Chapter 2 Biological Classification romeo © Introduction Introduction Siar cere Biological classification is the scientific procedure to classily th Classtfeation organisms into different groups on the basis of their similarities and dissimilarities and placing the groups in a hierarchy of categories. © Kingdom : Monera ‘Since the starting of civilization, many attempts were made to classify ee the organisms. The criteria of classification used at that time. were not fit in scientific approach. Just for example, one attempt was to © Kingdom : Pungt classify organisms on the basis of a need to use organisms for our own use like food, shelter and clothing. Over time, an attempt has + Kingdom : Plantae been made to evolve a classification system which reflects not only SMart rede the morphological, physiological and reproductive similarities, but is also phylogenetic te., based on evolutionary relationships. in this © Viruses, Viroids and Lichens chapter, we will study. the characteristics of kingdoms Monera, Protista and Fungt of the Whittaker system of classification. We will study Kingdom Plantae and Animalia also but in brief. © Some Important Definitions © Quick Recap KINGDOM SYSTEMS OF CLASSIFICATION ‘The earlier systems of classification of organisms were simple and based on fone or two characters. First scientific attempt for classification was performed by Aristotle in following manner [> Herbs Plants ‘Shrube L_. Trees Living Organisms [Anima + Animals without RECS Aiea | Enaima > Animals having RECs Aristotle used simple morphological characters to classify plants into herbs, ‘shrubs and trees. He classified animals into Anaima and Enaima, on the basis of absence and presence of RBCs respectively. Example 1: Who classified plants into trees, shrubs and herbs? Solution: Aristotle Aakash Educational Services Pvt. Lid. - Regd, Office : Aakash Tower, Pusa Road, New Dethi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 44 Tabk haracteristics of the Five Kingdoms Call type. Prokanyotic Eukaryot Eukaryotic | Eukaryotic Eukaryotic Cell wall ‘Non-celulosic Present in some | Present Present ‘Absent (Polysaccharide + (without (Cellulose) ‘amino acid) cellulose) Nuclear ‘Absent Present Present Present Present Caliuar Caiar ‘wulicellular’ | Tissue/organ Tissue/organy loose tissue organ system Mode of “Rutotrophic ‘Rutotrophie Heterotrophie | Autotrophic Fleterotrophic ‘ution (chemosynthetic and | (Photosynthetic) | (Saprophytic! | (Photosynthetic) | (Holozoic etc.) photosynthetic) and | and Heterotrophic | Parasitic) Fieterotrophic (saprophytic/parasite) Example 2: Name the kingdom system proposed by RH. Whittaker. Solution: Five Kingdom System Try Yourself 3. Write the name of five kingdoms which were proposed under Five Kingdom System. 4. Which kingdom includes only photosynthetic organisms w.r.. Whittaker classification system? Earlier classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under ‘Plants’. The character that unified this whole kingdom was that all the organisms. included had a cell wall in their cells. This placed together groups which widely differed in other characteristics. It brought together the prokaryotic bacteria and the blue green algae with other groups which were eukaryotic. It also grouped together the unicellular organisms and the multicellular ones. Chlamydomonas and Spirogyra were placed together under algae. The classification did not differentiate between the heterotrophic group — fungi and the autotrophic green plants, though they also showed a characteristic difference in their walls ‘composition — the fungi had chitin in their wall while the green plants had a cellulosic cell wall. When such characteristics were considered, the fungi were placed in a separate kingdom — Kingdom Fungi. Al prokaryotic organisms were grouped together under kingdom Monera and the unicellular eukaryotic ‘organisms were placed in kingdom Protista, Kingdom Protista has brought together Chlamydomonas, Chlorella (earlier placed in Algae within plants and both having cell walls) with Paramoecium and Amoeba (which were earlier placed in the animal kingdom) which lack it. It has put together organisms which, in earlier classifications, were placed in different kingdoms. This happened because the criteria for classification changed. Such kind of changes will take place in future also. This will depend on the improvement in our understanding of characteristics and evolutionary relationship. ‘Six kingdom classification : Carl Woese proposed six kingdom classification. These six kingdoms are Kingdom-Archaebacteria, Kingdom-Eubacteria, Kingdom-Protista, Kingdom-Fungl, Kingdom-Plantae and Kingdom-Animalia. He separated the archaebacteria from eubacteria on the basis of some major differences such as the absence of peptidoglycan in the cell walls of the former and the occurrence of branched chain lipids (a monolayer instead of a phospholipid bilayer) in the membrane. Based on the sequence of 16S ribosomal RNA genes, Woese found that the six kingdoms naturally cluster into three main categories. He called these categories as domains of life. These domains are Bacteria, Archaea and Eukarya and are believed to have originated from common ancestor called progenote. ‘Aakash Educational Services Pvt. Lid. - Rogd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345640 Biological Classification Board & Competitive Exams. 4. Name the group of animals which have red blood cells. 2. Who was the earliest to attempt a more scientific basis for classification? Linnaeus later classified all living organisms into two kingdoms ~ Plantae and Animalia. The criteria for classification used by him include cell wall, locomotion, mode of nutrition, response to external stimuli and contractile vacuole. 1. Cellwall Present, ‘Absent 2. Locomotion Absent Present 3. Mode of nutrition Do not eat Eat 4. Response to external stimulus. Slow Fast 5. Contractile system Absent Present 6. Organisms Bacteria, algae. fungi, | Protozoa, vertebrates, bryophytes, “pteridophytes, | invertebrates gymnosperms, angiosperms ‘This two kingdom classification system does not distinguish between ~ (i) Unicellular and multicellular organisms, (i) Eukaryotes and prokaryotes and (ji) Photosynthetic (green algae) and non-photosynthetic (fungi) organisms. There are few organisms like Chlamydomonas, Euglena and the slime moulds which share the characteristics of both animals and plants. Since there are certain organisms that do not fall naturally into either plant or animal kingdom, it was proposed that a new kingdom is to be established to accommodate such organisms. A. Three kingdom classification : Haeckel, suggested that a third kingdom Protista should be created to include all unicellular microorganisms. This includes a wide variety of unicellular, mostly aquatic eukaryotes. Example - Fungi, Protozoa, Algae, Bacteria and Slime moulds. ‘Thus, he proposed three kingdoms, namely - Plantae, Protista and Animalia, 8. Four kingdom classification : Copeland gave four kingdom of classification and included ‘Monera as fourth kingdom. This kingdom includes all the prokaryotic organisms ie. eubacteria {including cyanobacteria or blue-green algae) and archaebacteria. R.H. Whittaker (1969) proposed five kingdom classification. He divided organisms into kingdom Monera, Protista, Fungi, Plantae and Animalia, on the basis of following criteria 4 geen Cell structure (either prokaryotic or eukaryotic) ‘Thallus organisation (body differentiated or not) ‘Mode of nutrition (autotrophic or heterotrophic) Reproduction Phylogenetic (or evolutionary) relationship ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110008 Ph.011-4762345642 Biological Classification Board & Competitive Exams. Example 3: in which kingdom, all prokaryotic organisms are included? Solution : Kingdom Monera Try Yourself 5. Name the kingdom under which all unicellular eukaryotes are included, 6. Paramoecium and Amoeba are included under kingdom, EXERCISE 1. Position of bacteria in a kingdom system of classification proposed by Linnaeus is (1) Monera @) Protista (3) Plantae (4) Mychota 2. In three kingdom classification, the kingdom Protista includes (1) Unicollular eukaryotic organisms only (2) Unicettular prokaryotic organisms only (8) Wide variety of unicellular, mostly aquatic eukaryotes (4) Wide variety of unicellular, mostly terrestrial Prokaryotes 3. Which of the following was given the status of kingdom in the classification system given by Copeland? (1) Prokaryotes (@) Myxomycetes (3) Eukaryotic algae (4) Protista 4. Which one of the following is not the basis of five kingdom classification? (1) Cell type (@) Body organisation (3) Reproduction (4) Reserve food materials 5. Multicelular eukaryotic organisms with holophytic mode of nuttin belong to how many kingdoms in Whittaker system’ (1) One @) Two (3) Thee (4) Five 6. _ In-six kingdom classification, Monera was divided into two separate kingdoms on the basis of (1) Celt wall composition @) Lipid nature in plasma membrane (3) Absence of sap vacuole (4) Both (1) & (2) 7. Select correct statement weet, monera (1) All are autotrophic prokaryotes 2) Allare chemoheterotrophs (3) Unicettular, colonial or filamentous organisms (4) Prokaryotes with 70 S ribosome and histonic DNA 8. Multicellular with loose tissue body organisation is a characteristic feature of (1) Monera Q) Protista (3) Plantae (4) Fungi ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623450Board & Competitive Exams. Biological Classification | 44 Tabk Characteristics of the Five Kingdoms Cell type. Prokaryotlc Eukaryouc ‘Eukaryotic | Eukaryotic Eukaryotic Cell walt Non-celulosic Present in some | Present Present “Absent (Polysaccharide + (without (Collulose) ‘amino acid) cellulose) Nuclear ‘Absent Present Present Present Present membrane Body Callalar Cotiarar ‘Wulicellar’ | Tissue/organ Tissuororgany ‘organisation loose tissue organ system ‘Mods of “Autotrophic ‘Autotrophic Hotorotrophic | Autotrophic Heterotrophic ‘utrtion (chemosynthetic and | (Photosynthetic) | (Saprophytic! | (Photosynthetic) | (Holozoic etc.) photosynthetic) and | and Heterotrophic | Parasitic) Heterotropnic (saprophytic/parasite) Example 2: Name the kingdom system proposed by R.H. Whittaker. Solution: Five Kingdom System Try Yourself 3. Write the name of five kingdoms which were proposed under Five Kingdom System. 4. Which kingdom includes only photosynthetic organisms w.rt. Whittaker classification system? Earlior classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under ‘Plants’. The character that unified this whole kingdom was that all the organisms. included had a cell wall in their cells. This placed together groups which widely differed in other characteristics. It brought together the prokaryotic bacteria and the blue green algae with other groups which were eukaryotic. It also grouped together the unicellular organisms and the multicellular ones. Chlamydomonas and Spirogyra were placed together under algae. The classification did not differentiate between the heterotrophic group — fungi and the autotrophic green plants, though they also showed a characteristic difference in their walls. ‘composition — the fungi had chitin in their wall while the green plants had a cellulosic cell wall. When such characteristics were considered, the fungi were placed in a separate kingdom — Kingdom Fungl. Al prokaryotic organisms were grouped together under kingdom Monera and the unicellular eukaryotic ‘organisms ware placed in kingdom Protista. Kingdom Protista has brought togather Chlamydomonas, Chlorella (earlier placed in Algae within plants and both having cell walls) with Paramoecium and Amoeba (which were earlier placed in the animal kingdom) which lack it. It has put together organisms which, in earlier classifications, were placed in different kingdoms. This happened because the criteria for classification changed. ‘Such kind of changes will take place in future also. This will depend on the improvement in our understanding of characteristics and evolutionary relationship. ‘Six kingdom classification : Carl Woese proposed six kingdom classification. These six kingdoms are Kingdom-Archaebacteria, Kingdom-Eubacterla, Kingdom-Protista, Kingdom-Fungl, Kingdom-Plantae and Kingdom-Animalia. He separated the archaebacieria from eubacteria on the basis of some major differences ‘such as the absence of peptidoglycan In the cell walls of the former and the occurrence of branched chain lipids (a monolayer instead of a phospholipid bilayer) in the membrane. Based on the sequence of 16S ribosomal RNA genes, Woese found that the six kingdoms naturally cluster into three main categories. He called these categories as domains of life. These domains are Bacteria, Archaea and Eukarya and aro believed to have originated from common ancestor called progenote. Aakash Educational Services Pvt. Lid. - Regd. Office : Askash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345644 Biological Classification Board & Competitive Exams. BACTERIAL LIFE PROCESSES Discussion of bacterial life processes revolves around the study of the prominent metabolic activities like respiration and nutrition. ‘A. Respiration: On the basis of mode of respiration, the bacteria are divided into two main groups ie., aerobes and anaerobes. Each group is further of two types Le. strict or obligate and facultative. (a) Obligate or strict aerobes : These bacteria can live only in presence of oxygen as they possess the enzyme system for aerobic respiration only. In the absence of oxygen, they cannot respire and thus, die, eg., Bacillus subtilis. (b) Facultative anaerobes : They normally respire aerobically. However, they are capable of switching over to anaerobic mode to get eneray for their survival, if sufficient oxygen to sustain aerobic respiration is not available in the environment, 6.g., Pseudomonas. (©) Obligate or strict anaerobes : These bacteria respire anaerobically only. The growth of such bacteria will certainly be slower as anaerobic respiration liberates much less amount of energy as compared to aerobic respiration. They lack enzymes necessary for carrying out aerobic respiration e.g... Clostridium botulinum. (@) Facultative aerobes : They normally respire anaerobically, but are capable of respiring aerobically as well, f oxygen is available. Most of the photosynthetic bacteria are facultative aerobes e.g., photosynthetic bacteria Chiorobium. B. Nutrition : Bacteria is place land electron, () Photolithoautotrophic bacteria : ‘These bacteria are capable of entrapping solar energy and utilizing it for the synthesis of complex food materials due to the presence of pigments like bacteriochlorophyll (bacteriopurpurin) and bacterioviridin. Purple sulphur bacteria (e.g.. Thiospirilum) and green sulphur bacteria (Chiorobium limicola) are the ‘most familiar examples containing pigment bacteriochlorophyll, bacteriopurpurin and bacterioviridin respectively. Bacterial photosynthesis, however, differs from photosynthesis of higher plants in not liberating ‘oxygen. This type of photosynthesis, characteristic of bacteria, is termed as anoxygenic. Normal photosynthesis, occurring in higher plants, is termed as oxygenic. In bacterial photosynthesis water is not the source of electron that acts as reducing power to convert CO, into glucose. The bacteria obtain reducing power from various compounds such as hydrogen sulphide, thiosulphate or even some organic compounds. No oxygen is evolved as it does not involve splitting particular nutritional class based on their primary source of carbon, energy of water Photolthoqutotrophic bacteria Purple sulphur bacteria Green sulphur bacteria + Bacteriopurpurin pigment SBacerowndin proment * Use inorganic sulphur or compounds ase and H’ donor __Chiorobium chlorophyll e.g., Chromatium, Thiospirillurn © Use HS as & and H” donor e.g., Chlorobium Hydrogen released by various compounds mentioned above is picked up by NAD* which gets reduced to NADH, acting as reducing power. NADH, alongwith ATP, produced generally by entrapping solar eneray are used to reduce CO, to glucose. Simple equation for anoxygenic photosynthesis may be written as follows cOz+ Hes —Se-enew8_, Sugar + (Sulphur or other oxidised compound) + HO oSmpauhd acing ‘mievconory Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 43 9. 10. Cell wall is made of polysaccharide and amino acid in most of the members of (1) Monera 2) Protista @) Fungi (4) Animalia Cyclosis is absent in (1) Diatoms. 2) Eubacteria 8) Algae (4) Plantae KINGDOM : MONERA. Kingdom Monera includes the most ancient, the smallest, the simplest and the most abundant micro-organisms. ‘These organisms are most primitive, They were the first inhabitants of the earth, and they stil continue to flourish, Bacteria are the sole members of this kingdom. They occur almost everywhere. Hundreds of bacteria are present in a handful of soil, They also live in extreme habitats such as hot springs, deserts, snow and deep oceans where very few other life forms can survive. Many of them live in or on other organisms as parasites. Characters of Monera 1. They are unicellular, colonial or filamentous, prokaryotic organisms without nuclear membrane, nucleolus, chromatin and histone proteins. 2, Nucleoid or incipient nucleus is composed of naked DNA, RNA and non-histone proteins. DNA is circular ‘and double stranded. Cell wall is made up of peptidoglycan (Amino acids + Sugar) except in Archaebacteria and Mycoplasma, Membrane bound cell organelles are absent. Ribosomes are of 70 type. Some of the bacteria are autotrophic but vast majority are heterotrophic. Respiratory enzymes are found associated with plasma membrane. Reproduction is asexual type. Bacteria show both autotrophic and heterotrophic nutrition. Autotrophic nutrition involves synthesis of ‘organic material from inorganic substances with the help of light energy (photosynthetic autotrophic) or chemical energy (chemosynthetic autotrophic). Majority of them show heterotrophic nutrition which involves the obtaining of readymade organic nutrients from outside sources. It is of three types — saprotrophic, symbiotic and parasitic. On the bs 1. The spherical Goccus (pl: Coe), 2. The rod-shaped Bacillus (pl: Bacilli, 3. The comma-shaped Vibrium (pl.: Vibrio), and. 4 ©o@Nevae is of their shape, bacteria are grouped under four categories : ‘The spiral Spirilum (pl: Spirilla) Cocet Bacili Fig. : Bacteria of different shapes. Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 45 (i!) Photoorganoheterotrophic bacteria ‘Some photosynthetic bacteria use organic matter as their electron donor and carbon source. Photoorganoheterotrophic bacteria Purple non-sulphur Green non-sulphur + Bacteriopurpurin pigment + Bacterioviridin pigment + Use nonsulphur aliphatic organic + Use non sulphur aliphatic organic ‘compounds as. 6 and H’ donor ‘compounds as 6 and H’ donor e.g, Rhodospirillum, Rhodopseudomonas _@.g., Chloronema, Chlorofiexus Most of the photosynthetic bacteria are anaerobes (facultative aerobes). (il) Chemosynthetic autotrophic bactes Bacteria belonging to this category obtain energy for the synthesis of food by oxidising certain inorganic substances like ammonia, nitrates, nitrites, ferrous ions, etc. Thus, they do not utilise light as energy source. The chemical energy thus obtained, is trapped in ATP molecules. This energy is then used in carbon assimilation with the help of hydrogen from some source other than water, ¢.g., hydrogen bacteria, nitrifying bacteria, sulphur bacteria, etc. They play a great role in recycling nutrients like nitrogen, phosphorous, iron, sulphur. (a) Hydrogen bacteria. Hydrogenomonas. (b) Nitrifying bacteria. Nitrosomonas, Nitrococcus, Nitrobacter and Nitrocystis (©) Sulphur bacteria. Thiobacillus thioxidans, Beggiatoa (d) Iron bacteria. Ferrobacillus, Leptothrix (IV) Chemoorganotrophic heterotrophic bacteria : ‘These bacteria are incapable of synthesizing their own food from simple raw materials. They obtain nourishment either from dead and decaying organic matter or directly from a living host. They are segregated into three main categories, /e., saprophytic, symbiotic and parasitic forms. () Saprophytic bacteria : They are free living bacteria, obtaining nourishment from organic remains such as dead animals, animal excreta, fallen leaves, decaying vegetables, fruits, bread and other products of animal and plant origin. These bacteria secrete digestive enzymes into the substrate and the complex insoluble substances are converted into simple soluble compounds like water, hydrogen sulphide, ammonia, CO, etc. Some of the simpler substances are absorbed and assimilated by the bacteria, whereas the others are added to the soil and atmosphere to complete the nature's material cycie. (ii) Symbiotic bacteria : They are mainly Gram negative type. A familiar example of symbiotic bacteria is Rhizobium leguminosarum, associated with roots of leguminous plants. They are capable of fixing atmospheric nitrogen as ammonia, inside the nodule only and not in free state. However, some bacteria like Azotobacter, Bejjerinckia, Klebsiella are free living, aerobic and capable of nitrogen fixation in free state, enriching the soil. Clostridium pasteurianum is anaerobic N, fixing bacteria, (ili) Parasitic bacteria ; These bacteria draw nourishment and obtain special organic compounds required for growth from living organisms, either plants or animals, called hosts. The disease causing bacteria are termed pathogenic and the ones not causing any disease are termed as non-pathogenic. REPRODUCTION Bacteria reproduce mainly by asexual method and also show sexual recombination (True sexual reproduction is absent). A. Asexual Reproduction : Bacteria produce several types of asexual spores like, sporangiospores, oidia, conidia and endospores. However, the most common mode of asexual reproduction is binary fission. Under favourable conditions of nutrient availability, moisture and temperature, daughter cells may repeat binary fission many times and may forms a large population. Fortunately, such a rapid rate is seldom achieved. The process gradually slows down and ultimately stops because of ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 45 (i) Photoorganoheterotrophic bacteria : Some photosynthetic bacteria use organic matter as their electron donor and carbon source. Photoorganoheterotrophic bacteria Purple non-sulphur Green non-sulphur ‘+ Bacteriopurpurin pigment + Bacterioviridin pigment + Use nonsulphur aliphatic organic ‘+ Use non sulphur aliphatic organic ‘compounds ase and H’ donor ‘compounds as 6” and H” donor e.g., Rhodospirillum, Rhodopseudomonas _¢.g., Chioronema, Chioroflexus Most of the photosynthetic bacteria are anaerobes (facultative aerobes). (il) Chemosynthetic autotrophic bacteria : Bacteria belonging to this category obtain energy for the synthesis of food by oxidising certain inorganic substances like ammonia, nitrates, nitrites, ferrous ions, etc. Thus, they do not utilise light as energy source. The chemical energy thus obtained, is trapped in ATP molecules. This energy is then used in carbon assimilation with the help of hydrogen from some source other than water, e.g., hydrogen bacteria, nitrifying bacteria, sulphur bacteria, etc. They play a great role in recycling nutrients like nitrogen, phosphorous, iron, sulphur. (a) Hydrogen bacteria. Hydrogenomonas. (®) Nitrifying bacteria. Nitrosomonas, Nitrococcus, Nitrobacter and Nitrocystis (©) Sulphur bacteria. Thiobacillus thioxidans, Beggiatoa (@) Iron bacteria. Forrobacillus, Leptothrix (IV) Chemoorganetrophic heterotrophic bacteria : ‘These bacteria are incapable of synthesizing their own food from simple raw materials. They obtain nourishment either from dead and decaying organic matter or directly trom a living host. They are ‘Segregated into three main categories, /.c.. saprophytic, symbiotic and parasitic forms. (0). Saprophytic bacteria : They are free living bacteria, obtaining nourishment from organic remains such as dead animals, animal excreta, fallen leaves, decaying vegetables, fruits, bread and other products of animal and plant origin These bacteria secrete digestive enzymes into the substrate and the complex insoluble substances are converted into simple soluble compounds like water, hydrogen sulphide, ammonia, CO, etc. Some Of the simpler substances are absorbed and assimilated by the bacteria, whereas the others are added to the soil and atmosphere to complete the nature's material cycle. (W) Symbiotic bacteria : They aro mainly Gram negative type. A familiar example of symbiotic bactoria is Rhizobium leguminosarum, associated with roots of leguminous plants. They are capable of fixing atmospheric nitrogen as ammonia, inside the nodule only and not in free state. However, some: bacteria like Azotobacter, Beljerinckia, Klebsiella are free living. aerobic and capable of nitrogen fixation in free state, enriching the soil. Clostridium pasteurianum is anaerobic N, fixing bacteria (lil) Parasitic bacteria : These bacteria draw nourishment and obtain special organic compounds required for growth from living organisms, either plants or animals, called hosts, The disease causing bacteria are termed pathogenic and the ones not causing any disease are termed as non-pathogenic. REPRODUCTION Bacteria reproduce mainly by asexual method and also show sexual recombination (True sexual reproduction is absent). A Asexual Reproduction : Bacteria produce several types of asexual spores like, sporangiospores. oidia, conidia and endospores. However, the most common mode of asexual reproduction is binary fission Under favourable conditions of nutrient availabilty, moisture and temperature, daughter cells may repeat binary fission many times and may forms a large population. Fortunately, such a rapid rate is seldom achieved. The process gradually slows down and ultimately stops because of ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762945648) Biological Classification Board & Competitive Exams. >) © Griffith concluded that something passed from heat killed S-lll to R-ll bacteria, so that non virulent strain ‘changed or transformed into virulent bacterial strain. Avery, MacLeod and McCarty (1944) repeated this experiment using various enzymes and proved that the transformation principle Is DNA of heat killed S-Ill strain. They proved that DNA is a genetic material. Conjugation : Lederberg and Tatum (1946) demonstrated in E. coli that during conjugation, one cell containing F-plasmid acts as donor (F* or male) cell and the other lacking F-plasmid as recipient (F- or female) cell. The plasmid contains fertility factor or F gene which produces protrusions termed sex pili ‘These help the donor F* cell in attaching to the recipient cell. The plasmid replicates and a replica is transferred {o recipient cell, changing it into F*. Often the plasmid integrates with bacterial chromosome, ‘converting it into Hifr (High frequency of recombination) cell or super male and a part or whole of bacterial chromosome is transferred to recipient cell through conjugation tube. Such association of episome with the endogenoie increases the efficiency of genetic transfer. The number of genes transferred depends. upon the time for which the two cells remain joined together. When F> conjugates with super male, the frequency of recombination increases by 1000 times, that is why it is called as Hfr (super male), a «4 tae feo) Ea al = Mice died. (®) Rul bacteria —H#S*¢ 2, Healthy mice ——> Mice survived (i) S—Ibacteria—###4!"_, Healthy mice ——+ Mice survived. (oaths) (w) Rul (living) + S-Ill (heat killed) bacteria —!eee fect”’_ Healthy mice ——> Mice died. (But Rul is not virulent and S-IIl lost its virulent capacity upon heating). ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-1 10005 Ph.011-47629456Board & Competitive Exams. Biological Classification | 49 ECONOMIC IMPORTANCE A. Some Useful Bacteria : L._ Soil fertility / biofertilisers Free-tiving N,-fixing bacteria: Azotobacter, Clostridium, Klebsiella, Beijerinckia ‘Symbiotic N,-fixing bacteria Rhizobium, Frankia, Xanthomonas Ammonifying bacteria Bacillus vulgaris, B.ramosus I. Vinegar production : Acetobacter aceti I, Curd, cheese, yoghurt production : Lactobacillus, Streptococcus lactis IV. Petroleum pollution control : Pseudomonas putida V. Antibiotics production : 6.9, Bacitracin : Bacillus licheniformis ‘Subtilin : B. subtilis VI. Retting of fibres : ¢.g., Clostridium perfringens, Pseudomonas fluorescence VIL Curing of leaves : To improve the flavour and taste in tea by Micrococcus candidans and in tobacco leaves by Bacillus megatherium B. Harmful activities (Vibrio cholerae — Cholera (i) Salmonetta typhi — Typhoid (i) Clostridium tetani — Tetanus (Xanthomonas citri— Citrus Canker Let us Discuss various Monerans in detail: I Archaebacteria Those archaobacteria are special sinca they live in some of the most harsh habitats such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens) ‘Archaebacteria difer from other bacteria in having a different cell wall structure and this feature is responsible for thoir survival in extreme conditions. The coll membrane contains branched chain lipids (phytanyl side chains) which decreases membrane fuidty Archaebacteria have introns in their genetic sequence. ‘Archaebacteria are divided into three groups~ methanogens, halophiles and thermoacidophiles. ( Mothanogens : Those bacteria are of marshy habitats. They are capable of converting CO,, methanol and formic acid into methane so named methanogens. These methanogens are present in the-guls of several ruminant animals such as. cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals. These are chemoautotrophs. Examples : Methanococcus, ‘Methanobactorium ete (i) Halophites : These bacteria live in extreme saline environment such as salt lakes. sea, brines etc in strong light, these halophilos develop a pigmented mombrane (purple mombrane) composed of a pigment called bacterio-rhodopsin (related to the one found in our own eyes) to harness the sun's energy. ‘Tho light energy is utlised to carry on ATP production but they cannot use this ATP in food synthesis Hence, they are heterotrophs. Examples : Halobacterium and Halococcus. Thermoacidop! : These are capable of tolerating high temperature as well as high acidity and hence, the name thermoacidophiles. They often live in hot water springs where the temperature is as high as 80°C and the pH as low as 2. They oxidise sulphur to sulphuric acid under aerobic conditions land the energy obtained in this reaction is utlised for the synthesis of organic food. Hence, these are Ghemosyntheti in nature. The medium becomes highly acidic due to the production of sulphuric acié Under anaerobic conditions sulphur is reduced to H,S. Examples : Thormoplasma, Thermoprotous ote. Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345650 Biological Classification Board & Competitive Exams. Example 4: Name the group of bacteria, present in the gut of ruminant animals which are responsible for the Solution: Methanogens production of methane from the dung. Try Yourself 7. Which group of bacteria live in extreme salty areas? 8. _How can archaebacteria live In harsh conditions? Eubacteria ‘There are thousands of different eubacteria or ‘true bacteria’. Most of them are characterised by the presence of rigid cell wall, and if motile, a flagellum. Eubacteria include several subgroups like Cyanobacteria, Mycoplasma, Actinomycetes, Rickettsiae, Chlamydiae, Spirochaetes etc. Let us discuss Cyanobacteria and ‘Mycoplasma in detail (Cyanobacteria : Cyanobacteria are Gram negative photosynthetic prokaryotes, being the most primitive organisms to have oxygenic photosynthesis. Thoy added oxygen to the atmosphere, which is indispensible for the existence of aerobic forms of living organisms. They are also known as BGA (Blue green algae) and are classified variously under eyanophyceae or myxophyceae. Occurrence : They are mainly fresh water forms, though few are marine. Red sea is named so because of abundant occurrence of a cyanobacterium Trichodesmium erythraoum, which imparts red colouration to water. They occur in symbiotic association with almost every group of eukaryotes Le. green algae, fungi, bryophytes like mosses and Anthocoros, ferns, gymnosperms, angiosperms, sponge, shrimps, mammals etc. Anabaena azollae is associated with Azolla, an aquatic fern. Anabaena cycadeae is associated with coralloid roots of Gycas. In many lichens (symbiotic association of algae and fungi) the algal partner may be a cyanobacterium. When they live endozoically in protozoans they are called eyanelle. Structural Organization : These may be unicelled, filamentous and colonial. Filamentous form consists of one or more cellular strands, called trichomes, surrounded by mucilagenous sheath. Cyanobacteria fro characterised by the absence of flagellum throughout life cycl A filamentous blue-green algae— Nostoc Coll Structure : The cell structure in cyanobacteria is typically prokaryotic. The cell lacks a well defined nucleus and the chromatin material is centrally located, resembling the bacterial chromosome. The cell wall is 4 layered and is invariably covered by mucilagenous sheath, composed largely of mucopeptides. Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Puss Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 51 Protoplasm in cyanobacterial cell can be distinctly divided into two parts the centroplasm and chromoplasm. The central colourless centroplasm contains the chromatin material. The peripheral protoplasm is coloured or pigmented because of the presence of thylakoids, called as chromoplasm. ‘The protoplast lacks membrane-bound organelles like endoplasmic reticulum, golgi bodies, mitochondria, lysosomes, plastids and contains 70S ribosomes. Similar to the mesosome of bacteria, a group of colled membrane called lamellasome is found which connects nucleoid to the cell membrane. It helps in respiration and replication of DNA. The cell membrane lack sterols. The sap vacuoles are absent. Instead, the cell may contain gas filled vacuoles which help to regulate the buoyancy of the organism in water. The characteristic feature of cyanobacterium cell is the presence of a system of photosynthetic lamellae called thylakoids. The characteristic photosynthetic pigments present in the thylakoids are chlorophyll a and phycobilins e., phycocyanin (blue coloured), phycoerythrin (red coloured) and allophycocyanin (light blue coloured) ‘The cyanobacterial cell contains reserve food material in the following forms (© Cyanophycean granules (Protein) (ii) B-granule (Fat droplets) (il) Cyano-or myxophycean starch or c-granule (Similar to glycogen but negative to iodine test) (W)_Volutin body (Reserve phosphate) ( Polyhedral body (Rubisco rich) Galdukov's phenomenon or complementary chromatic adaptation — Cyanobacteria or blue green algae can adaptively change their body colour according to different wavelengths of available light, e.g., Trichodesmium ‘erythraeum. It is also known as “red sea” causing alga. Lametiasome: Shromasore Fig. : Ultrastructure of a cyanophycean cell Metabolism : They are the most self-dependent organisms, because most of these are capable of converting atmospheric nitrogen into ammonium compounds besides utilizing atmospheric CO, for synthesis of organic food during photosynthesis. Biological nitrogen fixation is an anaerobic process as nitrogenase ‘enzyme required for the process acts efficiently in the absence of oxygen. Nitrogen fixation under anaerobic conditions occurs mainly in large, specialized cells called heterocysts as in Nosfoc. Heterocyst has terminal pores which at maturity develops a polar granule. Thickened cell wall of these cells Is impermeable to oxygen 0 this creates anaerobic environment in the cell even under aerobic conditions. Besides this, heterocysts also lack PS Il activities and CO, fixation is done only by vegetative cells. Oxygen is not evolved due to absence of PSII. However, PSI remains active in heterocyst which generates ATP required to fix nitrogen. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-1 10005 Ph.011-4762945652 Biological Classification Board & Competitive Exams. Besides N, fixation heterocyst promotes fragmentation. Because of this property of nitrogen fixation, most of the BGA enrich the soil by releasing nitrogenous compounds in the surroundings. Reproduction : Cyanobacteria reproduce asexually. Typical sexual reproduction is absent. Asexual reproduction occurs by following methods = (Binary fission : It occurs in unicellular forms. The daughter cells formed by amitotic division separate immediately after the division. (Fragmentation : It occurs in filamentous forms. The filament breaks up into short pieces or fragments which grow to form new filaments. (ii) Heterocysts : Under special conditions, the heterocysts germinate to form new filaments. (¥) Hormogonia : Due to the formation of biconcave, mucilage filled dead cells called necridia, in between living cells of trichome, the filament breaks into hormogonia. () Akinetes : Vegetative cells are transformed into thick walled akinetes due to the deposition of food material followed by the thickening of wall. On the arrival of favourable conditions, they germinate to form new filaments, Importance of Cyanobacteria (They are the most ancient organisms having oxygenic photosynthesis and thus, played a significant role in the evolution of aerobic forms of life. (i) They convert atmospheric nitrogen into ammonium compounds and excess of these compounds is ‘excreted out, enriching the soil. The death and decay of these also increase the soil fertility, particularly the nitrogen content of the soil. Tolypothrix and Auiosira fix N, non-symbiotically in rice fields. Cyanobacteria like Nostoc and Anabaena have been used for reclaiming usar soils. As they can live in damp or aquatic habitat, they enrich the root environment in any wetland condition as in rice fields. (il) Cyanobacteria are associated in symbiotic relationship with almost every group of plants. They benefit the partner by providing nitrogenous compounds because of their capability of nitrogen fixation. () Some cyanobacteria serve as food to several aquatic animals. Spirulina is edible, non-toxic, fast growing cyanobacterium. It is cultivated in tanks as source of protein rich animal food (SCP) (Extract of Lyngbya is used for the manufacture of antibiotic. (¥) Some cyanobacteria like Microcystis aeruginosa, Anabaena flos-aquae, Aphanizomenon flos—aquae are known to cause algal blooms in water bodies. These also secrete toxins into the surroundings, which are harmful to aquatic animals and even to human beings. Water from such sources is harmful and may even prove fatal for organisms drinking it. They also deplete the oxygen from the water reservoir and thereby, cause large scale death of the fishes and other aquatic animals. Mycoplasma E. Nocard and E.R. Roux (1898)-two French Scientists, discovered these organisms from pleural fluid of cattles suffering from pleuropneumonia. These are pleomorphic and were called PPLO (Pleuropnoumonia Like Organisms) or Jokers of plant kingdom. This organism was later on given the name Asterococcus mycoides by Borrel ef al. (1910) Nowak (1929) placed Asterococcus mycoides under the genus Mycoplasma. All such organisms are now called Mycoplasma, or MLO’s (Mollicutes like organisms). These are sometimes placed in a separate class called Mollicuta Mycoplasma infects animals (¢.9., dog, sheep, mice and man) and plants (e.g., potato, corn, brinjal etc.). They are generally found in soil, sewage water, plants and animals. ‘Structure : These are unicellular, simplest free living prokaryotes. They do not have cell wail so they are highly pleomorphic and can assume various shapes like spherical, granular, filamentous, coccoid etc. Cell membrane is the outermost limiting layer. It is trilamellar unit membrane structure. In culture, colonies of Mycoplasma show a characteristic fried egg appearance with an opaque central area and translucent peripheral zone. The cells are generally non motile, but a few are gliding type. The protoplasmic matrix contains ribosomes (70 S type), fatty substances and proteins. Organized nucleus, endoplasmic reticulum, ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, Now Dolhi-110008 Ph.011-4762345664) Biological Classification Board & Competitive Exams. Example 5 : What is name of common reproductive umt of Mycoplasma? Solution: Elementary bodies n. 12 13. 14 16. 16. 17. 18. Try Yourself 9. Photosynthetic pigment in cyanobacteria is 10. Name the special cells, where nitrogen fixation takes place in cyanobacteria. Select nconec statment wit eubacteria (1) Have very simple structure (2) Peptidoglycan nature of cell wall (3) Heterotrophs are most abundant in nature (4) Show most simple metabolic diversity Fd ed one nr pcp nian (1) Chromatium and Chiorobium (2) Rhodopseudomonas and Thiospirium (8) Chioronema and Chlorofiexus (4) Pseudomonas and Clostridium Mark the incorrect option (w-rt. nitrifying bacteria) (1) Mitrococcus 2) Leptothnix (3) Nitrobacter (4) Nitrocystis Genetic recombination in which a small double stranded piece of DNA is transferred from donor bacterium to recipient bacterium by a bacteriophage was first demonstrated by (1) Griffiths (2) Lederberg and Tatum (3) Zinder and Lederberg: (4) Avery et.al. Select correct match Columnt Column a. Retting of fires Pseudomonas putida b. Pollution contro! Pseudomonas fluorescence ©. Curing of leaves il) Bacilus licheniformis d. Bacitracin (¥) Micrococcus candidans (1) ai), BG), ef, i) 2) ali), BG), efi), i) (3) afi), bei), efiv), Ail) 4) alii), bG, efiv), dCi) Archaebacteria do not show (1) Peptidoglyean in cell wall 2) _Introns in NA @) Branched chain lipids in cell membrane (4) Ribosomal proteins with highly acidic nature ‘Thermoacidophiles are capable of withstanding extremely low pH and high temperature due to the (1) Presence of branched chain of lipid in cell membrane @) Presence of resistant enzyme which can operate in basic conditions (3) Presence of higher concentration of KCI in their cells (4) More than one option is correct Which group of monerans played significant role in the evolution of aerobic forms of life? (1) Mycoplasma @) Cyanobacteria (3) Archaebacteria (4) Actinomycetes ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110008 Ph.011-47623456Board & Competitive Exams. Biological Classification | 53 plastids, mitochondria, golgi bodies, lysosomes, centrioles, flagella, etc. are absent. Mycoplasma has both RNA and DNA. RNA is single stranded, present in both ribosomes and cytoplasm and DNA is double stranded, long coiled thread extending almost throughout the cell. Enzymes are present freely in the cytoplasm as well as associated with the plasma membrane. Replicating disc assist in replication and ‘separation of the genetic material Lipoprotein membrane layers) Fig. Mycoplasma : Structural details Nature of Mycoplasma : Mycoplasma can pass through bacteriological fters and lack cell wall. This shows that they are not bacteria. Since they can multiply in abiotic medium having sterols, so they are not considered as virus. Due to many similarities with bacteria they are said to be “Bacteria with their coats off”. Mode of nutrition is heterotrophic. Some are saprophytic, but mostly they are parasitic. They are parasitic because they are unable to synthesize required growth factors, e.g., M. gallisepticum (0.3 to 0.5 um, ‘smallest prokaryote). They can survive without oxygen, Sensitivity to Antibiotics : Mycoplasma are insensitive to penicillin but sensitive to streptomycin, erythromycin, chloramphenicol (metabolic inhibitors) etc., They are insensitive to penicillin because they are wall less and penicillin interferes in the synthesis of peptidoglycan, a component of coll wall of bacteria, Reproduction : Much is not known about reproduction of Mycoplasma but they mainly reproduce by means of elementary bodies. From foregoing discussion, it is quite clear that bacterial structure is very simple but they are very complex in behaviour compared to many other organisms, bacteria as a group show the most extensive metabolic activity, Cyclosis is absent in bacteria. Flagella consist of flagellin protein. Bacillus is most common form. Pseudomonas putida - superbug. ‘Methanogens - obligate anaerobes. ‘Thermoacidophiles - Facultative anaerobes. Cell wall of Archaebacteria consists of NAT [ N-Acetyltalosamiuronic Acid]. Exogenote: Transferred DNA of Hir is called exogenote and homologous part of F genophore is called endogenote. 9. Mycoplasma: Facultative anaerobes. 10._Hererocyst in BGA: Facultative anaerobe. eX EP MEENA ‘Aakash Educational Services Pvt. Ltd. - Regd! Office : Aakash Tower, usa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 55 19. The characteristic photosynthetic pigments in cyanobacteria are (1) Chlorophyll a and & (@) Chlorophyll a and carotenes (3) Chlorophyll a and phycobitins (4) Chlorophyll a, carotenoids and phycobilins ‘Smallest wall-less monerans (1) Develop fried egg appearance in culture @) Are motile (@) Have definite shape (4) Are mostly saprophytic KINGDOM : PROTISTA General Characteristics of Protist All unicellular eukaryotes, irrespective of their mode of nutrition, are included in the kingdom Protista in Whittaker’s system. The term protista was coined by Ernst Haeckel. This kingdom forms a link between kingdom Monera on one hand and other three kingdoms /e., Plantae, Fungi and Animalia on the other hand. Protistans are ancestors of all multicellular eukaryotes (plants, fungi and animals). Kingdom : Protista includes Protista (1) Autotrophic (2) Consumer (3) Protozoans or Decomposer organisms Photosynthetic organisms e.g, Dinoflageliates e.g., Cellular slime moulds eg, Zooflagellates Diatoms Acellular slime moulds. ‘Sarcodines Euglencids. ‘Sporozoans Ciliates 1. Unicellular, eukaryotic organisms. Some are colonial without much cellular differentiation. Organisation at tissue level is absent. 2. Mostly aquatic organisms. 3. Cell structure is eukaryotic type having all kinds of membrane bound organelles and 80 $ cytoplasmic ribosomes and cells may possess cellulosic cell wall. 4. Flagella and cilia have (942) pattern of microtubule organization consisting of tubulin protein. 5. Movement by pseudopodia, flagella or cilia where cillary mode is fastest. 6. Mode of nutrition may be photosynthetic (holophytic), holozoic (ingestive). saprobic or parasitic (absorptive), ‘Some have mixotrophie nutrition (photosynthetic and saprobic) as in Euglena. 7. Reproduction occurs by asexual and sexual means. 8. Life cycle is of two types (i) Showing zygotic meiosis (ii) Showing gametic meiosis. 9. These are decomposers, photosynthetic or parasites. Parasitic protists may cause diseases like dysentery, malaria, sleeping sickness, etc. Photosynthetic protists and Slime moulds are described below : (1) Photosynthetic Protists These are popularly called protistan algae. Protistan algae constitute the major portion of the phytoplanktons. A. Diatoms : Diatoms are gokien brown photosynthetic protists and are called Chrysophytes (including both iatoms and desmids). They are both aquatic and terrestrial. Some are marine. They support much of ‘marine life. Their important characters are 1. These are microscopic organisms possessing varying colours. 2. They are basically unicellular, but may form pseudofilament and colonies, lacking flagella except the reproductive stage. They may be free floating (phytoplanktonic), remaining afloat on surface of water due to presence of light weight lipids. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345656 Biological Classification Board & Competitive Exams. 3. The cell wall is impregnated with silica to form transparent siliceous shell, known as frustule. Depending upon the symmetry, diatoms may be pennate type, having bilateral symmetry (e.9., ‘Navicula) and centric type, having radial symmetry (e.g., Melosira). 4. The coll wall is characteristic, made up of two halves; one half covering the other (epitheea over hypotheca) resembling a soap box. 5. The cell wall encloses the peripheral layer of cytoplasm (primordial utricle) surrounding a large central vacuole, 6. Nucleus lies in the central vacuole, suspended with the help of cytoplasmic strands. 7. Mode of nutrition is holophytic (photoautotrophic), photosynthetic pigments are chlorophyll a, chlorophyll c, B-carotene and special carotenoids containing fucoxanthin; xanthophylls like diatoxanthin, diadinoxanthin, 8. The reserve food is oil and a polysaccharide called leucosin (chrysolaminarin), volutin granules are also present. 9. They are responsible for almost 50% of the total organic matter synthesized in the biosphere. 10. Movernent ocours by mucilage propulsion ‘11. They mainly undergo asexual reproduction. The common mode of asexual reproduction is binary fission. 12. During binary fission, one-half of the cell wall is retained by each of the daughter cells formed. The ‘other half of the cell walll is secreted afresh 13. Resting spores are called statospores (centric diatoms). 14. They reproduce sexually as well. Sexual reproduction varies from isogamy to oogamy. It involves gametic meiosis as diatoms are generally diploid (diplontic life cycle). Did You Know? 1. Silica shells of dead diatoms are nearly indestructible and thus, get accurnulated at the sea bed. Such huge rock-like deposits of hard shells of diatoms constitute diatomaceous earth, which is mined to obtain a whitish powder called diatomite or kieselguhr or diatomaceous earth. Diatomite is rough and gritty. Because of these features, it is used in filters in brewing industry, sugarcane refineries, in polishes for metals, tooth pastes, for making insulating bricks, in insulation of refrigerators, houses and for making the latter sound proof, in the manufacture of dynamite, water glass or sodium silicate and strong acids. This is added to paint to increase their night visibility. 2. They are very good indicators of water pollution. ‘Common examples of diatoms are Triceratium, Melosira, Navicula, Cymbella. 3._Auxospores: Zygote formed during sexual reproduction in Diatoms is called Auxospore. B. Dinoflagellates: Dinoflageliates are golden brown photosynthetic protists, belonging to class Dinophyceae (Pyrrophyta). They are mainly marine, though few are fresh water forms. They may appear red, Yellow, green, brown or blue depending upon the main pigment present in cell Fig. : Some Dinoflageliates: ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110008 Ph.011-4762345668) Biological Classification Board & Competitive Exams. 40. un. 12, 43, 14, Locomotory organs are flagella. ‘The cell bears a single long tinsel type flagellum (stichonematic) arising at the anterior end. Actually, there are two flagella but one of these is reduced. The longer flagellum has two branches at the base ‘each having its own basal granule. In the area of union of two flagella is present a photosensitive paraflagellar body. Myonemes are oblique but parallely arranged strips in pellicle. Euglenoids perform creeping movement of contraction and expansion with the help of myonemes which is called metaboly or euglenoid movement The apical end of the cell bears an invagination with three distinct parts, i.e., mouth (cytostome), canal (gullet or cytopharynx) and reservoir. It helps in the ingestion of solid food particles. Stigma or an eye spot is attached to the membrane of the reservoir at the level of paraflagellar body and along with it seems to be involved in perception of light stimulus. It contains photosensitive red- ‘orange pigment called astaxanthin. A contractile vacuole occurs in the anterior end of the cell just below the reservoir, meant for ‘osmoregulation and excretion Single large nucleus lies near the centre of the protoplast. Nutrition in Euglena viridis is photoautotrophic. However, it is capable of getting nourishment from dead and decaying organic matter in the substrate by secreting digestive enzymes (saprophytic nutrition) in the absence of light. This dual mode of nutrition is termed as mixotrophic. Holozoic nutrition is absent in Euglena. Some forms are holozoic (Paranema) or saprobic (Rhabdomonas). Photosynthetic pigments are chlorophyll a, chlorophyll b, xanthophyll and P-carotene. Reserve food material is paramylon, stored in cytoplasm in the form of paramylum granules. They are chemically B-1, 3-glucans, Under favourable conditions, they mainly reproduce by longitudinal binary fission. During unfavourable conditions, palmella stage and cysts are formed for perennation. Sexual reproduction is not known to occur in euglenoids, e.g., Euglena and Paranema. Fig, Content Builder 1. Euglena is producer-decomposer protist 2. It's studied as plant as well as animal and is called as plant animal 3. Plant characters of Eugiona’ (© Presence of chloroplast with photosynthetic pigments. (i) Holophytic nutrition 4. Animal characters of Euglena: (Absence of cell wall and presence of proteinaceous pellicle. (Presence of stigma and paraflagellar body. (ii) Presence of contractile vacuole. (@)_Presence of longitudinal binary fission. Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 57 General characters of dinoflagellates are as follows = 1. Unicellular, motile, biflagellate, golden brown photosynthetic protists (some are non-motile, amoeboid, palmelloid or filamentous). 2. They are mostly marine, some are found in fresh water. 3. The body is enclosed by a rigid coat called theca or lorica consisting of 2 to many articulated or sculptured plates of cellulese and pectin, hence are also called armoured dinoflagellates. 4. Theca has generally two grooves i.e., longitudinal called sulcus and transverse called eingulum or annulus or girdle. 5. Flagella are heterokont (different). One is longitudinal and other is transverse. The flagella pass out through the pores in the lorica and lie in the grooves. The transverse flagellum lies in the circular groove and the longitudinal flagellum in the longitudinal groove. The longitudinal flagellum is narrow, ‘Smooth directed posteriorly and the transverse flagellum is ribbon like. Both are oriented at right angle to each other producing spinning movements. Therefore, these protists are also called ‘whirling whips’ 6. Most of the species have brown, green or yellow chromatophores with chlorophyll a, c. B-carotene and «-carotene, xanthophyll (e.g., Peridinin). Plastids are generally surrounded by 3 membrane envelope and contain 3-thylakoid lamellae, They are autotrophic or photosynthetic (Ceratium), a few are saprobic or parasitic. 7. Reserve food is carbohydrate and oils. 8. Nucleus is relatively larger in size, has condensed chromosomes even in interphase, chromosomes do not have histone. Nuclear envelope and nucleolus remain present even during call division. This ‘organisation is called Mesokaryen (Dodge, 1966). 9. Anon-contractile vacuole called pusule is present near the flagellar base. It may have one or more vesicle and takes part in floatation and osmoregulation. 10. Some dinoflagellates possess trichocysts and cnidoblasts like those of coelentrates. 11. Reproduction is commonly asexual and occurs through cell division. 42. Isogamous and anisogamous sexual reproduction is reported from some dinoflagellates e.g., Ceratium. 13. Life cycle involves zygotic meiosis (Ceratium, Gymnodinium). Gametic meiosis occurs in Noctiluca. 4. Some marine dinoflagellates show bioluminescence, i-e., emit light, e.g., Noctiluca, Pyrodinium, Pyrocystis. Due to phosphorescence the sea glows at night. 2. Some dinoflagellates like Gonyaulax catenella produce a toxin called saxitoxin into the sea ‘water which is highly poisonous to vertebrates, e.g., fishes and other aquatic animals. Marine shell fish consume dinoflagellates and accumulate the poison which is not harmful to the shell fish (mussel) but upon being consumed causes severe illness in man called paralytic shell fish poisoning (PSP) and even prove fatal. 3. Some dinoflagellates proliferate in large number and cause red tide of the sea, e.9.. Gonyaulax, Gymnodinium. Euglenoid (Euglena-tike) : It is a group of chiorophyllous and non chiorophyllous flagellate protists. Largest genera being Euglena amongst them. 1. Euglenoids are unicellular, flagellate protists found in water or damp soll. Majority of them are fresh water organisms found in stagnant water. 2. Body is spindle shaped with blunt anterior end and pointed posterior end, 3. Cell wall is absent but a covering periplast or pellicle is present which is proteinaceous (elastic) in structure, ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 59 @) sl e moulds or consumer-decomposer protists ‘They were included in class myxomycetes of fungi in two-kingdom classification. They were called mycetozoa by DeBary as they are closely related to animals. Mycologists include them in gymnomycota. Because of their nature they are called protistan fungi General characteristics of the slime moulds are 1 2 3, 4 Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, ‘They are usually free-living, creeping over debris like fallen leaves and rotting logs of wood. ‘They have naked protoplast, not covered by any cell wall in vegetative stage. ‘They lack chlorophyll and have saprobie or phagotrophic mode of nutrition. ‘The body moves along decaying twigs and leaves engulfing organic material. Under favourable conditions, they form an aggregation called plasmodium which may grow and spread over several feet. During unfavourable conditions, the plasmodium differentiates and forms fruiting bodies bearing spores at their tips. During life cycle they are amoeboid and non-cellulosic, but spores have cellulosic wall so that their vegetative phase resembles with animals while reproductive phase resembles with plants, Amoeboid plasmodial stage resembles protozoa and spore forming nature is like fungi ‘Spores are extremely resistant and survive for many years, even under adverse conditions. The spores are dispersed by air currents. Reproduction is both asexual and sexual ‘This group is represented by two separate types of organisms i.e. acellular and cellular Acellular or Plasmodial Slime Moulds ‘Spor Sy Fig. : Life cycle of an acellular slime mould General Characters : 4. Slimy masses found on decaying leaves and lumber. 2. Somatic body is free living, multinucleate, naked, diploid mass called Plasmodium. Movement occurs by means of pseudopodia. 3. During unfavourable conditions, entire plasmodium forms many fructifications/fruting bodies. (polycentric). The fruiting body is called sporocarp which contains a stalk having a sporangium at its tip. The wall of sporangium is called peridium. 4. Sporangium has an intricate network of cytoplasmic threads called capillitium. 5. Diploid protoplast forms haploid spores by meiosis usa Road, New Delhi-110005 Ph011-4762345660 Biological Classification Board & Competitive Exams. Spore wall is double, outer wall is spiny and sculptured, 7. On germination, spores produce biflagellate swarm cells or non-motile myxamoebae which act as gametes. 8. Sexual reproduction is isogamous. 9. Diploid zygote directly forms the plasmodium which becomes multinucleate by repeated mitotic divisions of the diploid nucleus. 10. Chief mode of nutrition is saprotrophic. 11. Vegetative reproduction is by fission. e.g., Physarum, Physarella, Fuligo. B. Cellular slime moulds or communal slime moulds General characters = 4. Wall less, uninucleate myxamoebae present. Complete absence of flagellated cells during life cycle. 2. Sporangia are naked, 3. Spores have cellulosic wall 4, Sexual reproduction is anisogamous. Germination —— Spore ‘Substratum Fig. : Life cycle of Cellular slime moulds (Dictyostelium) Common cellular slime mould, Dictyostelium, is a colonial form in which hundreds of uninucleate, haploid amoeboid cells are aggregated without any fusion to form a colony. The colony gives the appearance of single multinucleate mass of protoplasm and thus, called pseudoplasmodium. Under exhausted food supply and stimulation by CAMP and chemical acrasin, many cells come close together by chemotactic movement during the formation of pseudoplasmodium. Pseudoplasmodium ‘exhibits primitive form of multicellularity and division of labour. So these are also called as. communal slime moulds. On these basis cellular slime moulds are regarded as advanced protists ‘and primitive fungi. During unfavourable conditions, the myxamoebae may form a cyst called microcyst for perennation and dispersal Under dry conditions, the pseudoplasmodium produces stalked sporocarp, which may be branched or unbranched, each branch bearing single sporangium terminally (monocentric). Sporangium is wall less. Within the sporangium, amoeboid cells become rounded to secrete a spore wall around. On the approach of favourable conditions, spores are liberated. Each spore germinates by rupturing cellulosic wall to form myxamoeba and the myxamoebae may live independently, multiply by repeated mitotic divisions or get aggregated to form pseudoplasmodium. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110008 Ph.011-4762345662 Biological Classification ANTERIOR END Board & Competitive Exams. Fig. : Paramoecium (a protozoan) 21. Which kingdom includes nutritionally most diversed group of organisms and has no well defined boundaries? (1) Monera (@) Fungi 22. Chrysophytes are (1) Diatoms and desmids (1) Pecto-cellulosic cell wall (2) Multicelular eukaryotes @) Protista (@) Plantae (2) Diatoms and dinofagellates (3) Slime moulds and desmids (4) Slime moulds and dial 23. Which of the following option for diatoms is correct? 2) Stlicifed cett wal (4) Produce saxitoxin toms 24. The cell wall encloses the peripheral layer of cytoplasm surrounded a large central vacuole in (1) Euglena 2) Diatoms (3) Amoeba (4) Autosira 25. Red lide is caused by rapid multiplication of (1) Nostoc @) Desmids @) Diatoms. (4) Gonyaulax 26. Mark the mis-matched pair (1) Pyrocystis — Bioluminescence (2) Whirling whips — (3) Diatomite = (4) Gymnodinium - ‘Soap box like body structure Kieselguhr Zygotic meiosis ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, |. New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 61 ‘Sexual reproduction is anisogamous type. During sexual reproduction, a number of myxamoebae form ‘a clump. One of the myxamoeba becomes larger and engulfs the surrounding smaller myxamoebae. The plasmogamy occurs and the fused protoplast secretes a thick wall around to form macrocyst. In the macrocyst, karyogamy occurs and it thus, becomes zygote. It is followed by meiosis and several mitotic divisions to form a large number of haploid myxamoebae, which are released by rupture of macrocyst wall. e.g., Dictyostelium, Polysphondylivm, By taking example of slime mauld, now we can justify that protista forms a connecting link with plants, ‘animals and fungi. Fung} like feature : Formation of fruiting bodies. Plant @ feature : Cell wall around spores. Animal like feature : Plasmodium is without cell wall, Example 6 : In which type of slime mould somatic body is free living, multinucleate, naked and diploid? Solution: Acellular/Plasmodial slime mould Try Yourself 11. Give one example of euglenoid. 12._Which type of nutrition Eugiona shows? PROTOZOANS These are unicellular organisms with heterotrophic nutrition. They are believed to be primitive relatives of animals. There are four major groups of protozoans. 1. Habitatand habit Fresh water, seawater or| Free living (aquatic) or] Fresh water or| Allendoparasites moist soil "mostly free | parasitic. marine, fewparasite. living, few parasites. 2. Lecomotory structure Pseudopodia (false feet) | Flagelia Cilia Absent 3. Special feature Silica shells in some|Rare sexual reproduction| Possess definite | Infectious spore-like forms. with diverse type off region of ingestion | stage is present in life associations — commensal, | (gullet) and cycle. symbiont, parasitic. egestion). 4. Example and diseases Amoeba, Entamoeba| Trypanosoma (Sleeping | paramoecium Plasmodium (Most (Dysentery) sickness) notorious causing malaria) ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 63 27. 28. 29. Red-orange photosensitive pigment in Euglena is (1) Astaxanthin @)Chlorophyt (8) Phycooyanin (4) Phycoenythrin Acellular slime moulds show (1) Haploid uninucleato plasmodium @) Naked sporangia @)_Autotrophie nutrition (4) Isogamous type reproduction In acellular slime moulds, sporangium has an intricate network of cytoplasmic threads called (1) Peridium @) Pseudopodia (3) Capit (4) Trichoeyst Mark the correct match : (1) Amoeboid protozoan — All endoparasite @)_ Flagellated protozoan = Paramoecium (@)Sporozoan = Absence of locomotory structure 4) Giliated protozoan — Entamooba KINGDOM : FUNGI ‘This kingdom contains achlorophyllous, eukaryotic, heterotrophic, spore producing, thalloid organisms. Fungi include diverse organisms which range in structure from unicellular yeasts to highly complex edible mushrooms, non-edible toad stools. They are cosmopolitan in occurrence being present in air, water, soil and ‘on the animals and plants. They are more abundant in warm and humid areas. So, they show great diversity in morphology and habitat. Why we keep food in the refrigerator? Foods are protected from attack of bacteria and fungi by refrigerating them because at low temperature they become inactive. General Characters: (1) They are cosmopolitan and occur in air, water, soil and on animals and plants. They are mostly terrestrial ‘They prefer to grow in warm and humid places. They may grow on tree bark, dung, wood, burnt wood and keratinous material (e.g., hair, horns) and are called corticolous (bark), coprophilous (cow dung), epixylic (wood), xylophilous (burnt wood) and keratinophilous (keratin) respectively, 2) The body is haploid (n) and thalloid, /.e., not differentiated into root, stem and leaves. They are ‘mutticellular (except Yeast and Synchytrium). The fungal body is made up of thread like elongated tubular structures, called hyphae. These cris-cross with one another to form a network known as mycelium. (8) The hyphae may be aseptate and multinucleate. Such a hypha is termed coenecytic. In most of the fungi, the mycelium is septate. The septum, however, is not complete, but has a pore through which continuity of the cytoplasm of the adjoining cells is maintained. The septum may have simple central pore as in ascomycetes, but in higher fungi (class basidiomycetes), the septum is dolipore septum, in which central pore possesses a barrel shaped inflation. In septate mycelium, individual cell may contain single nucleus (monokaryotie — feature of primary mycelium) or an intermediate phase of two nuclei (dikaryotic — feature of secondary mycelium). (4) The cell wall of the hyphae is made up of chitin or fungal cellulose, which is a polysaccharide containing nitrogenous compound and it is basically made up of acetylglucosamine. In some fungi, the cell wall is made up of cellulose (e.9., Phytophthora, Pythium and other oomycetes). Reserve food material is stored in the form of oil and glycogen. (6) Cells have unicisternal golgi bodies. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345664) Biological Classification Board & Competitive Exams. (©) Mitosis in somatic cells is Karyochorisis type (mitosis with intranuclear spindle formation). (7) Nutrition is heterotrophic which includes saprophytes, parasites and symbionts. (8) In most of the fungi, there are two distinct phases in the life cycle, the vegetative or assimilative phase and the reproductive phase. in vegetative phase, fungus is microscopic hidden in the substratum and is hardly visible to the naked eyes. The fungus enters into reproductive phase after attaining maturity in the vegetative phase. In unicellular yeasts, the same coll performs both assimilative and reproductive functions. Such type of fungal bodies in which entire cell gets transformed into reproductive structures are known as holocarpic. Fungal body is termed eucarpic in which a part of mycelium is used up in the development of reproductive structures. Reproduction in Fungi Fungi reproduce by all the three modes, /e., vegetative, asexual and sexual. 4. Vegetative reproduction: It occurs by the following methods (a) Fragmentation : The mycelium breaks up into two or more fragments due to mechanical injury, decay ‘or some other reasons. Each fragment grows into independent mycelium. (b) Fission : Here, simple splitting of vegetative cells into two daughter cells takes place by simple constriction (©) Budding : Some fungi like yeast produce smalll outgrowths, i.¢., buds from their vegetative body. Eventually, the buds are cut off from parent cell and mature to form new individuals. 2. Asexual reproduction : It occurs through spores. These are single celled specialized structures which separate from the organism, get dispersed and germinate to produce new mycelium after falling on suitable substrate. The spores produced during asexual reproduction in fungi are formed by mitotic division and are thus termed, mitospores. The various means of asexual reproduction are as follows : (a) Zoospore: Many fungi, especially aquatic members produce these types of spores. Zoospore may be uniflagellate, 0.9., Synchytrium or biflagellate, e.g., Saprolegnia, Pythium and are naked uninucleate structures formed in zoosporangia. They germinate to give rise to new mycelium. Biflagellate zoospores. are of two kinds (e.g., Saprolegnia) pear shaped or pyriform with 2 flagella placed at anterior end (primary zoospore) and kidney shaped or bean shaped, bearing two laterally inserted flagella (secondary Zoospore). This phenomenon of having two types of zoospores is called diplanetism. oes = vena ( ee Fig.: A-F. evict ities asic reproduction ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345566 Biological Classification Board & Competitive Exams. (e) Gametangial contact : In this process two gametangia come in contact with one another. A fertilization tube is developed to facilitate the migration of entire contents of male gametangium into the female gametangium. Both the gametangia never fuse together losing their identity, e.g., Pythium, Albugo (Comycetes) (©) Gametangial copulation : In this process, direct fusion of entire contents of two gametangia is accomplished by dissolution of their common walls resulting in the formation of a single cell, in Which protoplasts of two gametangia fuse, 0.9., Mucor, Rhizopus (Zygomycetes). (@) Spermatization : Some fungi produce many minute, spore like, single-celled structures called ‘spermatia (non motile male gametes) on spermatiophores (hyphae). These structures are transferred through agencies like water, wind and insects to special female receptive hyphae (Basidiomycetes). The contents migrate into receptive structure. Thus, dikaryotic condition is established, e.g., Puccinia (0) Somatogamy : This takes place in most of the higher true fungi, where formation of gametes is absent. In such fungi, direct fusion of somatic hyphal cells occur to establish dikaryophase, e.g., Agaricus. 2. Karyogamy : Fusion of two nuciei is called karyogamy. In some fungi, the fusion of two haploid cell immediately results in diploid cells (2n). However, in some fungi (e.g. Agaricus, Aspergillus), an intervening dikaryotic stage (n + ne. two nuclei per cell) occurs; such a condition is called a dikaryon and the phase is called dikaryophase. Later, the parental nuclei will fuse and the cells become diploid in karyogamy. Meiosis : The fungi form fruiting bodies in which reduction division (melosis) occurs leading to the formation of haploid spores. Kingdom fungi is classified on the basis of Morphology of the Mycelium, Mode of Spore Formation and Fruiting Bodies into various classes. Fungi Phycoffycetes Asconlycetes —BasidioInycates Deutercinycetes, Comycetes: Zygomycetes Example 7: Name the asexual reproductive spores in fungi Solution : __Conidia or sporanglospores or zoospores. Try Yourself 413. What is the basis of classification in kingdom fungi? 14, _Name the sexual spores in fungi. 1. Oomycetes : The Algal Fungi 4. Hyphal wall contains cellulose and other glucans in many members. 2. The mycelium is coenocytic (multinucieate and aseptate). 3. Asexual reproduction involves the formation of spore containing sacs or sporangia. In aquatic forms, the sporangia produce zoospores. 4. Zoospores generally have two laterally inserted flagella with heterokont condition, in which one flagellum is smooth (whiplash) while the other is of tinsel type (having fine surface outgrowths called mastigonemes) 5. Sexual reproduction is by planogametic fusion or gametangial contact. 6. The product of sexual reproduction and site of meiosis is oospore. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 65 Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, (b) Sporangiospore: Sporangiospores are thin walled non-motile spores produced endogenously in a ‘sporangium during favourable conditions, which after liberation give rise to new mycelium, e.g., Rhizopus, Mucor. (©) Conidia: Conidia are_non motile, thin walled exogenous spores produced at the tips of erect hyphae called conidiophore. They are arranged in chains upon the conidiophore, e.g., Aspergillus and Penicilium. (@) Chlamydospore: In some fungi the hyphae under unfavourable conditions, forms thick walled resting resistant spores which later get separated from each other. They may be terminal or intercalary. They ‘may remain viable for several years. On ratum to favourable conditions they germinate to give rise to new individuals. Thus, chlamydospores are structures for perennation also, e.g., Rhizopus. (e) Oidia: Non-motile thin walled spores developing under sugar rich conditions in medium. Their budding condition is called torula stage Sexual reproduction: It occurs through eospores, ascospores and basidiospores. The various spores are Producad in distinct structures called fruiting bodies. The fruiting bodies are ascocarps and basidiocarp which contain asci and basidia respectively. The ascospores: are a type of non-motile spores which are produced inside special sacs called asci (singular-ascus) Basidiospores are non-motile which are formed exogenously (e. outside the body) on short outgrowths of club-shaped structure called basidium. Sexual cycle involves three steps 1. Plasmogamy: There is union of protoplasm between two haploid hyphae of compatible mating type or gametes. Basidium A B Plasmogamy occurs by the following methods : Fig. : A. Ascospores, B. Basidiospores (a) Planogametic copulation / Gametic fusion : This is the simplest form of sexual reproduction. In this process, fusion of two gametes of opposite sex or strains takes place. One or both of the fusing gametes are motile. It results in the formation of a diploid zygote, e.g., Allomyces. 2 re (©) Gametangial contact, | ee | (©) Gametangial copulation Fig.: Different modes of plasmogamy in fungi This process is usually of three types : Isogamy, Anisogamy, Oogamy. Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 67 0 O} w Phytophthora infestans causes late blight of potato and occasionally of tomato as well. Great Irish famine of 1845 — 1847 was due to late blight of potato. Albugo candida (Cystopus candidus) causes white rust of crucifers and is characterised by the ‘appearance of irregular white blisters on the leaves and stems. Pythium debaryanum causes damping off disease in seedlings of tomato, chillies, castor, mustard Sclerospora graminicola causes downy mildew in cereals particularly, Pennisetum typhoides (vern. Bajra) green ear disease. Poronospora parasitica causes downy mildew in a number of plants, such as pea, mustard, spinach, onion etc. ‘Saprolegnia causes salmon disease of gils in fishes. Zygomycetes : The Conjugation Fungi 1. It is class of terrestrial fungi which are mostly saprotrophic and rarely parasitic. 2. Hyphal walll contains chitin or fungal cellulose. 3. The mycelium is coenocytic (multinucleate, aseptate) like the one found in Oomycetes. 4. Motile cells (zoospores or planogametes) are absent. 5. Mitospores are non motile. They are called sporanglospores as the spores are formed inside ‘sporangia that are borne at the tips of special hyphae called sporangiophores. 6. Sexual reproduction occurs through gametangial copulation or conjugation. Because of it, zygomycetes are also called conjugation funy The gametes are commonly multinucleate and are called coenogametes. 8. Sexual reproduction produces a resting diploid spore called zygospore. Because of the presence of zygospore, the group of fungi is called zygomycetes. Zygospore differs from oospore in that, for its formation a distinct food laden, non motile, large female gamete is not produced. 9. Zygospore is the site of meiosis and does not give rise to new mycelium directly. Instead it produces ‘a new sporangium called germ sporangium (previously called zygosporangium). Germ sporangium forms meiospores called germ spores. 10. Sometimes, gametangia fail to fuse. Gametangia become surrounded by a thick wall resulting in formation of azygospore (parthenogenetically produced zygospore). Fig. : Common Phycomycetes ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-476234566B Biological Classification Board & Competitive Exams. (Rhizopus stolonifer (= R. nigricans) is popularly known as black bread mould. M. mucedo Is called dung mould or pin mould. Rhizopus and Mucor are the common saprotrophic fungi that attack a variety of food stuffs. Soft rot or lek disease of strawberry, apple, jack fruit, sweet potato etc. is due to Rhizopus. Mucor pusillus causes infection of internal organs in human beings. Absidia corymbilera causes bronchomycosis. (W)__ Ramysin (antibiotic) is obtained from Mucor ramannianus. Ill, Ascomycetes : The Sac Fungi 1. The mycelium consists of septate hyphae. (Yeasts are an exception in that they are basically unicellular) 2. They are saprophytic, decomposers, parasitic or coprophilous (growing on dung). 3. The septa possess central pores called septal pores. The pores allow communication and transport between adjacent cells. 4. Cell wall contains chitin. Motile structures do not occur In the life cycle. 6. In majority of ascomycetes, the common mode of asexual reproduction is through the formation of conidia. Conidia are bore on branched or unbranched hyphae called conidiophores, e.9., Penicillium, Aspergillus. o Vesicle Fig. : Asporgillus. A mature conidiophore bearing sterigmata and chains of conidia 7. Female sex organ is called ascogonium. 8. Plasmogamy occurs by means of (@ — Gametangial contact (e.g., Pyronema) (i) Conjugation (e.g, Yeast) (ii) Spermatization (0.9., Ascobolus) (w) Somatogamy (e.g., Peziza) (v) Autogamy (e.., Morchella). 9. Karyogamy is delayed after plasmogamy. A new transitional phase appears in the life cycle. It is called dikaryophase. The cells of dikaryophase are called dikaryotic cells. Each such cell possesses two different nuciei (Dikaryon). This forms a shorter phase of life cycle. 10. Once a cell becomes dikaryotic, it transfers the nucleus to other cells by the crozier method (method of dikaryotization) to make them dikaryotic. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345570) Biological Classification Board & Competitive Exams. Example 8 Solution : What is the name of bread mould? Rhizopus Try Yourself 15. Write the name of an unicellular fungi 46. What are coprophilous fungi? IV. Basidiomycetes : The Club Fungi 1. nn 42. 43, ‘They are the most advanced and most commonly seen fungi. Their fructifications are often large land conspicuous, e.g., mushrooms, toadstools, puff balls, bracket fungi etc. Basidiomycetes are among the best decomposers of wood. They are able to decompose both cellulose and lignin. Lignin is not metabolised by most other fungi and even bacteria. Ganoderma species causes decay of wood even on standing trees. Motile structures or cells are absent. Mycelia are of two types, primary and secondary. Primary mycelium contains monokaryotic cells and is short lived Monokaryotic phase or primary mycelium may multiply by oidia, conidia-tike spores and pycniospores. Secondary mycelium is long lived and dominant phase of life cyct dikaryophase. It consists of profusely branched septate hyphae. Septa possess dolipores or central pores with barrel-shaped outgrowths (except rusts and smuts). Handle like outgrowths are found on the sides of septa. They are called clamp connections. Clamp connections are meant for proper distribution of dikaryons at the time of cell division. Parenthosome Pore It is represented as Fig. : Dolipore septum ‘Secondary mycelium can perennate in the soil or wood by means of sclerotia or rhizomorphs. Dikaryophase or secondary mycelium may multiply by different types of spores chlamydospores, aecidiospores, uredospores, teleutospores etc. There is often differentiation of two mating types (+) and (-) in thallus. Sexual reproduction does not involve sex organs. Instead fusion occurs between basidiospores and other monokaryotic spores, between a spore or spermatium and a hypha or between two hyphal cells of primary mycelia. Karyogamy and meiosis occur in club-shaped structures known as basidia (singular ~ basidium), The name of the class is based afer them, Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 69 0 Ww wi) ow “ ow (vi) (&), ‘Members of this class are said to be our worst fungal enemies. (vit) Brewing Industry : Under anaerobic conditions, sugary solutions inoculated with yeasts are converted 11. Some dikaryotic cells function as ascus mother cells. This converts the cells into asci (singular — ascus). Ascus is a sporangial sac peculiar to Ascomycetes. Ascus is the site of karyogamy and meiosis. 4 to 8 haploid meiospores namad ascosperes ara producad endogenously in each ascus. In most of the cases, half the number of ascospores belong to one mating type(+) while the other half belong to the second mating type (-). 12. Ascospores may be arranged linearly (Neurospora) or unorderly (yeast). 13. The asci may occur freely or get aggregated into specific fructifications called ascocarps. Ascocarps are of many types : cup-like (apothecium, e.g., Peziza), flask-shaped (perithecium, 6.9.. ‘Neurospora, Claviceps), elongated with a slit (hysterothecium), closed (cleistothecium, 0.9. Penicillium) cushion like, chambered (Ascostroma, 0.g., Pleospora). The fructifications of some ascomycetes are edible, ¢.g., morels, truffles, Knowledge Cloud Morels (sponge mushroom) are Ascomycetes with edible ascocarps having fleshy sponge-like conical cap or pileus and a stalk like stipe, e.g., Morchella esculenta (vern. Guchhi), M. deliciosia. ‘Truffles : They are edible tuber-like subterranean ascocarps, e.g., Tuber aestivum. Claviceps purpurea causes ergot of rye and C. microcephala causes ergot of bajra in which ears are filled with sclerotia of the fungus. Eating of infected cereals produces ergotism. (It produces an alkaloid called ergotine which causes abortion, if eaten, unknowingly). This is used as a drug to promote expulsion of foetus). Neurospora crassa (Pink bread mould), is often employed in biochemical and genetic work (experimental genetics), so is called Drosophila of plant kingdom. Erisyphe : The fungus produces powdery mildew (fungal disease in which pathogen results in a powdery coating of spores on the surface of the host), e.g. Erysiehe graminicola. Penicilium chrysogenum is used in commercial production of the antibiotic penicillin. The later was the first commercial antibiotic. It was discovered from P. notatum. The fungus is employed in ripening of cheese, e.g., P. roqueforti and P. camemberti Aspergillus : It is common green smoky mould which not only contaminates laboratory cultures (hence called weed of laboratory), but also various food stuffs including bread, butter etc. Aspergillus flavus is highly poisonous due to the presence of aflatoxins. A. oryzae is the source of diastase enzyme. into alcoholic beverages, e.g., beer, wine, cider, toddy. The two common yeasts used by brewing industry are Saccharomyces cerevisiae (Beer or Baker's yeast) and S. ellipsoidens (Wine yeast). Gibberellins: They were first discovered in the extracts of Gibberella fujikuroi growing on rice (bakanae disease of rice). It is the perfect stage of fungus Fusarium moniliforme (Deuteromycete). Gibberellins are natural plant growth hormones. Penicillium : important characters (@ Facultative parasite and saprophytic fungi )) Mycelium is branched septate, with simple septal pore and each cell Is uni or multinucieate depending upon the species. Asexual reproduction occurs by conidia. Conidiophores are often branched. The first branch level is called rami and second or ultimate branches are called metulae having bottle shaped ‘sterigmata. Each sterigmata produces a chain of conidia. The conidia in chain are arranged in basipetal order. Each conidium is uninucieate, non motile, two layered, dispersed by air and germinates to form new mycelium. () Sexual reproduction : It exhibits dikaryophase and produces ascocarp. The ascocarp is cleistothecium type. Each ascus has 8 ascospores. Ascospore germinates to form new mycelium. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 74 14. A basidium commonly produces four meiospores or basidiospores exogenously at the tips of fine ‘outgrowths called sterigmata or directly on the basidium. 15. The fungi may or may not produce fructiications called basidiocarps. The basidiocarps vary from microscopic forms to large macroscopic structures. Some puff balls and brackets can be over 50 em in diameter. Knowledge Cloud @ Smuts : They produce thick-walled, black-coloured resting spores called smut spores. Smuts are of two types, covered and loose. In covered smut, the spore mass remains within the membranous, covering of sorus, e.g., Ustiiago horde! (covered smut of barley), Ustilago maydis (smut of corm). In loose smut the spores are exposed while attached to the host, €.g., Ustilago nude tritici (loose smut of wheat), U. avenae (loose smut of oat). (i) Mushrooms : They are edible and non edible Agaricales which possess umbrella like basidiocarp. ‘Common examples of edible mushrooms are Agaricus campestris, A. bisporous, Volvariella volvacea (Paddy straw mushroom), Pleurotus ostreatus etc. (i) Teadstools : Toadstools are poisonous mushrooms which generally have white spores. Amanita caesarea (Caeser’s mushroom) was used in poisoning Roman emperor Caesar. The other toadstools. are Amanita phalloides (Death cup), A. muscaria (Fly agaric) and Gynomitra esculenta (heat labile carcinogenic toxin). (¥) Rusts : They are characterised by the formation of rusty pustules containing the spores. (@)Puccinia graminis tritici — Black rust of wheat. (©) Puccinia glumarum or P. stniformis — Yellow rust of wheat. (©) P. recondita - Brown rust of wheat ™ (@) _Puccinia is heteroecious obligate parasite which completes its life cycle on two hosts; Primary host ~ wheat ‘Secondary or alternate host ~ Barberry () Itthas macrocyclic life cycle with five types of spores: uredospores (n + n), toleutospores. (a + n) on wheat plant, basidiospore (n) in soll, pycniospores (n) and aeciospores (n + n) on barberry leaf. (W) Hallucinogens : Psiiocybe mexicana (Sacred mushroom) has hallucinating properties similar to LSD. Itis used by Mexican Indians during certain religious ceremonies. (vi) Armiltaria (largest fungi): A. mellea (Honey mushroom) is a serious root parasite of both hardwoods ‘and conifers. The fungus develop mhizomorphs into the phloam of the host and hence, blocks the food supply. (vii) Puffballs : The basidiocarp is a stalked rounded structure which, upon ripening, releases out puffs of spores, The fructification may grow above or below the substratum, e.g., Lycoperdon oblongisporum, L. giganteum. (6) Bracket fungi (Shelf fungi) : They are basidiomycetes whose basidiocarps or fructifications appear on tree trunks, logs, lumber etc. just as brackets or shelves, e.g, Fomes applanatus, Polyporus sulphureus, Ganoderma. (®) Predator fungi :, e.g., Dactylaria, Arthrobotrys. (xi)_Stink hom. Phallus impudicus (Dead man's finger). Spore mass produces a stinking odour to attract fle. Life History of a Mushroom Agaricus campestris is the common field mushroom which has edible basidiocarp. The fungus is saprotrophic. ‘The vegetative or assimilative part of mycelium is subterranean. It is found in moist humus rich soil of open fields, grassland, piles of straw or within rotting logs. ‘The mycelium multiplies by fragmentation; occasionally by oidia and chlamydospores. Life cycle of mushroom contains two types of mycelia, primary and secondary. Sex organs do not differentiate. Primary mycelium is short lived. It consists of septate hyphae having monokaryotic cells. The Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345672> Biological Classification Board & Competitive Exams. mycelia are heterothallic, [having two mating types, (+) and (-)]. The hyphae of two mating types come in contact and show somatogamy. However, only plas mogamy occurs at this time. It gives rise to a dikaryotic call that grows, divides and produces a long-lived and extensive dikaryotic or secondary mycelium. The hyphae of secondary mycelium show clamp connections and dolipore septa. Its cells possess two haploid nuclei instead of single diploid nucleus. Fig. : Agaricus : Stages in the development of Basidiocarp Under favourable conditions, hyphae of secondary mycelium collect at places and give rise to rounded or Pyriform compact masses of hyphae called buttons. The buttons enlarge and produce aerial fructifications or basidiocarps. The latter are popularly termed as mushrooms. In contrast the secondary mycelium, from which mushrooms develop, is known as spawn. The basidiocarps or mushrooms often lie in rings. The latter are called as fairy rings, its diameter increases centrifugally every year. Each basidiocarp or mushroom is cream to pinkish brown in colour and consists of two parts, stipe and pileus. The stipe or stalk is fleshy. It is slightly swollen at the base. Pileus is umbrella-like cap of the mushroom. In the button stage, the pileus is connected to stipe by membrane called veil or velum. It ruptures ‘during growth of pilous. However, its remains can be seen on the upper part of stipe as annulus. The pilous is circular in outline. Its upper surface is more or less convex. The under surface is flat or concave. It bears 300-600 radiating rows of vertical plates named gills (lameliae), Subhymenium —Trama Fig. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, Now Dolhi-110008 Ph.011-47623456 \garicus: Internal structure of Gill74 Biological Classification Board & Competitive Exams. Example 10 > Name the asexual reproductive bodies of Deuleromycetes. Solution: Conidia. Try Yourself 19. Name the main groups in which fungi are classified 20. Give three examples of deuteromycetes. After this discussion, we can easily differentiate between various classes of fungi features | __ Phycomycetes Ascomycetes | Basidiomycetes | Deuteromycetes: 4. Mycelium ‘Aseptate/coenocytic 2. Asexualspore | Zoospore (Planospore)/ Sporangiospore (Aplanospore) 3. Sexualspore | Zygospore/Oospore 4. Fruiting bodies | Absent Septate, branched | Septate, branched | Septate, branched Ascospore Generallyabsent | Conidia Basidiospore Absent Basidiocarp Absent DIGEST Common names of some Fun; Fungus/Group Rhizopus Morchella Saccharomyces Phallus Hydnum Ganoderma, Polyporus Aspergillus flavus ‘Mucor mucedo Peniciium READ (€.>) Peziza Lycoperdon, Clavatia Cyathus Clavaria ‘Common names Black/Bread mould ‘Morels (sponge mushroom) Yeasts (sugar fungus) ‘Stink hors “Tooth fungi (Hedge hog fungi) Wood / Bracket / Shelf fungi Guinea pig of plant kingdom Dung mould Blue/green mould Cup fungi Puff balls Bird's nest fungus Coral fungi Toad stool Jelly fungi/Trembiing fungi Oyster mushroom, Button mushroom Drosophila of plant kingdom. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 73 The two sides of vertically placed gills are lined by thousands of club-shaped basidia alongwith sterile paraphyses. The two, together constitute the fertile layer or hymenium of the gill. Hymenium is subtended by compact subhymenium. The centre consists of interwoven hyphae called trama, Each basidium functions as the site for both karyogamy and meiosis. The two nuclei fuse to form a shortlived diploid synkaryon. The latter, then divides meiotically giving rise to four haploid nuclei, two of (+) strain and two of (-) strain. The free end of the basidium now develops four peg-like outgrowths called sterigmata, Each sterigmata bears an ovoid pinkish-purple meiospore termed as basidiospere. A droplet appears at the tip of sterigmata which creates tension and hanging basidiospores are carried away by air currents. The basidiospores are liberated successively for several days. After falling on a suitable substratum, each basidiospore germinates to produce monokaryotic primary mycelium. Example 9: What is the name of rust fungus? Solution Puecinia. Try Yourself 17. Name the group to which bracket fungi belong. 18. Where karyogamy and meiosis take place in basidiomycetes? V. Deuteromycetes : The Fungi Imperfecti ‘There is only asexual and vegetative phase known so these are commonly regarded as imperfect fungi It is also possible that the asexual and vegetative stage have been given one name (and placed under deuteromycetes) and the sexual stage another (and placed under another class). By the establishment of linkages, the perfect stage (or sexual form) discovered in these fungi, they are moved out of deuteromycetes to ascomycetes and basidiomycetes. The deuteromycetes reproduce only by asexual spores known as conidia. The mycelium is septate and branched in these fungi. Some of them are saprophytes or parasites while a large number of them are decomposers of litter (organic matter) and help in mineral cycting Examples : Alternaria, Colletotrichum and Trichoderma. Leaf spot of rice : Helminthosporium oryzae causes leaf spot disease of rice commonly called brown leaf spot of rice. It caused Bengal famine in 1942-43, (i) Early blight: Alternaria solani causes early blight of potato. The leaves develop small oval brown ‘spots with concentric rings (target board symptom). (i) Tikka disease: Circular necrotic dark brown or blackish leaf spots develop in groundnut due to Cercospora personata. () Red rot : Colletotrichum falcatum produces red rot of sugarcane. (™ Wilts: Many economically important plants (e.g... cotton, pigeon pea) show sudden signs of wilting due to blockage of tracheary elements by growth of fungus, Fusarium especially F oxysporum, F udum. (™) Ringworm of fool/Athlete’s foot is caused by Trichophyton interdigitate. ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 75 Did You Know? Common Fungicides and their composition 1. Bordeaux mixture — (CuSO, : Ca(OH), : H,0). First fungicide discovered by RMA Millardet = Commonly known as holy water of plant pathology 2. Burgandy mixture — Mixture of CuSO, + Na,CO, + H,O was discovered by Mass (Soda Bordeaux) 3. Chestnut mixture _— Ammonium carbonate + copper sulphate MYCORRHIZA (FUNGAL ROOTS) ‘The mutual beneficial or symbiotic association of a fungus with roots of higher plants (gymnosperms and angiosperms) represents mycorrhiza. Benefits to fungi Bonofits to plant 1. Nourishment from root cortical cells. | 1. Surface area for absorption increases. 2. Shelter 2. Enhanced supply of H,0, N.P. S. The mutually beneficial or symbiotic association of a fungus with the roots of higher plants is termed mycorrhiza. Mycorthizal roots differ in shape from normal roots and often show a wooly covering. These roots lack root cap and root hairs. A fungus may get associated with roots of a number of plants and a particular plant may form association with a number of fungi. Depending upon the location of the fungus, the mycorrhiza is of two types, /e., ectomycorrhiza and endomycorrhiza, In ectomycorrhiza, the fungal hyphae are mainly external, forming a wooly covering on extemal surface of root and forms network of mycelium (Hartig net) in the intercellular spaces of the cortex. Fungal partner is commonly basidiomycetes like Boletus, e.g., Pinus roots In endomycorrhiza, the fungal hyphae enter the tissue of the root, spreading intercellularlly and intracellularly, The fungus is able to break the cell wall in a limited way and is restricted to cortical region of the root. Some hyphae send small projections into cortical cells without destroying them. Such fungi are termed VAM (Vesicular Arbuscular Mycorrhiza), e.g., Orchid roots. Mycorrhizal association is a symbiotic relationship as both the partners are mutually beneficial to each other. The fungal partner ‘obtains nourishment from the cortical cells of the root and depends. upon the plant for shelter. The root cells excrete sugars and other soluble gradients which are used by fungal hyphae spreading in intercellular spaces. The hyphae may get nourishment from the cells directly and also by sending small projections into cortical cells. The fungus seems to be essential for the growth of the plant having mycorrhiza. The plant also gets benefit from the association as the fungal hyphae spreading in soil substantially increases the surface area of absorption, thereby enabling the plant to get ‘enhanced supply of water, nitrogen, phosphorus and other minerals from the soil. Orchids seldom occur without mycorrhiza, Certain forest trees like pines, birches show stunted growth if their roots are not associated with fungus. vices Pvt. Lid. - Regd. Office : Aakash Towor, 8, Pusa Road, New Delhi-110005 Ph.011-47623456 ‘Aakash Educational76) Biological Classification Board & Competitive Exams. KINGDOM : PLANTAE ‘All eukaryotic chlorophyll containing organisms commonly called plants are included under kingdom plantae. Few of them are partially heterotrophic such as insectivorous plants (e.g. Bladderwort and Venus fly trap) or parasites (e.g., Cuscuta). The plant calls have an eukaryotic structure with prominent chloroplasts and cell wall which is mainly made up of cellulose. Kingdom Plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms. In plants, life cycle has two distinct phases /.e. the diploid sporophytic and haploid gametophytic that alternate with each other. This phenomenon is called alternation of generation. The lengths of haploid and diploid phases, and whether these phases are free living or dependent on others, vary among different groups in plants. KINGDOM : ANIMALIA “The members of this kingdom are multicellular and their cells lack cell walls. They directly or indirectly depend ‘on plants (autotrophs) for nutrition. In these members, the digestion of food takes place in an internal cavity land they store their food reserves in the form of glycogen or fat. Their mode of nutrition is holozoic by ingestion of food. They follow a definite growth pattern and grow into adults that have a definite shape and size. Most of them are capable of locomotion. Higher forms of kingdom animalia show elaborate sensory and neuromotor mechanism. Example 11: Give two examples of insectivorous plant. Solution Bladderwort and Venus fly trap. a4 32, 33, 21. Members of kingdom animalia store food reserves in the form of 22._Which mode of nutrition is found in kingdom animalia? Mar he ot one ng (1) Unite go bcos (2) Show 2 rat dvorty mn morphology and habit (3) Nest of ie members are equa (2) Raver fod mettle erento fom fo and sro Select correctly mched par (1) Rhizopus = Sporangiospore (2) Penicitium = Ascocarp 8) Mucor = Dikaryophase (4) Aspergilus = Conia Coenocytic dimorphic vegetative mycelium is found in (1) Neurospora 2) Rhizopus (8) Penicitium (4) Ustilago ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, Now Dolhi-110005 Ph.011-4762345576 Biological Classification Board & Competitive Exams. KINGDOM : PLANTAE ‘All eukaryotic chlorophyll containing organisms commonly called plants are included under kingdom plantae. Few of them are partially heterotrophic such as insectivorous plants (0.9. Bladderwort and Venus fly trap) or parasites (¢.g.. Cuscuta). The plant cells have an eukaryotic structure with prominent chloroplasts and cell wall which is mainly made up of cellulose. Kingdom Plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms. In plants, life cycle has two distinct phases /.e. the diploid sporophytic and haploid gametophytic that alternate with each other. This phenomenon is called alternation of generation. The lengths of haploid and diploid phases, and whether these phases are free living or dependent on others, vary among different groups in plants. KINGDOM : ANIMALIA “The members of this kingdom are multicellular and their cells lack cell walls. They directly or indirectly depend ‘on plants (autotrophs) for nutrition. In these members, the digestion of food takes place in an internal cavity and they store their food reserves in the form of glycogen or fat. Their mode of nutrition is holozoic by ingestion of food. They follow a definite growth pattern and grow into adults that have a definite shape and size. Most of them are capable of locomotion. Higher forms of kingdom animalia show elaborate sensory and neuromotor mechanism. Example 11: Give two examples of insectivorous plant. Solution: Bladderwort and Venus fly trap, 34 22, 33. Try Yourself 21. Members of kingdom animalia store food reserves in the form of 22._Which mode of nutrition is found in kingdom animalia? Mark the odd one (wert. fungi) (1) Unicisternal golgi bodies (2) Show a great diversity in morphology and habitat (3) Most of the members are aquatic (4) Reverse food material is stored in the form of oil and glycogen. Select Incorreetly matched pair (1) Rhizopus — Sporangiospore (2) Penicitium = Ascocarp @) Mucor — Dikaryophase (4) Aspergilus = Conia Coenocytic dimorphic vegetative mycelium is found in (1) Neurospora (2) Rhizopus (8) Peniciium (4) Ustiago ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 77 34. Choose Incorrect match w.rt. different classes of fungi (1) Comycetes ~ zoospore ~ gametic copulation 2) Zygomycetes — sporangiospore — zygophore: () Ascomycetes ~ conidia ~ monokaryotic aseptate mycelium (4) Phycomycetes — algal and conjugation fungi — coenocytic mycelium 35. Asci are not organised into ascocarps in (1) True yeast 2) Drosophila of plant kingdom (3) Pigmented mould (4) Morets, 36. Ultimate branches of conidiophore in Penicilfium is (1) Rami 2) Phiatide @)_Sterigmata (4) Metulae 87. The common type of asexual spore in sac fungi is (1) Uninucleate and motile @)_Unilayered and non-motile (3) Two layered and non-motile (@) Multinucteate, two layered and motile 38. The name of the class is based on sexual structure as the site of karyogamy and meiosis in (1) Phycomycetes and Actinomycetes @) Deuteromycetes and Zygomycetes (3) Ascomycetes and Basidiomycetes (4) Basidiomycetes and Actinomycetes 39. In Agaricus, clamp connections and dolipore septa are shown by the hyphae of (1) Primary mycelium @) Secondary mycelium (3) Monokaryotic mycelium (4) Coonocytic mycelium 40. Select correct statement w.rt. mycorrhizal roots (1) They do not differ in shape from normal roots, @) Often show a wooly covering (@) Possess root cap but lack root hairs (4) Fungal partner is commonly a member of Ascomycetes VIRUSES, VIROIDS AND LICHENS In the five kingdom classification of Whittaker, there is no mention of some acellular organisms like viruses, viroids and lichens. These are briefly introduced here. VIRUSES Viruses are infectious agents, with simple, acellular organisation. They are exception to the cell theory. The study of virus is called virology. Viruses are connecting link between living and non-living entities. They have the properties of both living and non-living things. Viruses can reproduce only within living cells and are obligatory intracellular parasites. Non-living Nature of Virus: Lacking protoplast. Ability to get crystallized, e.g., TMV, poliomyelitis virus. Inability to live independent of a living cell. (Lack functional autonomy) High specific gravity which is found only in non living objects Absence of respiration. Absence of energy storing system. ‘Absence of growth and division. NOgaEne ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 79 (@) DNA containing viruses are called deoxyviruses. These are of two types (Double stranded DNA (dsDNA) virus e.g. Pox virus, Cauliflower mosaic virus, Herpes virus. (i) Single stranded DNA (ssDNA) e.g. Coliphage © * 174, M13 phage. (©) RNA containing viruses or riboviruses are of two types () Double stranded RNA (dsRNA) virus e.g. Reavirus, Wound tumour vieus. (i) Single stranded RNA (ssRNA) virus e.g. TMY, Influenza virus, Foot and Mouth disease virus, Retroviruses (HIV). On the basis of host specificity viruses are divided into three groups: 1. Phytophagineae/Plant viruses: 2. Zoophagineae/Animal viruses 3. Bacteriophages/Bacterial viruses. Structure of Some Viruses 1. Tobacco Mosaic Virus (TMV) is elongated rod like, 3000 A long, 180 A in diameter with molecular weight 39.4 10° dalton. 2130 capsomeres are arranged helically to form the capsid. RNA strand is helical. ssRNA consists of 6400 nucleotides. Thus, the ratio of nucleotides : capsomeres = 3: 1 Fig. : Tobacco Mosaic Virus (TMV) 2. Bacteriophage (or bacterial viruses) are the viruses that infect the bacteria. Bacteriophages usually have double stranded DNA. T, Bacteriophage has a tadpole like structure with polyhedral head connected to a helical tail (binal). The head consists of nucleic acid surrounded by a protein coat or capsid. Nucleic acid is double stranded DNA. Tail is proteinaceous tube-like, core surrounded by sheath. At one end, tube is joined to the head by thin collar. At the other end, it has a hexagonal base plate with six small tail pins and six tail fibres which help in attachment of the phage to the host cell sok Head (DNA coverod LS~ with protein coat) Eng piate (about 2004 thick) Fig. : Structure of T, bacteriophage ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110005 Ph.011-476234567B Biological Classitication Board & Competitive Exams. Living Nature of Virus : 1. Being formed of organic macromolecules. 2. Presence of genetic material 3. Ability to multiply. 4. Occurrence of mutations. 5. Occurrence of certain enzymes like, neuraminidase (first discovered), transcriptase and lysozyme in certain viruses. 6. Infectivity and host specificity. 7. Viruses can be ‘killed’ by autoclaving and ultraviolet rays. 8. They take over biosynthetic machinery of the host cell and produce chemicals required for their mttiplication, 9. Viruses are responsible for a number of infectious disease like common cold, epidemic influenza, chicken pox, mumps, poliomyelitis, rabies, herpes, AIDS, SARS etc. Discoveries of Virology : + Term virus (means venom or poisonous fluid) was coined by Pasteur (1880) * DJ. lvanowsky (1892) recognised certain microbes as causal organism of the mosaic disease of tobacco. ‘These were found to be smaller than bacteria because they passed through bacteria proof filters. + MLW. Beljerinck (1898) demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants and called this fluid as Contagium vivurn fluidur (infectious living fluid), + W.M. Stanley (1935) crystallised TMV (Tobacco mosaic virus) for the first time. He showed that viruses. could be crystallised and crystals consists largely of proteins. Note: * Viruses are obligate parasite and are inert outside their specific host cell. © An inert virus is called virion. Viruses did not get place in classification because they are not truely living. To understand living organisms, they should have cell (fundamental unit of life) but viruses does not follow it. Viruses do not have their own cellular machinery. When they enter (or infect) a cell then these take over the cellular machinery of host to replicate themselves. Example 12 : Name the connecting link between living and non-living. Solution: Viruses. Try Yourself 23. Who coined the term ‘Virus’? 24. Who demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants? Structural Components of Viruses The structural components of viruses are envelope, capsid and nucleoid: 1. Envelope : tis the outer thin loose covering composed of proteins (from virus), lipids and carbohydrates (both from host). This layer may or may nol be present. Envelope is present in HIV, Herpes virus. 2. Capsid : It is the outer protein coat made up of small subunits called capsomeres for the protection of nucleic acid (their genetic material). 3. Nucleoid : Viruses contain either DNA or RNA. ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345580 Biological Classification Board & Competitive Exams. Reproduction It is of two main types: Phagie and Pinocytic (a) Phagic Reproduction : Only nucleic acid of virus enters the host cell. It is further of two types (Lytle eyele : Occurs in virulent phages, e.g., T, bacteriophages. (il) Lysogenic cycle : Occurs in temperate viruses such as 2 phage. (b) Pinocytic Reproduction : It is found in viruses like TMV, HIV, Hepatitis B etc., in which whole of virus article enters host cell except envelope (if present). List of some Diseases caused by viruses Table : Viral diseases of Man 1. Influenza 1. Influenza virus, 2. Smallpox 2. Variola virus. 3. Mumps 3. Paramyxovirus 4. AIDS 4. Retroviruses 5. Poliomyelitis 5. Poliovirus 6. Germanmeasies 6. Rubella virus 7. Measles. 7. Measles virus Table : Viral diseases of Plants 1. Tobacco mos 1. TMV 2. Cucumbermosaic 2. Cucumber mosaic virus 3. Potatoleafroll 3. Potatoleatroll virus 4. Bunchy top ofbanana 4. Banana bunchy top virus Note = In plants, the viral symptoms can be mosaic formation, leat rolling and curling, yellowing and vein clearing, dwarfing and stunted growth. Knowledge © Interferons: Small group of glycoprotein released by virus infected animal cells which prevent non-infected calls from infection, Example 13 : Name the genetic material found in viruses. Solution: DNA or RNA. Try Yourself 25. Vinuses that infect the bacteria are called 26. Name five diseases caused by viruses in man. Sub-viral Agents : ‘These are viruses which lack one of the essential component, e.g., viroids, virusoids, prions Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345582 Biological Classification Board & Competitive Exam: ‘The bulk of lichen body is formed by fungal partner called myeebiont. It includes the surface, medulla (or interior) and rhizines (attaching devices). The algal partner or phycobiont constitutes hardly 5% of the lichens body. It is generally restricted to a narrow zone (algal zone) below the surface. Relationship The fungus performs following functions. (). Body structure and covering. (i) Anchoring (ii) Absorption of water and minerals. It can absorb water from wot air (atmosphere), dew and rain. Minerals are picked up both from substratum and atmosphere. Special chemicals are excreted by the fungal partner of the lichen to dissolve minerals from the substratum, (@) Sex organs and fruitifications are of fungal origin. ‘The major function of alga is photosynthesis. The cyanobacterial alga additionally takes part in nitrogen fixation. The alga picks up water and mineral salts from the fungus while the fungus obtains part of the food manufactured by the alga. Therefore, in a lichen the association between alga and fungus is that of mutual benefit (mutualism) popularly called symbiosis. Fig. : V.S. of lichen showing an isidium and algal zone Reproduction Lichens multiply by four methods () Progressive death and decay resulting in the separation of a lichen thallus into two or more parts. (i) Fragmentation caused by mechanical injury, due to wind or animal bites. (il) Isidia are superficial outgrowths of the lichens which are primarily meant for increasing surface area and photosynthetic activity. At time, they are broken off. Each isidium is capable of forming a new lichen because it has a core of a few algal cells surrounded by a sheath of fungal hyphae. (iv) Seredia. These are most efficient means of asexual reproduction. They are microscopic lichen propagules which are produced in large numbers inside sori called pustules. Soredia are dispers air currents. After falling on a suitable substratum each soredium gives rise to a lichen, because it has. {a few algal cells surrounded incompletely by a weft of fungus. ‘Special structures in the thallus of lichen : () Cyphetiae : Help in exchange of gases, present in lower cortex. (i) Cephalodia : Help to retain moisture and its algal partner fix nitrogen also. (ii) Breathing pores: For aeration, present in upper cortex of thallus. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, Now Dolhi-110008 Ph.011-47623456Board & Competitive Exams. Biological Classification | 81 (1) Viroids (L. virus — poison, eidos — diminutive) : They are the smallest self replicating particles which wore discovered by Diener (1971). Viroids are infectious RNA particios which are dovoid of protein coat. They are obligate parasites. Molecular weight of a viroid is low. The RNA is tightly folded to form circular or lingar structures. Viroids aro known to cause diseases (some 20) in plants only, 0.g., Potato spindle tuber disease (PSTD), Chrysanthemum stunt and Citrus exocortis. (2) Virusoids : Discovered by Randle of. a, these are RNA viruses but inside the capsid of other larger virus. They replicate within the host and do not cause any infection. (8) Prions : Discovered by Alper ot al Proteinaceous infectious particles, causing certain diseases like (i) Kuru disease (laughing death disease in humans) (ji) Bovine spongiform encephalopathy (BSE or Mad cow disease) (ii) Scrapie disease in sheep (w) Creutz Feldt Jakob disease LICHENS Lichens are dual (composite) organisms or entities which contain a permanent association of a fungal partner or mycobiont and an algal partner or phycobiont. Mycobiont is dominant partner and mostly belongs fo ascomycetes (Ascolichens-, e.g.. Graphis, Cladonia, Parmelia, Usnea, etc.) or sometimes basidiomycetes (Basidicichens—, e.g., Corella, Cora, efc.). Phycablont_ is mostly a member of Chloraphyceae (e.g., Chlorella, Trebouxia, Protococcus, Palmela, etc.) or can be a BGA (e.g., Nostoc, Chlorococcus, Scytonema, etc.). The term lichen was coined by Theophrastus (370 — 285 B.C), also called Father of Botany. Lichens often grow in most inhospitable and uninhabited places like barren rocks (saxicolous), soil (terricolous), icy tundra oF alpines, sand dunes, roofs, walls, wood (lignicolous), tree bark (corticolous), leaves, etc. They commonly live under humid and exposed conditions but can tolerate extreme desiccation. However, lichens, cannot tolerate air pollution, especially due to sulphur dioxide (so are considered indicators of SO, pollution) Lichens are perennial. Their growth is slow. Lichens have greyish, yellowish, greenish, orange, dark brown ‘or blackish colouration, ‘Structure Based upon external morphology, the lichens are of three types () Crustose : Crust like, closely appressed to the substratum and attached to it at several places, 0.9. Graphis, Lecanora, Rhizocarpon. (i) Foliose : The body of the lichen Is flat, broad, lobed and leaf-like, which is attached to the substratum at one or a few places with the help of rhizoid like structures called rhizines, ¢.9., Parmelia, Peltigera. (iil) Fruticose : The lichen is branched like a bush and attached to the substratum by means of a disc, e.g., Cladonia, Usnea, Evernia, Bryonia fruptecaton Fig. : Forms of Lichens Pusa Road, New Delhi-110005 Ph.011-47623456 Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower,Board & Competitive Exams. Biological Classification | 83 (Early Colonisers : Lichens are early or ploneer colonisers of barren rocks, ciffs, mountains and new terrains. During their growth, lichens stick to the rocks and cliffs by secreting acids. It produces minute crevices where organic matter accumulates. It paves the way for growth of mosses. (i) Food : In tundra, Cladonia rangifera (Reindeer Moss) constitutes the staple food of reindeer, caribou, musk ox, etc. Cetraria islandica (Iceland Moss) is used as a food article in Iceland, Sweden and Norway. Locanora esculenta is regarded as bread of heaven by Jews. Parmolia (Rock Flower) is also a table delicacy. Dermatocarpon miniatum (Stone Mushroom) is a vegetable in Japan. (ill) Dyes : Orchil is obtained from Rocella tinctoria. The latter was also the source of litmus (R. montagne’) before the advent of synthetic products. Litmus is a pH indicator. (iv) Perfumes : Scented incense is got from species of Ramalina and Evernia. (¥) Medicines : Usnic acid got from Usnea (Old Man’s Beard) and Ciadonia has antibiotic properties. It is used in preparation of ointment for buns and wounds. (Wi) Air Pollution = Decrease in lichen population of an area is indicative of SO, pollution. (vi) Fires : In hot season, Usnoa may produce forest fires. EXERCISE 41. Lichens growing on tree bark are called (1) Lignicotous @) Terticolous (8) Corticotous (4) Saxicolous 42. Common mycobionts and phycobionts of lichen body are respectively (1) Ascomycetes, Chlorophyceae (2) Ascomycetes, Cyanophyceae (8) Basidiomycetes, Chlorophyceae (4) Basidiomycetes, Cyanophyceae 43. Foliose lichens are attached to the substratum at one or few places with the help of (1) Branched, multicellular rhizoids Q) Holdfast @) Rhizines (4) Rhizomorph 44, Specialised structure in the thallus of lichen for nitrogen fixation and retaining moisture is (1) Cyphellae 2) Isidia (8) Cephalodia (4) Soredia 45. Which of the following feature is not related with virus? (1) Infectivity and host specificity @) Presence of genetic mater (@) Occurrence of certain enzymes (4) Presence of respiration 46. Most of the viruses are/have (1) Enveloped nucteo-protein structure @) Non-enveloped nucieo-protein structure (8) Infectious protein particles (@) Double stranded DNA as well as dsRNA 47. Select incorrect statement wrt. T, bacteriophages: (1) Have polygonal prismatic head Q) Motile organisms (@) Six tail fibres (@) _ds-DNA as the genetic material Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 79 (@) DNA containing viruses are called deoxyviruses. These are of two types (Double stranded DNA (dsDNA) virus e.g. Pox virus, Cauliflower mosaic virus, Herpes virus, (i) Single stranded DNA (ssDNA) e.g. Coliphage @ * 174, M13 phage. (©) RNA containing viruses or riboviruses are of two types () Double stranded RNA (dsRNA) virus 6.9 Reovius, Wound tumour virus. (ii) Single stranded RNA (ssRNA) virus e.g. TMY, Influenza virus, Foot and Mouth disease virus, Retroviruses (HIV). (On the basis of host specificity viruses are divided into three groups 1. Phytophagineae/Plant viruses: 2. Zoophagineae/Animal viruses 3. Bacteriophages/Bacterial viruses Structure of Some Viruses 1. Tobacco Mosaic Virus (TMV) is elongated rod like, 3000 A long, 180 A in diameter with molecular weight 39.4 x 10° dalton. 2130 capsomeres are arranged helically to form the capsid. RNA strand is helical. ssRNA consists of 6400 nucleotides. Thus, the ratio of nucleotides : capsomeres = 3: 1 Fig. : Tobacco Mosaic Virus (TMV) 2. Bacteriophage (or bacterial viruses) are the viruses that infect the bacteria. Bacteriophages usually have double stranded DNA. T, Bacteriophage has a tadpole like structure with polyhedral head connected to a helical tail (binal). The head consists of nucleic acid surrounded by a protein coat or capsid. Nucleic acid is double stranded DNA. Tall is proteinaceous tube-like, core surrounded by sheath. At one end, tube is joined to the head by thin collar. At the other end, it has a hexagonal base plate with six small tall pins and six tail bres which help in attachment of the phage to the host call Head (DNA covered 50A—» 950 Ao: End plate (about 2004 thick) Fig. : Structure of T, bacteriophage Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345684 Biological Classification 48. 49. 50. Board & Competitive Exams. TMV is (1) ds Ribovirus @) ds Deoxyvirus (3) ss Ribovirus (4) Ribovirus with 6400 capsomeres Infectious RNA particles without protein coat (1) Have high molecular weight (@) Were discovered by Alper @) Known to cause disease in plants (4) More than one option is correct Mark the odd one (wrt. prions) (1) CFJ disease (2) Mad cow disease (3) Potato leaf roll >, @) Scrapie disease © Anaima : Animals without RECs. ‘+ Enaima : Animals having RBCs. = Phylogenetic : Evolutionary inter-relationship. + Heterocysts : Specialised cells in cyanobacteria for N, fixation. + Saprophytes : Are organisms which obtain (absorb) their food from dead and decaying substances, + Parasites : Depend on living plants and animals for nutrition + Plasmogamy : Fusion of protoplasm between two motile or non-motile gamete plasmogamy. = Mycelium : The network of hyphae. * Phycobiont : Algal component of lichens. ‘*__Mycobiont : Fungal component of lichens. . called ‘Quick Recap 1. Atistotle classified plants into herbs, shrubs and trees and animals into Anaima and Enaima. 2. Linnaeus was the founder of two kingdom system of classification. These two kingdoms were Plantae and Animalia Whittaker proposed five kingdom classification. ‘Monerans are unicellular prokaryotes. Protists are unicellular eukaryotes. Fungi are multicellular eukaryotes having chitinous cell wall Plants are multicellular, eukaryotic having cellulosic cell wall Viruses are the connecting link between living and non-living. In the five kingdom classification there is no mention of viruses, viroids and lichens. eeXagee gaa ‘Aakash Educational Services Pvt. Ltd. - Regd. Office = Aakash Tower, 8, Pusa Road, New Delhi-110008 Ph.011-47623456Board & Competitive Exams. Biological Classification | 83 Early Colonisers : Lichens are early or pioneer colonisers of barren rocks, cliffs, mountains and new terrains. During their growth, lichens stick to the rocks and cliffs by secreting acids. It produces minute crevices where organic matter accumulates. It paves the way for growth of mosses. (il) Feod : In tundra, Cladonia rangifera (Reindeer Moss) constitutes the staple food of reindeer, caribou, musk ox, etc. Cetraria islandica (Iceland Moss) is used as a food article in Iceland, Sweden and Norway. Lecanora esculenta is regarded as bread of heaven by Jews. Parmelia (Rock Flower) is also a table delicacy. Dermatocarpon miniatum (Stone Mushroom) is a vegetable in Japan. (ill) Dyes : Orchil is obtained from Rocella tinctoria. The latter was also the source of litmus (R. montagnei) before the advent of synthetic products. Litmus is a pH indicator. (iv) Perfumes : Scented incense is got from species of Ramalina and Evernia. (¥) Medicines : Usnic acid got from Usnea (Old Man's Beard) and Ciadonia has antibiotic properties. It is used in preparation of ointment for buns and wounds. (vi) Air Pollution : Decrease in lichen population of an area is indicative of SO, pollution. (vil) Fires : In hot season, Usnea may produce forest fires. 41. Lichens growing on tree bark are called (1) _Lignicotous 2) Terricolous (@) Corticotous (4) Saxicolous, 42. Common mycobionts and phycobionts of lichen body are respectively (1) Ascomycetes, Chlorophyceae (2) Ascomycetes, Cyanophyceae @) Basidiomycetes, Chlorophyceae (4) Basidiomycetes, Cyanophyceae 43. Foliose lichens are attached to the substratum at one or few places with the help of, (1) Branched, multicellular rhizoids. 2) Holdfast @) Rhizines (4) Rhizomorph 44. Specialised structure in the thallus of lichen for nitrogen fixation and retaining moisture is (1) Cyphetlae 2) Isidia (@)_ Cephalodia (4) Soredia 45. Which of the following feature is not related with virus? (1) Infectivity and host specificity @) Presence of genetic material (8) Occurrence of certain enzymes (4) Presence of respiration 46. Most of the viruses are/have (1) Enveloped nucteo-protein structure @) Non-enveloped nucieo-protein structure (3) Infectious protein particles (@) Double stranded DNA as well as dsRNA 47. Select incorrect statement w.rt. T, bacteriophages: (1) Have polygonal prismatic head 2) Motil organisms @) Six tail fibres (@) _ds-DNA as the genetic material ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Be rssignmont (SET - 1) School/Board Examinations Students are required to solve and write the solutions in their exercise book. For referring solutions to the a (Set-1), please visit our Library at the log on to our website: www.aakash.ac.inBiological Classification Board & Competitive Exams. SECTION -A ‘School/Board Exam. Type Questions Very Short Answer Type Questions : 0. What are monerans? ‘Why some fungi are called ‘ung! imperfect’? Who coined term virus? Name the chemical substance present in the bacterial cell wall Expand TMV. Who classified plants into herbs, shrubs and trees? Who classified animals into Anaima and Enaima? Red tide causing organism belongs to which group of photosynthetic protists? First scientific approach to classify the organisms was done by Give the mode of nutrition in fungi Short Answer Type Questions "1 12 13. 14, 16. 16. 17. 18 19, 20. 24 22. 23. 24, 25. 26. 27. 28, 29, 30. According to two kingdom classification system, differentiate kingdom Plantae and Animalia in terms of cell wall, locomotion, nutrition and response to external stimuli Write down three drawbacks of two-kingdom classification system. In which kingdom, Whittaker placed Chlamydomonas and Chlorella? What was the earlier position of these ‘organisms in two-kingdom system? Why do we expect the criteria of classification to change in the future? Which type of similarities are reflected in existing classification system? ‘What are the sole members of the kingdom Monera and mention about their habitat? Give a characteristic feature of kingdom Monera, in terms of their nucleus and cell walll (composition) Which type of nutrition and reproduction is found in kingdom Monera? How are bacteria grouped on the basis of their shape? Why Archaebacteria are special? Which feature of Archaebacteria allow them to survive in extreme conditions? Give two example of Methanogens, Halophiles and Thermoacidophiles. How are bacteria classified on the basis of their mode of nutrition? Why are cyanobacteria called photosynthetic autotrophs? In which habitat cyanobacteria exist? Give their effect on aquatic animals. Why chemosynthetic bacteria oxidise inorganic substances? ‘Write a note on the uses of heterotrophic bacteria, Mention the damage caused by pathogenic bacteria to human beings. Write a note on Mycoplasma. Discuss the habitat and mode of nutrition of chrysophytes. Long Answer Type Questions a4 32, Give five features of dinoflagellates and their impact on marine ecosystem. (@) Write a note on the mode ef nutrition in Euglena. (©) Explain the reproduction in Euglena ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-476234564 5 6 7 8 8 1 Short Answer Type Questions = 1 2 13, 14 15, 0. Biological Classification Board & Competitive Exams. Name the type of ribosomes present in Monerans. Carl Woese divided bacteria into two groups. Name them, ‘What is the habitat of halophiles? Name the group of bacteria under which methanogens, halophiles and thermoacidophiles are included? Which group of bacteria are characterised by the presence of rigid cell wall? How can we say that cyanobacteria are photosynthetic autotrophs? In which way, heterotrophic bacteria are useful for human being? In what way sexual reproduction of bacteria is different from eukaryotic organisms? ‘Which essential feature of sexual reproduction is not performed by bacteria?” Mention the type of reproduction in Protist. ‘What is pellicle and what is its advantage in Euglenoids? What are basidiocarps? Short Answer Type Questions : 16. 17, 18 19 20. 24 Explain the structure of cell wall in diatoms, How diatomaceous earth is formed? Write its advantage. ‘What is the reason of keeping food into refrigerator? How asexual reproduction takes place in fungi? (a) Name the common forms of basidiomycetes. (©) What is the habitat of basidiomycetes? (©) Which type of mycelium do they have? (@) In what way Neurospora is useful? (©) Edible morels and truffies belong to which group of fungi? (©) What is Contagium vivurn fluidum? Long Answer Type Questions : 22. 23. (2) Give the symptoms of plant diseases caused by viruses. (©) Name a disease caused by viroid. (©) How algae and fungi take benefit from each other in association as lichens? (@) What are heterocysts? (©) Write a note on dikaryophase. (©) Differentiate kingdom Protista and Fungi in terms of their nutrition gaa [2 Marks} [3 Marks] [5 Marks] ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110008 Ph.011-47623456d & Competitive Exams. Biological Classification | 87 (@) How do slime moulds aggregate? (©) How do slime moulds form fruiting bodies and how they are extremely resistant? (@)_ Mention the diversity of fungi. (©) Give an account of their habitat (©) Why they are regarded as heterotrophs? (@) In what way they are useful? (©) What is mycorrhiza? (@) Discuss fragmentation, budding and fission in fungi. (©) What is coenocytic hyphae? Explain sexual reproduction in Basidiomycates and give three examples of this group. (a) Why some fungi were grouped under Deuteromycetes? (©) Why the fungi imperfecti were moved into classes Ascomycetes and Basidiomycetes? (©) How these fungi reproduce asexually? (@) What is the mode of nutrition in members of Deuteromycetes and how some of them help in mineral cycling? (@) Explain alternation of generation in kingdom Plantae. (©) Do few members of kingdom Plantae have partially heterotrophic mode of nutrition, if yes, then give example? (©) Differentiate between kingdom Plantae and Animalia on the basis of growth pattern. Give the contribution of D.J. vanowsky, M.W. Beijerinck and W.M. Stanley for studying viruses. (@) What is bacterial virus? (®) What is advantage of capsomeres? (©) Do viruses have their own genetic material? (@) Name the infectious part of virus. Tabulate the characteristics of five kingdom, on the basis of cell type, cell wall, nuclear membrane, body ‘organisation and mode of nutrition. (@) Write a short note on methanogens. (©) Write the shape of Coccus, Bacillus, Vibrio and Spiriliium type of bacteria, What are halophilos? Write an explanatory note on thermoacidophiles. Write a note on (@) Mycorthiza (©) Sac fungi (©) Imperfect funai SECTION -B Model Test Paper Short Answer Type Questions : [1 Marky Who proposed six kingdom system of classification? ‘What name was given to animals having RBCs by Aristotle? ‘What is the mode of nutrition in kingdom Animalia? h Educational Services Pvt. Ltd. - Rogd. Office = Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456FS. Assignment (SET - 2) NEET & AIIMS (Competitive Entrance Exams.)90 Biological Classification Board & Competitive Exams. SECTION - A Objective Type Questions 1, Statement-1 : Linnaeus classified plants into trees, shrubs and herbs, on the basis of morphological characters. Statement-2 : Aristotle divided animals into group = Anaima and Enaima. (1) Only statament-t is correct @) Only statement-2 is correct (@) Both statement-4 and statement-2 are correct, () Both statement-1 and statement-2 are incorrect 2. In members of which kingdom, nuclear membrane is absent? (1) Monera @) Protista @) Fungi (4) Plantae 3. In five kingdom classification, the kingdom that includes the blue-green algae, nitrogen-fixing bacteria and methanogenic archaebacteria, is. (1) Monera @) Protista @) Fungi (4) Plantae 4, Which one of the following is not the basis of five kingdom classification? (1) Cell structure @) Body organisation @) Reproduction (4) Reserve food material 5. Position of bacteria in the kingdom system of classification proposed by Linnaeus is (@) Monera @) Protista @) Plantae (4) Animatia 6. Who was the founder of five kingdom system of classification? (1) C. Linnaeus @) RH. Whittaker @) Aristotle (@) TO. Diener 7. According to five kingdom system, gymnosperms and angiosperms are grouped under the kingdom (1) Monera 2) Protista (@) Fungi (4) Plantae 8. Which organisms are not included in the five kingdom system of classification? (1) Protozoans @) Viruses. @) Lichens (4) Both (2) & (3) 10. n 12, 13, 14, 15, Who for the first time classified organisms on the basis of scientific approach? (1) Aristotle @) Linnaeus 8) Whittaker (@) Pasteur Aristotle classified animals in two groups on the basis of presence or absence of RBC. The group which does not have RBCs is (1) Anaima: (@) Enaima (9) Ovipera (4) Vivipera Heterotrophic, eukaryotic, multicellular organisms lacking a cell wall are included in the kingdom, (1) Protista @) Fungi (8) Plantae (4) Animalia Match the following Column-1 Column-t (Group of bacteria) (Their shape) a. Cocous () Rod-shaped b. Bacillus (i) Spherical c. Spiritlum (i) Spiral 4. Vibrium (¥) Comma-shaped (1) ad), BG, efi), div) (2) alii), BA), etl), div) @) (i), Bi), ef), di) (4) afi, BG, eC), iy During favourable conditions bacteria mainly reproduce by (1) Budding (2) Fragmentation (8) Sporuation (4) Fission Select the correct statement (1) Cholera, typhoid, tetanus are well-known diseases caused by viruses. (2) Dinoftagellates, euglenoids and slime moulds are placed under kingdom Monera (@) Members of kingdom Protista are primarily aquatic (4) Dinoftagellates are the chief ‘producers’ in the Select the Incorrect statement. (1) Nostoc and Anabaena have heterocysts for nitrogen fixation (2) Cyanobacteria often form blooms in polluted water bodies (@) Heterotrophic bacteria are more abundant in nature (4) The cell wall of Mycoplasma are made up of chitin Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345592° Biological Classification 31. 32, 33, 36. 36. 37. Board & Competitive Exams. Vegetative reproduction by fragmentation is 38. (1) Agaricus (2) Saccharomyces (2) Eugiona @) Gonyauiax Select the incorrect match Class, Phycomycetes Basidiomycetes. — @) Ascomycetes = Penicitium (4) Deuteromycetes Trichoderma Haploid sexual spore produced exogenously is (1) Ascospore (2) Basidiospore (3) Oospore: (4) Zygospore Coenocytic mycelium is found in (1) Deuteromycetes 2) Phycomycetes (3) Ascomycetes: (4) All of these ‘The members of which group are commonly known ‘as sac fungi? (1) Phycomycetes Q) Deuteromycetes (3) Basidiomycetes (4) Ascomycetes Identify A, 8 and C in given diagram. A B c (1) A= Mucor, B = Aspergillus, C = Agaricus (2) A= Mucor, B = Agaricus, C = Aspergillus (8) A= Agaricus, 8 = Mucor, C = Aspergillus (4) A= Agaricus, B = Aspergillus, C = Mucor Member Albugo Claviceps a @ 39. Which one is correctly matched? (1) Agaricus = Smut (2) Ustiago = Mushroom (8) Puccinia ~ _ Insectivorous plant (4) Deuteromycetes - _ Imperfect fungi Which of the following statement is incorrect about viruses? (1) Viruses contain either RNA or DNA. @) Viruses do not have their own metabolic system Bacteriophages are usually double stranded DNA viruses. TMV contains both RNA and DNA as their genetic material Viruses that infect the bacteria are termed as (1) Cyanophages @) Bacteriophages @) Mycophages (4) Both (1) & (2) Who demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants? (1) Pasteur (@) MW. Beljerinek (@) D.J. Wanowsky (4) WM. Stanley The protein coat called capsid made of small subunits called capsomeres are present in (1) Viruses. @) Bacteria (8) Fungi (4) Gymnosperms ‘Select the incorrect match w.rt. genetic material ® @) (1) Herpes virus = ssDNA (2) Bacteriophage = dsDNA @ ™v = ssRNA (4) Influenza virus — ssRNA Identify A, B, C and D bacteriophage. parts in this diagram of ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 91 16. 47. 18, 19. 2 23. 24, Heterocysts present in Anabaena is specialised for 25. (1) Nitrogen fixation (2) Food storage @) Fission (4) Sexual reproduction Mark the odd one wrt. cell wall (1) Halophites (2) Methanogens (@) Thermoacidophiles (4) Cyanobacteria Primitive bacteria living in salty areas are called as (1) Methanogens (2) Thermoacidophiles (@) Heliophytes (4) Halophiles 2s Select the non-protistan group. (1) Slime moulds 2) Dinofiagellates () Phycomycetes @) Chrysophytes Which of the following is correct? (1) All slime moulds are haploid on (2) Protezoans lack coll wall @) Dinoftagellates are non-motile @) Policte Is absent in Eugiona Which is not a feature of dinoflageliates? (1) They cause red tides (2) ‘Their cell wall has stiff cellulose plates on the 9g outer surface (3) They release toxins (@ These are mostly fresh water rnon-photosynthetic are saprophytic protists, whose body moves along decaying twigs and leaves engulfing organic material and (2) Dinoflagetiates 29, (4) Slime moulds (1) Euglenoids (3) Chrysophytes Being photosynthetic, which organism in absence of sunlight behave like heterotrophs? (1) Slime moulds (2) Euglenoids (3) Sporozoans (4) Clliated protozoans 3g Which is the incorrect statement regarding fungi? (1) Wheat rust causing agent is Puccinia 2) Ponicilium is a source of antibiotic (@) The cell wall of fungi are composed of peptideglycans (4) Fungi preter to grow in warm and humid places ‘Statement-1 : Yeast is a multicellular fungus. ‘Statement-2 : Penicillium is an unicellular fungus. Statement-3 : Albugo is a parasitic fungus on mustard. (1) Only statament-1 and statement-2 are correct @) All the above statements are incorrect (@) Only statement-3 ie correct (@) Both statement-1 and statement-3 are correct ‘Mark the correct statement. (1) Phycomycetes include mushrooms, bracket fungi or puff balls (2) The mycelium of basidiomycetes is branched and septate (@) Neurospora is used extensively in biochemical and genetic work, it belong to group basidiomycetes (@) Morels and truffles are non-edible With respect to fungal sexual cycle, choose the correct sequence of events. (1) Karyogamy, plasmogamy and meiosis. (@) Meiosis, plasmogamy and karyogamy (@) Plasmogamy, karyogamy and meiosis. (4) Meiosis, karyogamy and plasmogamy ‘Mark the odd one wet. kingdom fungi (1) ‘They reproduce asexually and sexually @) They show a great diversity in structure and habitat (@) Most of fungi are saprophytic in their mode of nutrition (@) They do not reproduce by zoospores. ‘The sex organs are absent, but plasmogamy is brought about by fusion of two vegetative or somatic cells of different genotypes. It is the feature of (1) Phycomycetes (2). Basidiomycetes @) Ascomycetes (4) All of these ‘The fungi form fruiting bodies in which division occurs, leading to formation of spores. (1) Mitotic, diploid @) Reduction, haploid (@) Mitotic, haploid (@) Reduction, diploid Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 93 46. 47. 49. (1) A-Head, B ~ Sheath, C —Coltar, D Tail fibres 2) A-Head, 8 — Collar, C-Sheath, D ~ Tail fibres @) A-Head, B - Collar, ¢ — Tall fibres, D~ Sheath (@) A-Head, 8 — Sheath, C~ Tall fibres, D— Collar Select the correct statement. (1) Viroids have double stranded RNA (2) RNA of viroids have high molecular weight than viruses (8) Mumps and Herpes are viral diseases. (4) The name virus was given by D.J. Ivanowsky Lichens show symbiotic relationship between (1) Algae and fungi (2) Algae and bacteria (3) Fungi and bacteriophage (4) Algae and bacteriophage: Which is correct w.nt. lichens? (1) Mycobiont is autotrophic component (2) Phycobiont is heterotrophic component (3) They are good pollution indicators (4) They do not grow in non-polluted areas The association of fungi with the roots of higher plants is called (1) Lichens (2) Mycorrhiza @) Slime mould (4) Neurospora Solect the incorrect statement. (1) Cuscuta is a parasitic plant (2) Bladderwort and Venus fly trap are examples of insectivorous plants. @) Plantae includes algae, bryophytes, pleridophytes, gymnosperms and angiosperms (4) The mode of nutrition in plants is holozoic In which group of organisms, reserve food is stored in the form of glycogen and fat? (1) Man and Monkey (2) Cuscuta and Dog (3) Bladdorwort and Cuscuta (4) Bladderwort and Venus fly trap Diatomaceous earth is formed due to which substance? (1) Phosphorus @) Silicon (2) Calcium (4) Copper SECTION -B Objective Type Questions Which kingdom was introduced in four kingdom classification and who proposed it ? (1) Protista and Copeland @) Plantae and Linnaeus (8) Monera and Whittaker (4) Monera and Copeland Select correct match w.rt. Whittaker’ system of classification (1) Monera : Unicellular, osmotrophs, producers. and decomposers, true cellulosic call wall @) Protista : Unicellular, eukaryotic, photoauto- trophs and chemoautotrophs @) Fungi: Mullicellularfoose tissue, eukaryotic, ‘osmetrophs, chitinous wall (@) Animalia: Multicellular, eukaryotic, organ or organ system, holozoic, no saprobic Domain Eukarya includes how many kingdoms (wrt six kingdom system)? a2 as @1 4 Bacteria are considered primitive organisms: because they (1) Possess incipient nucleus (2) Are small, microscopic plants, which are not seen by the naked eyes (@) Cause serious diseases to human being, domesticated animals and crop plants (4) Produce endospores which are very resistant to adverse conditions 70S ribosomes, chromatophores and circular DNA, are found in (1) All eukaryotes @) All prokaryotes (@) Some prokaryotes (@) Some eukaryotes and some prokaryotes ‘There is no alternation of generation in Escherichia coli because of the absence of (1) Syngamy (2) Reduction division (@) Conjugation (4) Both (1) & (2) ‘Aakash Educational Services Pvt. Lid. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345694 Biological Classification 7 10. 1" 12. 13, 14, 16 Board & Competitive Exams. Branched chain lipids occur in the cell membranes of (1) Methanobacterium (2) Mycoplasma 3) Actinomycetes (4). Streptomyces Cyanobacteria do not possess (1) Gene recombinations (2) Flagella @) Plasmids (4) Pigments Bacterial cell divides every one minute. It takes 15 minutes a cup to be one-fourth full. How much time will it take to fill the cup? (1) 30 minutes: Q) 45 minutes (2) 60 minutes, (4) 17 minutes: Highly resistance nature of endospore is due to the presence of (1) Dipicolinic acid and peptidoglycan in spore coat 2) Peptidoglycan in exosporium (3) Dipicolinic acid and Ca in cortex (4) Dipicolinie acid and Ca in cell membrane. Endospores formed by certain bacteria are actually the means for (1) Reproduction (2) Perennation (3) Bioluminescence (4) Red snow formation Select an incorrect statement for F* bacteria (1) thas F plasmid 2) Only somatic pill are present (8) It is considered as donor bacterium (4) It cannot conjugate with another F* form Sea water glows during night mainly due to ‘occurrence of (1) Gonyaulax @) Noctiluca @) Euglena (4) Cycloteta Rejuvenescent spore of diatom is (1) Haploid and exospore (2) Diploid and statospore (3) Haploid and statospore (4) Diploid and auxospore Leucosin (Chrysolaminarin) is a carbohydrate which is stored as reserve food in case of (1) Diatom (2) Euglena (3) Dinohagottates, (4) Paramoecium 17. 18, 19, 20. 2 Flagellation in Euglena is (1) Uniflageliation and stichonematic (2) Isokont and whiplash type @) Heterokont and whiplash type: (@) Heterokont and stichonematic Special type of red pigment present in the ‘eye-spot of Euglena and Crustacea is called (1) Phycoerythrin (2) Astaxanthin @) Carotene (4) Xanthophyi Parafiagellar body of Euglena helps in (1) Locomotion (2) Photoreception (@) Reproduction (@) Osmoregulation ‘The structure formed in the life cycle of cellular slime-mould due to chemotactic movement is. (1) Pseudoplasmodium (2) Swarm cells (8) Macrocyst (@) Capititia Myxamoeba are formed in the life cycle of () Physarum @) Amoeba @) Entamoeba (@) Diatoms Difference between a red sea and red tide is (1) Red tide takes place in red sea @) Associated with a cyanobacteria and protist, respectively @) One is by virus and other by bacteria (4) Associated with Rhodophyceae and diatoms respectively Consider the following statements and select correct set of features w.rt. the life cycle of acallular slime moulds a. Haploid vegetative stage as myxamoebae b. Diploid vagetative stage as plasmodium ©. Capilitium, d. Photosynthetic protists. ©. Sporic meiosis f. Isogamous sexual reproduction 9. Anisogamous sexual reproduction with zygotic meiosis Macg @beog @ daet @boet ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345596) Biological Classification 35. Read the following statements carefully and identify correct statements w.rt. Lichens ‘a. The association cannot tolerate air pollution, ‘especially due to sulphur dioxide b. Lichens are annuals and their growth is slow ‘The fungal partner mostly belongs toascomycetes. 4. Soredia are most efficient means of asexual reproduction @. Orchids seldom occur without this association {. Foliose lichens are pioneers of succession in a water body, cat Qacdet @ abe @ acd SECTION - Previous Years Questions 1. Which one of the following is wrong for fungi? INEET (Phase-2) 2016] (1) They are eukaryotic (2) Ail fungi possess a purely cellulosic cell wall (3) They are heterotrophic (4) They are both unicellular and multicellular 2. Methanogens belong to [NEET (Phase-2) 2016] (1) Eubacteria (2) Archaebacteria (3) Dinoftagettates (4) Slime moulds 3. Select the wrong statement. INEET (Phase-2) 2016] (1) The walls of diatoms are easily destructible (2) ‘Diatomaceous earth’ is formed by the cell walls of diatoms (3) Diatoms are chief producers in the oceans (4) Diatoms are microscopic and float passively in water 10. Board & Competitive Exams. Select the wrong statement (1) Bacterial cell wall is made up of peptidoglycan 2) Pili and fimbriae are mainly involved in motility of bacterial cells (8) Cyanobacteria lack flagellated calls (@) Mycoplasma is a wall-less microorganism Which one of the following statements is wrong? INEET-2016] (1) Phycomycetes are also called algal fungi (2) Cyanobacteria are also called blue-green algae (@) Golden algae are also called desmids (4) Eubacteria are also called false bacteria Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the kingdom INEET-2016] (1) Animalia @) Monera @) Protista (4) Fungi ‘One of the major components of cell wall of most fungi is INEET-2016} (1) Hemiceltulose @ Chitin (8) Peptidoglycan (4) Cotulose The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the INEET-2016] (1) Eubacteria (@) Halophiles (@) Thermoacidophiles (4) Methanogens Which of the following statements is wrong for viroids? INEET-2016] (1) Their RNA is of high molecular weight (2) They lack a protein coat (@) They are smaliar than viruses (@) They causes infections. Choose the wrong statement [Re-AIPMT-2015] (1) Yeast is unicellular and useful in fermentation @) Penicillium is multicellular and produces antibiotics (8) Neurospora is used in the study of biochemical genetics (@) Morets and truffies are poisonous mushrooms ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110008 Ph.011-47623456Board & Competitive Exams. Biological Classification | 95 23. 24. 26. ar. 28. 29. Find the correct match Column | Column It a. Gill fungi Salmon disease b. Cup fungi Trama ©. Black mould Penicitin d. Blue / green mould (wv) Zygophore Apothecium @) atid, BG, 6, A(¥) 2) alin, By), eft), tI) @) alld, b(v), ett), dil) 4) adi, BU, efi), AC) Select incorrectly matched pair (1) Mucor mucedo =~ Coprophilous (2) Albugo candida = ‘Facultative parasite @) Agaricus bisporus - Edible basidiocarp (4) Puccinia graminis - Black rust fungi Fungi differs from bacteria in (1) Mode of nutrition (2) Having NAG in cell wail @) Flagella structure (4) Reserve food material as glycogen Fruiting body in Aspergillus (or Penicillium) is known as (1) Cleistothecium (2) Apothecium (8) Perithecium (4) Ascus: ‘The famous Irish famine is related to a disease of potato known as (1) Late blight of potato (2) Early blight of potato () Dry rotof potato (4) Potato scab A dolipore septum is a characteristic feature of (1) Phycomycetes (2) Ascomycetes (8) Basidiomycetes (4). Zygomycetes Which one of the following combination of characters is correct for the given fungal group? (1) Algal fungi: Coenocytic, cellulosic wall, zoospore, __zygospore, dikaryophase present : Septate mycelium, chitinous wall, sporangiospore, shorter (nn) phase Septate mycelium, Ascogonium, Crozier stage, meiospores as ascospores, shorter dikaryophase Shorter primary mycelium stage, No sex organs, dominant dikaryophase, zygosporic meiosis 2) Conjugating fungi @) Sac fungi (4) Club fungi 30. a1 32, 33, Find set of edible basidiocarps. (1) Agaricus, Pleurotus (2) Agaricus, Morchella (@) Volvariella, Tuber (4) Amanita, Morchella Read the statements carefully a. Hartig net is the network of intracellular mycelium of Boletus b. Ectomycorthiza forms ten percent of total mycorrhiza ©. Fungal partner of endomycorthiza belongs to zygomycetes or phycomycetes (1) Only a & ¢ are correct @) Only b & ¢ are comect @) Only ¢ is comect (@) Allare correct ‘Symptom not seen in plants due to viruses is (1) Mosaic formation 2) Leaf rolling and curling @) Yellowing, vein clearing (4) Root knot Viruses possess all the following properties, excopt (1) They are non-cellular organisms @) Possess both DNA and RNA @) Capsid protects nucleic acid (@) Have inert crystalline structure outside living cells Identity A and B given below: () A - DNAvius — - Cauliflower mosaic virus B - RNAvius - Pox virus @ A - RNAvus | -TMV B - DNAvius - T, bacteriophage @ A - RNAvius — - Hepatitis B virus B - Relerovius - TMV (@) A - Reterovirus - Hepatitis B virus B - RNAvius -T, bacterophage Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 97 11. In which group of organisms the cell walls form 17. Five kingdom system of classification suggested two thin overlapping shells which fit together? 16. The guts of cow and buffalo possess [AIPMT:2015] (1) Cyanobacteria (2) Fucus spp. (8) Chiorelia spp. (4) Methanogens by RH. Whittaker is not based on [AIPMT-2014] [Re-AIpMT-2015] (1) Presence or absence of a well defined nucleus (1) Slime moulds @) Mode of reproduction (2) Chrysophytes @) Mode of nutrition (9) Euglenoids (4) Complexity of body organisation (4) Dinotagetlates 18. Archaebacteria differ from eubacteria in 12. Choose the wrong statement [Re-AIPMT-2015] wen (aIpMT-2014] ell membrane structure (1) Mosaic disease in tobacco and AIDS in human being are caused by viruses @) Mode of nutrition (2) The viroids were discovered by DiI. Ivanowski 1) Cal. shave (4) Mode luction @) WM. Stanley showed that viruses could be EO), Mods Sf reprocics crystallized 19. Which of the following shows coiled RNA strand and capsomeres? TAIPMT-2014) (@) The term Contagium vivun fuidum was coined by MW. Beljerinek (1) Potio virus (2) Tobacco mosaic virus 13, The imperfect fungi which are decomposers of titer Gy Meenas we (4) Retrovinus and help in mineral cycling belong to: 20. Viruses have TAIPMT-2014) cycling belong [Re-AIPMT-2015] (1) DNA enclosed in a protein coat (1) Ascomycetes @) Prokaryotic nucleus (2) Deuteromycetes @) Single chromosome (8) Basidiomycetes (4) Both ONA and RNA (4) Phycomycetes 21. The motile bacteria are able to move by 14. Pick up the wrong statement [Re-AIPMT-2015] [atpr-2014) (1) Nuclear membrane is present in Monera (1) Fimbriee @) Flagetla (2) Cell wall is absent in Animalia @, aie. @) Pil 22, Pigment-containing membranous extensions in {) Pratista have photosynthaic and heterotrophic to crencbadat we pe (4) Some fungi are edible (1) Basal bodies (2) Pneumatophores Chromatophores feterocysts 18. Which one of the following matches is correct? ° ) terre 23. Which statement is wrong for viruses? Laniinhinadl [AIPMT (Prolims)-2012} G) | Agariaus | Paraalicfongus | Saetiomycaton Bae Wace | geationsocise (1) They have ability to synthesize nucleic acids phitiora— |rmyetium and proteins 9] Atemaria [Sexual Deuteromycotes| {@) Antibiotics have no effect on them absent @) Allare parasites (#)|mucor |Reproduction by | Ascomyestes (@) Allof ther have helical symmetry 24, The cyanobacteria are also referred to as [AIPMT (Prelims)-2012] (2) Blue green algae (4) Golden algae (1) Slime moulds @) Protists ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-4762345698 Biological Classification 25. 26. 27. 28. 29. 30. Board & Competitive Exams. Which one single organism or the pair of organisms is correctly assigned to its or their named taxonomic group? [AIPMT (Prelims)-2012] (1) Yeast used in making bread and beer is a fungus (2) Nostoc and Anabaena are examples of protista (3) Paramecium and Plasmodium belong to the same kingdom as that of Penicillum (4) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan How many organisms in the list given below are autotrophs? Lactobacillus, Nostoc, Chara, Nitrosomonas, Nitrobacter, Streptomyces, Saccharomyces, Trypanosoma, Porphyra, Woltia [AIPM (Mains)-2012] (1) Four 2) Fre () Six (4) Three: In the five-kingdom classification, Chlamydomonas and Chlorella have been included in [AIPMT (Mains)-2012] (1) Protista (2) Algae @) Plantae (4) Monera Which one of the following organisms is not an ‘example of eukaryotic cells? [AIPMT (Prolims)-2011] (1) Amoeba proteus (2) Paramecium caudatum (@) Escherichia colt (4) Euglena viriais Membrane-bound organelles are absent in IAIPMT (Prelims)-2010] (1) Plasmodium @) Saccharomyces (8) Streptococcus (4) Chlamydomonas Single-celled eukaryotes are included in IAIPMT (Prelims)-2010] (1) Monera 2) Protista (8) Fungi (4) Archaea 3 32. 33. 36. Virus envelope is known as IAIPMT (Prelims)-2010] (1) Core. @) Capsia (8) Virion (4) Nucleoprotein ‘Algae have cell wall made up of IAIPMT (Prelims)-2010] (1) Cellulose, hemicellulose and pectins (2) Cellulose, galactans and mannans (3) Hemicellulose, pectins and proteins (4) Pectins, cellulose and proteins ‘Some hyperthermophilic organisms that grow in highly acidic (pH = 2) habitats belong to the two ‘groups: IAIPMT (Prelims)-2010} (1) Liverworts and yeasts (2) Eubacteria and archaea (@) Cyanobacteria and diatoms (4) Protists and mosses Infectious proteins are present in [AIPMT (Prolims)-2010} (1) Satellite viruses (2) Gemini viruses (8) Prions. (4) Viroids Black (stem) rust of wheat is caused by [AIPMT (Mains)-2010] (1) Alternaria solani (2) Ustilago nuda (@) Puccinia graminis (4) Xanthomonas oryzae Given below is the diagram of a bacteriophage. In which one of the options all the four parts A, B,C and D are correct? ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Askash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456100) Biological Classification 46. Which one of the following is a stime mould? [AIPMT (Protims)-2007} (1) Anabaena 2) Rhizopus (3) Physarum (4) Thiobacitus 47. Which one of the following statements about Mycoplasma is wrong? [AIPMT (Prelims)-2007} (1) They cause disease in plants (2) They are also called PPLO (3) They are pleomorphic (4) They are sensitive to penicillin 48. Which pair of the following belongs to Basidiomycetes? [AIPMT (Prelims)-2007] (1) Morcholta and Mushrooms 2) Birds’ nest fungi and Puffballs @) Puftballs and Claviceps (4) Poziza and Stink horns. 49. Ergot of rye is caused by a species of [AIPMT (Prelims)-2007] (1) Claviceps (2) Phytophthora (2) Uncinula (4) Ustitago 50. The thalloid body of a slime mould (Myxornycetes) is known as [AIPMT (Prelims)-2006] (1) Protonema @) Plasmodium (8) Fruiting body (@) Mycelium 51, The bacterium (Crostridium botulinum) that causes botulism is [AIPMT (Pretims)-2006] (1) A facultative anaerobe (2) An obligate anaerobe (8) A facultative aerobe (4) An obligate aerobe 52. Which of the following environmental conditions are essential for optimum growth of Mucor on a piece of bread 7 ‘A. Temperature of about25°C B. Temperature ofabout °C C._ Relative humidity of about 5% Board & Competitive Exams. D. Relative humidity of about 95% E. Ashady place FA brightly illuminated place Choose the answer from the following options IAIPMT (Prelims)-2006] (1) A.Cand E only @) A DandE only @) B, Dand E only (4) B, Cand F only Curing of tea leaves is brought about by the activity of [AIPMT (Pretims)-2006] (1) Bacteria (2) Mycormhiza @) Viruses (4) Fungi What is common about Trypanosoma, Noctiluca, Monocystis and Giardia ? [AIPMIT (Prelims)-2006] (1) These are all unicellular protists (2) Theyhaverlagelia @) Theyproduce spores (4) These are alll parasites Barophilic prokaryotes [AIPMT (Prelims)-2005] (1) Grow slowly in highly alkaline frozen lakes at high altitudes. (@) Occur in water containing high concentrations of barium hydroxide @) Grow and multiply in very deep marine sediments. (4) Readily grown and divides in sea water enriched in any soluble salt of barium Auxospores and hormocysts are formed, respectively, by [AIPMT (Prolims)-2005] (1) Several diatoms and a few cyanobacteria (2) Several cyanobacteria and several diatoms (8) Some diatoms and several cyanobacteria (4) Some cyanobacteria and many diatoms ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Options a A 8 c D (@) [Tail fires [Head [Sheath | Collar (@)| Sheath _[“Collar_[ Head [Tail fibres’ (@)| Head [Sheath | Collar [Tail fibres. @|Cottar [Tail ftores | Head | Sheath 37. Select the correct combination of the statements 38. 39. ‘Aakash Educational Services Pvt. Lid. - Regd. Office (an .d) regarding the characteristics of certain organisms @ ) © @ Methanogens are Archaebacteria which produce methane in marshy areas. ‘Nostoc is a filamentous blue-green alga which fixes atmospheric nitragen 42. Chemosynthetic autotrophic bacteria synthesize cellulose from glucose. Mycoplasma lack a cell wall and can survive without oxygen, ‘The correct statement are [AIPMT (Mains)-2010] a 2 ® “ ©). ©) as. (@), ©), (©) ©). (©). @) @), ©). @) .0. Dienerdiscoverada a 2 ® “ [AIPMT (Prelims-2009) & (Mains-2010)] Free infectious DNA, Infectious protein Bacteriophage Free infectious RNA, aa, Which one is the wrong pairing for the disease and its a causal organism? Black rust of wheat [AIPMT (Prelims)-2009] Puccinia graminis 2) Loose smut of wheat — Ustilago nuda (3) Root-knot of vegetables — Moloidogyne (4) Late blight of potato Which of the following is a symbiotic nitrogen fixer? = Alteraria solani 46. [AIPMT (Prelims)-2009] (1) Azotobacter (2) Frankia (8) Azolla (4) Glomus Biological Classification | 99 Thermococcus,Methanococcus and Methano- -bacterium exemplify [AIPMT (Prelims)-2008) (1) Bacteria that contain a cytoskeleton and ribosomes @) Archaebacteria that contain protein homologous to eukaryotic core histones ° Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled (4) Bacteria whose DNA is relaxed or positively ‘supercoiled but which have a cytoskeleton as well as mitochondria Cellulose is the major component of call walls of [AIPMT (Prelims)-2008] (1) Saccharomyces @) Pythium (@) Xanthomonas (@) Pseudomonas In the light of recent classification of living ‘organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statements is true about archaea? [AIPMT (Prelims)-2008] (1) Archaea completely differ from prokaryotes. (@) Archaea resemble eukarya in all respects @) Archaea have some novel features that are ‘absent in other prokaryotes and eukaryotes from both (@) Archaea completely differ prokaryotes and eukaryotes Bacterial leaf blight of rice is caused by a species of [AIPMT (Prelims)-2008] (1) Erwinia @) Xanthomonas (@) Pseudomonas (@) Alternaria Biological organisation starts with: [AIPMT (Prolims)-2007] () Atomic tevel (2) Submicroscopic molecular level @) Cellular level (@) Organismic level ‘Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification |101 57. All of the following statements concerning the actinomycetous filamentous soil bacterium Frankia are correct except that Frankia [AIPMT (Prelims)-2005] (1) Can induce root nodules on many plant species (2) Can fix nitrogen in the free-living state @) Like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host's cortex (4) Forms specialized vesicles in which the nitrogenase is protected from oxygen by a ‘chemical barrier involving triterpene hopanoids 58. Which of the following unicellular organism has a macronuceus for trophic function and one or more: micronuclei for reproduction? [AIPMT (Prelims)-2005] (1) Euglena 2) Amoeba (8) Paramoecium (4) Trypanosoma 59. For retting of jute the fermenting microbe used is: [AIPMT (Prelims)-2005] (1) Heticobacterpylori (2) Methophilic bacteria (@) Streptococcus lactin (4) Butyric acid bacteria Questions asked prior to Medical Ent. Exams. 2005 60. In the five kingdom system of classification, which single kingdom out of the following can include blue-green algae, nitrogen fixing bacteria and methanogenic archaebacteria? (1) Plantae (2) Protista (@) Monera (4) Fungi 61. In five kingdom system, the main basis of classification is (1) Structure of nucieus 2) Mode of nutrition @) Structure of cell wall (4) Asexual reproduction 62. In which kingdom would you classify the archaea and nitrogen-fixing organisms, if the five-kingdom system of classification is used ? (1) Plantae 2) Fungi @) Protista (4) Monera 63. 6s. 67. 68. 69. 70. nm 72. ‘Maximum nutritional diversity is found in the group (1) Monera (2) Plantae @) Fungi (4) Animalia ‘Specialized cells for fixing atmospheric nitrogen in Nostoc are (1) Akinetes 2) Hoterooysts (8) Hormogonia (4) Nodules Nuclear membrane is absent in (1) Volo 2) Nostoc (8) Penicitiom (4) Agaricus ‘The most abundant prokaryotes helpful to humans. in making curd from milk and in production of antibiotics are the ones categorised as (1) Chemosynthetic autotrophs: @) Heterotrophic bacteria @) Cyanobacteria (4) Archaebacteria Organisms called Methanogens are most abundant (1) Hot spring (2) Sulphur rock @) Caitle yara (4) Polluted stream Which of the followings is mainly produced by the activity of anaerobic bacteria on sewage? (1) Marsh gas (2) Laughing gas (@) Propane (4) Mustard gas ‘A peculiar odor that prevails in marshy areas and cow-sheds is on account of a gas produced by (1) Mycoplasma, (2) Archaebacteria @) Slime moulds (4) Cyanobacteria ‘Organisms, which fix atmospheric nitrogen in the soil, fall under the category of (1) Bacteria (2) Green algae @) Soil fungi (4) Mosses ‘Transduction in bacteria is mediated by (1) Plasmid vector (2) Phage vector (@) Cosmic (4) Fetactor Many blue-green algae occur in thermal springs. (hot water springs). The temperature tolerance of these algae have been attributed to their (1) Mitochondrial structure @) Importance of homopolar bonds in their proteins @) Cell wall structure (@) Modem cell organization ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-1 10008 Ph.011-47629456102) Biological Classification 73. 74, 75. 76. 17. 78. 79. 80, at 82, Board & Competitive Exams. For the first time, the bacteria were observed by 83, (1) Robert Koch (2) AV. Leeuwenhoek (3) WH. Stanley (4) Louis Pasteur A large number of organic compounds can be ‘decomposed by a4, (1) Photoheterotorphs (2) Pseudomonas (3) Photolithotrophs (4) Chemoheterotrophs What are the sex organs provided in some bacteria? (1) Sex pill (3) Circular DNA (2) Plasmid (4) Gametes BGA (blue green algae) are included in which of 85: the following groups? (1) Bryophytes 2) Prokaryotes @) Protista (4) Fungi ‘Which type of DNA is found in bacteria? (1) Circular DNA (2) Membrane bound DNA (3) Straight DNA ea: (4) Helical DNA. A few organisms are known to grow and multiply ‘at temperatures of 100-105°C. They belong to (1) Thermophilic sulphur bacteria er (2) Hot spring blue-green algae (3) Thermophilic subaerial fungi (4) Marine archaebacteria ‘The DNA of E.coll is (1) Double stranded and linear 2) Double stranded and circular (3) Single stranded and linear (4) Single stranded and circular i: Photosynthetic bacteria have pigments in (1) Chromoplasts (2) Chromatophores (3) Leucoplasts (4) Chloroplasts What is true for Archaebacteria? (1) Ail are halophiles 2) All are photosynthetic. 3) All are fossils (4) Oldest living beings ‘What is true for cyanobacteria? (1) Oxygenie with nitrogenase (2) Oxygenic without nitrogenase (3) Non oxygenic with nitrogenase (4) Non oxygenic without nitrogenase 89. Organisms which obtain energy by the oxidation of reduced inorganic compounds are called (1) Photoautotrophs (2) Chemoautotrophs @) Saprozoie (8) Coproheterotrophs Which statement is correctfor bacterial transduction? (1) Transfer of some genes from one bacteria to another bacteria through virus (2) Transfer of genes from one bacteria to another bacteria by establishing contact ) Bacteria obtained its DNA directly from mother cell (@) Bacteria obtained DNA from other external source Chromosomes in a bacterial cell can be 1 in umber and (2) Are always circular with more G = C content (2) Are always linear with more G = C content (8) Can be either circular or linear, but never both within the same cell (@) Can be circular as well as linear within the same cell Viruses that infect bacteria and cause their lysis, are called (1) Lysozymes @) Lipolytic @) Lytic (@) Lysogenic The most thoroughly studied bacteria plant interactions is the (1) Cyanobacterial symbiosis with some aquaticferns @) Gall formation on certain angiosperms by Agrobacterium @) Nodulation of Sesbania stems by nitrogen fixing bacteria (4) Plant growth stimulation by phosphate- solubilising bacteria What is true for photolithotrops?, (2) Obtain energy from radiations and hydrogen from organic compounds. (2) Obtain energy from radiations and hydrogen from inorganic compounds (@) Obtain energy from organic compounds (@) Obtain energy from inorganic compounds ‘The protists have (1) Only free nucleic acid aggregates (2) Membrane bound nucleoproteins lying ‘embedded in the cytoplasm (@) Gene containing nucleoproteins condensed together in loose mass (4) Nucleoprotein in direct contact with the rest of the cell substance Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-476234564104) Biological Classification 106. 107. 108, 109. 110. 111. 112. 113, An example of endomycorthiza is (1) Nostoc (2) Glomus (@) Agaricus (4) Rhizobium Satellite RNAs are present in some (1) Plant viruses (2) Viroids (3) Prions: (4) Bacteriophages A cell-coded protein that is formed in response to infection with most animal viruses, is called (1) Histone (2) Antibody (9) Interferon @) Antigen ‘Tobacco mosaic virus (TMV) genes are associated with (1) Single stranded RNA (2) Double stranded DNA (3) Single stranded DNA (4) Double stranded RNA ‘The tailed bacteriophages are (1) Motile on surface of bacteria (2) Non-motile (3) Motile on surface of plant leaves 4) Actively motile in water Viruses posses (1) Ribosomes to synthesize protein (2) Organelles for its vital mechanisms. (@) Either DNA or RNA (4) None of these Enzymes are generally not found in (1) Fungi (2) Algae (3) Virus (4) Cyanobacteria Viruses are living, because they (1) Multiply in host colts (2) Carry anaerobic respiration @) Cary metabolic activities (4) Cause infection 14. 15. 16. 17. 18. 109. 120, Board & Competitive Exams. Viruses are no more “alive” than isolated chromosomes because (1) They require both RNA and DNA. @) They both need food molecules (@) They both require oxygen for respiration (4) Both require the environment of a cellto replicate Tobacco mosaic virus is elongated rod like with size (1) 300 * 10 nm @) 300 * 5mm @) 300 « 18 nm (4) 700 x 30 nm Which one of the following statements about viruses is correct ? (1) Viruses possess their own metabolic system (2) All viruses contain both RNA and DNA. @) Viruses are obligate parasites (4) Nucleic acid of viruses is known as capsid Which of the following statements is not true for retroviruses? (1) DNA is not present at any stage in the life cycle of retroviruses Retroviruses carry gene for RNA-dependent DNA polymerase ‘The genetic material in mature retroviruses is RNA Retroviruses are causative agents for certain kinds of cancer in man ‘The causative agent of mad-cow disease is a () Virus, (@) Bacterium 8) Prion (4) Worm, Which one of the following statement about lichens is wrong? (1) These grow very rapidly (2 em per day) (2) They show fungal and algal symbiotic relationships (@) Some of its species are eaten by reindeers (4) These are pollution indicators. Most of the lichens consist of (1) Green algae and ascomycetes 2) Brown algae and higher plant (@) Blue green algae and basidiomycetes (@) Red algae and ascomycetes. 2 ® @) ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623455Board & Competitive Exams. Biological Classification | 103 90. on. 92. 93. 95. Which of the following organism possesses characteristics of a plant and an animal? (1), Eugtena @) Paramoecium (8) Bacteria (@) Mycoplasma Capiltium is present in the sporangium of (1) Dictyostelium @) Polysphondyfium (3) Physarum (4) Navicula Which one of the following is true for fungi? (1) They are phagotrophs (2) They lack a rigid cell wall @) They are heterotrophs (@) They lack nuclear membrane ‘When there are two haploid nuclei per call in some fungi before the formation of diploid, this stage is called (1) Diplotene 2) Diplophase (8) Dikaryophase (4) Dikaryote Which one of the following is linked to the discovery of Bordeaux mixture as a popular fungicide? (1) Black rust of wheat @) Bacterial leaf blight of rice (8) Downy mildew of grapes (4) Loose smut of wheat The black rust of wheat is a fungal disease caused by (1) Albugo candida @) Puccinia graminis tritici () Ustitago nuda (4) Cleviceps purpurea ‘The smut of maize is caused by (1) Ustitago avenae (2) Ustitago nuda (8) Ustilago hordei (4) Ustitago maydis 97. 98. 99, 100. 101. 102. 103. 104, 105, Puceinia forms uredia and (1) Telia on wheat leaves (2) Aecia on barberry leaves (@) Pycnia on barberry leaves (@) Aecia on wheat leaves. Columella is a specialized structure found in the ‘sporangium of () Spirogyra (2) Utothrix (8) Rhizopus (4) Peniciium Dikaryotisation occurs in Puccinia on (1) Upper surface of Barberry leaf (2) Lower surface of Barberry leaf (8) Upper surface of wheat leaf (@) Lower surface of wheat leaf ‘Adhesive pad of fungi penetrate the host with the help of (1) Mechanical pressure and enzymes (@) Hooks and suckers (@) Softening by enzymes only (@) Only by mechanical pressure Which fungal disease spreads by seed and flowers? (1) Loose smut of wheat @) Com smut (@) Covered smut of barley () Sof rot of potato Which of the following secrete toxins during storage conditions of crop plants? (1) Aspergillus (2) Peniciium (8) Fusarium (4) Colletotrichum Mycorthiza exhibits the phenomenon of (1) Parasitism (2) Symbiosis (@) Antagonism (4) Endemism Mycorthiza is correctly described as, (1) Parasitic association between roots and some fungi @) Symbiotic relationship between fungi and roots. of higher plants, (@) Symbiosis of algae and fungi (@) Relation of ants with the stem of some trees VAM is an example of (1) Endomycorrhiza (@) Endoparasitism (2) Ectoparasitism (4) Ectomycorthiza ‘Aakash Educational Services Pvt. Ltd. - Rogd. Office : Aakash Tower, 8, Pusa Road, New Dolhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 105 121 422, 423, 124, 125. 126. 427, 128, Aakash Educational Which of the following is the use of lichens in case of pollution? (1) They promote pollution 2) Lichens are not related with pollution () They treat the polluted water (4) They act as bioindicators of pollution Lichens are well known combination of an alga and a fungus where fungus has (1) A saprophytic relationship with the alga 2) An epiphytic relationship with the alga @) A parasitic relationship with alga (4) A symbiotic relationship with alga ‘There exists a close association between the alga and the fungus within a lichen. The fungus (1) Provides protection, anchorage and absorption for the algae @) Provides food for the alga (3) Fixes the atmospheric nitrogen for the alga (4) Releases oxygen for the alga ‘What is the genetic material in Influenza virus? (1) Double helical DNA (2) RNA @) Single helix DNA (4) None of these ‘The sexual reproduction is absent in (1) Spirogyra 2) Nostoc @) Ulothrix (4) Volvox Which one of the following fungi contains hallucinogens? (1) Morchelta esculenta (2) Amanita muscaria (8) Neurospora sp. (4) Ustitago sp. Anoxygenic photosynthesis is characteristic of (1) Rhodespiniturn 2) Spirogyra (@) Chlamydomonas (4) Uva A location with luxuriant growth of lichens on the trees indicates that the (1) Trees are very healthy @) Trees are heavily infested (9) Location is highly polluted (4) Location is not polluted SECTION - D Assertion - Reason Type Questions In the following questions, a statement of assertion (A) is followed by a statement of reason (R) 10. (1) If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1). 2) If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2). () If Assertion is true statement but Reason is false, then mark (3). (4) If both Assertion and Reason are false statements, then mark (4). A: Slime moulds have the characters of both plants and animals. R: Reproductive phase is animal like and vegetative phase is plant like. A: Methanogens can show symbiotic association with eukaryotic organisms. R= They are used for the production of biogas. A: Lichens do not grow in polluted area having SO,. R:: Lichens secrete carbonic acid and oxalic acid fon barren rocks. A: Secondary mycelium of Agaricusis binucleated, R: Secondary mycelium is formed by somatogamy of primary mycelium. A: Phycobient is dominant parent in lichens. R:: Algal component in the dual organisms can be eukaryotic only. A= Unicellular eukaryotes are included in Monera R: Unicellular eukaryotes have 70S cytoribosomes. A: Slime moulds form fruiting bodies under unfavourable conditions, RR: Naked plasmodium is formed during favourable conditions. A: DNase can inhibit the process of transformation. R: Transformation is absorption of DNA segment from the surrounding medium by a living bacterium. A: MLOsare pleomorphic and non-motile monerans. R: They are resistant to antibiotics like penicilin. A: Majority of bacteria are autotrophs. R: Chemoheterotrophic nutrition is absent in bacteria jervices Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456106. Biological Classification nA: R A R Holophytic protistans are important phytoplanktons and they contribute 80% of the total photosynthesis, ‘They lack chemosynthetic nutrition and utilize ‘non sulphur organic compound as the source of electron and proton in carbon assimilation. ‘Sexual spores in pink mould are meiospores produced endogenously. ‘They develop flask shaped fruiting body in sexta life cycle, a 13, 14. 45, Board & Competitive Exams. : Azotodesmic lichens are biofertilisers enriching nitrogen contents in soil ‘This abilly is due to the presence ofheterocystous blue-green algae as phycobiont component. Virolds are not included in five kingdom system ‘They are non-cellular. : Viruses which infect animals generally possess. ‘8sRNA or dsRNA or dsDNA. Phytophagineae generally contain dsDNA. ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456Board & Competitive Exams. Biological Classification | 79 (@) DNA containing viruses are called deoxyviruses. These are of two types » (Double stranded DNA (dsDNA) virus ¢.9. Pox virus, Cauliflower mosaic virus, Herpes virus. (i) Single stranded DNA (ssDNA) e.g. Coliphage o x 174, M13 phage. (®) RNA containing viruses or riboviruses are of two types : @ Double stranded RNA (dsRNA) virus e.g. Reovirus, Wound tumour virus. (i) Single stranded RNA (ssRNA) virus e.g. TMY, Influenza virus, Foot and Mouth disease virus, Retroviruses (HIV). (On the basis of host specificity viruses are divided into three groups 1. Phytophagineae/Plant viruses 2. Zoophagineae/Animal viruses 3. Bacteriophages/Bacterial viruses. Structure of Some Viruses 1. Tobacco Mosaic Virus (TMV) is elongated rod like, 3000 A long, 180 A in diameter with molecular weight 39.4 x 10° dalton. 2130 capsomeres are arranged helically to form the capsid. RNA strand is helical. ssRNA consists of 6400 nucleotides. Thus, the ratio of nucleotides : capsomeres = 3 : 1 Fig. : Tobacco Mosaic Virus (TMV) 2. Bacteriophage (or bacterial viruses) are the viruses that infect the bacteria. Bacteriophages usually have. double stranded DNA. T, Bacteriophage has a tadpole like structure with polyhedral head connected to a helical tail (binal). The head consists of nucleic acid surrounded by a protein coat or capsid. Nucleic acid is double stranded DNA. Tail is proteinaceous tube-like, core surrounded by sheath. At one end, tube is joined to the head by thin collar. At the other end, it has a hexagonal base plate with six small tall pins and six tail fibres which help in attachment of the phage to the host cell 650A, Ol) Head (ONA coveree i cae g _- Collar { Nock « _= Tal a Ta tres (©) ~ End plate (about 200 thick) Fig. : Structure of T, bacteriophage ‘Aakash Educational Services Pvt. Ltd. - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph.011-47623456