1:1. In eukaryotic cell DNA is found mainly in mitochondria and chloroplasts. It is the genetic material and contains all the information needed for development and existence of an organism. Structure of Ribose Nucleic Acid (RNA) RNA is single stranded and the strand may be straight or variously folded upon itself. The nitrogenous -base thymine is replaced by uracil in RNA. 1) Genetic RNA : RNA is the genetic material in most of the plant viruses and some animal viruses. 2) Non-genetic RNA: This type of RNA is present in organisms in which the genetic material is DNA. I) m-RNA (Messenger RNA): (1) It is a linear moteaule. Its synthesis takes place on DNA by the process called ‘Transcription’. (2) It carries genetic information from nucleus to the site of protein synthesis. (3) It forms about 5% of the total cell RNA. II) r-RNA (Ribosomal RNA): (1) It is a linear molecule folded at certain regions due to complementation of nitrogenous bases. (2) It is associated with ribosome. (3) It forms about 80% of the total cell RNA. III) t-RNA (Transfer RNA) : (1) It is soluble RNA with hair pin or clover leaf like structure. (2) This is the smallest among three types. (3) It forms about 10-15% of the total cell RNA. (4) It carries activated amino acids to ribosomes and helps in elongation of polypeptide chain during the process of translation. Enzymes: In livings cells the reactions occur at normal body temperature and pressure due to the presence of specialized macromolecular, proteinaceous substances called enzymes. The enzymes that are produced within a cell for metabolic activities are known endoenzymes those which act away from the site of synthesis are called exo-enzymes. General properties of enzymes and factors affecting enzyme activity. 1) Enzymes accelerate the reaction but do not initiate it. 2) Enzymes themselves do not participate in the reaction and remain unchanged at the end reaction. 3) The molecule of an enzyme is larger than that of substrate molecule and hence during reaction a specific part of enzyme molecule comes in contact with the substrate molecule. That part is called active site of enzyme. 4) Amphoteric nature: Chemically most of the enzymes are proteins and, therefore, show amphoteric nature. 5) Specificity: Most of the enzymes are specific in their action. 6) Colloidal nature: All enzymes are colloidal in nature and thus provide large surface area for reaction to take place. 7) Enzyme optima: Enzymes generally work best under certain narrowly defined conditions referred to as optima. 8) Concentration of enzyme and substrate The rate of reaction is proportionate to the concentration of the reacting molecules. 9) Enzyme inhibitors- Enzyme inhibitors are certain products which inhibit enzyme activity. Some important Diagrams