Mtg neet biology.pdf

R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES Page No. Nature and Scope of Biology vi ♂░▀♀–σ∟–▼▀♠◄☻☼▀♀♦–▒◘–▌▀◘◄–...

R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES Page No. Nature and Scope of Biology vi ♂░▀♀–σ∟–▼▀♠◄☻☼▀♀♦–▒◘–▌▀◘◄– σ– –φφ 1. Systematics 1 2. Viruses 7 3. Kingdom Monera 11 4. Kingdom Protista 20 5. Fungi, Lichen and Mycorrhiza 24 ♂░▀♀–τ–∟–█▀░◙▼▒▐–▓▌○░♀○◄– φ←– –↓τ 6. Plant Classification 34 7. Algae 36 8. Bryophyta 43 9. Pteridophyta 47 10. Gymnosperms 52 11. Angiosperms 60 ♂░▀♀–φ–∟–█▀░◙▼▒▐–○░▀▐○▌▀○– ↓φ– –στ↨ 12. Evolutionary Trends & Classification of Animals 63 13. Protozoa 71 14. Non-Chordates 79 15. Chordates 106 ♂░▀♀–←–∟–►◄▌▌–▲▀▒▌▒◙♦– σφε– –τσε 16. Tools and Techniques in Cytology 130 17. Cell as a Unit of Life 137 18. Biomembrane 145 19. Structural Organization of Cell 153 20. Biomolecules 170 21. Enzymes 182 22. Cellular Metabolism 188 23. Cell Reproduction 200 ♂░▀♀–↑–∟–◄♠▒▌♂♀▀▒░– τσσ– –τφ↨ 24. Origin of Life 211 25. Relationship Among Organisms and Evidences of Evolution 216 26. Theories of Evolution 225 27. Human Evolution 234 ♂░▀♀–↓–∟–☼♀☻♂►♀♂☻○▌–○░▼–▒☻◙○░▀☼○♀▀▒░–▀░–▓▌○░♀☼–○░▼–○░▀▐○▌☼– τ←ε– –φτε 28. Plant Taxonomy 240 29. Morphology of Flowering Plants 245 30. Anatomy of Flowering Plants 270 31. Animal Tissue 282 32. Integumentary System 298 33. Morphology and Anatomy of Animals (Frog, Cockroach, Rabbit, Earthworm) 303 ♂░▀♀– –↔–∟–▓▌○░♀–▓Ř♦☼▀▒▌▒◙♦– φτσ– –φ↓τ 34. Water Relations of Plants 321 R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES v ŕďőĽę– ĐĽŐńŐĹť 35. Mineral Nutrition in Plants 332 36. Photosynthesis 342 37. Respiration in Plants 352 ♂░▀♀– –↕–∟–Ř♂▐○░–▓Ř♦☼▀▒▌▒◙♦– φ↓φ– –←←φ 38. Nutrition & Digestive System 363 39. Breathing & Exchange of Gases 377 40. Locomotion and Movement 384 41. Body Fluids and Circulation 392 42. Excretory System 401 43. Nervous System 410 44. Sense Organs 419 45. Endocrine System 428 ♂░▀♀– –↨–∟–☻◄▓☻▒▼♂►♀▀▒░Θ–▼◄♠◄▌▒▓▐◄░♀–○░▼–◙☻▒♣♀Ř– ←←←– –←↕↨ 46. Reproduction in Flowering Plants 444 47. Plant Growth and Movement 455 48. Phytohormones 463 49. Human Reproduction 469 50. Embryonic Development 478 51. Growth, Repair, Regeneration, Ageing & Death 486 ♂░▀♀– –σε–∟–◙◄░◄♀▀►☼– ←↨ε– –↑τ↕ 52. Heredity and Variation 490 53. Genes & Chromosomes 498 54. Genetic Material & Protein Synthesis 509 55. Gene Expression & Regulation 518 56. Human Genetics and its Disorders 524 ♂░▀♀– –σσ∟–◄►▒▌▒◙♦–○░▼–◄░♠▀☻▒░▐◄░♀– ↑τ↨– ↑↔↓ 57. Organisms and Environment 529 58. Population, Biotic Community & Succession 536 59. Ecosystem 542 60. Natural Resources and Their Conservation 548 61. Biodiversity 557 62. Pollution & Global Environmental Changes 562 63. Wildlife and Conservation 570 ♂░▀♀– –στ–∟–○▓▓▌▀◄▼–▲▀▒▌▒◙♦– ↑↔↔– –↓↨↨ 64. Biotechnology and Genetic Engineering 577 65. Domestication of Plants and Crop Improvement 589 66. Plant Tissue Culture 599 67. Economic Botany 606 68. Plant Pathology 616 69. Pesticides and Biofertilizers 622 70. Mental health, Addiction and Community health 630 71. Immune System & Defence Mechanisms 635 72. Common Human Diseases 646 73. Biomedical Technologies 661 74. Domestication and Improvement of Animals 672 75. Animal Behaviour 687 76. Bioenergy 692 77. Growth of Human Population 695 R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES vi ŕďőĽę– ĐĽŐńŐĹť WHAT IS BIOLOGY Biology, the word comes from Greek bios meaning life and logos meaning thought or science of, can be defined as the study of various aspects of living beings (plants and animals). Biology is the study of life from the simplest forms of plants and animals (including one­celled animals and algae) to highly complex structures of the human being. It includes the study of how organisms are structured as well as how they function and relate to each other. Biology is also called life science as it makes to understand how living things perform their life activities and interacts with the other living and non­living things. Main branches of biology are botany, zoology and microbiology. Pure biology is concerned with gaining fundamental knowledge of the subject and studied only for better understanding of natural phenomenon. It has no direct practical application in human welfare, eg. taxonomy, physiology etc. Applied biology is related to well being of mankind and is directly beneficial economically. Some of the main branches of applied biology are agriculture, animal husbandary, sericulture, poultry, genetic engineering, breeding, biotechnology, bioinformatics etc. Table : Branches of biology Branch of Biology Definitions Agriculture The study of how best to grow and improve crops. Horticulture Development and management of orchards and gardens. Apiculture The rearing of bees especially for commercial purpose. Sericulture The breeding and treatment of silkworms for raw silk. Anthropology The study of physical and mental constitution of man with social conditions exhibited both in the present and the past. Entomology The study of insects. Medicine The study of structure and functioning of the human body and mind in sickness and health. Agronomy Branch of agricultural science which deals with the study of crops and soils. Soil Science Study of structure, types and dynamics of the soil. Breeding To produce or procreate improved varieties by selective mating. Veterinary Medicine Deals with the diseases of domesticated animals and their health care. Fishery Occupation or industry of catching fish or other products of the sea, lakes or rivers. Poultry Science Deals with study of domestic fowls such as chickens, ducks and geese. Forestry Science of developing, cultivation and conserving forests. Dairy Technology Application of science for the manufacture of milk products. Microbiology Science that deals with the structure, function, uses etc. of microscopic organisms. Pharmacy Science that deals with preparing and compounding medicines and dispensing them according to the medical prescriptions. Pharmacology Science that deals with the knowledge of drugs and preparation of medicines. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES vii ░ŕĚ–ŕďőĽę– ĐĽŐńŐĹť ·– ☼ĘŐőĚ– Őě– ▲ĽŐńŐĹť Forensic Science Application of scientific knowledge to questions of civil and criminal law (includes use of finger­prints, blood typing, identification of narcotics etc). Surgery Surgery involves physical operations to cure diseases or injuries to the body. Human Reproductive Biology Science of understanding and regulating reproduction. Nutrition Study of the nourishment of human beings or other organisms. Physiotherapy Science of treatment of diseases, bodily weaknesses or defects by physical remedies such as massage and exercise. Occupational Therapy A method of treatment of convalescents and the physically handicapped utilising light work for diversion, physical exercise or vocational training. Genetic Engineering Science that involves manipulations at gene level so as to produce an organism with a new combination of inherited properties. Biomedical Engineering Science for production of spare parts for man, implants, artificial limbs, heart lung machines etc. Food Technology Application of science for processing and preservation of foods. Silviculture Management of useful forest. Olericulture Cultivation of vegetables. Anatomy Internal structures of living organisms. Biochemistry Science connected with chemistry (composition, chemical nature, mode of formation, functioning) of living matter. Biogeography Distribution of organisms on various parts of earth. Cytology Structure and functions of cells and their organelles. Ecology Relationship between organisms and environment. Embryology Development stages of organisms up to hatching or birth. Endocrinology Endocrine glands and hormones. Evolution Origin of life and the gradual differentiation or descent of species. Eugenics Factors related to improvement of human race. Exobiology Life on other planets. Genetics Heredity and variations. Histology Tissues by microscopy. Immunology Resistance of organisms to infection. Limnobiology Fresh water lakes, ponds and streams. Morphology External shape of living organisms in contrast to function. Molecular biology Physio­chemical organization of biomolecules. Palaeontology Fossils and their distribution in time. Palaeozoology/Palaeobotany Fossil animals/fossil plants. Physiology Functions of various organs within the organisms. Psychology Behaviour and working of mind. Parasitology Parasitic organisms. Pathology Diseases and their control. Radiobiology Effects of radioactivity on life. Taxonomy Classification of organisms and their evolutionary relationship with other organisms. Teratology Malformation or birth defects. Zoogeography Distribution of animals over the earth. Zoopathology Diseases of animals. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES viii ŕďőĽę– ĐĽŐńŐĹť RELATIONSHIP OF BIOLOGY TO OTHER SCIENCE In order of study biology one has to understand and know other sciences like physics and chemistry as well. Because our present knowledge of biology has reached to such an extent that it has become a multidisciplinary branch of science involving participation of the fundamental knowledge of all the basic sciences. Structure/ Example Related Science Knowledge of other sciences is required Mechanism because Studied Cell membrane Structure of lipids, Chemistry Living organisms are made up of inorganic and and proteins organic compounds. Transportation of Formation of Chemistry All metabolic pathways involve chemical changes. O2 in body oxyhaemoglobin Excretory system Absorption and Chemistry Homeostasis involves acid­base equilibrium to elimination of salts maintain pH of living organism. Absorption of Absorption of sugars Chemistry During diffusion and osmosis molecules move food/water amino acids, fatty in and out of cells. acids, water or salts Transportation of Conduction of water Physics Liquids have certain properties like cohesion and water in plants from root to leaves adhesion that result in surface tension and capillary action which help in certain processes. Release of energy Electron transport Chemistry Energy transfer and transformation are important during respiration chain in all the living cells. Effect of light on Absorption of Physics Light induces definite pattern of responses in flowering different wave plants and animals. lengths of light Similarly other branches also have relationship with Biology in their particular characters like – l Geography – Required for studying the distribution of organisms. l Climatology – There is an intimate relationship between distribution and adaptations of organisms with the climate of the area. l Geology – Study of palaeobiology and soil types cannot be carried out without the knowledge of geology etc. UTILITY OF STUDY OF BIOLOGY The scope and application of biology is quite vast. Its study provides a necessary knowledge and perfect understanding about almost all the spheres of life, its requirements and the various ways by which they can be fulfilled. Study of biology is connected with the following objectives. l To help us to understand ourselves better. It explains the basic concepts like structure and functions of cells, organs and organ systems. It explains about heredity i.e., why do we resemble our parents and why are we different. It helps us to answer the basic questions about ourselves like what happens during sleep, when we eat food, when we get hurt, and how do we remember things etc. l To help us to meet our needs by utilising the sources available. The knowledge of medicine, surgery, crops rotation, animal husbandry help us to cure diseases and improve the quality of plants and animals. Meeting our basic requirements of food, clothing and shelter. l To acquaint us with the fundamentals of nutrition, health and population control. To have a scientific approach while solving problems. l To enlighten us about our place in the universe. It helps us to understand that man is only a small part of the living system and we have a responsibility to protect and respect other living things on earth. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES ix ░ŕĚ–ŕďőĽę– ĐĽŐńŐĹť– ·– ☼ĘŐőĚ– Őě– ▲ĽŐńŐĹť l To increase the awareness of the inter­relationships of organism with the environment. It makes us aware about the threat that lies before us if the natural resources are not taken care of. It helps us to identify measures to overcome them. l To warn us about health hazards due to indiscriminate use of pesticides, fertilizers, cutting of forests, depletion of the ozone layer, dumping of radioactive wastes in water, discharge of pollutants in air and water and wastage of our natural resources. l To help us overcome the superstitions and to remove the biases of sex, race and colour. l To enable us to enjoy nature and appreciate the rich, varied life of living things on earth. BIOLOGY : SCIENCE OF EXCEPTIONS Physical sciences are governed by a set of laws, such as the laws of gravity, magnetism, thermodynamics and so on. Biology, however, is a science which have many exceptions. This is due to the fact that it deals with living organisms which show enormous variations and are capable of change. Some of the common exceptions are given below. Ü DNA is the hereditary material in all living organisms except in some plant viruses such as Tobacco mosaic virus where RNA is the hereditary material. Ü RNA is usually single stranded but in Rheovirus it is double stranded. Ü DNA is normally double stranded except in some viruses in which it is single stranded. Ü Most roots grow towards the centre of gravity but in mangrove plants (Rhizophora) the roots are negatively geotropic. Ü Cuscuta (Amerbel) is classified as dicotyledonous plant but lacks cotyledons. Ü Normally the roots lack chlorophyll and are non­green but the assimilatory roots of Tinospora (Gilo) contain chlorophyll, are green and perform the function of photosynthesis. Ü The venation in monocot leaf is as a rule parallel but in Smilax (a monocot plant) the leaf show reticulate venation. Ü Stem is the part of plant above the ground but potato, corn and ginger are underground stems. Ü Most plants follow Calvin cycle during dark phase of photosynthesis but sugarcane follows Hatch Slack cycle. Ü All living cells have a nucleus except red blood cells (RBC) of mammals. Ü RBCs of mammals are without nucleus excepts those of camel. Ü Blood of all vertebrates is red due to the presence of a pigment­haemoglobin but in a shark (Carcharhinus) it is colourless. Ü The heart of all reptiles is three chambered but in crocodile it is four chambered. Ü Birds fly, but some birds like Kiwi and Ostrich are unable to do so. Ü Lungs, as a rule are absent in fishes, but some fishes the Protopterus possess lungs as well as gills. Ü Larval stage in the life history of an animal is not capable of sexual reproduction sexually before they change into adults. Ü All mammals give birth to young ones (viviparous) but some primitive mammals like Duck billed platypus and spiny ant earter (Echidna) lay eggs (oviparous). Ü All land inhabiting animals drink water but Kangaroo rat never drinks water. Ü Lacerta saxicola, a kind of lizard found in Caucasian region of Soviet Union has only females but no males. A student of biology must be prepared to accept exceptions. Some exceptions has been explained. In other cases the reasons for the exceptions are still no known. It is worth noting that the quantum of unexplained phenomena in biology is much larger than in any other natural science. SERENDIPITY Discoveries of important facts by chance unexpectedely, intuition and thoughts without making well planned conscious effect are called serendipity. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES x ŕďőĽę– ĐĽŐńŐĹť Some of the examples of serendipity are – Ü Discovery of antibiotic – Penicillin : Alexander Fleming (1881­1955) was culturing the bacterium – Staphylococcus (the causal organism infection) in Petri dishes on agar medium. He found that one of his culture plate was contaminated by blue­green mould – Penicillium notatum. Such a contamination in laboratories was not new. Normally such contaminated cultures are discarded but Fleming retained it and observed minutely. To his surprise, he noticed that fungal growth inhibited in those areas where fungus was growing. By flash idea Fleming poured the extract of fungus over fresh bacterial cultures and found that even the extract inhibited the bacterial growth. This curious observation led the discovery of the most important antibiotic – Penicillin. Ü Law of Gravitation : Newton was simply sitting in the garden when an apple fell on the ground. He started thinking about the cause of its fall and came to a conclusion that some force is present in the earth which attracts everything towards it. This observation led the formation of Newton’s law of gravitation. Ü Structure of Benzene ring : Chance observation of snake licking its tail led the discovery of ring – structure of benzene by Kekule. Ü Archimede’s Principle : While taking bath he came to the conclusion that a body which is immersed partially or completely in a liquid, experiences an up thrust equal to the weight of the liquid displaced by it. This led to the discovery of principle of floatation by Archimedes. Table : Fathers of Biology Antibiotics Alexander Fleming (1881­ Histology Xavier Bichat (1771­1802) 1955) Homeopathy Hahnemann (1755­1843) Ayurveda Charaka Immunology Edward Jenner Bacteriology Antony Van Leeuwenhoek Indian palaeobotany Birbal Sahni (1891­1949) (1632­1723) Medicine Hippocrates (460­377 BC) Biochemical genetics Archibald Garrod Microbiology Antony Van Leeuwenhoek Biochemistry Justus vol Liebig (1803­73) Microbiology Louis Pasteur (1822­1895) Biology Aristotle (384­322 BC) Microscopic Anatomy Marcello Malpighi (1628­ Blood circulation William Harvey (1578­1657) 1694) Blood groups Karl Landsteiner Microscopy Antony Van Leeuwenhoek Botany Theophrastus (372­287 BC) Modern embryology Von Baer (1792­1876) Chromatography Micheal Tswett Modern genetics William Bateson (1861­ Comparative anatomy Georges Cuvier (1769­1832) 1926) Cytology Robert Hooke (1635­1703) Modern palaeontology Georges Cuvier (1769­1832) ECG Einthoven Palaeontology Leonardo da Vinci Ecology Theophrastus (370­285 BC) Parasitology Platter Embryology Aristotle Protozoology Antony Van Leeuwenhoek Endocrinology Thomas Addison (1793­1860) Science Aristotle Eugenics Francis Galton Surgery Susruta Experimental genetics Thomas Hunt Morgan (1866­ Taxonomy Carolus Linnaeus (1707­ 1945) 1778) Gene Therapy Anderson Tissue culture Harrison Genetic engineering Paul Berg Virology Wendell M. Stanley Genetics Gregor Johann Mendel Zoology Aristotle (1822­1884) nn R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 1 ☼ťřŚĚŇĘř– Chapter 1 Systematics l Systematics is the study of the historical group of organisms in category according to a relationships of groups of biological organisms particular system and in conformity with a – the recog nition an d un d erstan ding of nomenclature system. biodiversity. l Aristotle (father of zoology) made the first l The term systematics was coined by Linnaeus recorded attempt to classify the animals in his book (1735). Historia Animalium. l The terms systematics, taxonomy and classification l Aristotle made two main groups ­ anaima (animals are often held as synonyms but technically they with no RBC, invertebrates) and enaima (animals carry different meanings. with RBC, vertebrates). l G. Simpson (1961) has distinguished the three l Theophrastus (372 ­ 287 BC), referred to as father terms. of botany, classified plants on the basis of form l Taxonomy is the branch of study which deals with and texture and described 480 plants in his book identification, nomenclature and classification of Historia Planatarum. organisms. l Identification is to determine the exact place or l Term taxonomy was first given by French botanist position of an organism in the set plan of A.P. de Candolle (1778­1841) for the theory of classification. Identification is carried out with plant classification. the help of taxonomic keys. l Taxonomy is also called systematic botany. l A key provides a convenient way for easy l Carolus Linnaeus is called father of taxonomy. identification of an organism by applying l H. Santapau is called the father of Indian diagnostic or distinguishing characters. taxonomy. l Taxonomy discovers and describes new species, l Taxonomy is of three types – alpha (a) taxonomy, w hile s ys tematics use s ev olutionar y beta (b) taxonomy and omega (w) taxonomy. relationships to understand biogeography, l When only morphological characters are used for coevolution, adaptation and options for biological identification and classification of plants then it is conservation. called alpha taxonomy. l Systematists or taxonomists are thus the scientists l b­taxonomy involves genetical, anatomical whose expertise provides the data about the cytological, palynological, physiological and identification, description, distribution and other characters. relationship of life on Earth. l b­taxonomy is also called biosystematics. l New systematics or biosystematics is concept of l a and b taxonomy terms were given by Turill. systematics which brings about taxonomic affinity l Analysis and synthesis of all information and types on the basis of evolutionary genetic and of data to develop classification system based on morphological traits. phylogenetic relationships is called omega taxonomy. l Julian Huxley (1940) proposed the term new l Classification is the placing of an organism or a systematics. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 2 ŕďőĽę– ĐĽŐńŐĹť Table : Types of taxonomy l Trinomial nomenclature is a taxonomic naming Cytotaxonomy based on cytological study system that extends the standard system of binomial nomenclature by adding a third taxon. It is used in Karyotaxonomy based on nucleus and biology when the organisms within a species fall chromosomes into separate groupings that need to be distinguished. Morphotaxonomy based on morphological l Trinomial nomenclature is different for animals characters and plants. Biochemical based on biochemical studies l In animals trinomen or trinominal name refers to taxonomy the name of a subspecies. Chemotaxonomy based on specific chemicals l Trinomen is a name consisting of three names – like secondary metabolites generic name, specific name and subspecies name. All three names are typeset in italics and Numerical based on statistical methods only the generic name is capitalised. Eg. Buteo taxonomy (also jamaicensis borealis is one of the subspecies of the called adansonian red tailed hawk (Buteo jamaicensis). taxonomy) l For plants trinomial nomenclature provides three Experimental based on experimental part name (ternary name) for any taxon below the taxonomy determination of genetical inter rank of species. ­relationships and role of l Binomial nomenclature is a system of providing environment in their formation distinct proper scientific names to organisms with each name consisting of two words, generic and Nomenclature specific. l Nomenclature is giving distinct scientific names l Binomial nomenclature was developed by Linnaeus to various structures including living organisms, (a swedish biologist) who gave certain principles for their identification. (called Linnaean principles) for this in his book l Biological nomenclature is of two types ­ Philosophica Botanica (1751). The standard vernacular and scientific. references recognised for this are Species Planatarum l Common names by which plants and animals are (1733) and Systema Naturae (1758). known in their regional places are called vernacular l According to binomial system, each organism is names. given a name made of two Latin words. l The vernacular name or common names are based l For nomenclature the Latin language is used on some peculiarity of the organisms, eg. Kandiali because it is the dead language and no changes (a plant having spines). are supposed to occur in it. l Scientific name are names given to organisms based l Binomial system of nomenclature was introduced on agreed principles and criteria for their by Gaspard Caspar Bauhin (1956). But he did acceptability all over the world. not follow it scrupulously. l Scientific names are distinct and specific, they have l Binomial names are of universal application for particular spellings which are not changed. all the countries and languages. l Three types of nomenclature are – polynomial, l The names indicate relationship of a species with trinomial and binomial nomenclature. others present in the same genus. l Polynomial nomenclature was the first scientific l In binomial nomenclature following rules are attempt at nomenclature, in which an organism applicable. is given a name consisting number of words that – Name consist of two words – first word incorporate all its important characteristics. Eg. represents the genus and is called generic Caryophyllum saxatilis folis gramneus umbellatis name (generic epithet), whereas the second corymbis which means caryophyllum growing on word represents the species called the specific rocks, having grass like leaves and umbellate name (specific epithet). corymb flowers. – The generic epithet always starts with capital R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 3 ☼ťřŚĚŇĘř letters & specific epithet starts with small l A specimen or other element selected from the letter. original material cited by the author when no – Both these name must be underlined separately holotype was originally selected or when it no (if handwritten) or italised (if printed). longer exists is called lectotype. – No comma, hyphen etc. between specific and l A lectotype is selected from isotypes, paratypes generic name is used. or syntypes. – To the two word, name is appended the name l A specimen or illustration selected to serve as of taxonomist who discovered the organism nomenclatural types as long as all of the material and provided with a scientific name, e.g., Ficus on which the name of the taxon was based is missing bengalensis L, Homo sapiens L. is called neotype. – The different names given to same species by l Epitype is a specimen or illustration selected to different workers are called synonyms, but serve as an interpretative type when the holotype, the name given first is considered to be valid. lectotype or previously designated neotype, or all l The foundations of International Code of original material associated with a validly published Botanical Nomenclature (ICBN) was found in name is demonstrably ambiguous and cannot be Philosophia Botanica, a book written by C. critically identified for purposes of the precise Linnaeus. Current code of botanical nomenclature application of the name of a taxon. appeared in 1978. l Topotype is often the name given to a specimen l Botanical nomenclature is independent of collected from the same locality from which the zoological and bacteriological nomenclature holotype was originally collected. which are governed by their own code. l When many names are given to the same species, Some important abbreviation then the name under which the species was first ICBN – International code of botanical described is valid, provided the publication is nomenclature effective and valid. ICZN – International code of zoological Taxonomic hierarchy or Linnaean hierarchy nomenclature l Taxonomic hierarchy is the sequence of ICBacN – International code of bacteriological arrangements of taxonomic categories in a nomenclature ICVN – International code of viral descending order during the classification of an nomenclature organism. ICNCP – International code of nomenclature l The word taxa represents taxonomic groups of any for cultivation plants rank i.e. any unit of classification. l In Linnaean hierarchy, the number of taxa is five, Types of specification namely – class, order, genus, species and variety. l The particular illustration designed by author of l The rank of species is basic and relative order of the species to represent the type of species is called the rank of taxa are species, genus, tribe, family, holotype. order, series, class, division (= phylum) and l A specimen which is a duplicate of the holotype, kingdom. collected from the same place, same time and by l These categories/rank are ranked one over the other the same person is called isotype. called ‘hierarchy’. l Any one of the two or more specimens cited by the l Kingdom is the highest and species is the lowest author when no holotype was designated, or any category in this hierarchy. one of the two or more specimens simultaneously l Species is the basic unit of taxonomy. designated as types is called syntype. l John Ray introduced the term animal species. l A paratype is a specimen cited in the protologue l Species inhabiting the same geographical area that is neither the holotype nor an isotype, nor one (identical or overlapping) are sympatric. of the syntypes if two or more specimens were l Species inhabiting different geographical areas are simultaneously designated as types. allopatric. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 4 ŕďőĽę– ĐĽŐńŐĹť– l Related species which are reproductively isolated l Microbiologists and botanists (Eichler) use the term but morphologically similar are called sibling species. ‘division’ instead of ‘phylum’. l A species restricted to a given area is called endemic l All kingdoms have more than one phylum. species. l The kingdom plantae contains several divisions l Classical systematics is based on the ‘typological (=phyla), including flowering plants, conifer trees, concept’ by Plato and Aristotle. mosses, ferns and several other groups. l The traditional concept of species was given by l Taxonomic hierarchy is useful in that it provides Linnaeus in Systema Naturae; this is based on information about relationships of an organism morphology, and is also known as ‘morphological with others quick identification of a taxon, all concept’. major traits and nonrepetition of correlated traits l Genetic species concept was given by Lotsy of various categories. (1918), according to which, a species is a group l According to ICBN different ranks or categories of genetically identical individuals. have following specific ‘endings’ (Refer table given l Species that contain two or more subspecies are below). called polytypic species. l Species that are not subdivided into subspecies are Ranks Plants Algae Fungi Animal called monotypic species. Division/ ­ phyta ­ mycota l Modern concept of species is biological species Phylum concept introduced by Ernst Mayr (1942). Subdivision/ ­ phytina ­ mycotina l Mayr defined species as groups of interbreeding subphylum natural populations that are reproductively isolated Class ­ opsida ­ phyceae ­ mycetes from each other group. Subclass ­ idae ­ phycidae ­ mycetidae l Genus is an assembly of related species which Superorder ­ anae evolved from a common ancestor and have certain common characters called correlated characters, Order ­ ales e.g., Solanum tuberosum and Solanum melongena Suborder ­ ineae are two species which belong to same genus of Infraorder ­ aria Solanum. Superfamily ­ acea ­ oidea l A family subdivision of an order consists of a group Family ­ aceae ­ idae of closely related genera, which in turn are composed of groups of closely related species. Subfamily ­ ordeae ­ inae l The taxon commonly encountered in routine Tribe ­ eae ­ ini taxonomic work is the family. Subtribe ­ inae ­ ina l Family with a single genus is called monogeneric family. Table : Taxonomic status of human & pea l An order is a category within a class. Carnivora Rank Human Pea is an order of flesh­eating animals within the class Domain Eukarya Eukarya mammalia and there are several other orders of Kingdom Animalia Plantae mammals like cattle, rodents, bats, seals, Phylum or Division Chordata Magnoliophyta Subphylum or Vertebrata Magnoliophytina whales, etc. Subdivision l A class is a subdivision within a phylum made of Class Mammalia Magnoliopsida one or more related orders, for e.g., within the Subclass Placentalia Magnoliidae phylum chordata there are five classes: mammals, Order Primates Fabales birds, reptiles, amphibians and fishes. Suborder Haplorrhini Fabineae l Georges Leopold Cuvier (1769­1832), the French Family Hominidae Fabaceae naturalist, added the ‘phylum’ in taxonomy. Subfamily Homininae Faboideae l In taxonomy, the correct sequence is: class ­ Genus Homo Pisum order ­ family ­ tribe ­ genus ­ species. Species H. sapiens P. sativum R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 5 ☼ťřŚĚŇĘř System of biological classification l In this system, flowering plants are placed in l There are four different systems of classification, ascending series related to complexity of floral mainly used by taxonomists. They are (i) artificial, morphology. (ii) natural, (iii) phylogenetic, and (iv) phenetic. l This classification was also adopted by the English l A classification based on one or a few superficial botanist John Hutchinson (1884–1972) in two similarities is called an artificial system of volumes of his book “Families of Flowering classification. Plants”. l Artificial system of classification was adopted by l “Taxonomy without phylogeny is similar to bones Pliny the Elder (first century AD) for animals on without flesh” is the statement of A.L. Takhtajan the basis of habitats, e.g., land, air and water. (1967) who wrote the book “A system of l The plants are classified on the basis of habit into phylogeny of flowering plants”. (i) herbs, (ii) undershrubs, (iii) shrubs, (iv) trees in l According to zoologists, the natural system of an artificial classification. classification includes the phylogenetic and l The Linnaean system of classification of plants on evolutionary trends. the basis of number and arrangement of stamens l A modern method of classification called cladistics is artificial. Linnaeus used number, union, length is based on evolutionary history. and certain other characters of stamens as the basis l The phylogenetic tree is also known as genealogical of classification of plants in his book ‘Genera tree or dendrogram. Planatarum’ (1737). l Phenetic taxonomy (classification) is based on l In natural systems of classification organisms are the overall similarity of organisms evaluated arranged according to their natural affinities through without regard to phylogeny. the use of all important permanent characteristics, l Phenetic classification is based on observable especially structural, cytological (chromosomal) characteristics of existing organisms. reproductive and biochemical. l Phenetic classification did not have a strong l The first natural system of plant classification impact on animal classification and scientific was proposed by Schimper (1879) followed by interest in this aproach is on the decline. Eichler (1833). Table : Historical accounts l The most important and last of natural systems A.P. de Candolle (1813) – Term Taxonomy for classification of seed plants was developed E.H. Haeckel (1866) – Three Kingdom by Bentham (1800–1884) and Hooker (1817– Classification 1911) in the treatise called Genera Planatarum Copeland (1956) – Four Kingdom (1862–1883). Classification l The first natural system of animal classification Whittaker (1969) – Five Kingdom Classification was developed by Linnaeus in his book “Systema John Ray (1627­1705) – Termed species Naturae”. Improvements were subsequently made Carolus Linnaeus (1753) – Binomial System of by Haeckel (1864) and Lankester (1874). Classification l The classification based on evolutionary sequence Adolf Meyer (1926) – Used taxon term w.r.t. and the genetic relationships among the animal kingdom organisms is termed phylogenetic system. H.J. Lam (1948) – Used term taxon in l Darwin’s book “On the Origin of Species by plant kingdom Means of Natural Selection” (1859) provided Haeckel – Concept of support to taxonomy. phylogeny l The phylogenetic classification of the plant Turill (1938) – Alpha taxonomy kingdom was proposed by Adolf Engler (1844– Julian Huxley (1940) – Termed New systematics 1930) and his associate Karl Prantl (1849–1893) Cuvier – Coined term phylum in their book Die Natürlichen Pflanzen Familien. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 6 ŕďőĽę– ĐĽŐńŐĹť– System of classification Two Kingdom Three Kingdom Four Kingdom Five Kingdom [Proposed by [Proposed by [Proposed by Plant Kingdom Haeckel, (1866)] R.H. Whittaker, (1969)] * Copeland, (1956)] Animal Kingdom Used three criteria Plant Protista – Complexity of cell structure *(Not approved as fungi and (for unicellular organisms) Animal – Complexity of body structure organisms like Euglena, Monera (all plants) Chlamydomonas etc. were – Mode of nutrition Protista not justified in these two Plant (all plants) (for unicellular kingdoms). Divided into organisms) Animal (all animals) Monera Protista Plantae (non­mobile and Animalia (all prokaryotic (unicellular (eukaryotic, photosynthetic organisms) (Metazoa) organism) eukaryotes) heterotrophic Algae Archaebacteria Photosynthetic organisms) Bryophyte Eubacteria Consumer Pteridophyte Gymnosperms Protozoa Angiosperms l Organisms are classified according to two, three, Botanical Garden, Moscow covering an area of four, five and six kingdom system (Ref er 900 acres. flowchart). l The Royal Botanical Garden, Kew England covers l The major criteria used for delimitation of an area of 300 acres. kingdoms are ­ modes of nutrition, presence or l Indian Botanical garden, Sibpur, Kolkata, is the absence of locomotion, complexity of largest botanical garden in India. organisation, and cell structure. l The collection of plants and animals are preserved and kept in museums for study and reference. l Viruses do not fit neatly into any classification of l Zoological parks are zoos which help to study living organisms because they have a very simple wild animals and their food habits. noncellular structure and cannot exist independently l Camerarius was the person who first recognised of other organisms. sexuality in plants. l Herbarium is a collection of plant parts that usually l If the generic and specific names are same it is have been dried, pressed, preserved on sheets. called tautonym. But tautonyms have been rejected l Largest herbarium of the world is at Kew. by modern scientists. l Botanical gardens are the collections of living l Angiosperms are the most advanced type of plants maintained for reference. plants. l The largest botanical garden is the Main l Angiosperms contain seeds enclosed in fruits. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 7 ♠ĽŕśřĚř– Chapter 2 Viruses l The term ‘Virus’ has been derived from Latin, l A complete virus particle is called virion whose which means poison or venom or viscous fluid. main function is to deliver its DNA or RNA genome l Viruses are defined as infectious nucleoproteins. into the host cell. So that genome can expressed l Virus are obligate intracellular parasite which can (transcribed and translated) by the host cells. reproduce only by invading and taking over other Characteristic features cells as they lack the cellular machinery for self l These are submicroscopic organisms generally less reproduction. than 200 mm. Important inventions Ø Viruses were discovered after Chamberland developed bacterial filters (1884). Ø Meyer (1886) describe tobacco mosaic disease but he couldn’t isolate the causal organism. Further, he said that the disease is transmissible and infectious. Ø Russian botanist D. Ivanowski (1892), discovered the causal organisms of tobacco mosaic disease and this causal organisms could pass through the filters which retained bacteria. Ø Beijerinck (1898) confirmed the earliest studies and named these organisms as “Contagium vivum fluidum”, living infectious fluid. Ø F.W.T’wort. (1915) and F.H.d’Herelle (1917) discovered certain viruses which infect bacteria or bacteria eaters i.e., bacteriophages or phages. Ø Stanley (1935) crystallized tobacco mosaic virus and said that these crystals retain their infectivity for a long time if kept in bottles. Ø Bawden and Pirie (1936) first of all studied the chemical nature of viruses and said that these are nucleoproteins. Ø Edward Jenner (1796) discovered vaccination against small pox Ø Louis Pasteur (1880) discovered vaccination against rabies Ø Loeffler and Frosch (1898) discovered first animal pathogenic virus (Foot and mouth virus of cattle). Ø S. Luria, M. Delbruck and Lwoff (1942 ­ 48) discovered mechanism of replication in bacteriophages. Ø A. Harshey and M. Chase (1952) said that nucleic acids are infective and proteins are non­infective parts of a bacteriophages. Ø T. O. Diener (1971) discovered some new infectious agents, which are still smaller than viruses. Ø Stanley B. Prusiner discovered certain infectious agents or slow viruses which contain only proteins. Prusiner got Nobel prize for this work in 1997. Ø Alliac Issacs and Lindeman (1957) gave the term interferons to the chemical substances responsible for viral interference. Ø Mycophages, viruses infecting fungi, were discovered by Sinden (1957) in Agaricus bisporus. These are having double stranded RNA and are spherical or polygonal in shape. Ø A. Salk (1957) invented vaccination against Polio Ø Lu Montagnier et. al. (1893); R. Gallo et. al. (1984) discovered AIDS virus for HIV. Ø Safferman and Morris (1963) discovered cyanophages (viruses infecting cyanobacteria like Lynggya). R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 8 ŕďőĽę– ĐĽŐńŐĹť– l Shape of virus is variable, eg., brick shaped l Capsid is the protein coat that surrounds the central (influenza virus), rod shaped (TMV), tadpole like protein of nucleoid and enzymes (if present). The (bacteriophages). capsid consists of a specific number and l They are obligate parasites i.e., can live inside arrangement of small sub­units called capsomeres. living host only. l The nucleic acid present in the virus is called l They have either RNA or DNA. nucleoid. It is the infective part of virus which l They can pass through bacterial filters. utilizes the metabolic machinery of the host cell l They have characteristic mode of multiplication, for synthesis and assembly of viral components. i.e., once a virus enters into the host cell, it takes l Nucleoid represents the viral chromosomes. control of whole biochemical machinery of host l The genetic material of viruses are of 4 types – cell and orders the metabolic machinery to double stranded DNA (ds DNA), single stranded synthesize their own (viral) components. DNA (ssDNA), double stranded RNA (dsRNA) l Non living characters of viruses are – and single stranded RNA (ssRNA). – No protoplasm l Double stranded or dsDNA are – adenovirus, – No enzyme system herpes simplex virus, pox virus, cauliflower – No respiration mosaic, coliphage lambda T4 (linear), hepatitis B, – They can be crystallized simian virus SV – 40, polyoma (circular or cyclic). – Do not grow in culture medium. l Single stranded or ssDNA are – coliphage MS 2, l Living characters of viruses are – coliphage fd (linear), coliphage f × 174 (cyclic). – They contain nucleic acid as a result of which l Single stranded or ssRNA are poliomyelitis virus, they are capable of synthesizing proteins. foot and mouth disease virus, influenza virus, rous – They can multiply inside living host cell. sarcoma virus, retroviruses, turnip yellow mosaic – They causes diseases. viruses, tobacco necrosis virus, TMV, potato l On the basis of above characters it can be said that mosaic virus, bean mosaic virus (all linear). viruses form a transitional group between living l ssRNA is of two types – negative stranded (RNA and non­living. – RNA viruses) and positive stranded (RNA – l Viruses are divided into two main groups on the DNA viruses or retroviruses). basis of the type of nucleic acid present in them. l Double stranded or dsRNA are reo­virus, wound – Deoxyvira (having DNA). tumour virus (all linear). – Ribovira (having RNA). l Only few viruses contain certain enzymes. For eg., l Deoxyvira are further divided into three classes – lysozyme in bacteriophages, reverse transcriptase deoxyhelica (helical), deoxycubica (cuboidal) and in retroviruses. deoxybinala (binal). l Symmetry of viruses may be – l Ribovira is divided into two classes ­ ribohelica – Helical symmetry : Capsomeres are (helical) and ribocubica (cuboidal). arranged in helical l F. O. Holmes (1948) divided order ­ Virales into manner in the capsid, three sub­orders – e.g., TMV. – Phytophaginae – Viruses, infecting plants – Cubical symmetry : Capsomeres are – Zoophaginae – Viruses, infecting animals arranged on the surface – Phaginae – Viruses infecting bacteria to form a 20 side cube, l Structurally viruses are made up of envelope, capsid, e.g., turnip mosaic virus. nucleoid and occasionally one or two enzymes. – Biosymmetrical or : Bacteriophages l Some viruses possesses an outer thin loose covering mixed symmetry called envelope. It is composed of proteins (from TMV (Tobacco Mosaic Virus) virus), lipids and carbohydrates (both from host). l TMV is the most thoroughly studied virus and was It has subunits called peplomeres. discovered by the Russian worker D. Ivanowski l The viruses, which do not possess envelope, are (1892). called naked. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 9 ♠ĽŕśřĚř– l It is a rod shaped virus measuring 300 × 18 nm and followed by synthesis of capsid protein, have helical symmetry. polyamines and lysozymes. l Have single stranded DNA which is 330 nm in l The components assemble and form phage particles length and having 7300 nucleotides. or viruses. l Number of capsomeres in capsid is 2130. l The host cell ruptures to release viruses (lysis). l 5% RNA and 95% protein is present in TMV. Lysogenic cycle (l phage) Bacteriophages l The multiplication process of temperate phage is l Viruses infecting bacteria are known as called lysogenic cycle. bacteriophages or phages. Sea water can hold 100 l The phenomenon of existence of non­virulent million bacteriophages per µl. prophage in the host cell is called lysogeny. l Bacteriophages may be virulent or avirulent. l The host cell in which lysogeny occurs is called l Prophages or non­virulent phages or non­ lysogenic cell. infective phages are the phages which do not cause l Lysogen is a strain of bacteria carrying prophage. lysis of bacteria soon after their formation inside. l Lysogenic cycle is shown by 1 (lambda) phage Such bacterial cells which are having prophages which also infects E.coli bacterium. inside them are called lysogenic bacteria. l Lytic bacteriophage multiply in host bacterium l Virulent phages or infective phages are the phages which then undergoes complete lysis (degeneration) which cause lysis of bacterial cell at once. to release the resulting daughter phages. l Most studied series of bacteriophages is T­series l The phage attaches to the surface of bacteria by (T2, T4, T6 etc.). means of tail, which produces a hole in host cell l T­even phages are characterized by angular head wall and injects the phage DNA. and contractile tail. l Phage DNA produces a repressor, (C1) becomes l Bacteriophages have tadpole like structure, i.e., with nonvirulent or temperate and gets integrated to head and tail. Inside the head is present nucleic bacterial chromosome at a specific site by means acid, generally DNA. of enzyme integrase. l Head is prism like hexagonal having length 950Å l The viral genome is now called prophage/provirus. and breadth 650Å, tail is also 950Å in length, joined l It multiplies alongwith bacterial genome and is to head by neck and collar, tail is having hollow passed on to the progeny. core of 80Å and is surrounded by tail sheath. l Occassionally the synthesis of repressor is stopped l At the end of tail, end plate is present to which 6 due to ultra violet radiations or chemical factors. tail fibres are attached and each is 1500Å in length. l The temperate/non­virulent phage is now changed to lytic/virulent phage. Lytic cycle (T4 bacteriophage) l The single strand DNA of f × 174 or coliphage fd l The multiplication process of virulent phage is is known as plus strand. It forms its complementary called lytic cycle. or negative strand. The double strand or replicative l The main steps include adsorption, penetration, DNA takes over the metabolic machinery of host formation of new phages and lysis. to synthesize plus strands DNAs and protein for l Bacteriophage attaches to the surface of assembly of new phages. bacterium by its tail fibres. l Lysozymes creates a hole in the host cell wall. Pinocytic reproduction l The tail sheath contracts and ejects the viral l The whole virus enters the host cell except the chromosome/DNA into the bacterium. envelope. It is quite common in RNA viruses l Viral DNA controls the metabolic machinery of which are of two types as RNA­RNA virus and the host cell. It produces nucleases. RNA­DNA virus. l Nucleases degrade DNA and mRNAs of the host. l In RNA­RNA viruses DNA has no role in their l Viral DNA is not affected as its cytosine bases are multiplication. After entering the host cell the methylated. viruses produce enzyme replicase which helps l A number of copies of viral DNA are produced in producing more genetic RNA over the template R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 10 ŕďőĽę– ĐĽŐńŐĹť of parent RNA genome. The latter also produces – Bunchy top of banana mRNAs for synthesis of viral proteins. – Tungro disease of rice l RNA­DNA viruses are also called retroviruses – Tomato leaf curl (Temin, 1970), e.g., Tumor/Cancer viruses, HIV. l Human diseases caused by viruses are – The virus es p os sess enzyme rev e rs e Chicken pox : Varicella virus transcriptase (Temin and Baltimore, 1972; in Small pox : Variola virus Rous Sarcoma Virus or RSV of Mouse). The Measles : Rubeola virus enzyme builds DNA over RNA genome. The Rabies : ssRNA (Rabies virus ­ phenomenon is called reverse transcription or Lassa virus) teminism. AIDS : ARV (Aids associated l The copy DNA (cDNA) builds its complementary retrovirus) strand. The double strand copy DNA attaches to Yellow fever : Transmitted by Aedes host DNA/chromosome and is now called aegypti mosquito provirus. Dengue fever : Transmitted by Aedes l Application of bacteriophages are – aegypti mosquito – Studying viral infection mechanism. Polio : Transmitted through food, – Control of certain bacterial diseases. water, contact – Purity of Holy Ganges is due to presence of Hepatitis­B : Transmitted through contact bacteriophages. and body fluid. Viroids are sub­viral infectious agents, which l Transmission of viruses occurs by – contains only very low molecular weight RNA and – Polluted air, water and food stuffs help the not protein coat. Viroids cause potato spindle tuber dissemination of viruses in man and animals. disease (PSTV), citrus exocortis etc. The only – Fly and mosquitoes usually act as carriers. human disease known to be caused by a viroids is – Such virus transmitting agents are called vectors. hepatitis D. – Most of the virus diseases of plants are Interferons are protein molecules which prevent transmitted through insects. viral multiplication. These are produced by cells in – Sap sucking insects like aphids and white flys mammals, rodents, birds, etc. and provide resistance are the important ones among such vectors. against viruses. – Virus diseases are also transmitted through stem cuttings, seeds, tubers, agricultural Diseases caused by viruses implements etc. l Virus causes diseases in plants, animals and human l Disease can be controlled by – brings. – Removal of diseased plants and plants parts. l Plant diseases caused by viruses are – – Using disinfested seed. – Tobacco mosaic disease – Testing the germplasm and selecting virus free – Leaf curl of papaya seed. – Yellow vein mosaic of bhindi – Destruction of alternative hosts. – Potato leaf roll – Destruction of insect vectors. – Vein bandings mosaic disease of potato – Practising crop rotation. – Grassy shoot of sugar cane – Growing disease resistant varieties. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 11 █ĽňĹęŐŇ– ▐ŐňĚŕď– Chapter 3 Kingdom Monera l Monera are the group of all prokaryotes. l Ribosomes are 70S type (subunit 30S and 50S). l They are basically unicellular, may be mycelial, l Reproduction is by binary fission or budding. colonial and filamentous. l They have a various modes of nutrition like l Cell wall is made up of peptidoglycan, saprobic, parasitic, chemoautotrophic, polysaccharides and cellulose. photoautotrophic, symbiotic. l They do not contain any organised nucleus with l Some are capable of nitrogen fixation. distinct membrane. l Monera occur in all environment, eg archaebacteria l DNA is naked, i.e., not associated with histone live in extreme climates. proteins. It is called nucleoid. l The kingdom includes all prokaryotes like bacteria, l All the membrane bound cell organelles are absentlike actinomycetes, mycoplasma and cyanobacteria. mitochondria, lysosomes, golgi bodies, plastids etc. l In photoautotrophic forms thylakoids are present ­ BACTERIA without chloroplasts. l Bacteria are the smallest of free living organism, l Spindle apparatus do not develop at the time of cell mostly unicellular. division. l Bacteria possess various forms and shapes, and are l Single stranded flagella, composed of flagellin, is of 4 different types – coccus, bacillus, vibrio, present. and spirullum. Bacteria based on shape Coccus Bacillus Vibrio Spirullum (round) (rod shaped) (comma shaped, (spiral like cork­screw, e.g., Vibrio cholerae) e.g., Spirochaete) Diplobacillus (In groups of two) Palisade bacillus (Like a stack) Streptobacillus (In chains) Micro Diplo Tetracoccus Streptococcus Staphylococcus Sarcinae (Occurs singly) (Groups of two) (In groups of four) (Forms a chain) (Bunch of grapes) (Cubes of 8, 64 or more) Bacteria based on flagellation Atrichous Monotrichous Lophotrichous Amphitrichous Peritrichous flagella absent single flagella groups of flagella single flagella flagella present all e.g., Lactobacillus at one end, e.g., at one end, e.g., at each end, e.g., over the body, Vibrio cholerae Spirullum Nitrosomonas e.g., E. coli Flow chart : Classification of bacteria R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 12 ŕďőĽę– ĐĽŐńŐĹť– l Bacteria possess a distinct cell wall, with different Table : Difference in the cell walls of gram +ve & wall layers like capsule or slime layer, plasma gram –ve bacteria membranes, flagella and pilli. Gram +ve bacteria Gram –ve bacteria l Slime layer or capsule is made up of 1. Cell wall more thick, Cell wall thin.Thickness polysaccharides and amino acids and acts as thickness varies from varies 10­15 nm. osmotic barrier. 25­30 nm. l Cell wall is made up of polysaccharides, proteins 2. Cell wall is a Three layered. and lipids and peptidoglycan or murein. homogenous layer. l Plasma membrane is tripartite in nature. l Mesosomes are simple infolding of plasma 3. High content of Less content of membrane containing respiratory enzymes, like peptidoglycan (20­80% peptidoglycan (10­20% of of the dry weight of the the dry weight of the cell). oxidases and dehydrogenase. cell). l Flagella is made up of flagellin. l Pili are small hair like outgrowth present on 4. Teichoic acids may be Teichoic acids absent. bacterial cell surface made up of pilin protein. present. l Pilin helps in formation of conjugation tube and 5. Very little lipid content High lipid content (10­ agglutination. (0­2%). 20%). l Based on the nature of staining, bacteria may be 6. Only a few aminoacids Large variety of Gram + ve (retains the blue stain) or Gram –ve are associated with the aminoacids are associated. (does not retain the stain). muramic acid complex. Gram staining 7. Lipopolysa ccha ride Present. layer (LPS) absent. Heat fixed smear of bacteria 8. Periplasmic space is Present. Crystal violet absent. Rinse with water l The plasmid are small, circular, double­ Add dilute iodine solution stranded DNA molecules that are separate from ma in b acteria l chromosome and rep lica te All bacterial cell appears deep blue independently. l The term plasmid was given by Lederberg (1952). Treat with 95% alcohol l Plasmids have an independent existence. l Plasmids carry genes for fertility, antibiotic Cells retain purple Destained and appear resistance (R­factor) and bacterium (Colicin) colour red in colour production (colicinogenic factor). Gram +ve bacteria Gram –ve bacteria l F­factor or fertility factor is responsible for l Inner to the wall layers, there is present matrix or transfer of genetic material. protoplasm which includes nucleoid, plasma, l R­factor or resistance factor provides resistance episomes, ribosomes, and granules. against drugs. l In the centre of the bacterial cell, there is present l Colicinogenic factor produces ‘colicines’ which nuclear material (DNA) without any nuclear kill other bacteria (other than which produces these membrane (naked). DNA in bacteria is double colicines). helical and circular. l The term episome is applied to extranuclear genetic l This incipient nucleus or primitive nucleus is named material which may remain in integrated or free as nucleoid or genophore (sometimes called single state, e.g., F­factor, temperate phage, etc. naked chromosome). l Ribosomes are evenly distributed in the matrix. l Besides this nuclear DNA, there is some Ribosomes are of 70S type (50S + 30S). extranuclear or extrachromosomal DNA, which is l Ribosome are the seat of protein synthesis and are known as plasmid. made up of r­RNA and protein. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 13 █ĽňĹęŐŇ– ▐ŐňĚŕď– l There are present different types of granules like l Nitrifying bacteria, Nitrosomonas and volutin granules, fatty acid granules (lipid granules), Nitrosococcus obtain energy by oxidising ammonia glycogen and sulphur granules. to nitrite. l According to the mode of respiration, bacteria NH4+ + 2O2 ® NO2– + 2H2O + Energy can be aerobic or anaerobic. Each of them is further Nitrocystis and Nitrobacter oxidise nitrites to of two types, obligate and facultative. nitrates. l Obligate aerobes are bacteria which can respire 2NO2– + O2 ® 2NO3– + Energy only aerobically. They generally get killed under l Sulphur oxidising bacteria, Beggiatoa, a anaerobic mode of respiration, e.g., Bacillus subtilis. colourless sulphur bacterium, oxidises hydrogen l Facultative aerobes are bacteria which respire sulphide to sulphur in order to obtain energy for anaerobically under normal conditions but can chemosynthesis. respire aerobically when oxygen is available. Most Beggiatoa 2 H 2 S+ O 2 ¾¾¾¾¾ ® 2S+ 2 H 2 O+ Energy of the photosynthetic bacteria belong to this group. Thiobacillus thioxidans, another sulphur bacterium, l Obligate anaerobes are bacteria that respire only oxidises sulphur to sulphate state. anaerobically. They generally get killed under 2S+ 2 H 2 O + 3O 2 ¾¾¾¾ Beggiatoa ¾® 2H2SO4 + Energy Thioxidans aerobic condition, e.g., Clostridium botulinum. l Facultative anaerobes are bacteria which generally l Iron bacteria, Ferrobacillus ferro­oxidans obtains respire only aerobically but switch over to anaerobic energy by oxidising ferrous compounds to ferric mode of respiration if oxygen becomes deficient. forms. 4FeCO3 + 6H2O + O2 ® Nutrition 4Fe(OH)3 + 4CO2 + Energy l Bacteria show both autotrophic and heterotrophic l Other chemosynthetic bacteria, bacterium nutrition. Methanomonas oxidises methane into CO2 and l Autotrophic nutrition consists of manufacture of H2O. organic materials from inorganic raw materials with CH2 + 2O2 ® CO2 + 2H2O + Energy the help of energy obtained from outside sources. l Heterotrophic bacteria may be saprophytic, It is of two types – chemosynthesis and parasitic or, symbiotic. photosynthesis. l Saprophytic are living bacteria which obtain l The bacteria possess photosynthetic pigments of their food from organic remains, e.g., corpses, two types, bacteriochlorophyll and animal excreta, fallen leaves, vegetables, fruits, bacteriophaeophytin (chlorobium chlorophyll). meat, jams, jellies, bread and other products of The two types of pigments respectively occur in plant and animal origin. purple bacteria (e.g., Thiopedia rosea, l Symbiotic bacteria live in mutually beneficial Rhodopseudomonas) in membranes of thylakoids. association with other organisms. Enteric bacterium l No oxygen is evolved in bacterial photosynthesis. Escherichia coli, live as a symbiont in human intestine. Such type of photosynthesis is known as l Parasitic bacteria, live in contact with other living anoxygenic photosynthesis. beings for obtaining nourishment or special organic l Water is not used as a source of reducing power. compounds required for growth (growth factors). Instead, hydrogen is obtained either directly (some l Bacteria show four major phases of growth in a purple bacteria) or from various types of inorganic fresh nutrient rich medium – (i) lag phase, (ii) log and organic compounds, e.g., H2S (green bacteria), phase (logarithmic or exponential phase), aliphatic compounds (purple nonsulphur bacteria). (iii) stationary phase, and (iv) decline phase (death l Chemoautotrophic bacteria are bacteria which phase). These phases constitute the standard are able to manufacture their organic food from bacterial growth curve. inorganic raw materials with the help of energy derived from exergonic chemical reactions Reproduction involving oxidation of an inorganic substance l Bacteria show 3 methods of reproduction – present in the external medium. They are of various vegetation reproduction, asexual reproduction, types. sexual reproduction. R. K. MALIK’S Downloaded from rkmaliksnewtonclassesranchi.wordpress.com NEWTON CLASSES 14 ŕďőĽę– ĐĽŐńŐĹť– l Vegetative reproduction includes budding and l In abortive transduction the new gene does not binary fission. integrate with the recipient genome and is lost. l Binary fission takes place during favourable l Conjugation : Cell to cell union occurs between conditions. The bacterial cell divides by a two bacterial cells and genetic material (DNA) of constriction into 2 halves. The nuclear material also one bacterial cell goes to another cell lengthwise divides into 2 equal halves. through conjugation tube which is formed by sex l Asexual reproduction takes place by endospore pili. formation, conidia and zoospores. l Conjugation was first reported by Lederberg and l During unfavourable condition, highly resistant Tatum (1946) in E. coli bacteria. single spore is formed inside the bacterial cell, l Conjugation occurs between donor cell and which is known as endospore. (Endo means inside recipient cell. Donor cell is having sex pili and F­ or within + spore). factor whereas recipient cell is having both. l Endospore is having a characteristic structure i.e., l In donor cell, F­factor may unite with main genome having outer thin exosporium followed by one or or nuclear DNA and this donor cell is called Hfr­ many layered spore coat, followed by many donor cell (High Frequency donor cell) and here concentric layers of cortex, which is followed by transfer of DNA is rapid. cell wall, cell membrane and matrix. Importance of bacteria l Endospore is highly resistant to very high and Useful activities very low temperature, strong chemicals and l Role of bacteria in agriculture in increasing soil acids, etc. due to calcium, dipicolinic acid and fertility peptidoglycan in cortex. Dipicolinic acid (DPA) – Some free living nitrogen fixing bacteria like helps in stabilizing its proteins. Azotobacter and Clostridium have the capacity l DPA and Ca ions provide resistance to heat. of fixing atmospheric nitrogen into l When favourable conditions come, outer layers nitrogenous substances, hence increases soil rupture and active bacterial cell comes out. So this fertility. is a method of perennation (i.e., to tide over – Similarly symbiotic bacteria Rhizobium also unfavourable condition) and some people say it fix atmospheric nitrogen. “reproduction without multiplication”. – Nitrosomonas converts ammonia into nitrites, l Sexual reproduction occurs in the form of genetic which is further converted into nitrates by recombination. Nitrobacter (nitrification). l There are there main methods of genetic l In dairy industry, lactic acid bacteria (Bacteri