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Vol. XVIII No. 1 January 2016 Corporate Office: Plot 99, Sector 44 Institutional Area, Gurgaon -122 003 (HR), Tel : 0124-4951200 e-mail : [email protected] website : www.mtg.in Regd. Office: 43 17 406, Taj Apartment, Near Safdarjung Hospital, 59 Ring Road, New Delhi - 110029. Managing Editor : Mahabir Singh 31 Editor : Anil Ahlawat 46 COnTenTs 19

8 CBSE Board 2016 (XII) 16 Unitwise Practice Paper (Unit V) 16 Bio-Gram 84 ELISA

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MTBIOLOGY TODAY | january ‘16 7 UNIT V

Organisms and Populations Ecosystem Biodiversity and Conservation 66 Environmental Issues

GENERAL INSTRUCTIONS (i) All questions are compulsory. (ii) This question paper consists of five Sections A, B, C, D and E. Section A contains 5 questions of one mark each. Section B contains 5 questions of two marks each, Section C contains 12 questions of three marks each. Section D contains 1 question of VBQ type with four marks and Section E contains 3 questions of five marks each. (iii) There is no overall choice. However, an internal choice has been provided in one question of 2 marks, one question of 3 marks and all the three questions of 5 marks weightage. A student has to attempt only one of the alternatives in such questions. (iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.

SECTION - A 9. What do you mean by reservoir pool in terms of nutrient cycling? What is its function? 1. Which type of biotic interaction is mainly responsible for the biological control method of managing the pests? 10. At a particular segment of a river near a sugar factory, 2. A tadpole and an adult frog occupy different ecological the BOD is much higher than the normal level. What is it niches. Give reason. indicative of? What will happen to the living organisms in this part of the river? 3. What is the percentage of photosynthetically active radiation (PAR) in the incident solar radiation? SECTION - C 4. Mention the broadly utilitarian argument for the conservation 11. We have many threads which weave the different areas of of biodiversity. biological information into a unifying principle. Ecology is one 5. Why species richness increases with increased study area? such thread which gives us a holistic perspective to biology. SECTION - B Justify the above statement with suitable explanation. 6. Give an example of mutualistic association in which the 12. How are the animals living in arid or desert areas adapted to organisms involved are commercially exploited in agriculture. survive in conditions of water scarcity? Explain with suitable example. OR 13. How do organisms cope with stressful external environmental How is primary productivity affected by sunlight? Give conditions which are localised or of short duration? example. 7. Cryopreservation help in the conservation of biodiversity. OR Explain. Name the pioneer community and climax community in a 8. What does the given age pyramid signify about the status xerosere. How does the pioneer species help in establishing of a population? The bar at the base represents pre- next type of vegetation in xerosere? reproductive individuals. 14. (a) In a population, per capita birth rate is 0.025 and per capita death rate is 0.008 during a unit time period. What is the value of intrinsic rate of natural increase, 'r' for the population? ...... (b) Define resource partitioning......

8 MTBIOLOGY TODAY | JANUARY ‘16

15. Study the given figures showing two regions X and Y in an industry. containing different numbers and types of species, and (a) Which values have been shown by Mayank in above answer the accompanying question. situation? (b) How does an electrostatic precipitator work? Site 1 Site 2 (c) State the consequences if the electrostatic precipitator of a factory or a thermal power plant stops functioning? SECTION - E Site 3 Site 4 24. (a) How are herbs and shrubs able to survive under the shadow of big canopied trees in thick forests? (b) A cuckoo bird lays her eggs in the crow's nest. How do you describe this interaction between the cuckoo and the crow? Region X Region Y (c) What are osmoconformers? Which out of the two regions shows higher beta diversity OR and why? Differentiate between : 16. Give diagrammatic representation of carbon cycle. (a) Primary succession and secondary succession. (b) Primary productivity and secondary productivity. 17. Explain the odd shape of the given pyramid of numbers. 25. What is decomposition? Describe the different steps Buzzard involved in the process of decomposition in an ecosystem. OR Black birds (a) With the help of a graph explain the effect of sewage discharge Caterpillars in river and recovery of the same after some distance. Oak tree (b) Mention the four main greenhouse gases along with their percentage contribution towards greenhouse effect. 18. Among plants and animals, which group exhibits greater 26. Explain species area relationship of biodiversity with the species diversity? Support your answer with explanation. help of suitable graph. 19. (a) What is meant by the term 'hotspot' in biodiversity? OR Mention two criteria used for determining a hotspot. Name any one hotspot of India. Winner: Ankita Singh, Ranchi (b) Exotic species often become invasive and drive away the SOLUTIONS TO NOVEMBER 2015 CROSSWORD 132 4 5 6 78910 native species. Give an example to justify this statement. ACFLI IA TNPIP

11 12 13 20. Explain any three measures to control vehicular air pollution NL RNM U TERNA in Indian cities. 14 15 T OX INTA MA M COTR

21. Why does biomagnification occur with toxic substances HC SRT OXU RSET such as heavy metals, persistent pesticides etc? 16 RSENS O RYU OTORTH 22. What are hybrid vehicles? Enlist advantages and 17 OPERON IRN A SAFE

disadvantages of using hybrid vehicles. 18 19 PHOENIXHARTIGAN SECTION - D 20 OS TEOPOROS ISLSO

21 23. Mayank and Devansh are partners in a factory. After a few G LOME R U L U SO AGC

22 months of the establishment of the factory, the electrostatic E P HEDR INE N NIE

precipitator (ESP) stopped functioning and needed to be 23 N U CL EASE DCN replaced. Mayank wanted to replace it but Devansh said 24 25 that it had no impact on the productivity and income, and I U CN NE KTON I U E 26 27 therefore they should not waste money in buying a new C ONTAMINA TIONL S 28 29 electrostatic precipitator. Mayank convinced him by telling AS THMA C U L ASAI 30 him about the advantages and disadvantages of using ESP G EROMORPHISMRS

10 MTBIOLOGY TODAY | JANUARY ‘16

(a) Explain, by giving examples, any three different ways by 9. Reservoir pool is the reservoir of biogenetic nutrients from which population density can be measured. which the latter are slowly transferred to cycling pool, e.g., (b) Differentiate between interspecific competition and reservoir pool of phosphates are rocks. The function of intraspecific competition. reservoir pool is to meet deficiency of nutrient which occurs SOLUTIONS due to differences in the rate of influx and efflux. 1. Predation (between the pest and biocontrol agent) is 10. A higher BOD indicates that the particular segment of the biotic interaction which is mainly responsible for the the river is highly polluted. As a result, there will be sharp biological control method of managing the pests. decline in the dissolved oxygen content in this part. It will result in mortality of fish and other aquatic organisms. 2. A tadpole and an adult frog occupy different ecological niches because the former is herbivorous and aquatic while 11. Ecology is defined as the study of inter-relationships the later is carnivorous and amphibian. between living organisms and their environment. The two 3. The percentage of photosynthetically active radiation (PAR) main branches of ecology are – autecology and synecology. in the incident solar radiation is less than 50%. Autecology studies inter-relationship of the organisms of a single species with biotic or abiotic environment. Synecology 4. The broadly utilitarian argument says that biodiversity is studies inter-relationship of different groups of the living fundamental to ecosystem services that nature provides organisms, such as populations, biotic communities and like pollination, microbial waste treatment, biological pest their environment which are associated together as a unit. control etc. Thus it connects all organisms either plants or animals, 5. Species richness depends upon habitat variation. Larger aquatic or terrestrial together and analyses their influences study area includes larger variety of habitats, thus shows on one another, their co-existence, sustainance of life on greater species richness. earth etc. Thus, ecology is basically concerned with different 6. Mutualistic association between nitrogen fixing cyano- levels of ecological hierarchy or ecological organisation and bacterium Anabaena and water fern Azolla is of great works as the thread which gives us a holistic perspective to agricultural importance in increasing rice production. It biology. increases nitrogen content of soil. 12. Animals living in the conditions of water scarcity show OR two types of adaptations—reducing water loss from the Primary productivity increases with an increase in body and conserving water in the body. For example, desert availability of sunlight due to increased photosynthetic rate. rat who seldom gets to drink water due to scarcity has a For example, productivity in aquatic ecosystems is lesser thick coat to minimise evaporative desiccation. The animal than that in terrestrial ecosystems. It is because in aquatic seldom comes out of its comparatively humid and cool ecosystems, availability of light decreases with increasing burrow during the day time. 90% of its water requirement water depth. is met from metabolic water (water produced by respiratory 7. Cryopreservation refers to the storage of living cells, tissues, breakdown of fats) while 10% is got from food. Loss of embryos, gametes, etc. at –196°C (liquid nitrogen). The water is minimised by producing nearly solid urine and cryopreserved material is revived through special technique faeces. when required. In order to prevent extinction, endangered 13. Living organisms cope with stressful condition by any of the microorganisms or the propagules of other organisms are following methods: being cryopreserved so that they can be revived when required. Thus, cryopreservation is an important ex situ (i) Migration : The organism can migrate temporarily from method of conservation of biodiversity. the unfavourable habitat to more favourable area and return when unfavourable period is over e.g., Siberian 8. Given is a bell-shaped age pyramid which signifies that the birds migrates from Siberia to other parts in every population is stable. Such age pyramid is formed when the winter. number of pre-reproductive and reproductive individuals is almost equal and the post-reproductive individuals are (ii) Hibernation : The animal spends cold period in an comparatively fewer. It implies that the population is neither inactive stage and resumes activity in summers. e.g., decreasing nor increasing, instead is maintained at a stable polar bears undergo hibernation during winter season level. to escape extreme cold.

12 MTBIOLOGY TODAY | JANUARY ‘16

(iii) Aestivation : Animal spend dry hot period in an inactive interference of human activities. The two main criteria for stage and resumes activity in favourable conditions. determining a hotspot are: e.g., snails and fish. (i) Number of endemic species (iv) Diapause : Many insects and other invertebrates (ii) Degree of threat in terms of habitat loss. undergo diapause in which development or growth One of the hotspots of India is Western Ghats. is suspended and metabolism is greatly reduced. In (b) Water hyacinth (Eicchornia) had been introduced in Indian some long lived species adults may undergo diapause waters due to its aesthetic values. However, it spread rapidly while in some the egg is the diapausal stage. It enables in water bodies by vegetative propagation i.e., became the animal to survive unfavourable environmental invasive. Its rapid growth clogged water bodies and resulted conditions. in deaths of several native aquatic plants and animals. Thus, OR it drove away the native species. The pioneer species on a bare rock are usually lichens. They 20. Three measures to control vehicular air-pollution in Indian secrete acids to dissolve rock, helping in weathering and cities are : soil formation. These later, pave way to some very small – Use of CNG as fuel in the vehicles because it burns plants like bryophytes, which are able to take hold in the more efficiently and little of it is left unburnt. It is also small amount of soil formed by lichens' action. The climax cheaper. community that will ultimately get established is forest. – Use of unleaded petrol in the vehicles. 14. (a) Intrinsic rate of natural increase, – Use of catalytic converter in the vehicles as it reduces r = Per capita birth rate – Per capita death rate emission of poisonous gases. = 0.025 – 0.008 21. Biomagnification occurs with toxic substances because = 0.017 these toxic substances are generally lipophilic and get (b) When two or more species divide a niche to avoid competition deposited in the tissues of organism. These toxic substances for resources, it is called resource partitioning. Organisms accumulated by an organism cannot be metabolised or with similar requirements may evolve to reproduce at excreted, and are passed on to the next higher trophic level different times of the year, feed at different times of the day where they get accumulated and magnify in quantity as the or night, or use different parts of the habitat like different higher trophic level organism consumes multiple organisms areas of a forest or different depths of a lake. of the lower trophic level. Two such substances are mercury 15. Region Y has higher Beta (b) diversity than region X. It is and DDT. because Beta diversity measures the amount of change between two sites in a region and there is a higher turn over of species among the sites 2 and 4 in region Y. 16. Refer to answer 13, page no. 388, `MTG Excel in Biology’. READERS’ REVIEWS 17. Given diagram represents the spindle-shaped pyramid of numbers in a forest ecosystem, showing 4 different trophic You are doing a great job. I just love your “Biology Today”. Thanks for such a magazine. levels. The number of producers (oak trees) and the number Abhishek Gaurav of top consumers (buzzards) is small. This can be explained Biology Today is an immensely helpful magazine and I thoroughly as follows: A single large oak tree supports hundreds of enjoy reading it. The question papers are very helpful and has helped me to clear many of my previous doubts. With so much competition all caterpillars, so the number of organisms increases from first around, Biology Today has proved out to be a real life saver. Feeling to second trophic levels. However, a few black birds can privileged to be one of the readers of this amazing magazine. feed on these caterpillars (number in tens) and even fewer Joydeep Saha buzzards (birds of prey) can feed on these black birds. So Biology Today is the best magazine for Medical Entrance Exams. Suman Das the number of organisms decreases at the third and fourth MTG magazines and books are good enough to give a new trophic levels. approach to learning and get new idea about it. Abdul Rehman 18. Refer to answer 6, page no. 405, `MTG Excel in Biology’. 19. (a) Hotspots are those regions of rich biodiversity which have been declared sensitive due to direct or indirect

14 MTBIOLOGY TODAY | JANUARY ‘16 22. Hybrid vehicles are the vehicles which employ more than (b) CO2 – 60%, CH4 – 20%, one type of energy/fuel source, such as traditional internal CFCs – 14% and N2O – 6% combustion engine + an electric motor, e.g., diesel-electric 26. Refer to answer 15, page no. 410, `MTG Excel in Biology’. trains use diesel engines and electricity from overhead line. Advantages : (i) Hybrid vehicles are more fuel efficient. OR (ii) Hybrid vehicles cause less pollution. (a) Three different ways to measure population density are as Disadvantages : Hybrid vehicles prove to be costlier as they follows: employ two different types of fuel sources. (i) It can be measured as numerical density (number of 23. (a) Mayank shows responsibility and concern towards individuals per unit area or volume), e.g., number of environment and health of other organisms. Siberian cranes at Bharatpur wetlands in any year. (ii) It can be measured as biomass density (biomass per (b) Refer to answer 6(ii), page no. 429, `MTG Excel in Biology’. unit area or volume), e.g., a dense laboratory culture (c) Refer to answer 8(i), page no. 430, `MTG Excel in Biology’. of bacteria in a Petri dish. 24. (a) Herbs and shrubs survive under the shadow of big (iii) It can be measured as relative density, e.g., the number canopied trees in forests as they are perfect shade tolerant of fish caught per trap can give a relative measure of plants which show better growth in lower level of light the population density of the fish in water body. intensity. They grow in a manner, that they are arranged in (b) Differences between intraspecific and interspecific competi- different strata according to their shade tolerance. tion are as follows:

(b) Refer to answer 8, page no. 366, `MTG Excel in Biology’. Intraspecific Interspecific (c) Osmoconformers are those organisms which cannot competition competition maintain osmolarity of their body fluids constant and it (i) It is competition among The competition is varies according to their surrounding medium. individuals of the same amongst the members OR species. of different species. (a) Refer to answer 11, page no. 393, `MTG Excel in Biology’. (ii) The competition is for all The competition is for one (b) Refer to answer 9(f), page no. 387, `MTG Excel in Biology’. the requirements. or a few requirements. 25. Refer to answer 3, page no. 385, `MTG Excel in Biology’. (iii) The competing indivi- The competing indivi- OR duals have similar duals have different (a) The graph showing effect of sewage discharge on a water adaptations. adaptations. body is as follows: (iv) It is more severe due It is less severe as the to similar needs and similar needs are a few Dissolved oxygen adaptations. and the adaptations are different.



Concentration BOD

Direction of flow of river NOVEMBER 2015 Sewage discharge 1. VIROIDS 2. GINKGO Due to discharge of sewage into the river, micro-organisms 3. EPHEDRINE 4. SANGUIVORES present in the river get involved in biodegradation of added organic matter and in the process consume a lot of 5. CRYPSIS 6. GEMMULES dissolved oxygen present in river. Due to this, biochemical 7. EPIMORPHOSIS 8. NEELAKURANJI oxygen demand (BOD) of the river increases. As sewage 9. MIRACIDIUM 10. SPOROPOLLENIN is decomposed gradually, there occurs a rise in dissolved Winners : Raya Ghosh, oxygen downstream and decrease in the BOD of the river Akansha Deshmukh(Chattisgarh), water. Raja Faizan Nabi(Srinagar)

MTBIOLOGY TODAY | JANUARY ‘16 15 ELISA An ELISA (Enzyme Linked Immuno Sorbent Assay) test is a method that uses components of the immune system and chemicals to detect immune responses in the body (e.g., to infectious microbes). It determines if certain substance, such as specific cytokine or antigen is present within a sample or not. ELISA is important for early diagnosis of diseases. Direct ELISA, the simplest type of ELISA is explained here.

Sample Buffered samples that may contain the antigen to be tested coated well for, are added to each well of a microtiter plate, where the samples are given time to adhere to the plastic through charge interactions. The sample in each well is immobilised on the solid support i.e., microtiter plate (usually made up Sample

BIO-GRAM of polystyrene); either non–specifically (via adsorption to the surface) or specifically (via capture by another antibody Microtiter plate specific to the same antigen, in a “sandwich” ELISA). Antigens or ELISA plate

Wells containing different samples

After antigen immobilisation, the detection antibody (primary Primary antibody antibody) is added, forming a complex with the antigen. specific to antigen The plate is incubated at room temperature and is typically washed with a mild detergent solution (or deionised water) multiple times, to remove any proteins or antibodies that are non–specifically bound. Primary antibody binds to antigen

Enzyme linked Enzyme secondary antibody E E E Secondary A second set of antibodies specific for pathogen and antibody conjugated with an enzyme is added to the plate, which attaches with the primary antibody-antigen complex. Then it Primary is incubated at room temperature and plate is washed for the antibody second time to remove unbound secondary antibodies. Antigen

Chromogenic A substrate called chromogen is added that will change substrate E E E S S colour only when enzyme is present. If patient’s sample had S the antigen to which the enzyme linked antibodies bound (through the primary antibody) then colour change would be seen. After adding the chromogen, plate is incubated for 30 mins. Changed colour indicates presence of antigen

Dilute acid stop solution is added and the ELISA plate is read at 450 nm. The higher the concentration of the primary antibody present in the serum, the stronger is the colour change. Often, a spectrometer is used to give quantitative values for colour strength.

16 MTBIOLOGY TODAY | january ‘16 PRACTICE QUESTIONS ON Assertion & Reason

 MOrphOLOGY Of fLOwerInG pLAnTs  prIncIpLes Of InherITAnce AnD vArIATIOn

Direction : In the following questions, a statement of assertion 8. Assertion : The racemose type of inflorescence has is followed by a statement of reason. Mark the correct choice indefinite growth. as : Reason : In racemose inflorescence, the peduncle continues (a) If both assertion and reason are true and reason is the to grow forming new bracts and flowers in succession. correct explanation of assertion. 9. Assertion : Hypanthodium is found in Ficus carica. (b) If both assertion and reason are true but reason is not the Reason : In hypanthodium, receptacle is open from correct explanation of assertion. above. (c) If assertion is true but reason is false. (d) If both assertion and reason are false. 10. Assertion : Mustard flower has radial symmetry. Reason : Mustard bears actinomorphic flowers. MOrphOLOGY Of fLOwerInG pLAnTs 11. Assertion : Caryophyllaceous corolla is found in 1. Assertion : root cap is present at the apex of the root. carnation. Reason : root cap protects the root meristem as it Reason : Caryophyllaceous corolla has five or more sessile penetrates the hard soil. or shortly clawed petals bent horizontally like a saucer. 2. Assertion : Banyan tree has prop roots. 12. Assertion : In imbricate aestivation, one margin of a petal Reason : Prop roots help the plant to get oxygen for overlaps the margin of an adjacent petal and the other respiration. margin being overlapped by margin of adjacent petal. 3. Assertion : Leaves of dicot plants generally possess Reason : Imbricate aestivation is found in China rose. parallel venation. 13. Assertion : a true fruit is a ripened ovary which develops Reason : Veinlets are conspicuous in dicots. after fertilisation under the influence of ripening ovules. 4. Assertion : In Artabotrys the stem is modified into stiff Reason : Eucarp consists of a pericarp formed from the curved thorns or hooks. walls of ovary and seeds formed from ovules. Reason : The hooks help the plant in climbing. 14. Assertion : The outermost covering of a dicotyledonous 5. Assertion : roots are endogenous in origin. seed is the seed coat. Reason : root branches develop from the interior usually Reason : The seed coat has two layers outer testa and pericycle of the parent root. inner tegmen. 6. Assertion : In Mimosa pudica, the leaf base is swollen. 15. Assertion : The fruit of apple is called a pome. Reason : Pulvinus is responsible for sleep and shock Reason : Pome develops from the fleshy thalamus of movements in Mimosa leaves. multicarpellary, syncarpous, inferior ovary. 7. Assertion : The opposite type of phyllotaxy is the prIncIpLes Of InherITAnce AnD vArIATIOn arrangement of leaves in which two leaves are borne on the opposite sides of a single node. 16. Assertion : Genes are called the units of inheritance. Reason : The opposite type of phyllotaxy is seen in China Reason : Genes contain the information required to express rose and oleander. a particular trait in an organism.

MTBIOLOGY TODAY | January ‘16 17 17. Assertion : In monohybrid cross, in F2 generation, two traits 28. Assertion : Down’s syndrome is a genetic disorder of character are expressed in the proportion of 3 : 1. caused due to the presence of an additional copy of Reason : 3 : 1 ratio of F2 generation is due to segregation X-chromosome. of factors present in F1 plants during gamete formation. Reason : Both X chromosomes pass into single egg due to non disjunction during oogenesis. 18. Assertion : The F1 generation of andalusian fowls comprises of blue coloured fowls. 29. Assertion : Variety of coat colour in mice is result of Reason : Blue colour is due to epistatic suppression of dominant epistasis. black colour in one of parental fowls by alleles of white Reason : In dominant epistasis, a dominant gene at colour. one locus enhances the expression of another gene at a 19. Assertion : Mendel used true-breeding lines for conducting different locus. experiments on genetic studies. 30. Assertion : Monogenes produce continuous variations in Reason : True breeding lines show the stable trait the expression of traits. inheritance and expression for several generations. Reason : Monogenic inheritance controls quantitative 20. Assertion : aBO blood group system provides a good trait. example of incomplete dominance. ANSWER KEY Reason : In aBO blood group system, none of the two 1. (a) 2. (c) 3. (b) 4. (b) 5. (a) contrasting alleles is dominant. 6. (b) 7. (c) 8. (a) 9. (c) 10. (a) 21. Assertion : F2 progeny obtained by cross-breeding of 11. (c) 12. (d) 13. (b) 14. (b) 15. (b) white coat coloured short horned cattle with red coat 16. (a) 17. (a) 18. (c) 19. (a) 20. (d) colour, shows ratio of 1 : 2 : 1. 21. (b) 22. (b) 23. (b) 24. (c) 25. (b) Reason : In short horned cattle, roan colour is produced 26. (c) 27. (a) 28. (d) 29. (d) 30. (d) due to juxtaposition of small patches of red and white colour.  22. Assertion : Chromosomes have a definite role in the development of an individual. Reason : In many organisms, sex of an individual is determined by specific chromosomes, called sex chromosomes. 23. Assertion : Some insects have XO type of sex determination mechanism. Reason : Insect’s eggs bear one X-chromosome alongwith autosomal chromosomes. 24. Assertion : Xy type of sex determination mechanism is an example of male heterogamety. Reason : In birds, male heterogamety is seen as males produce two different types of gametes. 25. Assertion : Sickle-cell anaemia results from point mutation. Reason : In sickle-cell anaemia, haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in shape of rBCs. 26. Assertion : Haemophilia is a sex-linked recessive disease in which heterozygous female transmits the disease to 50% of her male progeny. Reason : Haemophilia is due to presence of recessive sex linked gene present on y chromosome. 27. Assertion : accumulation of phenyl pyruvic acid in brain results in mental retardation in case of phenylketonuria. Reason : The affected individual lacks enzyme for the conversion of phenylalanine into tyrosine.

18 MTBIOLOGY TODAY | January ‘16 (b) Gordon Moore, Co-founder of Intel (c) azim Premji, Chairman of Wipro (d) Mark Zuckerberg, Founder of Facebook 9. Who among the following won Macau Open Grand Prix Gold Women’s Singles title for 3rd consecutive time? (a) PV Sindhu (b) Minatsu Mitani (c) Saina nehwal (d) Carolina Marin 10. On 27th november 2015, LrSaM missile co-developed by India and Israel was successfully tested from an Israeli navel Platform. The missile is a/an ______. (a) air-to-surface missile (b) surface-to-surface missile (c) surface-to-air missile (d) air-to-air missile 11. Garden reach Shipbuilders and Engineers Limited (GrSE) handed the second anti-Submarine Warfare Corvette ‘Kadmatt’ to Indian navy. Which of the following statement(s) is/are correct regarding the highlights of this report? I. The warship was handed over by rear admiral he questionnaire contains multiple choice questions based (retd.) a. K. Verma, Chairman and MD of GrSE to the Ton current affairs and recent developments worldwide. Commanding Officer of the ship Mahesh C. Moudgil. Various facts are presented in question form to enable the II. The ship is capable to fight in nuclear, biological and chemical students to develop knowledge as well as to test their general warfare environments. awareness skills and equip them with all essentials to crack (a) I only (b) II only various PMTs (AIIMS, etc.) This will also help them to excel in (c) Both I and II (d) neither I nor II other competitive exams like Banking and various Government 12. Who has been recently appointed as Head of retail Banking in the recruitment exams. Mashreq’s Banking Group? 1. Who among the following was recently suspended by International (a) Som Subroto (b) Farhad Irani Cricket Council (ICC) for illegal bowling action? (c) arundhati Bhattacharya (d) naina Lal Kidwai (a) Saeed ajmal (b) Kane Williamson 13. The Mayyazhi Mahotsavam 2015 was held in which union Territory (c) Sunil narine (d) Sachithra Senanayake of India? 2. World aIDS Day was celebrated on ...... 2015. (a) national Capital Territory of Delhi (a) 25th november (b) 1st november (b) Chandigarh (c) 25th December (d) 1st December (c) Daman and Diu (d) Puducherry 3. ______was elected as the president of the West african 14. The first historic day-night Test match played ata delaide Oval was country Burkina Faso. played between which of the following two countries? (a) roch Marc Christian Kabore (a) australia and South africa (b) Zephirin Diabre (b) India and South africa (c) Tahirou Barry (d) Michel Kafando (c) new Zealand and Sri Lanka (d) australia and new Zealand 4. Which of the following was awarded Golden Peacock award for the Best Film at 46th International Film Festival of India? 15. Who among the following recently became the WBa (Super), IBF, (a) The Measure of a Man (b) Embrace of the Serpent WBO, IBO and The ring unified heavyweight champion? (c) Sealed Cargo (d) Eisenstein in Guanajuato (a) Wladimir Klitschko (b) Tyson Fury 5. robert Lewandowski, a polish footballer was recently awarded (c) rico Verhoeven (d) Benjamin adegbuyi with four Guinness World record certificates for scoring ____. 16. Which of the following countries recently allowed women to (a) five goals in eight minutes fifty nine seconds contest municipal elections? (b) four goals in eight minutes twenty seconds (a) Libya (b) Sudan (c) three goals in ten minutes ten seconds (c) Saudi arabia (d) Serbia (d) seven goals in ten minutes 17. Which of the following countries is building world’s largest animal 6. Which of the following currency was recently approved as Elite cloning factory? reserve Currency by International Monetary Fund (IMF)? (a) united States of america (b) China (a) Indian rupee (b) uS Dollar (c) Japan (d) India (c) British Pound (d) Chinese yuan 18. Which among the following countries recently launched its first 7. In which state of India, the coal miners recently switch to turmeric commercial satellite? farming after the ban on coal mining and transportation of coal by (a) China (b) South Korea national Green Tribunal (nGT) in april 2014? (c) India (d) Japan (a) assam (b) Meghalaya ANSWER KEY (c) nagaland (d) arunachal Pradesh 1. (c) 2. (d) 3. (a) 4. (b) 5. (a) 8. according to World’s 20 Most Generous People list released 6. (d) 7. (b) 8. (c) 9. (a) 10. (c) recently by Wealth–X and Business insider, ______ranks fourth 11. (c) 12. (a) 13. (d) 14. (d) 15. (b) in the world. 16. (c) 17. (b) 18. (d) (a) Warren Buffett, CEO of Berkshire Hathaway 

MTBIOLOGY TODAY | January ‘16 19 PRACTICE PAPER CLASS XI & XII

SInGLe OpTIOn COrreCT This paper contains 180 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct. (Mark only One Choice). Marks : 180 × 4 = 720 Negative Marking (–1)

CLASS XI 1. Which of the following is a correct statement? 4. Eight bacteria kept in cup divide repeatedly and produce (a) Methanomonas bacteria, present in gut of ruminant 64 bacteria in 2 hours. Find the time consumed in binary animals, are obligate anaerobic, which are used in fission. production of biogas. (a) 15 minutes (b) 20 minutes (b) Vast majority of bacteria are autotrophic and a few are (c) 40 minutes (d) 30 minutes heterotrophic. 5. How many of the following statements are true? (c) Bacterial structure is simple, they are very complex (i) Building block of fungal body is mycelium. in behaviour and show the most extensive metabolic (ii) Lichens exchange gases through ‘cephalodium’. diversity. (iii) Lichens and mosses are air pollution indicators. (d) Mycoplasma are facultative anaerobic. (iv) Oospores, zoospores and conidia are asexual spores of 2. ‘Citrus canker’ is a well known disease of citrus plants, fungi. characterised by development of holes in their leaves due (v) Trichonympha found in the intestine of termites help in to necrosis caused by their nutrition. (a) Pseudomonas citri (b) Penicillium citri (a) 2 (b) 4 (c) Trichoderma citri (d) Xanthomonas citri. (c) 3 (d) 1 3. Which of the following statements are true w.r.t. bacteria? 6. Which of the following statements are correct? (i) Dikaryon in higher fungi is n + n nuclei containing, (i) Typical bacteria are 1-2 mm in size. where two nuclei are commonly different in genetic (ii) Glycocalyx differs in composition and thickness among makeup. different bacteria. (ii) Fungus growing on dung is coprophilous, where as (iii) Fimbriae are elongated tubular structures formed of growing on bark is corticolous. special protein, help in attachment of bacteria to host (iii) Disease of fungus producing ‘sooty mass’ of spores is cell. called smut, which is caused by Puccinia. (iv) Mesosome of bacteria is formed of extensions of (iv) Alternaria, Colletotrichum and Trichoderma belong to plasma membrane in the cell anterior, in the form of Class Deuteromycetes. vesicles, tubules and lamellae helping in anaerobic (v) Morchella is an edible mushroom of Class Basidio- respiration. mycetes. (v) Polysome of bacteria is formed of one r-RNA attached (a) (i), (ii) and (iv) to many ribosomes. (b) (ii), (iv) and (v) (a) (i) and (ii) (b) (i) and (iv) (c) (i), (ii), (iv) and (v) (c) (ii), (iii) and (iv) (d) All except (ii) (d) All the five statements are true.

Contributed by : Harpal Singh, Harpal's Biology Classes, Chandigarh, 09781124215

20 MTBIOLOGY TODAY | JANUARY ‘16

7. Which of the following are incorrect matches? 12. Which of the following is a correct one? (i) Bracket fungi – Harmful to our timber resource X Y (a) NH3 ¾®¾¾ NO2 ®¾ NO3, where X = Nitrobacter, (ii) Neurospora – Used extensively in biochemical and Y = Nitrosomonas. genetic research (b) Pseudomonas and Thiobacillus → Denitrifying (iii) Lysergic Acid Diethyl amide – Hallucinogenic and bacteria. derived from Claviceps purpurea (c) Gram –ve bacteria susceptible to antibiotics. (iv) Albugo candida – Belongs to Class Phycomycetes (d) Frankia – Fixes nitrogen in leguminous root nodules. (v) Conidiospores – Deuteromycetes and Ascomycetes (a) (i) and (iii) (b) (ii), (iii) and (v) 13. Which of the following environmental conditions essential (c) (iii) and (v) (d) None of these for the optimum growth of Rhizopus on a stale bread 8. How many of the following fungi are members of piece? Basidiomycetes? (i) Darkness (ii) Relative humidity 95% (iii) Well lighted place Agaricus, Aspergillus, Alternaria, Puff balls, (iv) Temperature 5°C Claviceps, Ustilago, Puccinia, Albugo, (v) Relative humidity about 10% Trichoderma, Edible Morel (vi) Temperature of about 25°C (a) 5 (b) 4 (a) (i), (ii) and (vi) (b) (ii), (iii) and (vi) (c) 6 (d) 7 (c) (i), (v) and (vi) (d) (i), (iv) and (v) 9. Which of the following criteria used for classification of 14. Which is correct w.r.t. cell wall of bacteria and fungi? Fungi into its classes? (a) In both, it is highly selective for absorption. (a) Mode of spore formation (b) Both contain mucopeptide. (b) Morphology of mycelium (c) Both contain abundant cellulose. (c) Fruiting bodies (d) Both contain NAG. (d) All of these 15. Read carefully the table and fill up the blanks: 10. Which of the following is true of its label from 1 to 4? Classes Major Stored Cell Wall Flagellar Pigments Food Number & Position of Insertions Chloro- A Starch Celluose 2-8, equal, phyceae apical Phaeo- Chlorophyll-a Mannitol, C 2, unequal, (a) 4 – ‘Gills’ help in exchange of gases. phyceae and c laminarin lateral (b) 3 – Annulus, outgrowth of pileus for assisting in spore fucoxanthin dispersal. Rhodo- Chlorophyll-a B Cellulose D (c) 2 – Stipe edible part, rich in protein and formed of phyceae and d secondary mycelium. phycoerythrin (d) 1 – Primary mycelium produced by germination of A, B, C and D in the above table refer to teleutospore. (a) A-chlorophyll-a and d; B-Starch and Laminarin; 11. Bacteria differ from cyanobacteria by which of the following C-Cellulose; D-2-10 equal apical features? (b) A-Chlorophyll-a and c; B-Mannitol and starch; (i) Absence of flagella and fimbriae. C-Cellulose and algin; D-2-8 equal lateral (c) A-Chlorophyll-a and b; B-Floridean starch; (ii) dsDNA without attached histones. C-Cellulose and algin; D-Not present (iii) Anoxygenic photosynthesis. (d) A-Chlorophyll-a and b; B-Mannitol and floridean (iv) Stored food as glycogen. C-Cellulose; starch; D-Not present (v) Absence of N2 fixing cells like heterocyst. 16. In algae, vegetative reproduction mainly takes place by (a) (i), (iii) and (iv) (b) (ii), (iv) and (v) (a) budding (b) akinetes only (c) (iii), (iv) and (v) (d) (i), (iii), (iv) and (v) (c) fragmentation (d) heterocyst.

22 MTBIOLOGY TODAY | JANUARY ‘16 17. How many of the following statements are true? 25. Which of the following is the most distinguishing feature of (i) Volvox and Fucus show oogamy. bryophytes? (ii) Agar is commercially obtained from Gelidium and (a) Autotrophic gametophyte parasitised by sporogonium. Gracillaria. (b) Mostly homosporous, but, a few heterosporus. (c) 1st cell in the life of sporophyte is zygote. (iii) Gametophyte is parasite on sporophyte in Sphagnum. (d) Shows isomorphic alternation of generation. (iv) Funaria is monoecious and Marchantia is dioecious. (v) Source of SCP are Spirullina and Chlorella. 26. Which of the following is a heterosporus fern? (a) Salvinia (b) Selaginella (a) 4 (b) 3 (c) 5 (d) 2 (c) Dryopteris (d) Lycopodium 18. Group of sporangia on a sporophyll is known as (a) inducium (b) prothallus 27. Recognise the label ‘X’ in the following plant. (c) sorus (d) strobilus. Dwarf shoot 19. Assume that a fern sporophyte has two fertile leaves. Each containing 10 fertile pinnae. Each fertile pinna contains 4 sori. If each sorus contains 5 sporangia and each sporangium Long shoot contains 6 spore mother cells, then the total number of spores produced will be (a) 9600 (b) 2400 ‘X’ (c) 4800 (d) 19,200. 20. Which of the following statements is false? (a) Naked ovule (b) Fruit with few seeds (a) Floridean starch is a stored food in red algae which (c) Seed (d) None of these is very much similar to amylose and glycogen in 28. Which of the following is right code for matching shown in structure. Column-I and Column-II? (b) Sphagnum is monoecious and autoecious, whereas, Column-I Column-II Marchantia is dioecious. (c) ‘Horse tail plants’ belong to Class Sphenopsida and (i) Walking fern (p) Ginkgo contain scale leaves and photosynthetic stem. (ii) Bogg moss (q) Cycas (d) Polysiphonia and bryophytes show haplodiplontic life (iii) Living fossil (r) Adiantum caudatum cycle. (iv) Maiden hair tree (s) Sphagnum 21. Juvenile gametophyte, the protonema, is found in (a) (i)-r, (ii)-s, (iii)-p, (iv)-q (a) some mosses and vascular cryptogams (b) (i)-s, (ii)-r, (iii)-q, (iv)-p (b) all bryophytes (c) (i)-r, (ii)-s, (iii)-q, (iv)-p (c) all mosses and some liverworts (d) (i)-r, (ii)-q, (iii)-s, (iv)-p (d) mosses. 29. Giant red wood tree is 22. How many of the following structures are haploid? (a) Cedrus deodara (b) Eucalyptus regans (c) Rhododendron (d) Sequoia. Zygote of fern, Oosphere of liverwort, Gemma cell in Marchantia, Prothallus of fern, Sperm mother cell of 30. In _____ , a dominant independent gametophyte alternates Funaria, Leaf cell of a moss with a short lived, dependent sporophyte. (a) Volvox (b) Adiantum (a) 5 (b) 4 (c) 6 (d) 3 (c) Marchantia (d) Cedrus 23. Heterospory originated in 31. Which of the following statements are false? (a) seed bearing primitive dicots (i) Pollen grains released at 3, 4 and 2-3 celled stage in (b) Sphagnum Cycas, Pinus and angiosperms, respectively. (c) Selaginella (ii) Peat has long been used as fuel, is derived from aquatic (d) Adiantum. moss Sphagnum. 24. Assumed number of chromosomes in endosperm of a (iii) Bryophytes are of great ecological importance as they gymnosperm is 16. Find which of the following is a correct help in controlling soil erosion as well as soil formation match, w.r.t. organs and chromosome numbers. during ecological succession. (a) Leaf = 32 (b) Pollens = 16 (iv) Male cone of Pinus is equivalent to flower of (c) MMC = 32 (d) All of these. angiosperm.

MTBIOLOGY TODAY | JANUARY ‘16 23 (v) Endosperm of Cycas is a post fertilisation food laden (ii) Lack pericarp, but, endosperm is haploid. product. (iii) Gametophyte parasite on sporophyte. (a) (v) only (b) (iv) and (v) (iv) Haplontic life cycle. (c) (iii), (iv) and (v) (d) (i) and (v) (v) Few members homosporus. 32. Study the following diagrams very carefully and recognise (a) 3 (b) 2 (c) 4 (d) 1 them. 38. 1st cell in the life cycle of sporophyte and last cell in life of gametophyte, among ferns is (a) Spore and spore mother cell, respectively (b) Zygote and spore, respectively (c) Zygote and gametes, respectively (d) Spore and zygote, respectively. 39. Which of the following is an incorrect statement? (i) (ii) (iii) (iv) (a) Sphagnum used as moss stick and for trans-shipment of live plants. (i) (ii) (iii) (iv) (b) Mosses and lichens are air pollution indicators, as well (a) Polysiphonia Fucus Salvia Equisetum as, 1st to colonise bare rocks. (b) Porphyra Fucus Salvinia Horsetail (c) Marchantia, a dioecious bryophyte has multicellular (c) Porphyra Laminaria Salvinia Equisetum rhizoids. (d) Polysiphonia Laminaria Salvia Horsetail (d) In Funaria reductional division takes place in the theca 33. All of the following are correct statements, except region of capsule. (a) W.r.t. gymnosperms, [spore → sporangium → 40. Which of the following is a wrong match? sporophyll → strobilus] is correct pattern of (a) Spermatophyte, without flowers and fruits – arrangement of reproductive structures. Gymnosperms. (b) Most of the pteridophytes are homosporous and very (b) Cryptogams, without seeds, with vascular tissue – few are heterosporous. Pteridophytes. (c) Bryophytes differ from pteridophytes by containing (c) Thalloid plant body, abundant mitospores, non-vascular vascular tissue. cryptogams, with jacketed sex organs - algae. (d) ‘Taxol’ an anticancer drug derived from bark of stem in (d) Seedless, non-vascular cryptogams with antheridia and plant Taxus baccata. archegonia – Bryophytes. 34. Leaves of conifers are well adapted to withstand extremes 41. Gymnosperms contain of temperature, humidity and wind, because of the following (a) antheridia and no archegonia feature/s. (b) antheridia and archegonia (a) Acicular leaves (b) Absence of venation (c) no antheridia and no archegonia (c) Sunken stomata (d) All of these (d) archegonia and no antheridia. 35. Which of the following is a true statement? 42. Among pteridophytes Selaginella belongs to Class (a) Ferns are the first to appear after forest fire. (a) Anthocerotopsida (b) Sphenopsida (b) Chilgoza nuts are fruits of Pinus gerardiana. (c) Psilopsids (d) Lycopsida. (c) Ovuliferous scale is equivalent to stamen. (d) Coralloid roots are associated with Anabaena for N2 43. Archegonium of gymnosperm contains ____ neck canal fixation in Cycas, which are positively geotropic. cells. (a) 6-10 (b) 4-8 (c) One (d) Zero 36. “Green multicellular asexual buds developing in a small receptacle on thalli” are called 44. Funaria may be differentiated from Pinus by the (a) bulbils, found in Selaginella character(s) (b) gemmules, found in sponges (a) no fruit is produced (c) gemmae, found in liverworts (b) no seed is produced (d) reduction bodies, found in Sycon. (c) contains antheridia and archegonia (d) both (b) and (c). 37. How many of the following features pertain(s) to gymnosperms? 45. Prothallus of fern contains (i) Xylem commonly, lacks vessels and phloem lacks sieve (a) sporangia (b) strobilus tubes. (c) sorus (d) gametes.

24 MTBIOLOGY TODAY | JANUARY ‘16 46. Bryophytes are different from Fungi in having (iv) Most primitive vertebrates, ectoparasite on fish – (a) terrestrial habitat Cyclostomata. (b) sterile jacket around sex organs (v) Fish, amphibians and reptiles – Anamniotes. (c) multiflagellate gametes (a) 2 (b) 3 (c) 1 (d) None (d) gametophytic body. 53. Hemichordates have following body parts 47. What is common in all the three, Funaria, Dryopteris and (a) head, trunk and tail Ginkgo? (b) head, foot and visceral mass (a) Independent sporophyte (c) cephalothorax and abdomen (b) Presence of archegonia (d) proboscis, collar and trunk. (c) Well developed vascular tissues 54. How many of the following matches are correct? (d) Independent gametophyte (i) Uropygeal gland – Birds 48. The spreading of living pteridophytes is limited to narrow (ii) Collar cells – Sycon geographical region because of (iii) Well developed keel – Struthio (a) gametophytic growth needs cool, damp and shady (iv) Placoid scales – Chondrichthyes place. (v) Swim bladder – Scoliodon (b) requirement of water for fertilisation. (a) 5 (b) 4 (c) 3 (d) 2 (c) absence of stomata in leaf and absence of vascular 55. Metameric segmentation is found in tissue. (a) Annelida (b) Chordata (d) both (a) and (b). (c) Arthropoda (d) all of these. 49. Deep in the tropical rain forest, a botanist discovered an 56. Which of the following are true matches? unusual plant with vascular tissues, stomata, a cuticle, (i) Amphioxus – Flame cells flagellated sperm, strobilus like reproductive structures (ii) Crop and Gizzard – Birds bearing seeds and an alternation-of-generations in the life (iii) Collar cells – Water vascular system cycle. He was very excited about this discovery because it (iv) Colloblasts – Ctenophora would be rather unusual for a plant to have both (v) Tornaria larva – Balanoglossus (a) a strobilus and flagellated sperm (a) (i), (ii) and (iv) only (b) (iii), (iv) and (v) only (b) vascular tissues and alternation of generations (c) (i), (ii) and (iii) only (d) (i), (ii), (iv) and (v) (c) seeds and flagellated sperm 57. Which of the following taxa contains bilaterally symmetrical (d) alternation of generations and seeds. larva and radially symmetrical adult? 50. Distinguishing feature of angiosperm is (a) Hemichordata (b) Echinodermata (a) production of seeds (c) Protochordates (d) Cnidaria (b) poor adaptability to various environmental conditions 58. Which of the following animals contains alimentary canal, (c) double fertilisation but, lacks anus? (d) pollination and siphonogamy. (a) Fasciola (b) Taenia 51. Which of the following are correct statements? (c) Dog tape worm (d) Amphioxus (i) Unique features to all mammals are mammary glands, 59. Filaria disease is caused by hair on skin, diaphragm and ear pinnae. (a) female Culex (ii) Protochordates include cephalochordates, urochordate (b) female Anopheles and hemichordates. (c) female Aedes (iii) Annelids are metamerically segmented with schizo- (d) none of these. coelom. (iv) All chordates are vertebrates. 60. Which of the following excretory organ and the animal is (v) Reptiles are characterised by cornified skin. correctly matched? Balanoglossus (a) (i), (ii), (iii) and (v) (b) (ii), (iii) and (v) (a) Proboscis gland – Amphioxus (c) (i), (iii) and (v) (d) (iii) and (v) (b) Green gland – (c) Kidney – Prawn 52. How many of the following matches are wrong? (d) All of these (i) Marine animals with comb plates – Ctenophora. (ii) Animals containing canal system – Echinoderms. 61. Bilateral symmetry, worm like body, circular in T.S., sexual (iii) Pseudocoelomates with some parasites – Aschel- dimorphism, pseudocoelomate, coenocytic epithelium, is a minthes. group of characters, shown by

MTBIOLOGY TODAY | JANUARY ‘16 25 (a) tapeworm (b) Ascaris 70. Identify the following animals and the classes to which they (c) earthworm (d) sandworm. belong. 62. Which of the following is not an Echinoderm? (a) Sea urchin (b) Sea fan (c) Sea lily (d) Sea cucumber 63. Nematoblast is an organ of (a) offence (b) anchorage (c) defence (d) all of these. AB C (a) A-Salamandra, Amphibia; B-Testudo, Reptilia; 64. Which of the following is a correct statement? (a) Infective stage of Ascaris in human is egg. C-Chameleon, Reptilia (b) Vector for Wuchereria bancrofti is male Culex mosquito. (b) A-Salamandra, Reptilia; B-Chelone, Reptilia; (c) Walking worm is Peripatus, connecting link between C-Garden lizard, Reptilia Arthropoda and Mollusca. (c) A-Salamandra, Amphibia; B-Chelone, Reptilia; (d) Chloragogen cells of earthworm are equivalent to C-Tree lizard, Reptilia pancreas of human. (d) A-Salamandra, Reptilia; B-Testudo, Reptilia; 65. Which of the following is a wrong statement? C-Chameleon, Wall lizard (a) Nereis is dioecious and has parapodia for swimming. (b) Locust is a colonial arthropod. 71. Match column-I with column-II and select the correct option (c) Limulus is commonly called king crab. from the codes given. (d) Pinctada is a pearl forming mollusac. Column-I Column-II 66. Which of the following arthropods does not act as vector of A. Protochordata (i) Delphinus human diseases? B. Limbless amphibian (ii) Myxine (a) Xenopsella cheopsis C. Oviparous mammal (iii) Ornithorhynchus (b) Glossina palpalis D. Aquatic mammal (iv) Doliolum (c) Phlebotomus argentipus (d) Male Aedes mosquito E. Jawless vertebrate (v) Ichthyophis (a) A-(v), B-(iv), C-(iii), D-(i), E-(ii) 67. Match List-I (larval forms) with List-II (corresponding adults) and select the correct answer using the codes (b) A-(iv), B-(v), C-(iii), D-(i), E-(ii) given. (c) A-(iv), B-(v), C-(iii), D-(ii), E-(i) List-I List-II (d) A-(v), B-(iii), C-(i), D-(ii), E-(iv) A. Tornaria (i) Nereis B. Brachiolaria (ii) Balanoglossus C. Axolotl (iii) Starfish D. Trochophore (iv) Salamander (a) A-(ii), B-(iii), C-(i), D-(iv) (b) A-(ii), B-(iii), C-(iv), D-(i) 1. Make as many biological terms as possible (c) A-(iii), B-(ii), C-(iv), D-(i) using the given letters. Each word should contain the letter given in circle. (d) A-(i), B-(ii), C-(iii), D-(iv) 2. Minimum 4 letter word should be made. 68. Osphradium of Pila helps in 3. In making a word, a letter can be used as (a) osmoregulation (b) rasping many times as it appears in the box. (c) chemoreception (d) excretion. 4. Make at least 1 seven letter word. 69. Which of the following is a wrong match? (a) Central vascular cavity of Hydra – Coelenteron OG RI T YHM (b) Neophron in human are functional unit of kidney. (c) Endoskeleton fully ossified and long bones pneumatic E SOP Z AENO in flying birds. th (d) Duckbilled platypus is a monotreme mammal, a Send your response at [email protected] or post to us with complete address by 25 of every month to win exciting prizes. Winners’ name from October issue connecting link between reptiles and mammals. onwards will be declared on 1st of every month on www.mtg.in

26 MTBIOLOGY TODAY | JANUARY ‘16 72. Select the correct option in respect of characteristics of each 77. The figures given below show the types of coelom. Identify group. them and select the correct group of organisms which Cyclostomes Chondrichthyes Osteichthyes possess them. (i) Sucking mouth Ventral mouth Terminal mouth (ii) Scales absent Placoid scales Cycloid/Ctenoid scales (iii) Marine Marine Mostly fresh water, some marine (iv) 6-15 pairs of gills 5-7 pairs of gills 4 pairs of gills with without operculum operculum ABC (a) (i) and (ii) are correct (b) (i) and (iv) are correct A B C (c) All are correct (d) Only (iii) is correct (a) Annelids Aschelminthes Platyhelminthes (b) Molluscs Arthropods Platyhelminthes 73. Which of the following groups of animals are uricotelic? (c) Echinoderms Aschelminthes Annelids (a) Reptiles, birds, land snails and terrestrial insects (d) Echinoderms Arthropods Platyhelminthes (b) Reptiles, birds, land snails, all crustaceans. (c) Aquatic amphibians, birds, land snails, insects 78. Which of the following group is formed of only the (d) Amphibians, reptiles, birds, insects hermaphrodite organisms? (a) Earthworm, tapeworm, housefly,Nereis 74. Which of the following statements is correct for all sponges (b) Earthworm, tapeworm, sea horse, Nereis without exception? (c) Earthworm, leech, sponge, roundworm (a) They all have calcareous spicules. (d) Earthworm, tapeworm, leech, sponge (b) They have high regeneration power. (c) They are found only in cold marine water. 79. You have discovered an animal having characters like (d) They are all radially symmetrical. triploblastic, bilateral symmetry, coelomate, chitinous exoskeleton, head, thorax and abdomen as body parts, and 75. The figures (A-D) show four animals. Select the correct jointed appendages. You should place the animal under option with respect to a common characteristic of two of (a) Tetrapoda (b) Arthropoda these animals. (c) Annelida (d) Hemichordata. 80 . Post anal tail is found in (a) snails (b) scorpion (c) snakes (d) all of these. ASSerTIOn & reASOn ABCD In this type of questions, a statement of assertion (A) is followed (a) A and D respire mainly through body wall. by a statement of reason (R). Mark the correct choice as : (b) B and C show radial symmetry. (a) If A and R both are correct and R is the correct explanation (c) A and B have cnidoblasts for self-defence. of A. (d) C and D have a true coelom. (b) If A and R both are correct but R is not the correct explanation 76. Which one of the following groups of three animals is of A. correctly matched with their one characteristic morphological (c) If A is true but R is false. feature? (d) If both A and R are false. Animals Morphological features 81. Assertion : Deuteromycetes are commonly known as (a) Scorpion, spider, Ventral solid central nervous imperfect fungi. cockroach system Reason : In Deuteromycetes, only asexual and vegetative (b) Cockroach, locust, Metameric segmentation phases are known. Taenia (c) Liver fluke, sea Bilateral symmetry 82. Assertion: The cell wall of diatoms is indestructible. anaemone, sea Reason: The cell wall of diatoms is embedded with calcium cucumber carbonates. (d) Centipede, prawn, Jointed appendages 83. Assertion: In Ascomycetes and Basidiomycetes well distinct sea urchin dikaryophase is present during sexual life.

MTBIOLOGY TODAY | JANUARY ‘16 27 Reason: During sexual reproduction of Ascomycetes and Reason: Pteridophytes do not form seeds. Basidiomycetes, plasmogamy is immediately followed by 87. Assertion: Gymnosperms are first completely successful karyogamy. land plants. 84. Assertion: Rhodophycean algae can show change in their Reason: In gymnosperms vascular tissue is present. colour as per their presence on surface or bottom of water 88. Assertion: The body of reptiles is covered by dry and reservoir. cornified skin, epidermal scales or scutes. Reason: Rhodophycean have ability of complementary Reason: Reptiles are true terrestrial vertebrates. chromatic adaptation. 89. Assertion: Polyps produce medusae sexually and medusae 85. Assertion: Sporophyte of bryophytes is dependent on form the polyps asexually. gametophyte. Reason: Polyps and medusa are the common feature of Reason: Sporophyte of bryophytes lacks root like structures different group of cnidarians. to absorb nutrition from damp soil. 90. Assertion: All the members of platyhelminthes are proto- 86. Assertion: Living pteridophytes are limited and restricted stomes. to narrow geographical regions. Reason: Mouth is formed by blastopore in these animals. CLASS XII 91. Which of the following statements are true? 95. Which of the following is a correct sequence during life A. Four typed layers of cells, in the wall of angiospermic cycle of angiosperm for the following terms/events? microsporangium, are named as tapetum, middle layers, A. Pollen grain B. Sporogenous tissue endothecium and epidermis from outer to inner side. C. Microspore tetrad D. PMC B. Apomictic embryos of Citrus and mango seeds are E. Male gamete clone of their parent. (a) B → D → C → A → E (b) B → C → D → A → E C. Fruits produced from ovaries without the act of (c) C → B → D → A → E (d) C → D → B → A → E fertilisation are called parthenogenetic. 96. Which of the following is a correct statement? D. Ovary wall mature into testa. (a) Double fertilisation was discovered by Nawaschin from E. In angiospermic plant endosperm development proceeds Monotropa plant. the development of embryo. (b) Polygonum type of embryosac is bisporic, 7 celled 8 (a) A, B and E (b) B, C and E nucleate. (c) B, D and E (d) B only (c) Most common typed endosperm in angiosperm is 92. To produce 96 male gametes in angiosperms, minimum nuclear typed. number of meiosis required are (d) Epiblast is reduced coleoptile of grasses. (a) 24 (b) 48 (c) 12 (d) 96. 97. Shown diagram is a fertilised embryo sac. Which of the 93. Coffee is derived from perisperm of seed, which is following is true about it? (a) enlarged nucleus of PEC (b) remains of endosperm of seed C (c) remnants of nucellus (d) modified inner integument of ovule. 94. How many of the following statements are true? A (i) Tassels of maize are, sticky stigma containing, styles. (ii) Cleistogamy ensures seed setting but decreases hybrid vigorous. (iii) Geitonogamy in bisexual flowers is functional cross pollination but genetical self pollination. (iv) Eichhornia produces purple flowers and is pollinated B by bees. (v) Dioecy is a device to ensure cross pollination (a) A-produced by fusion of 2 cells and 3 haploid nuclei (a) 5 (b) 4 (c) 3 (d) 2. called PEN.

28 MTBIOLOGY TODAY | JANUARY ‘16 (b) B-degenerating 3 haploid cells of micropylar region. 105. Choose correct option for A, B, C and D of a dicot embryo. (c) C-Growing embryo and degenerating antipodals. Plumule (d) A-produces 3n food ladden tissue. 98. Which of the following is a true match, except? A (a) Carpel – Modified megasporangium. B (b) Michelia – Polycarpellary apocarpus gynoecium. (c) Callose – Polysaccharide found in thickenings of endothecial wall. D (d) Ubisch’s granules – Produces exine. C (a) A-Hypocotyl; B-Cotyledons; C-Root cap; D-Radicle 99. Site of origin of integument in angiospermic ovule is (b) A-Cotyledons; B-Hypocotyl; C-Root cap; D-Radicle (a) raphe (b) chalaza (c) A-Cotyledons; B-Hypocotyl; C-Radicle; D-Root cap (c) hilum (d) funicle. (d) A-Cotyledons; B-Radicle; C-Hypocotyl; D-Root cap 100. How many of the following listed plants will produce non- 106. Sequence of development during the formation of embryo endospermic seeds? sac is Castor, Barley, Orchids, Groundnut, Maize, Pea, (a) Archesporium → Megaspore → Megaspore mother Mustard, Wheat cell → Embryo sac. (b) Megasporocyte → Archesporium → Megaspore → (a) 3 (b) 6 Embryo sac. (c) 5 (d) 4 (c) Megaspore → Megaspore mother cell → Archesporium 101. In most of the water pollinated angiospermic species, pollen → Embryo sac. grains are protected from wetting by (d) Archesporium → Megaspore mother cell → Megaspore (a) lipid rich, yellowish, pollen–kit → Embryo sac. (b) exine formed of resistant substance sporopollenin 107. Total number of meiotic divisions required for production of (c) mucilaginous covering 100 grains in maize is (d) any of the above depending upon species. (a) 25 (b) 100 (c) 125 (d) none. 102. Which of the following is a true statement, except. 108. During siphonogamy of angiosperm pollen tube enters (a) Stamen is a modified microsporophyll and ovule is a embryo sac through megasporangium. (a) filiform apparatus of egg (b) Typical anther is dithecous, tetrasporangiate and (b) through healthy and persistent synergid tetragonal and its microsporangium is eusporangiate. (c) through degenerating synergid (c) Pollinium contain all pollens produced in one anther (d) through haustorial outgrowth of synergid. lobe and found in orchids. 109. Which of the following are incorrectly matched? (d) Bending of pollen tube towards synergid is a (i) Palynology – Study of pollen markings chemotactic movement. (ii) Stomium – Present in the line of dehiscence of anther. (iii) Canthrophily – Pollination by beetle. 103. Male plant 6n and female plant 4n takes part in sexual (iv) Vallisneria – Epihydrophily. reproduction. Which of the following is true match? (v) Papaya – Monoecious plant. (a) Aleurone grain layer cell – 7n (a) (i), (iii) and (v) (b) (iii) and (v) (b) Nucellus – 6n (c) (iii), (iv) and (v) (d) (v) only (c) PEN – 8n Citrus (d) Cells in epidermis of root in next generation – 4n 110. During polyembryony in , extra embryo arise from (a) both integument and nucleus 104. Which of the following statements is untrue? (b) synergids and antipodals (a) In angiosperms pollen grain commonly released at 3 (c) nucellus and antipodals celled stage. (d) nucellus only. (b) Most common typed ovule among angiosperm is 111. (A) Family planning programmes initiated in India in 1971. anatropus. (B) According to the 2001 census of Indian population, (c) 5 nuclei participate in double fertilisation. growth rate was about 1.7%. Indian population will (d) Pollen allergy is caused by Parthenium heterophorus. become double by the year 2034, a prediction.

MTBIOLOGY TODAY | JANUARY ‘16 29 (C) Saheli – an oral contraceptive pill, used once a week is C. Rarely adopted by Indian males from well to do families. rich in estrogen – progrestogen combination. D. May lead to impotency. (D) Hepatitis, genital herpes and HIV infection are E. Almost non reversible. incurable. (a) A and E only (b) A, C and E (E) Gonorrhea, syphilis and trichomoniasis are bacterial (c) A, B and C (d) All except C STDs. 117. Match column-I with column-II and select the correct option from the codes given below. How many of the above statements are false? Column-I Column-II (a) 3 (b) 2 (c) 4 (d) 1 A. Natural methods (i) Coitus interruptus 112. Most common contraceptive used by Indian women is IUDs, B. IUDs (ii) LNG-20 but, LNG-20, a contraceptive C. Barrier methods (iii) Diaphragms (a) is one typed lubricated condom enrich with D. Surgical methods (iv) Multiload 375 spermicides E. Oral contraceptive (v) Saheli (b) is one typed copper releasing IUD (vi) Nirodh (c) makes uterus unsuitable for implantation (vii) Sterilisation (d) is one typed barrier method of contraception. (viii) Vasectomy 113. How many of the following statements are false? (ix) CuT A. If STD is not timely detected and cured, it may lead to (a) A-(i); B-(ii), (iv), (ix); C-(iii), (vi); D-(vii), (viii); E-(v) complication like PID, ectopic pregnancy, even cancer (b) A-(i); B-(ii), (iv); C-(iii), (vi), (ix); D-(vii), (viii); E-(v) of the reproductive tract. (c) A-(i); B-(ii), (iv), (ix); C-(iii), (ix); D-(vii), (viii); E-(v), (vi) (d) A-(i); B-(iv), (ix); C-(ii), (iii), (vi); D-(vii), (viii); E-(v) B. In tubectomy conduction of gamete is interrupted and insemination is prevented. 118. Intensely lactating mothers do not generally conceive due C. Oral contraceptive inhibits ovulation, implantation, as to the well as alter the quality of cervical mucus to retard (a) suppression of gonadotropins entry of sperm. (b) hypersecretion of gonadotropins D. Amniocentesis, mainly, used to detect prenatal (c) suppression of gametic transport abnormalities of chromosomes leading to various (d) intense production of luteinising hormone. syndromes. 119. Which of the following is a correct match w.r.t. menstrual E. RCH stands for “Reversible Contraceptive Hazards”. cycle? (a) 2 (b) 3 (c) 1 (d) 4 (a) Menstrual phase – Break down of perimetrium of uterus 114. To form embryo in vitro, the male gamete is transferred into along with blood vessels which forms liquid that comes female gamete directly. Such a technique is called out through vagina along with unfertilised ovum. (a) GIFT (b) ICSI (c) IVF-ET (d) IUI. (b) Luteal phase – A temporary endocrine gland placenta is formed which released LH to maintain endometrium 115. Technique GIFT is recommended for those females who allow proper implantation and other events of (a) can’t provide suitable environment for fertilisation gestation. (b) can’t produce ovum (c) Follicular phase – Secretion of gonadotropin increase (c) can’t retain foetus long enough in uterus to complete leads to development of mature graafian follicle ready gestation for ovulation. (d) cervical canal too narrow to allow passage for the sperms. (d) Ovulatory phase – Surge in secretion of luteinising 116. Which of the following statements are true w.r.t. shown hormone to its maximum, rupturing of Graafian follicle, method of contraceptive device? release of egg at primary oocyte. 120. Parturition is induced by complex neuroendocrine mechanism involving hormone(s) such as (a) cortisol (b) estrogen (c) oxytocin (d) all of the above 121. Which of the following are false statements?

(i) Typically ovulation takes place on 14th day of menstruation A. Semen will be mixture of secretion from prostrate cycle, oocyte will be at metaphase II stage. gland, seminal vesicles and bulbourethral glands only. (ii) Out of ejaculated sperms 48-72 million sperms must B. Can prevent transmission of STD’s. show vigorous motality for normal fertility. Contd. on page no. 75 30 MTBIOLOGY TODAY | JANUARY ‘16 Class-12

Maximise your chance of success and your seat in AIPMT andPMT otherFOUNDATION PMTs by reading this column. This section is specially designed to optimise your preparation by practising more and more. It is a unitwise series having chapterwise question bank, allowing you to prepare systematically and become more competent. Recall question or single concept question – indicated by a single finger. Application question or question which requires 2 or 3 concepts to solve - indicated by 2 fingers. Application question or question which requires 3 or more concepts - indicated by 3 fingers. unIT-VI : rePrODucTIOn

chAPTer-1 : rePrODucTIOn In OrGAnIsms 6. Which of the following four phases, in the post emergence multiple choice Questions life of an angiospermic plant, begins just after germination of seed and ends when the plant develops the capacity to 1. Find out correct order of vegetative propagules of plants like reproduce? potato, ginger, Agave, Bryophyllum and water hyacinth. (a) Death (b) Maturity (a) Offset, bulbil, leaf bud, rhizome and eyes (c) Ageing (d) Juvenility (b) Leaf bud, bulbil, offset, rhizome and eyes 7. Fusion of two organisms is called (c) Eyes, rhizome, bulbil, leaf bud and offset (a) homogamy (d) Rhizome, bulbil, leaf bud, eyes and offset (b) syngamy 2. In which one pair both the plants can be vegetatively (c) allogamy propagated by leaf species? (d) hologamy. (a) Agave and Kalanchoe 8. Gametogenesis refers to the process of (b) Bryophyllum and Kalanchoe (a) fusion of two gametes (c) Asparagus and Bryophyllum (b) fusion of two gametangia (d) Chrysanthemum and Agave (c) formation of two types of gametes 3. Oestrous cycle is reported in (d) formation of male gamete only. (a) cows and sheep (b) humans and monkeys 9. Choose the correct pair. (c) chimpanzees and gorillas (a) Coconut, Cucurbits - dioecious (d) none of these (b) Honeybee, Rotifers - parthenogenesis (c) Ornithorhynchus, Whale - viviparity 4. Vegetative reproduction by layering is found in (d) Frog, Peacock - external fertilisation (a) rose (b) jasmine (c) mango (d) all of these 10. Product of sexual reproduction generally generates 5. The growth phase of an organism before attaining sexual (a) new genetic combination leading to variation maturity is referred to as (b) large biomass (a) juvenile phase (b) vegetative phase (c) longer viability of seeds (c) both (a) and (b) (d) none of these (d) prolonged dormancy.

MTBIOLOGY TODAY | JANUARY ‘16 31 True or False Passage Based Questions 11. Asexual reproduction is common among single-celled 23.(A) Complete the given passage with appropriate words or organisms, and in plants and animals with relatively simple phrases. body organisation. In flowering plants, the (i) is formed inside the ovule. 12. Asexual reproduction involves formation of the male and After (ii) , the sepals, petals and (iii) of the flower female gametes, either by the same individual or by different wither and fall off. The (iv) remains attached to the individuals of the opposite sex. plant. The zygote develops into the (v) and the ovules 13. The reproduction by zoospores occur in some lower fungi develop into the (vi) . The (vii) develops into the fruit like phycomycetes and some algae. which develops a thick wall called (viii) . 14. In anisogamy, fusing gametes differ in size or motility. (B) Read the given passage and correct the errors, wherever 15. In monoecious plant, both male and female flowers are present. present on different plants. The process of formation of male and female gametes is called sporogenesis. Gametes are diploid cells. In some algae, 16. Monocarpic plants flower only once in their life and die the two gametes are similar in appearance and are called after producing fruits. anisogametes. In most of asexually reproducing organisms 17. Endogamy involves the fusion of two gametes produced the gametes are of morphologically dissimilar types, hence, by different parents. they are known as isogametes. In anisogametes the male 18. Embryogenesis is the formation and development of a gamete is called the egg and the female gamete is known multicellular embryo from unicellular zygote. as the antherozoid. 19. In arrhenotoky type of parthenogenesis, only females are produced by parthenogenesis. Assertion & reason 20. In oviparous animals, the zygote develops into a young one In each of the following questions, a statement of Assertion inside the body of the female organisms. (A) is given and a corresponding statement of Reason (R) is given just below it. Of the statements, mark the correct match The columns answer as : (a) if both A and R are true and R is the correct explanation 21. Match Column I with Column II. of A Column I Column II (b) if both A and R are true but R is not the correct explanation A. Conidia (i) Eichhornia of A B. Polyembryony (ii) Rotifers (c) if A is true but R is false C. Offsets (iii) Penicillium (d) if both A and R are false. D. Arrhenotoky (iv) Chlamydomonas 24. Assertion : In external fertilisation, gametes are released E. Zoospores (v) Armadillo in water in large numbers. Reason : Gametes released in water in external 22. Match Column I with Column II. (There can be more than fertilisation are subjected to harsh environmental one match for items in Column I) conditions. Column I Column II 25. Assertion : Chlamydospores store reserve food material A. Binary fission (i) Date palm and are capable of withstanding long unfavourable B. Dioecious plants (ii) Apus conditions. C. Parthenogenesis (iii) Amoeba Reason : Chlamydospores are thin walled spores D. Sporangiospores (iv) Rhizopus produced directly from hyphal cells. E. Corms (v) Colocasia 26. Assertion : Coconut is a dioecious plant. (vi) Crocus Reason : In coconut, male and female flowers are present on different plants. (vii) Euglena 27. Assertion : In binary fission a parent cell divides into (viii) Mucor two identical daughter cells. (ix) Papaya Reason : The nucleus of the parent body divides (x) Cypis repeatedly during binary fission.

32 MTBIOLOGY TODAY | JANUARY ‘16 28. Assertion : Non-primate females permit copulation 2. During the process of sexual reproduction in flowering only during oestrous period. plants, double fertilisation involves Reason : During oestrous period, sex urge is (a) fertilisation of egg cell by two male gametes increased. (b) fertilisation of egg cell and a central cell by two male gametes brought by same pollen tube Figure Based Questions (c) fertilisation of egg cell and a central cell by two male 29. Refer to the given figure and answer the following gametes brought by different pollen tubes questions. (d) fertilisation of two egg cells by two male gametes brought by same pollen tube.

A 3. If the number of chromosome in root cell is 14, then what will be the chromosome number in synergids? (a) 14 (b) 21 (c) 7 (d) 28 4. The portion of embryonal axis above cotyledon is called B as (a) epicotyl (b) hypocotyl (c) coleoptile (d) radicle. C 5. Exine of pollen grain is made up of . (a) pectocellulose (b) lignocellulose ... .. (c) sporopollenin (d) pollen kit...... 6. Entry of pollen tube through the chalazal end is called (a) porogamy (b) mesogamy (a) Identify A, B and C in the given figure. (c) chalazogamy (d) syngamy. (b) Briefly describe the process of A, B and C. 7. If 400 pollen grains are produced in a single monothecous 30. Refer to the given figures and answer the following anther then, what was the number of pollen grain mother questions. cells in each of the sporangia ? (a) 200 (b) 100 (c) 50 (d) 25 8. Apomixis is (a) formation of seeds by fusion of gametes (b) formation of seeds without syngamy and meiosis (c) formation of seeds with syngamy but no meiosis (d) none of the above AB 9. Identify the wrong statement regarding post-fertilisation (a) Identify figures A and B. development. (b) Briefly describe figures A and B. (a) The ovary wall develops into pericarp. (b) The outer integument of ovule develops into tegmen. chAPTer-2 : sexuAL rePrODucTIOn (c) The fusion nucleus (triple nucleus) develops into In FLOwerInG PLAnTs endosperm. multiple choice Questions (d) The ovule develops into seed. 1. Which of the following feature(s) is/are common to both 10. The sequence of development of embryo sac is wind and water pollinated flowers? (a) archesporium → megaspore → embryo sac I. Pollen grains are long and ribbon-like. → megasporangium (b) archesporium → megaspore → megaspore mother II. Stigma is large and feathery. cell → embryo sac III. The flowers are not colourful. (c) archesporium → megaspore mother cell IV. The flowers do not produce nectar. → megaspore → embryo sac (a) III and IV only (b) II and III only (d) megaspore mother cell → archesporium (c) I and II only (d) II only → megaspore → embryo sac.

MTBIOLOGY TODAY | JANUARY ‘16 33 True or False in the (iii) towards micropylar half of the ovule. The typical and most common type of (i) is (iv) type. It 11. Epicotyl is the part of embryonal axis in between contains (v) nuclei but (vi) cells – (vii) micropylar, cotyledonary node and radicle. (viii) chalazal and one (ix) . 12. Solid style has a special tissue of pectinised thick walls known as transmitting or conducting tissue. (B) Read the given passage and correct the errors, wherever 13. Xenogamy is transfer of pollen grains from the anther to present. the stigma of another flower of the same plant. Seed and fruit formation are stimulated by the act of pollination. In angiosperms this process produces two 14. Occurrence of more than one embryo in a seed is referred structures – a haploid zygote and a diploid endosperm cell. to as polyembryony. The zygote gives rise to a nutritive tissue and endosperm 15. Cleistogamous flowers always remain closed so that anthers cells forms the embryo. With the growth of embryo the and stigmas are never exposed. peripheral part of the nutritive tissue is eaten up. Nutritive 16. Intine is inner layer of pollen grain made up of tissue in turn crushes the micropyle. sporopollenin. 17. The wall of ovary develops into the wall of fruit called Assertion & reason pericarp. In each of the following questions, a statement of Assertion 18. Innermost wall layer of microsporangium is endothecium (A) is given and a corresponding statement of Reason (R) which nourishes the developing pollen grain. is given just below it. Of the statements, mark the correct 19. Non-albuminous seeds have no residual endosperm as it answer as : is completely consumed during embryo development. (a) if both A and R are true and R is the correct explanation 20. The synergids have special cellular thickenings at the of A micropylar tip called filiform apparatus. (b) if both A and R are true but R is not the correct explanation of A match The columns (c) if A is true but R is false 21. Match Column I with Column II. (d) if both A and R are false. Column I Column II 24. Assertion : Megasporogenesis is meiotic formation of A. Ategmic ovule (i) Areca haploid megaspores from diploid megaspore mother B. Homogamy (ii) Zostera cell. C. Ruminate endosperm (iii) Santalum Reason : The arrangement of megaspores in a tetrad D. Hydrophily (iv) Catharanthus is commonly tetrahedral. E. Tritegmic ovule (v) Asphodelus 25. Assertion : Cross pollination involves the transfer of 22. Match Column I with Column II. (There can be more than pollen from anther of one flower to the stigma of a one match for items in Column I) genetically different plant. Column I Column II Reason : In dichogamy the anthers and stigmas mature A. Stamen (i) Syngamy at different times. B. Double fertilisation (ii) Anther 26. Assertion : Scientists are trying to identify genes for C. Sporoderm (iii) Intine apomixis. D. Seed coat (iv) Triple fusion Reason : Increasing cost of hybrid crop production can E. Dichogamy (v) Filament be avoided if apomictic genes can be introduced in hybrid (vi) Protandry seeds. (vii) Testa 27. Assertion : Emasculation is not required in unisexual (viii) Protogyny flowers. (ix) Exine Reason : Emasculation is the removal of stamens from (x) Tegmen the floral buds of bisexual flowers to eliminate chances of self pollination. Passage Based Questions 28. Assertion : Orinithophilous flowers are generally dull 23.(A) Complete the given passage with appropriate words or coloured with strong fermenting or fruity odour, abundant phrases. nectar and pollen grains. In angiosperms, the female gametophyte is called (i) . It Reason : Ornithophily is cross pollination performed by is an oval multicellular (ii) structure which is embedded insects.

34 MTBIOLOGY TODAY | JANUARY ‘16 Figure Based Questions (a) fertilizin of A and antifertilizin of B are not compatible 29. Refer to the given figure and answer the following (b) antifertilizin of A and fertilizin of B are not questions. compatible A (c) fertilizin of A and B are not compatible (d) antifertilizin of A and B are not compatible. B 4. Choose the correct statement. (a) hPL plays a major role in parturition. (b) Foetus shows movements for the first time in the 7th month of pregnancy. C (c) Signal for parturition comes from fully developed foetus and placenta. (d) Embryo’s heart is formed in the 5th month of pregnancy. 5. Starting from the maximum, arrange the following male reproductive accessory organs in the correct order, based D on the amount of secretion. (i) Prostate glands (ii) Seminal vesicles (a) Identify A, B, C and D in the given figure. (iii) Bulbourethral glands (a) (i) > (ii) > (iii) (b) (iii) > (ii) > (i) (b) Briefly describe part B and D. (c) (ii) > (iii) > (i) (d) (ii) > (i) > (iii) (c) Which labelled part represent rudiments of second cotyledon? 6. Which of the following hormone stimulates Sertoli cells? (a) FSH (b) Estrogen 30. Refer to the given figure and answer the following (c) ACTH (d) Testosterone questions. A 7. Which of these combinations is most likely to be present B before ovulation occurs? C (a) FSH, corpus luteum, oestrogen, secretory uterine lining (b) LH, corpus luteum, progesterone, secretory uterine D lining (c) FSH, Graafian follicle, oestrogen, uterine lining becoming thick (a) Identify A, B, C and D in the given figure. (d) Luteinizing hormone (LH), Graafian follicle, (b) Which labelled part is known as fibrous layer? progesterone, thick uterine lining (c) Write the function of labelled part D. 8. LH surge occurs during which phase of the menstrual chAPTer-3 : humAn rePrODucTIOn cycle? (a) Menstrual phase multiple choice Questions (b) At the beginning of proliferative phase 1. In humans, what is the ratio of number of gametes produced (c) Just before the end of the luteal phase from one male primary sex cell to the number of gametes (d) Ovulatory phase produced from one female primary sex cell? 9. The foetal ejection reflex in humans triggers the release of (a) 1 : 4 (b) 1 : 1 (a) oxytocin from foetal pituitary (c) 4 : 1 (d) 1 : 3 (b) human chorionic gonadotropin (hCG) from placenta 2. The correct sequence of embryonic development is (c) human placental lactogen (hPL) from placenta (a) Blastula - Morula - Zygote - Gastrula (d) oxytocin from maternal pituitary. (b) Zygote - Blastula - Morula - Gastrula 10. Acrosome of sperm is derived from (c) Zygote - Morula - Blastula - Gastrula (a) centriole (d) Gastrula - Morula - Zygote - Blastula. (b) endoplasmic reticulum 3. Sperm of animal species A cannot fertilise ovum of species (c) Golgi bodies B because (d) peroxisome.

MTBIOLOGY TODAY | JANUARY ‘16 35 True or False The process of fusion of a sperm with an ovum is called fertilisation. During fertilisation, a sperm comes in contact 11. Insemination is the transfer of sperms by the male into the with the (i) layer of the ovum and induces changes in genital tract of the female. the membrane that (ii) the entry of additional (iii) . 12. Sertoli cells secrete androgen binding protein that The secretions of the (iv) help the sperm enter into the concentrates testosterone in the seminiferous tubules. (v) of the ovum. This induces the completion of the (vi) 13. Spermatogenesis is the process of the transformation of division of the (vii) . spermatids into spermatozoa. (B) Read the given passage and correct the errors, wherever 14. During embryonic development, a solid ball-like structure present. which looks like a little mulberry is known as blastula. The mature ovum or a female gamete is tubular in shape. 15. In ovulatory phase, both LH and FSH attain a peak level. The human ovum is said to be mesolecithal. Its cytoplasm 16. Chorion is composed of trophoblast present on inner side is called acroplasm containing mitochondria, termed as and somatopleuric extraembryonic mesoderm present mitochondrial vesicle. There are many centrioles in the towards the outerside. ovum. The cytoplasm is enveloped by the plasma membrane 17. Teratogens are certain agents or drugs that cause abnormal and very large vesicles called cortical granules are present development of embryo. below it. A wide perivitelline space is present inside the 18. Depolarisation of oocyte plasma membrane prevents plasma membrane. polyspermy and ensures monospermy. Assertion & reason 19. Vasa efferentia carries spermatozoa from cauda epididymis to the ejaculatory duct. In each of the following questions, a statement of Assertion 20. Colostrum contains several antibodies that provide passive (A) is given and a corresponding statement of Reason (R) immunity to the new born babies. is given just below it. Of the statements, mark the correct answer as : match The columns (a) if both A and R are true and R is the correct explanation 21. Match Column I with Column II. of A Column I Column II (b) if both A and R are true but R is not the correct explanation A. Leydig cells (i) Implantation of blastocyst of A B. Placenta (ii) Progesterone (c) if A is true but R is false C. Endometrium (iii) Fructose (d) if both A and R are false. D. Seminal vesicles (iv) Androgen 24. Assertion : Sex in human beings is determined by the E. Oviducts (v) Fallopian tube father. Reason : The set of sex chromosome present in the 22. Match Column I with Column II. (There can be more than human female is XY and male is XX. one match for items in Column I) Column I Column II 25. Assertion : Trophoblast forms the foetal part of placenta A. Male sex accessory (i) Relaxin and does not form any part of the embryo proper. ducts Reason : Trophoblast is the outermost layer of cells of B. Corpus luteum (ii) Seminal vesicles a blastocyst. C. Male accessory glands (iii) Rete testis 26. Assertion : Colostrum provides passive immunity to D. Ovarian stroma (iv) Progesterone the new born infant. E. Chorionic placenta (v) Epididymis Reason : Colostrum contains antibodies, having IgA as (vi) Medulla the major immunoglobulin. (vii) Bulbourethral gland 27. Assertion : Sertoli cells are present in between the (viii) Chorion seminiferous tubule. (ix) Decidua basalis Reason : Sertoli cells are found in small groups and (x) Cortex are rounded in shape. 28. Assertion : Primary oocytes are formed from the oogonia Passage Based Questions in the ovary of the foetus. 23.(A) Complete the given passage with appropriate words or Reason : Each primary oocyte forms two ovum and two phrases. polar bodies.

36 MTBIOLOGY TODAY | JANUARY ‘16 Figure Based Questions (b) prevents the production of semen (c) prevents the movement of sperms into the urethra 29. Refer to the given figure and answer the following (d) prevents a man from having an erection. questions. E 3. Which one of the following groups includes all sexually transmitted diseases? B A (a) AIDS, syphilis, cholera (b) HIV, malaria, trichomoniasis (c) Gonorrhoea, hepatitis-B, chlamydiasis (d) Hepatitis-B, haemophilia, AIDS

F 4. The technique called Gamete Intra Fallopian Transfer (GIFT) C is recommended for those females (a) who cannot produce an ovum D (b) who cannot retain the foetus inside uterus (a) Identify the labelled parts A, B, C, D, E and F. (c) whose cervical canal is too narrow to allow passage (b) Name the hormone secreted by the labelled part A for the sperms and write its one function. (d) who cannot provide suitable environment for fertilisation. (c) Briefly describe the role of hormone secreted by labelled part D. 5. Cu ions released from copper-releasing intra uterine devices 30. Refer to the given figure and answer the following (IUDs) questions. (a) make uterus unsuitable for fertilisation (b) decrease phagocytosis of sperms (c) suppress sperm motility (d) prevent ovulation. 6. The status of the foetus for genetic counselling can be determined by (a) foetoscopy (b) amniocentesis (c) aminoacidopathy (d) ultrasound imaging. 7. Which of the following pairs is not correctly matched ? (a) Gonorrhoea - Treponema pallidum (b) Genital Warts - Human papilloma virus (c) Chlamydiasis - Chlamydia trachomatis (a) Identify A, B, C, D and E in the given figure. (d) Scabies - Sarcoptes scabiei (b) Briefly describe the part labelled as D. 8. Diaphragms are contraceptive devices used by the females. (c) Name the enzyme present in labelled part B. Choose the correct option from the statements given below. chAPTer-4 : rePrODucTIVe heALTh (i) They are introduced into the uterus. multiple choice Questions (ii) They are placed to cover the cervical region. 1. IUDs which are used by females (iii) They act as physical barriers for sperm entry. (a) are implanted under the skin and they release (iv) They act as spermicidal agents. progestogen and estrogen (a) (i) and (ii) (b) (i) and (iii) (b) act as spermicidal jellies (c) (ii) and (iii) (d) (iii) and (iv) (c) release copper ions in the uterus having spermicidal 9. Which two of the following statements are incorrect effects regarding in vitro fertilisation? (d) block the entry of sperms into vagina. (i) In this method, ova from the wife/donor female and 2. Vasectomy sperms from the husband/donor male are induced to (a) prevents the production of sperms in the testes form zygote in the uterus.

MTBIOLOGY TODAY | JANUARY ‘16 37 (ii) If the embryo is having 2 blastomeres, it is transferred 22. Match Column I with Column II. (There can be more than into the uterus. one match for items in Column I) (iii) If the embryo is with more than 8 blastomeres, it is Column I Column II transferred into the uterus. A. Hormone releasing IUDs (i) Amoebiasis (iv) The baby thus produced is called test tube baby. B. Bacterial STDs (ii) i-pill (a) (iii) and (iv) C. Combined pills (iii) Unwanted 72 (b) (i) and (ii) D. Protozoan STDs (iv) Progestasert (c) (ii) and (iii) E. Emergency contraceptives (v) Trichomoniasis (d) (i) and (iv) (vi) Syphilis 10. Oral contraceptive pills prevents pregnancy by (vii) LNG-20 (a) killing the ovum (viii) Mala D (b) blocking fertilisation (ix) Gonorrhoea (c) preventing ovulation (x) Mala N (d) suppressing sperm motility. Passage Based Questions True or False 23.(A) Complete the given passage with appropriate words or 11. Immigration is the movement of individuals out of a place phrases. or country which results in the decrease in population. AIDS is a sexually transmitted (i) disease, caused by 12. Amniocentesis is a foetal sex determination and disorder (ii) . The patient gets immune deficiency because AIDS test based on the chromosomal pattern in the cells of pathogen attacks helper (iii) . It can be diagnosed by amniotic fluid surrounding the developing embryo. (iv) and (v) test. Pathogen of AIDS is transmitted via 13. Natality rate decreases population size and population blood and (vi) . Although there is no cure of AIDS, yet density. certain drugs like (vii) and (viii) can prolong the life of patient. 14. Exponential growth shows S-shaped or sigmoid growth curve whereas logistic growth shows J-shaped growth (B) Read the given passage and correct the errors, wherever curve. present. In test tube baby technique, i.e., advanced reproductive 15. Vasectomy is a sterilisation technique for males in which technology, the fusion of ovum and sperm is done inside the two vasa deferentia are cut and tied up. body of woman, to form a zygote which is allowed to divide 16. Population growth rate is indicated by the annual average to form embryo. This embryo is implanted in vagina where growth rate and doubling time, it can never be negative. it develops into a foetus (test tube baby). In this technique 17. Oral contraceptive pills contain either progestin alone or a zygote is allowed to divide and form 16 blastomeres. The combination of progestogen and oestrogen. proembryo thus formed is transferred into the uterus. If the 18. In females, ovulation is induced by clomiphene citrate. embryo is having more blastomeres, it is transferred into 19. In zygote intra-Fallopian transfer technique, zygote or early the Fallopian tube. embryo is transferred into the Fallopian tube. Assertion & reason 20. In foetoscopy, a needle-thin tube containing a viewing scope In each of the following questions, a statement of Assertion is inserted into the uterus for direct view of the foetus. (A) is given and a corresponding statement of Reason (R) is given just below it. Of the statements, mark the correct match The columns answer as : 21. Match Column I with Column II. (a) if both A and R are true and R is the correct explanation Column I Column II of A A. Non-medicated IUD (i) Human papilloma virus (b) if both A and R are true but R is not the correct explanation of A B. Chancroid (ii) Male condom (c) if A is true but R is false C. Genital warts (iii) Lippes loop (d) if both A and R are false. D. Nirodh (iv) Female condom 24. Assertion : Genital warts caused by human papilloma E. Femidom (v) Haemophilus ducreyi virus is a sexually transmitted disease.

38 MTBIOLOGY TODAY | JANUARY ‘16 Reason : Genital warts spreads through sexual intercourse with carriers of the viruses of this disease. E 25. Assertion : Population growth rate is indicated by the A annual average growth rate and the doubling time. Reason : It depends on birth rate and age-sex ratio B only. 26. Assertion : Mortality rate is the number of births per C D one thousand individuals per year. Reason : Mortality rate increases population size and population density. (a) Identify A, B, C, D and E in the given figure. 27. Assertion : Oral contraceptive pills are not recommended for women with a history of disorders of blood (b) Briefly describe the procedure given in the figure. clotting. 30. Refer to the given figure and answer the following Reason : Oral contraceptive pills increase the risk of questions. intravascular clotting. B 28. Assertion : Immigration results in the increase in population.

Reason : Immigration is the movement of individuals E out of an area. A C Figure Based Questions D 29. Refer to the given figure and answer the following (a) Identify A, B, C, D and E in the given figure. questions. (b) Briefly explain the method given in the figure.

U N S C R A M B L E M E Unscramble the letters using the given clues. Scrambled letters Clues Words 1. NPERSAIMTOI Release of sperms from seminiferous tubules...... 2. TNSPCEIAE Enzyme used for clearing of juice in bottled juices...... 3. RTOXIPHMCOI Mode of nutrition shown by Euglena...... 4. JTCONNOI Arrangement of vascular bundle in which xylem and ...... phloem are present together in the same bundle on the same radius. 5. NRTAKEI Water insoluble fibrous protein...... 6. LTAORY Scientist who experimentally proved semi-conservative ...... DNA replication in Vicia faba. 7. PYMIORMETHANU Cancer treatment involving the use of interleukin-2...... 8. HNCELIS Pioneer species of xerarch...... 9. CLSNIPGI Step of post transcriptional modification...... 10. GSYONNSGEIE Development of plants from unfertilised cells of female ...... gametophyte and ovules in tissue culture.

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MTBIOLOGY TODAY | JANUARY ‘16 39 sOLuTIOns

CHAPTER-1 : REPRODUCTION IN ORGANISMS or inside the body of the organism. ‘C’ represents 1. (c) 2. (b) 3. (a) 4. (b) 5. (c) embryogenesis, which is the development of the 6. (d) 7. (d) 8. (c) 9. (b) 10. (a) embryo from the zygote. During embryogenesis, 11. True zygote undergoes mitotic cell division and cell 12. False : Sexual reproduction involves formation of the male differentiation. Cell division increases the number of and female gametes. cells in the developing embryo while cell differentiation helps to form specialised tissues and organs to form 13. True 14. True an organism. 15. False : In monoecious plant, both male and female flowers 30. (a) A – Zoospores of Chlamydomonas are present on the same plant. B – Conidia of Penicillium 16. True (b) Figures A and B represent asexual reproductive 17. False : Endogamy involves the fusion of male and female structures-zoospores of Chalamydomonas and conidia gametes of the same parent. of Penicillium respectively. Zoospores are special kind 18. True of motile and flagellated spores produced inside the 19. False : In arrhenotoky type of parthenogenesis, only males zoosporangia. They are generally naked i.e., without are produced by parthenogenesis. cell wall. The flagella help to swim in aquatic habitat 20. False : In viviparous animals, the zygote develops into a for proper dispersal. Conidia are non-motile spores young one inside the body of the female organism. produced singly or in chains by constriction at the tip of lateral side of special hyphal branches, called 21. A-(iii), B-(v), C-(i), D-(ii), E-(iv) conidiophores. They are produced exogenously, 22. A-(iii, vii), B-(i, ix), C-(ii, x), D-(iv, viii), E-(v, vi) dispersed by wind and germinate directly by giving 23.(A) (i) zygote (ii) fertilisation out germ tubes. (iii) stamens (iv) pistil CHAPTER-2 : SExUAL REPRODUCTION IN FLOwERING PLANTS (v) embryo (vi) seeds (vii) ovary (viii) pericarp 1. (a) 2. (b) 3. (c) 4. (a) 5. (c) (B) The process of formation of male and female gametes is 6. (c) 7. (c) 8. (b) 9. (b) 10. (c) called sporogenesis gametogenesis. Gametes are diploid 11. False : Epicotyl is the part of embryonal axis in between haploid cells. In some algae, the two gametes are similar plumule and cotyledonary node. in appearance and are called anisogametes isogametes/ 12. True homogametes. In most of asexually sexually reproducing 13. False : Xenogamy is transfer of pollen grains from anther organisms the gametes are of morphologically dissimilar to the stigma of a different plant. types, hence, they are known as isogametes anisogametes/ 14. True 15. True heterogametes. In anisogametes the male gamete is called the egg antherozoid/sperm and the female gamete is 16. False : Intine made up of cellulose and pectin. known as the antherozoid ovum/egg. 17. True 24. (a) 25. (c) 26. (d) 27. (c) 28. (a) 18. False : Innermost wall layer of microsporangium is tapetum, 29. (a) A – Gametogenesis it nourishes the developing pollen grain. B – Fertilisation 19. True 20. True C – Embryogenesis 21. A-(iii), B-(iv), C-(i), D-(ii), E-(v) (b) The given figure is the schematic representation of 22. A-(ii, v), B-(i, iv), C-(iii,ix), D-(vii, x), E-(vi, viii) sexual reproduction. ‘A’ represents gametogenesis, the formation of two types of gametes - sperm (male 23.(A) (i) embryo sac (ii) haploid (iii) nucellus gamete) and ovum (female gamete). Gametes are (iv) Polygonum (v) 8 (vi) 7 haploid cells. ‘B’ represents fertilisation, which is a (vii) 3 (viii) 3 (ix) central complete and permanent fusion of two gametes from (B) Seed and fruit formation are stimulated by the act of different parents or from the same parent to form pollination fertilisation. In angiosperms this process a diploid zygote. It occurs either in external medium produces two structures - a haploid diploid zygote and a

40 MTBIOLOGY TODAY | JANUARY ‘16 diploid triploid endosperm cell. The zygote endosperm gives 15. True rise to a nutritive tissue and zygote forms the embryo. With 16. False : Chorion is composed of trophoblast present towards the growth of embryo the peripheral central part of the the outerside and somatopleuric extraembryonic mesoderm nutritive tissue is eaten up. Nutritive tissue in turn crushes present on inner side. the micropyle nucellus. 17. True 18. True 24. (c) 25. (b) 26. (a) 27. (b) 28. (d) 19. False : Vasa efferentia carries spermatozoa from the rete 29. (a) A – Scutellum B – Coleoptile testis to the epididymis. C – Epiblast D – Coleorrhiza 20. True (b) The given figure is L.S. of an embryo of a plant 21. A-(iv), B-(ii), C-(i), D-(iii), E-(v) belonging to grass family. B represents coleoptile and represents coleorrhiza. Coleoptile is a foliar structure 22. A-(iii, v), B-(i, iv), C-(ii,vii), D-(vi, x), E-(viii, ix) that encloses the epicotyl bearing shoot apex and leaf 23.(A) (i) zona pellucida (ii) block (iii) sperms primordia. It protects the plumule during emergence (iv) acrosome (v) cytoplasm from soil. Coleorrhiza is a sheath encapsulating both (vi) meiotic (vii) secondary oocyte radicle and root cap. It does not protect the radicle during its passage into the soil. (B) The mature ovum or a female gamete is tubular spherical in (c) Epiblast (labelled as C), represents rudiments of shape. The human ovum is said to be mesolecithal alecithal. second cotyledon. Its cytoplasm is called acroplasm ooplasm containing mitochondria large nucleus, termed as mitochondrial 30. (a) A – Epidermis B – Endothecium germinal vesicle. There are many no centrioles in the ovum. C – Middle layers D – Tapetum The cytoplasm is enveloped by the plasma membrane and (b) Endothecium (labelled part B) is known as fibrous very large small vesicles called cortical granules are present layer. Endothecial cells develop fibrous thickenings below it. A wide narrow perivitelline space is present inside of a-cellulose on the inner and radial walls and outside the plasma membrane. become dead. Because of the presence of these fibrous 24. (c) 25. (b) 26. (a) 27. (d) 28. (c) thickenings this layer is known as fibrous layer. 29. (a) A – Graafian follicle (c) Labelled part D represents tapetum. It has a number B – Tertiary follicle with antrum of functions, which are as follows: C – Ovum D – Corpus luteum (i) It provides nourishment to the developing microspore E – Primary follicle F – Corpus albicans mother cells and pollen grains. (b) The given figure is diagrammatic section view of (ii) It produces lipid rich Ubisch granules containing mammalian ovary. Labelled part A represents Graafian sporopollenin for exine formation, pollenkitt in case of follicle which secrete oestrogens mainly estradiol. entomophilous pollen grains, special proteins for the It stimulate proliferation of the endometrium of the pollen grains to recognise compatibility and hormone uterine wall. IAA. (iii) It secretes enzymes like callase which is responsible (c) Labelled part D represents corpus luteum. It secretes for the degradation of callose wall present around progesterone which stimulates the uterine glands to pollen tetrad. produce increased amount of watery mucus. It is also essential for maintenance of the endometrium. Such CHAPTER-3 : HUMAN REPRODUCTION an endometrium is necessary for implantation of the 1. (c) 2. (c) 3. (b) 4. (c) 5. (d) fertilised ovum and other events of pregnancy. 6. (a) 7. (c) 8. (d) 9. (d) 10. (c) 30. (a) A – Plasma membrane B – Acrosome 11. True 12. True C – Neck D – Middle piece 13. False : Spermatogenesis is the process of formation of sperms E – Tail which includes formation of spermatids and formation of (b) The given figure is the structure of a sperm. Labelled spermatozoa from spermatids. part D represents middle piece of human sperm. It 14. False : During embryonic development, a solid ball-like contains the mitochondria coiled around the axial structure which looks like a little mulberry is known as filament which is called as mitochondrial spiral. It morula. provides energy for the movement of tail that facilitate

MTBIOLOGY TODAY | JANUARY ‘16 41 sperm motility essential for fertilisation. So, it is also is implanted in vagina uterus where it develops into a known as the ‘power house of the sperm’. foetus (test tube baby). In this technique zygote is allowed (c) The labelled part B represents acrosome which to divide to form 16 8 blastomeres. The proembryo thus contains hyaluronidase and various proteolytic formed is transferred into the uterus Fallopian tube. If the enzymes collectively known as spermlysins that helps embryo is having more blastomeres, it is transferred into in fertilising the ovum. the Fallopian tube uterus. CHAPTER-4 : REPRODUCTIvE HEALTH 24. (a) 25. (c) 26. (d) 27. (a) 28. (c) 1. (c) 2. (c) 3. (c) 4. (a) 5. (c) 29. (a) A – Placenta 6. (b) 7. (a) 8. (c) 9. (b) 10. (c) B – Uterine wall 11. False : Immigration is the movement of individuals C – Amniotic fluid into a place or country which results in the increase in D – Cells shed by growing foetus population. E – Syringe with needle withdraws a small amount of 12. True fluid and cells. 13. False : Natality rate increases population size and population (b) The given figure represents the procedure of amnio density. centesis in which amniotic fluid containing cells 14. False : Exponential growth shows J-shaped growth curve from the skin of the foetus and other sources are whereas logistic growth shows S-shaped or sigmoid growth withdrawn by using a special surgical syringe with curve. needle. These cells are cultured and are used to 15. True determine chromosomal abnormalities such as 16. False : Population growth rate can be negative. Down’s syndrome, Klinefelter’s syndrome and 17. True 18. True 19. True 20. True metabolic disorders such as phenylketonuria; sickle 21. A-(iii), B-(v), C-(i), D-(ii), E-(iv) cell anaemia of the foetus. Unfortunately, it is being misused to kill the normal female foetus. Therefore, 22. A-(iv, vii), B-(vi, ix), C-(viii,x), D-(i, v), E-(ii,iii) it is legally banned for the determination of sex to 23.(A) (i) viral avoid female foeticide. (ii) Human immunodeficiency virus (HIV) (iii) T-lymphocytes 30. (a) A – Ovary B – Uterus (iv) ELISA (Enzyme-linked Immunosorbent Assay) C – Cervix D – Vagina (v) Western Blotting (vi) Semen E – Fimbriae (vii) Azidothymidine / Zidovudine (b) The given figure represents tubectomy, a permanent (viii) Dibanosine sterilisation method of birth control in females. In this method small part of the Fallopian tube is removed (B) In test tube baby technique, i.e., advanced assisted or tied up through a small cut in the abdomen or reproductive technology, the fusion of ovum and sperm is through vagina. This is very effective method of birth done inside outside the body of woman, to form a zygote control with very poor reversibility. which is allowed to divide to form an embryo. This embryo 

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42 MTBIOLOGY TODAY | JANUARY ‘16 HGH YIELD FACTS Class XI

Monerans

• Monera is a kingdom of prokaryotes. Therefore, it is also known as prokaryota. It includes the most primitive forms of life which developed from an early stock

known as progenote. Being the earliest forms of life, monerans are adapted to 2 – 1 3 2 – 2015 all types of habitats. • Monerans have very little morphological differentiation. Therefore, it is very difficult to distinguish groups, subgroups, genera and species on the basis of structural and

morphological characters alone. Many other characters are taken into consideration 2 – 1 – – – while classifying monerans e.g, biochemical, physiological and ecological characters. 2014 Molecular homology is being increasingly used in delimiting different taxa. Important characterIstIcs of monerans

• Monerans are basically unicellular (monos-single) prokaryotes and contain the 5 – 1 – – – most primitive of living forms. 2013 • They are varied in their nutrition—saprotrophic, parasitic, chemoautotrophic, photoautotrophic and symbiotic. The photoautotrophs include both aerobes and anaerobes.

• The cells are microscopic (0.1 to a few microns in length). 3 – 1 1 1 – 2012 • Cell wall is generally present. It contains peptidoglycan and polysaccharides other than cellulose. • Cells have one envelope type of organisation, i.e., the whole protoplast is covered Analysis of various PMTs from 2011-2015 from PMTs various of Analysis by plasma membrane but internal compartmentalisation is absent. 2 – 1 – 2 –

• Genetic material is not organised into a nucleus. 2011 • DNA is naked, i.e., it is not associated with histone proteins. DNA lies coiled inside the cytoplasm and is known as nucleoid. It is equivalent to a single chromosome. • All membrane bound cell organelles are absent, e.g., mitochondria, lysosomes, spherosomes, Golgi bodies, plastids, etc. • The flagella, if present, are single stranded instead of being 11 stranded in

eukaryotes. They are formed of protein called flagellin. AIPMT/NEET AIIMS AMU Kerala K.CET J & K

MTBIOLOGY TODAY | JANUARY ‘16 43 • Mitotic spindle is absent. • Archaebacteria are considered to be the `oldest of living • Gametes are absent. Gene recombination has been fossils’. discovered in certain cases. Otherwise reproduction is by bacterIa asexual methods. • The bacteria are microscopic, unicellular, true chlorophyll- • Some of the monerans have the ability to perform nitrogen free prokaryotes which reproduce by binary fission. fixation. • They may occur singly or in aggregations to form colonies. classIfIcatIon of monerans In bacterial colonies, the individual cells are functionally • There are two major groups of monerans, Archaebacteria independent. They are physiologically and biochemically and Eubacteria. diverse. • Archaebacteria include ancient and primitive forms • Bacteria possess rigid cell walls. Some are motile, of bacteria. Based on the occurrence they can be, whereas others are not. methanogens, halophiles and thermoacidophiles. • Eubacteria include true bacteria. They are of two types, Distribution and habitat bacteria and cyanobacteria. Rickettsiae, actinomycetes, • Bacteria are cosmopolitan in distribution and are ubiquitous mycoplasmas, etc., are various groups included in eubacteria. (everywhere). They occur in water, soil, air, animals, plants, in snow (upto – 190ºC) and also in hot water streams. They are archaebacterIa found floating in the atmosphere mostly as wanderers“ ” • This is simplest and most primitive group of bacteria. The on dust particles, up to height of several thousand feet, cell wall of these bacteria is made of polysaccharides and except just after heavy rains or snow storms when the air is proteins (peptidoglycans and muramic acid are absent in cell generally free of them. wall). • They are abundant on the surface of the human body • Further branched chain lipids are present in plasma and are present in large number in the intestinal tract membrane of archaebacteria, due to which these can face and on all the mucous membranes. Unlike many higher extremes of conditions of temperature and pH. organisms, bacteria have no natural death. • Three main types of archaebacteria are: • Under the three-domain system of taxonomy, introduced (i) Methanogens: These are strict anaerobic bacteria by Carl Woese (1977), which reflects the evolutionary and mainly occur in muddy areas and also in stomach of history of life, the organisms found in kingdom Monera cattle (Methanobacterium), where cellulose is fermented by have been divided into two domains–Archaea and microbes. Bacteria (with Eukarya as the third domain). Furthermore, • These are responsible for methane gas (CH4) formation in the taxon Monera is paraphyletic (does not include all biogas plants, because they have capacity to produce CH4 descendants of their most recent common ancestor), as from CO2 or formic acid (HCOOH) (e.g., Methanobacterium, Archaea and Eukarya are more closely related to each Methanococcus). other than either is to bacteria. (ii) Salt lover archaebacteria or halophiles: These bacteria occur in extreme saline or salty conditions (upto 35% types of bacteria of salt or NaCl in culture medium) (e.g., Halobacterium, • On the basis of shapes bacteria have been divided into six Halococcus). types: (i) Cocci : These are spherical or ellipsoidal in shape and • A purple pigmented membrane containing bacterio- rhodopsin is developed in sunlight in these bacteria, which are of 6 types : utilises light energy for metabolic activities (different from – Monococci : occur singly. photosynthesis). – Diplococci : occur in pairs. (iii) Thermoacidophiles: These are the bacteria which are – Tetracocci : occur in groups of 4. found in hot sulphur springs (upto 80°C). These are – Streptococci : occur in chains. aerobic bacteria, which have the capacity to oxidise – Sarcinae : occur in cubical forms of 8 or multiple of 8. sulphur to H2SO4 at high temperature and high acidity (i.e., – Staphylococci : occur in clusters like grapes. pH 2.0), hence given the name thermoacidophiles, i.e., (ii) Bacilli : These are rod-shaped and are of following temperature and acid loving. types: • Some of these bacteria are able to reduce sulphur to – Palisade bacilli : occur like a stack. H2S under anaerobic conditions (e.g., Thermoplasma, – Diplobacilli : occur in pairs. Thermoproteus). – Streptobacilli : occur in chains.

44 MTBIOLOGY TODAY | JANUARY ‘16 (iii) Spirilla : These are spiral or helical in shape, e.g., (i) Monotrichous : When single flagellum occurs at Spirillum, Spirochaete. one end only, e.g., Pseudomonas, Thiobacillus, Vibrio (iv) Vibrios : These are comma shaped bacteria, e.g., Vibrio cholerae, Xanthomonas citri. cholerae. (ii) Lophotrichous : When a group of flagella is present at (v) Stalked : The bacterium possesses a stalk, e.g., one end only, e.g., Spirillum volutans. Caulobacter. (iii) Amphitrichous : When single or group of flagella is (vi) Budding : The bacterium is swollen at places, e.g., present at both the ends, e.g., Nitrosomonas. Rhodomicrobium. (iv) Peritrichous : When flagella are present all over the surface of bacteria, e.g., E. coli, Salmonella, Proteus vulgaris. Monococcus Tetracoccus Sarcina Staphylococcus (v) Atrichous : When flagella are absent, e.g., Pasteurella Diplococcus Streptococcus pestis, Lactobacillus.

Bacillus Diplobacillus

Palisade bacillus Streptobacillus Spirillum Vibrio Stalked Budded Fig.: Various forms of bacteria Each flagellum is 4-5 m in length and arises from a basal structure of bacterial cell • m granule called blepharoplast. Flagella is made up of • The structure of the bacterial cell can be broadly divided as flagellin protein. follows : – Structure external to the cell wall. • Bacterial flagellum has three basic parts – filament, hook – Structure of the cell wall. and basal body. It is made up of one or three a-helical – Structure internal to the cell wall. strands. The basal body bears ring like swellings in the region • The structures that are present external to the cell of plasma membrane and cell wall. wall are glycocalyx or capsule, flagella, fimbriae and pili. • There are two pairs of rings in Gram –ve bacteria and only The structures internal to the cell wall include plasma a single pair of rings in Gram +ve bacteria. Hook is curved membrane, mesosome, cytoplasm, etc. tubular structure which connects the filament with the basal Glycocalyx body. It is the thickest part of flagellum. • It is a sticky, gelatinous material that collects outside the cell • Filament is long tubular structure which causes turbulence wall to form an additional surface layer. in the liquid medium. • When this layer is firmly attached to the surface of the cell, it is called a capsule. If it is loosely distributed around the cell, the glycocalyx is called a slime layer. Presence or absence of capsule is genetically fixed. Hook Filament • Capsule is made of polysaccharides and amino acids. • Glycocalyx helps in (i) prevention of desiccation, (ii) protection L-ring Cell wall from phagocytes, toxic chemicals, drugs, viruses, etc., (iii) P-ring attachment, (iv) immunogenicity, (v) virulence, etc. Rod S-ring • Capsulated bacteria forming smooth colonies are called M-ring S-type bacteria. These are highly virulent. Non- Fig.: Lower region of flagellum of a gram negative bacterium capsulated bacteria forming rough colonies are called R-type bacteria. Pili and fimbriae Flagella • Many Gram-negative bacteria possess a number of hair- • Flagellum is the organ of motility in bacteria. Bacteria are of like structures that are shorter, straighter and thinner than the following types on the basis of flagellation : flagella and are used for the attachment rather than for

MTBIOLOGY TODAY | JANUARY ‘16 45 flower is a highly condensed and modified shoot. It contains reproductive organs of the flowering plants, which develop fruits and seeds. There are four types of floral organs viz. sepals, petals, stamens and carpel or pistil. A flower having all the four types of floral organs is known as complete flower e.g., cotton. If Aone or more of the floral organs are absent it is called incomplete flower e.g., cucurbits. A flower having both the essential organs i.e., stamens and carpels is CONCEPT called hermaphrodite or bisexual flower, e.g., China rose, whereas a flower having only one of the two essential organs is known as unisexual flower e.g., mulberry. Flowers having only stamens are called staminate flowers and those having only carpels are called pistillate flowers. On the basis of symmetry flower can be FLORAL actinomorphic (two equal halves in any plane), zygomorphic (two equal halves in one plane), or asymmetrical.

COROLLA MAP ANDROECIUM l Second whorl inner to calyx made up of petals MORPHOLOGY l Third and male whorl of the flower made up of which protects the inner whorls and attracts insects stamens (microsporophylls) which consist of for pollination. Corolla may be polypetalous (petals free) filament (lower stalk-like part which may be absent in or gamopetalous (petals fused). some), anther (upper swollen part usually having two lobes or l Polypetalous corolla may be cruciform (four clawed or GYNOECIUM theca i.e., bithecous or in some monothecous, e.g., Althaea) and unguiculate petals arranged cross wise e.g., mustard), caryophy- connective (sterile band which connects two anther lobes). In Salvia, llaceous (five unguiculate or clawed petals with limbs placed at right l Central, female reproductive part l The stamens may be equal or unequal in length. When there is connective forms a long curved structure, its one end has a fertile anther angles, e.g., Dianthus), rosaceous (five or more sessile or shortly clawed which develops from thalamus and lobe and other has a sterile anther lobe. Stamens may be shorter than other consists of carpels (megasporophylls). two long and two short stamens, the petals with limbs spread regularly outwards, e.g., rose), campanulate or bell- whorls (inserted) or may protrude out of the flower (exserted). shaped (e.g., Physalis), papilionaceous (five unequal or irregular petals viz. l Each carpel consist of– stigma (the tip which condition is called didynamous, e.g., l On the basis of attachment to the filament, anthers can be adnate (filament runs 1 standard or vexillum – posterior largest–, 2 wings or alae –lateral, smaller– and receives pollen), style (elongated structure Ocimum. When out of six stamens, four are longer in inner whorls and two in outer whorl are shorter, along the back of the anther or becomes continuous with the connective, e.g., 2 anterior petals fused together to form keel or carina). connecting stigma and ovary), ovary (lower swollen Ranunculus), basifixed (filament fixed at anther its base, e.g., Datura), dorsifixed l part containing ovules). the condition is called tetradynamous, e.g., mustard. Gamopetalous corolla may be campanulate (bell-shaped or inverted cup l (filament attached to back and anther immobile, e.g., Passiflora), versatile (filament shaped e.g., Campanula), urceolate (urn-shaped e.g., Bryophyllum), tubular l On the basis of number of carpels present, it can be Dehiscence of anthers to expose the pollen grains attached to back and the anther can swing freely, e.g., grasses). (tube-like or cyclindrical e.g., disc floret of sunflower), infundibuliform (funnel moncarpellary (one carpel only) or multicarpellary can be longitudinal (long slits appear lengthwise e.g., l The cohesion between the stamens may be monadelphous (all the filaments shaped e.g., Petunia), rotate (corolla with short tube having limbs placed (many carpels) which can be apocarpous (carpels free e.g., mustard), transverse (breadthwise slits, e.g., Malva), united into a single bundle, anthers free, e.g., China rose), diadelphous (filaments transversely like a saucer or the spokes of a wheel, e.g., Solanum nigrum), Ranunculus) or syncarpous (carpels fused e.g., Petunia). porous (pores appear at the tip e.g., Solanum or base united in two bundles, anthers free, e.g., pea), polyadelphous (filaments united salver shaped or hypocrateriform (tubular corolla with spreading lobes, l On the basis of number of locules (chamber) present in e.g., Cassia), valvular (split at several places by lifting of surface layers, e.g., Barberry), irregular (e.g., Najas). into more than two bundles, anthers free, e.g., castor), syngenesious (anthers e.g., Clerodendrum), bilabiate (bilipped corolla with gaping, wide open the ovary, it can be unilocular (pea), bilocular united into a bundle, filaments free, e.g., sunflower), synandrous (anthers as l Longitudinal dehiscence may be laterorse (slits mouth, e.g., Ocimum), personate (bilipped corolla with closed lips, (mustard), trilocular (Asparagus), tetralocular well as filaments united throughout the length, e.g., Colocasia). The free on sides), introrse (slits towards the inner side e.g., Antirrhinum), ligulate or strap-shaped (short and narrow (Ocimum), pentalocular (China rose) or stamens are called polyandrous. or centre of the flower), extrorse (slits lie tube-like corolla with upper part flattened like a strap, e.g., multilocular (Althaea). l towards the outer side of flower). On the basis of adhesion of stamens to flower, it can be ray floret of sunflower), spurred (one or more petals epiphyllous (attached to perianth, e.g., Asphodelus), drawn out like a beak or spur, e.g., Larkspur). epipetalous (attached to petals, e.g., Datura), gynandrous (attached to gynoecium, e.g., PLACENTATION Calotropis). l Arrangement of placenta (which bear ovules) on the ovary wall which can be : AESTIVATION (i) Marginal : One or two longitudinal alternate Stigma l rows of ovules along the ventral suture in unilocular Arrangement of petals (or sepals) in a ovary, e.g., pea, Cassia etc. Pollens flower bud with respect to members of the (ii) Parietal : Ovules on walls of bi–multicarpellary but Style same whorls which can be open (margins of unilocular ovary e.g., Argemone. adjacent petals sufficiently apart from each other), valvate (margins of the adjacent petals lie close, (iii) Axile : In multicarpellary, syncarpous, multilocular Ovary Anther gynoecium; margins fuse at the centre of the ovary to form without overlapping, e.g., mustard), twisted or contorted an axis which bears ovule e.g., Solanum. (one margin of a petal overlaps the margin of an adjacent Filament petal (external) and the other margin is overlapped (internal) (iv) Free central : Unilocular ovary with ovules borne on central axis e.g., Dianthus. by the margin of adjacent petal, e.g., China rose), imbricate (one petal external, one internal; and of the remaining three (v) Basal : Ovary unilocular with a single ovule at its petals one margin is overlapped, other overlapping, e.g., base, e.g., sunflower. Ovule Cassia), quincuncial (special type of imbricate aestivation (vi)Superficial : Multicarpellary, syncarpous in which two petals external, two internal and in one gynoecium bears a large number of petal one margin is overlapped, one is overlapping, ovules that are borne on the walls of loculi without specific order, e.g., calyx of Cucurbita maxima), vexillary e.g., Nymphaea. (posterior petal overlapping the two lateral petals, the latter overlapping the two anterior petals, e.g., pea). THALAMUS (Torus/Receptacle) l Broadened or swollen part of the flower which CALYX lies at the tip of the pedicel and bears floral organs. l Outermost whorl made up of sepals l In most flowers the thalamus is condensed but in some, which are usually green but sometimes one or more internodes elongate viz. anthophore BRACTS coloured (i.e., petalloid). They protect the inner l (internode between calyx and corolla e.g., Dianthus), Specialised leaves from the axil of whorls and carry out photosynthesis when green. androphore or gonophore (internode between corolla and which flower arise. They can be foliaceous l The sepals may be free (polysepalous) or androecium, e.g., Passiflora), gynophore (internode between (leaf-like e.g., Adhatoda), petaloid (like petals, androecium and gynoecium, e.g., Capparis), gynandrophore or fused(gamosepalous). They can be caducous (fall just at e.g., Bougainvillea), scaly (membranous, small the time of opening of bud, e.g., poppy), deciduous androgynophore (both androphore and gynophore present, e.g., e.g., sunflower), spathy (large, boat-shaped bract Gynandropsis pentaphylla), carpophore (the thalamus in (attached till the flower withers, e.g., mustard), persistent enclosing an inflorescence, e.g., banana, maize), (remain attached to the fruit, e.g., tomato). between the two carpels elongates and after bifurcation glumes (small, dry, scaly as in spikelet of Poaceae ). protrudes out of the two carpels, e.g., Coriandrum). l Sepals can be modified to form pappus (hairy structure PEDICEL OR lThere are one or more whorls of bracts found at l On the basis of relative position of floral organs on which helps in dispersal e.g., sunflower), leafy petalloid STALK the base of calyx which form epicalyx in most (large leaf like coloured structure, e.g., Mussaenda), thalamus flower may be epigynous (ovary inferior, l members of Malvaceae, e.g., China rose. Lower internode of flower. spinous (persistent and modified into spines, e.g., placed below other whorls, e.g., guava), Sometimes, bracts are in one or more whorls A flower with pedicel is called Trapa), spurred (drawn out into beak or spur, e.g., hypogynous (ovary superior, e.g., China rose), or around and below the entire inflore- pedicellate and one without Larkspur), hooded (modified into a hood, perigynous (ovary half superior or half scence, e.g., coriander and are called it, is sessile. It may bear covering the whole flower, e.g., inferior and thalamus may be disc e.g., involucre. pea, cup e.g., Prunus or flask bracteoles along with Aconitum) or bilabiate (two- e.g., rose shaped). the bracts. lipped, e.g., Salvia). motility. These structures, which consist of a protein called attaching to recipient cell and forming conjugation tube. pilin, are divided into two types, fimbriae and pili. • Fimbriae are formed in large numbers. There are 300-400 • Pili are longer, fewer and thicker tubular outgrowths which of them per cell. Diameter is 3-10 nm and length is 0.5 – 1.5 develop in response to F+ or fertility factor in Gram mm. They help in attaching bacteria to solid surfaces or host –ve bacteria. So they are also called sex pili. They help in tissues.

Table : Differences between prokaryotic and eukaryotic flagella Prokaryotic flagella Eukaryotic flagella (i) They are single stranded. They are 11-stranded. (ii) A covering membranous sheath is absent. Flagella are covered by sheath derived from plasmalemma. (iii) The size is smaller. The size is larger. (iv) They are narrower. They are thicker. (v) Each flagellum has three parts—basal body, hook There are two parts, basal body and shaft. and filament. (vi) Basal body bears rings. Basal body bears rootlets. (vii) They are formed of protein flagellin. The strands are formed of protein tubulin. (viii) They perform rotatory movements. They perform lashing or undulatory movements.

Cell wall staining technique developed by Christian Gram in • Underlying the capsule and external to the cytoplasmic 1884, bacteria can be divided into two large groups : Gram membrane is the cell wall which provides rigidity and shape + ve and Gram – ve bacteria. to the bacterial cell. • In the cell wall of Gram +ve bacteria, both horizontal • The most important function of the cell wall is to protect the and vertical peptide linkages are present, due to cell contents from external stresses and from lysis resulting which mesh is dense and hence the stain does not come from osmotic pressure. out. Further outer layer of cell wall of Gram +ve bacteria is made of teichoic acid. In the cell wall of Gram –ve • Periplasmic space appears between plasma membrane and bacteria, either horizontal or vertical peptide cell wall. linkages are present, due to which mesh is loose and • Cell wall is made of polysaccharides, proteins and lipids. hence stain comes out. Further outermost layer of cell wall of • On the basis of differential staining technique called Gram Gram –ve bacteria is made of lipopolysaccharides.

Teichoic acid

48 MTBIOLOGY TODAY | JANUARY ‘16 • One of the unique components of cell wall of bacteria and is not destroyed by penicillin, whereas cell wall of is peptidoglycan or mucopeptide or murein (made of Gram +ve bacteria is thick (20-80 nm) and is destroyed mucopolysaccharide + polypeptide). In peptidoglycan, NAG by penicillin. Further, cell wall of Gram –ve bacteria (N-acetyl glucosamine) and NAM (N-acetyl muramic acid) is less homogenous, more complex and multilayered. are joined by short peptide chains or cross bridges of amino Lipids (including phospholipids, lipopolysaccharides and acids. The cell walls of Gram +ve bacteria contain 60–90% lipoproteins) make up 80-85% of the total cell wall. The cell peptidoglycan whereas cell walls of Gram –ve bacteria wall of Gram +ve bacteria is more homogenous and single layered and amorphous. Lipids are almost absent. Presence contain about 10% peptidoglycan. of lipopolysaccharides in cell wall of Gram –ve bacteria • Cell wall of Gram –ve bacteria is thin (8-12 nm) and hard makes them pathogenic.

Table : Differences between Gram +ve and Gram–ve bacteria Gram +ve bacteria Gram –ve bacteria (i) They remain coloured blue or purple with Gram stain The bacteria do not retain stain when washed with absolute even after washing with absolute alcohol or acetone. alcohol. (ii) The wall is single layered. Outer membrane is absent. The wall is two layered. Outer membrane is present. (iii) The thickness of the wall is 20-80 nm. It is 8-12 nm. (iv) The lipid content of the wall is quite low. The lipid content of the wall is 20-30%. (v) The wall is straight. The wall is wavy and comes in contact with plasmalemma only at few places. (vi) Murein or mucopeptide content is 60-90%. It is 10%. (vii) Porins are absent. Porins or hydrophilic channels occur in outer membrane. (viii) Cell wall contains teichoic acids. Teichoic acids are absent. (ix) Examples: Staphylococcus, Examples : Salmonella, E.coli, Pseudomonas, Vibrio and Streptococcus, Pneumococcus, Bacillus, Azotobacter. Clostridium,Mycobacterium, Streptomyces.

Plasma membrane not connected with nucleoid. It contains respiratory enzymes • Bacterial plasma membrane or plasmalemma has a structure and is therefore, often called chondrioid. similar to that of a typical membrane. It is made of a Cytoplasm phospholipid bilayer with proteins of various types (extrinsic, integral, transmembrane). However, typical sterols (e.g., • It is crystallo-colloidal complex that forms the protoplasm cholesterol) are absent. Instead pentacyclic sterols, excluding its nucleoid. called hopanoids, are found in some bacteria. Hopanoids • Cytoplasm is granular due to presence of a large number of stabilise the membrane. ribosomes. • Bacterial membrane is metabolically active as it takes part in • Membrane bound cell organelles as found in eukaryotes are respiration, synthesis of lipids and cell wall components. absent. However, all biochemical pathways are found in prokaryotic cells. Mesosome • Cytoplasmic streaming is absent. • It is a circular to villiform membranous structure which • Sap vacuoles are absent. Instead gas vacuoles are develops as an ingrowth from the plasma membrane. present. • It is less prominent in Gram –ve bacteria but is quite • Various structures present in cytoplasm are as follows: conspicuous in Gram +ve bacteria. • Mesosome is of two types, septal and lateral. Septal (i) Ribosomes mesosome connects nucleoid with plasma membrane. It • The ribosomes are 70S in nature. Each ribosome has two takes part in the replication of nucleoid. Lateral mesosome is subunits, larger 50S and smaller 30S.

MTBIOLOGY TODAY | JANUARY ‘16 49 • Ribosomes take part in protein synthesis. Free Lipid Respiratory or matrix ribosomes synthesise proteins for Glycogen Cell wall globule enzymes intracellular use while fixed ribosomes synthesise RNA Mesosome proteins for transport to outside. Pilus (ii) Chromatophores (Fimbria) • In certain photosynthetic bacteria, most of the Filament Hook cytoplasm is occupied by single-membraned, vesicular structures which are the extensions of the cytoplasmic membrane. These are called chromatophores and contain photosynthetic Basal pigments along with the enzymes and body Ribosome electron carriers for the photosynthetic Flagellum Cytoplasm phosphorylation. Polyribosome Mucilage Nuclear body Plasma (Nucleoid) (iii) Inclusion bodies membrane • They are non-living structures present in the Fig.: Cell structure under electron microscope (Plasmid and volutin cytoplasm. The inclusion bodies may occur freely granules not shown). inside the cytoplasm (e.g., cyanophycean granules, (c) Food reserves volutin or phosphate granules, glycogen granules) or covered • Cyanobacteria have cyanophycean starch or a-granules, by 2-4 nm thick non-lipid, non-unit protein membrane b-granules of lipid globules and cyanophycin or protein (e.g., gas vacuoles, carboxysomes, sulphur granules, PHB granules. In bacteria, starch is replaced by glycogen. granules). Neutral fats are absent. Instead polybetahydroxybutyrate • On the basis of their nature, the inclusion bodies are of or PBH granules are present. 3 types — gas vacuoles, inorganic inclusions and food Nucleoid reserves. • Bacteria lack nuclei and do not possess the complex (a) Gas vacuoles chromosomes characteristic of eukaryotes. Instead their • They are gas storing vacuoles found in cyanobacteria, genes are encoded within a single double-stranded ring of purple and green bacteria and a few other planktonic forms. DNA which is present in the centre of cell not surrounded by Gas vacuoles protect the bacteria from harmful radiations. any membrane (so DNA is considered naked). This primitive They also constitute buoyancy regulation mechanism type of nucleus is known as nucleoid or genophore or for their proper positioning in water during day time as per incipient nucleus. requirement of photosynthesis. Plasmids (b) Inorganic inclusions • Many bacterial cells also possess small, independently • Several types of inorganic granules occur in bacteria. replicating circles of DNA called plasmids. Plasmids They include volutin granules, sulphur granules, iron contain only a few genes, usually not essential for the cell’s granules, magnetite granules, etc. Because of the ability survival. They are best thought of as an excised portion of to pick up different colours with basic dyes, they are called the bacterial chromosome. metachromatic granules.

1. Why do most antibiotics selectively kill bacterial cells only and not human cells? 2. The bacteria which are surrounded by capsule (encapsulated bacteria) are more pathogenic (or virulent) than the bacteria which are not surrounded by capsule. Why is this so? 3. Differentiate between the cell wall composition of Gram +ve and Gram–ve bacteria.

50 MTBIOLOGY TODAY | JANUARY ‘16 • Plasmids which can get associated temporarily with nucleoid Rhodopseudomonas palustris) and green sulphur bacteria are known as episomes. Plasmids are used as vectors in (e.g., Chlorobium limicola). The pigments occur in the genetic engineering. membranes of thylakoids. • Plasmids carry non-vital genes which may or may not be • No oxygen is evolved in bacterial photosynthesis. Such type useful to bacteria. Plasmids which do not confer any useful of photosynthesis is known as anoxygenic photosynthesis. trait to the cells are called cryptic plasmids. Three types • Water is not used as a source of reducing power. Instead, of useful plasmids are F-plasmids, R-plasmids and Col- hydrogen is obtained either directly (some purple bacteria) plasmids. or from various types of inorganic and organic compounds, (i) F-Plasmids : They are plasmids which contain genes e.g., H2S (green bacteria), aliphatic compounds (purple non- for conjugation or fertility. An F-plasmid is, therefore, sulphur bacteria). also called fertility factor or F-factor. A bacterium having F-plasmid is called male or donor bacterium. Chemoautotrophic bacteria It develops sex pili for conjugating with female or • They are bacteria which are able to manufacture their recipient bacterium which is devoid of F-factor. organic food from inorganic raw materials with the help of F-plasmid not only pass into recipient bacterium but energy derived from exergonic chemical reactions involving can also help in transfer of nuclear genes from F+ to oxidation of an inorganic substance present in the external F– bacterium. medium. (ii) R-Plasmids : They are plasmids which carry genes • Nitrifying bacteria (e.g., Nitrosomonas and Nitrosococcus) for resistance against common antibiotics like are the chemoautotrophic bacteria which obtain energy by chloramphenicol, tetracycline, streptomycin and oxidising ammonia to nitrite. + – sulphonamide. Pathogenic bacteria having R-plasmids NH4 + 2O2 → NO2 + 2H2O + Energy are very difficult to treat. Nitrocystis and Nitrobacter oxidise nitrites to nitrates. (iii) Col-Plasmids : They are also called colicinogenic – 2 NO– + O → 2 NO + Energy factors. They produce toxins called colicins or 2 2 3 e.g Beggiatoa, bacteriocin which are lethal to other enterobacteria. • Sulphur oxidising bacteria ., a colourless Col-plasmid can also get transferred from one bacterium sulphur bacterium, oxidises hydrogen sulphide to sulphur in to another just like F-plasmid or R-plasmid. order to obtain energy for chemosynthesis. Beggiatoa Nutrition in bacteria 2H22 S + O 2S + 2H2 O + Energy Thiobacillus thioxidans, another sulphur bacterium, oxidises • Bacteria show both autotrophic and heterotrophic nutrition. Autotrophic nutrition consists of manufacture sulphur to sulphate state. of organic materials from inorganic raw materials with the 2S + 2H O + 3O Thiobacillus 2H SO + Energy 22 24 help of energy obtained from outside sources. thioxidans • It is of two types, chemosynthesis and photosynthesis.The Saprotrophic bacteria bacteria performing these modes of nutrition are respectively • They are free living bacteria which obtain their food from called chemoautotrophs and photoautotrophs. organic remains, e.g., corpses, animal excreta, fallen leaves, vegetables, fruits, meat, jams, jellies, bread and other • Heterotrophic nutrition involves the obtaining of products of plant and animal origin. readymade organic nutrients from outside sources. It is of further three types —saprotrophic, symbiotic Symbiotic bacteria and parasitic. • These bacteria live in mutually beneficial association with other organisms. Enteric Photoautotrophic bacteria bacterium Escherichia coli, lives as a • The bacteria possess photo- symbiont in human intestine. synthetic pigments of two types, bacteriochlorophyll Parasitic bacteria and bacterioviridin • These bacteria live in contact with (chlorobium chlorophyll). other living beings for obtaining The two types of pigments nourishment or special organic respectively occur in purple compounds required for growth (growth bacteria (e.g., Thiopedia rosea, factors) e.g., Vibrio cholerae.

MTBIOLOGY TODAY | JANUARY ‘16 51 Bacterial respiration • According to the mode of respiration, bacteria can be aerobic or anaerobic. Each of them is further of two types, obligate and facultative. (i) Obligate aerobes – They are bacteria which can respire only aerobically. They generally get killed under anaerobic conditions, e.g., Bacillus subtilis. (ii) Facultative anaerobes – They are bacteria which generally respire aerobically but switch over to anaerobic mode of respiration if oxygen becomes deficient, e.g., halophiles. Fig.: Binary fission in a bacterial cell (iii) Obligate anaerobes – The bacteria of this category respire only anaerobically. They generally get killed under Bacterial growth curve aerobic conditions, e.g., Clostridium botulinum. • Bacteria show four major phases of growth in a fresh (iv) Facultative aerobes – They are bacteria which nutrient rich medium – lag phase, log phase (logarithmic respire anaerobically under normal conditions but can or exponential phase), stationary phase and decline respire aerobically when oxygen is available. Most of phase (death phase). the photosynthetic bacteria (e.g., Rhodopseudomonas) • When a fresh medium is inoculated with a given number belong to this group. of cells, and the population growth is monitored over a Reproduction in bacteria period of time, plotting the data will yield a typical bacterial growth curve. • Three types of reproduction are known in bacteria. These are vegetative reproduction, asexual reproduction and Statio- Log or nary sexual reproduction. exponential phase growth Death or Vegetative reproduction phase decline phase • It is of following types: (i) Budding: It is a rare method of reproduction and is reported in Bigidi bacterium-bifidus. Lag phase (ii) Binary fission: It is the most common type of

reproduction in bacteria during favourable conditions. Log of numbers of bacteria Here bacterial cell divides by a constriction into two 0 5 10 Time (hr) halves. At the same time nuclear material elongates and divides into two equal halves probably helped by mesosomes. Asexual reproduction • Binary fission of bacteria and other prokaryotes does not • It occurs by following means : involve the formation of a spindle. In this regard, it is (i) Endospore formation : During unfavourable similar to amitosis. condition, highly resistant single spore is formed • A new mesosome develops and gets attached to the inside the bacterial cell, which is known as endospore. daughter chromosome. Membrane grows between the Endospore means spore inside bacterial cell or cell inside two mesosomes to push the daughter nuclear bodies or cell. Endospore formation is more common in rod-shaped chromosomes to the opposite side. bacteria or bacillus forms. • The cytoplasm now undergoes a transverse centripetal • Endospore is highly resistant to very high and very low constriction in the middle to form two daughter protoplasts, temperature, strong chemicals and acids, etc., due to each having a nuclear body. calcium, dipicolinic acid and peptidoglycan in cortex. When • Under favourable conditions of binary fission, bacterial cell favourable conditions come, outer layers rupture and active divides into two after every 20 minutes and at this rate in bacterial cell comes out. So it is a method of perennation 24 hours period, a single bacterial cell produces 4 × 1021 (i.e., to tide over unfavourable condition) also and some bacteria, but only about 10% of them survive. people say it “reproduction without multiplication”.

52 MTBIOLOGY TODAY | JANUARY ‘16 Exosporium • This was first studied by Griffith (1928) in Diplococcus Spore coat pneumoniae and hence is known as Griffith effect. Cortex Plasma membrane Later on it was studied in detail by Avery, McCarty and Air McLeod. Core wall (ii) Transduction : In this method, genetic material of Cytoplasm Nuclear body one bacterial cell goes to other bacterial cell by agency (Nucleoid) of bacteriophages or phages (viruses, infecting Fig.: Structure of an endospore bacteria). (ii) Conidia formation : Rarely in some filamentous forms • Transduction was first of all reported in Salmonella of bacteria (Streptomyces), conidia are formed. typhimurium by Zinder and Lederberg (1952). (iii) Zoospores: Motile spores are formed in Rhizobium • The process also occurs in E.coli and a number of other bacteria, but are rare in other bacteria. hosts. A virus may pick up gene of the host in place of its own gene during its multiplication in the host cell. Such a Sexual reproduction virus is never virulent. It passes over the gene of the previous • True sexual reproduction is absent in bacteria, but there host to the new host. Transducing viruses may carry the occurs genetic recombination, i.e., bringing together same genes (restricted transduction) or different genes of genetic material of two bacterial cells. There are 3 main (generalised transduction) at different times. methods of genetic recombination: (iii) Conjugation: Here cell to cell union occurs between – Transformation two bacterial cells and genetic material (DNA) of one – Transduction bacterial cell goes to another cell lengthwise through – Conjugation conjugation tube which is formed by sex pili. (i) Transformation: Here genetic material of one bacterial • Conjugation was first reported by Lederberg and Tatum cell goes into another bacterial cell by some unknown (1946) in E. coli bacteria. mechanism and it converts one type of bacterium into another type (Non-capsulated to capsulated form).

Pilus

MTBIOLOGY TODAY | JANUARY ‘16 53 and pickles caused by saprotrophic bacteria.

Saprotrophic bacteria act as nature’s scavengers.

Used for the formation of manure and gobar gas.

• Conjugation occurs between donor cell and recipient • Cyanobacteria do not have a fully functional Krebs’ cycle cell. Donor cell is having sex pili and F-factor whereas or citric acid cycle as they lack enzyme a-ketoglutarate recipient cell is lacking both. dehydrogenase. Pentose phosphate pathway (PPP) plays • In donor cell, F-factor may unite with main genome or nuclear a central role in their carbohydrate metabolism. DNA and this donor cell is called Hfr-donor cell (High • Most of the cyanobacteria are obligate photolitho- Frequency donor cell) and here transfer of DNA is rapid. autotrophs but some can grow slowly in dark as chemoheterotrophs by oxidising glucose and other sugars. cyaNoBacteRia They show considerable metabolic flexibility. • Although cyanobacteria are true prokaryotes, but • G + C content of this group ranges from 35 to 71%. their photosynthetic system closely resembles with that of eukaryotes because they have chlorophyll a and photosystem II and they carry out oxygenic photosynthesis. Like the red algae, cyanobacteria use phycobiliproteins as accessory pigments. Photosynthetic pigments and electron transport chain components are located in thylakoid membranes lined with particles called Diving bell spiders, found in Northern and Central Europe phycobilisomes, which contain phycobilin pigments, and Northern Asia, are the only spiders able to spend entire particularly phycocyanin and transfer energy to life underwater. They do this by spinning a ‘bell’ of air using photosystem II. silk and catching oxygen with her leg hairs. The silk bell • CO2 is fixed through C-3 cycle or Calvin cycle and the allows oxygen to diffuse in and CO2 to diffuse out just as reserve carbohydrate is glycogen. Sometimes they store gills do. As a result, this spider has to make only one trip out extra nitrogen as polymers of arginine or aspartic acid in of the water per day. cyanophycin granules.

54 MTBIOLOGY TODAY | JANUARY ‘16 • Cyanobacteria vary greatly in their shape and appearance. • Cyanobacteria are highly tolerant of environmental extremes They range about 1-10mm in diameter and may be unicellular, and are present in almost all aquatic and terrestrial exist as colonies of many shapes, or form filaments called environments. Thermophilic species may grow at temperatures trichomes. upto 75°C in alkaline hot springs. Some unicellular forms • Cyanobacteria have typical prokaryotic cell structures and a grow in fissures of desert rocks. In eutrophic warm ponds and normal Gram-negative type cell wall. lakes, surface cyanobacteria like Anabaena and Anacystis • They often use gas vesicles to move vertically in water and can reproduce rapidly to form blooms. The death of bloom many filamentous species have gliding motility. microorganisms releases organic matter, which stimulates • Cyanobacteria lack flagella but marine genus the growth of chemoheterotrophic bacteria which deplete Synechococcus are able to move at the rate of 25mm/ the available oxygen and this kills fish and other organisms. second by some unknown mechanism. • Oscillatoria, a cyanobacterium is highly pollution resistant and grows in fresh water with high organic matter, acts as indicator of water pollution. • Cyanobacteria successfully develop symbiotic relations /Chromatophore with other organisms. These are photosynthetic partners in many lichens. Further, these are symbionts with protozoa, liverworts, mosses, gymnosperms and angiosperms. • Nostoc is a colonial cyanobacterium that is popularly called moonspit, fallen star or star jelly. It also forms symbiotic association with Anthoceros, cycad roots, Gunnera stems and Trifolium roots. • The cyanobacterium Spirulina is cultivated for human consumption and has a dry weight protein content of about 70%. This is common in saline lakes and is sold as a • Cyanobacteria reproduce by binary fission, budding, nutritional food supplement in most health food stores fragmentation and multiple fission. Fragmentation of in USA. filamentous cyanobacteria can generate small, motile filaments Heterocyst called hormogonia. Some species develop akinetes. • Many filamentous or trichome-forming cyanobacteria fix • It is a large-sized pale coloured thick-walled cell which atmospheric nitrogen by means of special thick-walled occurs in terminal, intercalary or lateral position in cells called heterocysts. About 5–10% cells of a trichome filamentous cyanobacteria, e.g., Nostoc. The thick wall develop into heterocysts, which obtain nutrients from is impermeable to oxygen but permeable to nitrogen. adjacent vegetative cells and contribute fixed nitrogen in Mucilage sheath is absent. Photosystem II is absent. the form of amino acid glutamine. Thylakoids lack phycobilisomes. Therefore, photosynthesis is • There are five orders of cyanobacteria—Chroococcales absent but cyclic photophosphorylation occurs. Heterocyst (Chamaesiphon, Gleocapsa, Synechococcus); Pleuro- is dependent for its nourishment on adjacent vegetative capsales (Pleurocapsa, Dermocarpa); Oscillatoriales cells. It has enzyme nitrogenase. Heterocyst is specialised (Lyngbya, Spirulina, Oscillatoria); Nostocales (Anabaena, to perform nitrogen fixation. Nostoc, Cylindrospermum, Scytonema); Stigonematales (Stigonema, Fischerella). RicKettSiae • Rickettsiae are Gram negative obligate pleomorphic but intracellular parasites which are resident of or are transmissable by arthropods. • They are intermediate between true bacteria and viruses. • Rickettsiae require exogenous factors for growth. • Cell wall is like typical bacterial wall. ATP synthesis is absent, but ADP is exchanged with host cell ATP. • They have size 0.3-0.5 mm which is smaller than true bacteria but have a long generation time.

MTBIOLOGY TODAY | JANUARY ‘16 55 • Flagella, pili and capsule are absent. • Borrel et al (1910) gave them the name Asterococcus. Later, • Reproduction occurs by binary fission. Nowak (1929) placed them in the genus Mycoplasma. • The natural habitat of rickettsiae is in the cells of arthropod • Mycoplasma are now known to infect a large number of gut. animals (e.g., dog, sheep, mice and even man) and plants • They often become pathogenic in mammals and humans (e.g., potato, corn, brinjal, etc). where they cause typhus group of fever spread by droplet • In nature they occur in soil, sewage water and in plant method, lice, ticks, fleas, etc.,e.g ., Coxiella burnetti (Q fever), and animal bodies. Besides, they have also been found Rickettsia rickettsiae (Rocky mountain spotted fever spread in hot water springs. In the laboratory, they are common by ticks), R. typhi (Endemic typhus), R. prowazeckii (epidemic contaminants of cultures rich in organic matter. typhus), Rochalimaea quintana (Trench fever). • As mycoplasma have no cell wall, hence have no definite shape, i.e., pleomorphic and thus are called jokers of actiNoMyceteS microbiology. • Actinomycetes are mycelial (aseptate branched filaments) Structure of mycoplasma bacteria which form radiating colonies in culture. Because • The structure of mycoplasma varies from species to species, of this, actinomycetes were formerly called ray fungi. e.g., in Mycoplasma mycoides, filamentous form and in • Mycelial form is reduced in Mycobacterium and Coryne- Mycoplasma pneumoniae, coccus (rounded) form occurs. bacterium. Mycelia have a diameter of 1mm or less. Wall On outer side, there is tripartite (3-layered) cell membrane, contains mycolic acid (fatty acid), lipid and wax. made of lipoproteins as usual. • Different modes of reproduction occur by conidia, • In stationary phase, mesosomes are also present on plasma sporangiospores and arthrospores or oidia and membrane or cell membrane. Inner to cell membrane, matrix fragmentation. is present, which is mainly having double stranded, long, • Most of the actinomycetes are saprotrophic and circular DNA, single stranded RNA (in both ribosomes and constitute an important component of decomposers, cytoplasm), ribosomes of 70 S type and many metabolites e.g., Actinomyces, Streptomyces. A few are pathogenic like proteins (enzymes) and fatty substances. There is 4% in plants, animals and humans, e.g., Mycobacterium. In DNA and 8% RNA. pathogenic actinomycetes or Mycobacterium a derivative Replicating disc of mycolic acid called mycoside/cord factor is involved in Plasma membrane causing disease. Ribosomes • A number of antibiotics are produced by actinomycetes, especially the genus Streptomyces (streptomycin, DNA chloramphenicol, tetracyclines, terramycin, erythromycin, RNA viomycin, novobiocin, nystatin). Protein particle • Frankia produces root nodules in some non-legumes (e.g., Alnus) and takes part in nitrogen fixation. Enzymes

MycoPLaSMa Granules • Mycoplasmas or mollicutes are the smallest known Fig.: Ultrastructure of PPLO prokaryotic organisms, characterised by the absence of cell wall. Reproduction in mycoplasma • These organisms were discovered in • Reproduction in mycoplasma occurs by 1898 by Nocard and Roux in the – Budding. pleural fluid of cattles suffering – Fragmentation : Specially in from pleuropneumonia and filamentous forms. were, therefore, called – Binary fission: Most common pleuropneumonia like method of reproduction in organisms (PPLO). mycoplasma is binary fission. • They also demonstrated that • Bleb and infra bleb if healthy cattles were injected are peculiar structures which are with these microorganisms, the formed at both ends during binary symptoms of disease appear. fission in mycoplasma and as soon as

56 MTBIOLOGY TODAY | JANUARY ‘16 binary fission is complete, these structures disappear, so the as leafhoppers, mites and flies. Some of the commonly known significance of bleb and infra bleb is not known. plant diseases are aster yellows, potato witche’s broom, Diseases caused by mycoplasma mulberry dwarf, maize stunt, rice yellow dwarf, bunchy top of papaya, little leaf of brinjal, clover phyllody, etc. • Many plant diseases caused by mycoplasma were earlier Animal diseases like rheumatism, arthritis, several considered to be viral diseases. The symptoms of diseases • respiratory disorders and primary atypical pneumonia (PAP) caused by viruses and mycoplasma are similar and it is are caused by mycoplasma. M. hominis and M. fermentans, difficult to distinguish between them. Diseases caused by cause infertility in human males. mycoplasma are generally transmitted through insects such

4. Why were cyanobacteria initially classified under Kingdom Plantae finally placed into Kingdom Monera? 5. Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis? 6. What is the function of bacterial endospores?

1. Which of the following is free living N2 fixing bacteria? 6. The main difference in Gram +ve and Gram –ve bacteria (a) Rhizobium (b) Streptomyces resides in their (c) Nitrobacter (d) Azotobacter (a) cell wall (b) cell membrane 2. Read the given statements and select the correct option. (c) cytoplasm (d) flagella. Statement 1 : Peptidoglycan polysaccharides are one of 7. The bacterium (Clostridium botulinum) that causes botulism the unique components of the bacterial cell wall. is Statement 2 : The cell wall of Gram –ve bacterium (a) an obligate aerobe (b) a facultative anaerobe contains teichoic acid. (c) an obligate anaerobe (d) a facultative aerobe. (a) Both statements 1 and 2 are true and statement 2 is 8. Peptidoglycan is a characteristic constituent of the cell wall the correct explanation of statement 1. of (b) Both statements 1 and 2 are true but statement 2 is (a) bacteria and unicellular eukaryote not the correct explanation of statement 1. (b) bacteria and cyanobacteria (c) Statement 1 is true and statement 2 is false. (c) archaebacteria and eukaryote (d) Both statements 1 and 2 are false. (d) all members of monera and protists. 3. Which organelle is called `Chondrioid’ in bacteria? 9. Monerans do not include (a) Mitochondria (b) Chromatophores (a) bacteria (b) cyanobacteria (c) Pili (d) Mesosomes (c) archaebacteria (d) slime moulds. 4. When a group of flagella is present at one end only, bacteria are called 10. Bacterial conjugation was first shown by (a) amphitrichous (b) lophotrichous (a) Robert Hooke (b) Lederberg and Tatum (c) peritrichous (d) none of these (c) Dickson and Jolly (d) Skoog. 5. Which type of the bacteria are immunologically virulent? 11. Teichoic acid is found in the cell wall of (a) R-type (b) S-type (a) Gram +ve bacteria (b) Gram –ve bacteria (c) Both R and S-type (d) None of these (c) cyanobacteria (d) mycoplasma.

MTBIOLOGY TODAY | JANUARY ‘16 57 12. Mesosome in a bacterial cell is (a) (ii) and (iii) (b) (i),(ii) and (iii) (a) plasmid (c) (ii), (iii) and (iv) (d) (i), (ii) and (iv) (b) connection between two cells 23. What is a plasmid? (c) plasma membrane infolded for respiration (a) Bacterial linear dsDNA (d) none of the above (b) Extrachromosomal linear RNA 13. The characteristic cell wall material peptidoglycan has (c) Extrachromosomal circular dsDNA another covering of lipopolysaccharides. This specialised (d) Autonomously replicating circular RNA condition is found in 24. Read the given statements and select the correct option. (a) Gram +ve eubacteria (b) Gram-ve eubacteria Statement 1 : Endospores in bacteria are formed during (c) all eukaryotes (d) all fungi. unfavourable conditions. Statement 2 : Endospores are highly resistant to adverse 14. In the cell wall of Gram –ve bacteria (a) both horizontal and vertical peptide linkages are environmental conditions like extreme temperatures, strong present acids, etc. (b) only horizontal peptide linkages are present (a) Both statements 1 and 2 are true and statement 2 is (c) only vertical peptide linkages are present the correct explanation of statement 1. (d) either horizontal or vertical peptide linkages are present. (b) Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1. 15. Nitrosomonas converts (c) Statement 1 is true and statement 2 is false. (a) NH3 → Nitrite (b) N2 → NH3 (d) Both statements 1 and 2 are false. (c) Nitrite → Nitrate (d) NH3 → N2. 25. Which one of the following is not the characteristic feature 16. Respiratory enzymes in bacteria are present in of cyanobacteria? (a) mitochondria (b) Golgi complex (a) They are always multicellular. (c) mesosome (d) endoplasmic reticulum. (b) They may form colonies. 17. In bacteria, the site for respiration is (c) They form blooms in polluted water bodies. (a) episome (b) mesosome (d) They can fix atmospheric nitrogen. (c) cytoplasm (d) plasmid. 26. Which one of the following organisms is not an eukaryote? 18. Bacterial flagella are mainly made up of (a) Paramecium caudatum (b) Escherichia coli (a) protein (b) amines (c) Euglena viridis (d) Amoeba proteus (c) lipids (d) carbohydrates. 27. In eubacteria, a cellular component that resembles eukaryotic 19. Cyanobacteria are cell is (a) cyanophycean members which infect bacteria (a) plasma membrane (b) nucleus (c) ribosomes (d) cell wall. (b) virus which infect blue green algae (c) autotrophic prokaryotes with characteristic blue 28. Cell in some filamentous cyanobacteria which is specialised green pigments for nitrogen fixation is called (d) bacteria which infect cyanophycean algae. (a) heterocyst (b) mesosome (c) volutin (d) phycobilisome. 20. Monerans that are devoid of cell wall are 29. Spherical bacteria called (i) are found in pairs called (ii) , or (a) actinomycetes (b) cyanobacteria long chain-like clusters called (iii) , or grapelike aggregates (c) mycoplasma (d) eubacteria. called (iv) . 21. Some hyperthermophilic organisms that grow in highly acidic Select the correct option for (i), (ii), (iii) and (iv). habitats belong to the two groups (a) bacilli diplobacilli streptobacilli staphylobacilli (a) eubacteria and archaea (b) sprillia sarcina tetracoccus diplococcus (b) cyanobacteria and diatoms (c) cocci streptococci diplococci staphylococci (c) protists and mosses (d) cocci diplococci streptococci staphylococci (d) liverworts and yeasts. 30. Causal organisms of tuberculosis and leprosy belong to 22. Select the correct combination of the statements (i-iv) (a) mycoplasma (b) cyanobacteria regarding the characteristics of certain organisms. (c) actinomycetes (d) archaebacteria. (i) Methanogens are archaebacteria which produce ANSWER KEY methane in marshy areas. (ii) Nostoc is a filamentous blue-green alga which fixes 1. (d) 2. (c) 3. (d) 4. (b) 5. (b) atmospheric nitrogen. 6. (a) 7. (c) 8. (b) 9. (d) 10. (b) 11. (a) 12. (c) 13. (b) 14. (d) 15. (a) (iii) Chemosynthetic autotrophic bacteria synthesise 16. (c) 17. (b) 18. (a) 19. (c) 20. (c) cellulose from glucose. 21. (a) 22. (d) 23. (c) 24. (a) 25. (a) (iv) Mycoplasma lack a cell wall and can survive without 26. (b) 27. (a) 28. (a) 29. (d) 30. (c) oxygen. 

58 MTBIOLOGY TODAY | JANUARY ‘16 Class XI Animal Kingdom-IX class reptilia • Reptiles represent the first class of vertebrates fully adapted to live in dry places on land. 3 6 8 9 1 2 • The characters of reptiles are in fact a combination of characters that are found in 2015 fish and amphibians on one hand and in birds and mammals on the other. • The class name Reptilia refers to the mode of locomotion (L., repere or reptum, to creep or crawl), and the study of reptiles is called Herpetology (Gr., herpeton, 4 1 1 4 1 1

reptiles). 2014 • Reptiles are abundant in the tropical regions. Very few are found in the colder parts of the temperate region and none in the Arctic and Antarctic regions. General characters 8 3 4 – 2 –

• Predominantly terrestrial, creeping or burrowing, mostly carnivorous, air- 2013 breathing, cold-blooded, oviparous and tetrapodal vertebrates. • Body bilaterally symmetrical and divisible into 4 regions-head, neck, trunk and tail. • Limbs are of two pairs and pentadactyl. Digits bear horny claws. However, limbs 3 2 5 5 – 4

are absent in few lizards and all snakes. 2012 • Exoskeleton comprises of horny epidermal scales, shields, plates and scutes. • Skin is dry, cornified and devoid of glands. • Mouth terminal. Jaws bear simple conical teeth. In turtles teeth are replaced 2011-2015 from PMTs various of Analysis 4 – 2 4 4 by horny beaks. 6 2011 • Alimentary canal terminates into a cloacal aperture. • Endoskeleton bony. Skull with one occipital condyle (monocondylic). A characteristic T-shaped interclavicle present. • Heart usually three-chambered with a partly divided ventricle, four-chambered in crocodiles. Sinus venosus reduced. Two systemic arches present. Red blood AIPMT/NEET AIIMS AMU Kerala K.CET corpuscles oval and nucleated. J & K

MTBIOLOGY TODAY | JANUARY ‘16 59 • Respiration by lungs throughout life. from some primitive labyrinthodont Amphibia, in the • Kidneys metanephric. Crocodiles are ammonotelic. beginning of Carboniferous period. Turtles are ureotelic. Lizards and snakes are uricotelic. • The labyrinthodonts possessed characteristically folded or • Brain with better development of cerebrum than in Amphibia. labyrinthine teeth. Twelve pairs of cranial nerves. • They flourished through Carboniferous and Permian • Lateral line system absent. Jacobson’s organ present in the periods before extinction in the Triassic. roof of buccal cavity. • The earliest reptiles are called as stem reptiles. They belong • Most reptiles are carnivorous or insectivorous. Most to order Cotylosauria of the subclass Anapsida. tortoises are herbivorous. • These primitive or generalised reptiles had two common • Sexes separate. Male usually with a muscular copulatory characteristics; the complete roofing of skull (anapsid organ. Fertilisation internal. Mostly oviparous. Large yolky condition), and the flattened plate-like pelvic girdle. meroblastic eggs covered with leathery shells, always laid • From this generalised condition in the succeeding periods, on land. arose several lines of radiation or specialisations, some • Embryonic membranes (amnion, chorion, yolk sac and leading to the great array of reptiles, both extinct as well as allantois) appear during development. No metamorphosis. living, and others to birds and mammals. Young ones resemble adults. classification • Parental care usually absent. • The Class Reptilia is divided into five subclasses on the Origin of reptiles basis of presence or absence of certain openings through • It is generally agreed that primitive reptiles originated the posterolateral or temporal region of the skull.

 One temporal fossa is present. Fish or porpoise like  Extinct.  Mammal-like  Turtle like

(dorsal) (ventral)

Heart three chambered.

Small to medium, elongated Large-sized, tail laterally compressed Fixed quadrate Immovable quadrate

Heart is three chambered. Heart is three chambered. tuatara Male with an erectile, grooved penis O

60 MTBIOLOGY TODAY | JANUARY ‘16 Dinosaurs (ancient reptiles) • Tyrannosaurus is an example of gigantic carnivorous • The word ‘dinosaur’ is a blend of the Greek terms ‘deinos’ dinosaur. It was about 15 m long and stood 6 m high. (meaning terrible) and ‘saurus’ (meaning lizard). Richard • Many Saurischia changed to a plant diet and became Owen coined the term dinosaur. four legged forms. Brontosaurus, the largest of them • The dinosaurs were divided into two main types; one with a weighed approximately 50 tons. bird like pelvis and the other with reptilian pelvis. • The dinosaurs of Ornithischia group were herbivorous. • They were subdivided into two orders : Saurischia (reptile- Although, some of them walked upright, the majority were like dinosaurs) and Ornithischia (bird-like dinosaurs). four-legged. • Having lost their front teeth, they developed a stout, horny, • The early dinosaurs of Saurischia group were fast, bird-like beak. Iguanodon is an important example of this carnivorous, two legged forms. group. Table : Important examples of Reptiles Scientific name Common name Important notes Cotylosauria Seymouria – • Found in the lower Permian of Texas (Extinct). • Lizard-like, 60 cm long. • Thick body, pointed head, dorsally placed nostrils and a short tail. • Structure intermediate between amphibians and early reptiles. Chelonia Testudo Tortoise • Terrestrial form. • Large in size, ovoid carapace. • Head can be completely withdrawn into the shell. • Herbivorous. Chelone Turtle • Marine form. • Heart shaped carapace. • Fore and hind limbs are modified into paddles. • Some turtles are flesh eaters. Trionyx Soft shelled turtle • Smooth leathery shells without shields. • Snout forms short proboscis. • Clawed and webbed digits. Chrysemys picta Painted terrapin • Colourful. • Feeds on insects. Rhynchocephalia Sphenodon Tuatara • Living fossil, have primitive characters. punctatum • Median pineal or parietal or third eye. Widely roofed mouth. Three temporal bridges in skull. Absence of copulatory organs in male. Insectivorous, nocturnal reptile with vertical pupil. Colour is dull olive green with yellow spots above and white below. Upper surface covered with granular scales and bears mid-dorsal frill of spines. Lacertilia (Lizards) Hemidactylus House wall lizard, • It has power of autotomy and regeneration. Geckos • Digits have adhesive pads that adhere by vacuum. • Eyes lack movable lids and tongue is sticky and protrusible. • Some geckos are vocal, making clicking and peeping sounds. Draco Flying dragon or • Small brilliantly coloured lizard with a very long tail and well developed limbs. flying lizard • It has membranous parachute like fold of skin, (patagia), supported by ribs. These are used for gliding.

MTBIOLOGY TODAY | JANUARY ‘16 61 Phrynosoma Horned toad or • It has 2 enlarged horns on head and grotesque spines on body. Desert lizard • It shows desert adaptations. • It feeds on ants. Chameleon Chameleon • It can change colour in order to blend with the surroundings (camouflage). • Insectivorous, can catch insect about 20cm away by eversible tongue. • Long and prehensile tail. Heloderma Gila monster • Poisonous, venom glands and ‘fangs’ are in lower jaw. • Found in USA and Mexico. • Commonly called beaded lizard because resemblance of scales with beads. Varanus Monitor lizard, • Tongue long and protrusible. (Goh) • The largest living lizard in the world is the Komodo dragon, Varanus komodoensis. May reach a length of 3m and weigh 250 kg. Calotes Garden lizard, • Arboreal. (Girgit) • When excited, head and neck turn red and trunk becomes pale yellow. Uromastix Spiny-tailed lizard • Oil is extracted from its fat bodies. (Sanda) • Oil is used for treatment of muscular pain. Ophidia (Snakes) Poisonous Naja naja Cobra • Poisonous. • Can be recognised by presence of hood that bears spectacle mark. • Its venom is neurotoxic, attacks nerve centres and causes paralysis of respiratory muscles. • Shows cannibalism, oviparous. • Naja bungarus , the king Cobra is the only snake in the world that builds a nest. It guards the nests. Bungarus Krait • Venom is neurotoxic. Quantity of poison injected is three times more than cobra. Paralysis of trunk and limbs occur. • Its body has alternate broad black and yellow rings. • Nocturnal and true cannibals. Vipera Viper • Viviparous. • Head is triangular, flat and covered with scales. • Large plates on ventral surface. • Venom is haemotoxic. Hydrophis Sea snake • Viviparous. • Head is small and shielded, tail is laterally compressed. • Venom is neurotoxic. Crotalus Rattle snake • Viviparous. • Has rattle on tail. Non-poisonous Python Ajgar • Oviparous. • Huge and massive in size. • Lives on trees in forests. • Tail is short and prehensile. • Diamond shaped brown and green spots on body. Kills the prey by coiling around and crushing and swallowing its prey.

62 MTBIOLOGY TODAY | JANUARY ‘16 Typhlops Blind snake • Small burrowing snake, looks like earthworm. • Tail is blunt. • Eyes are vestigial. Harmless and feeds on insect larvae and termites. Ptyas Rat snake, • Colour is olive above, whitish below. (Dhaman) • Eyes are large. • Tail forms more than one-third of body. • Feeds on mammals, birds and frogs. Dendrophis Tree snake • Body elongated, slender and compressed. • Head depressed, vertebral scales enlarged. • It is diurnal and feeds on lizards and frogs. Eryx Sand boa (double • Tail is small, non prehensile, thick, gives false resemblance of head, hence the name headed snake) double headed snake. • Feeds on rat, mice etc. Crocodilia Crocodylus Indian fresh water • Found in Asia, Central America, Africa, Malaya, Indonesia and North Australia. palustris crocodile • Snout moderately long and pointed. • Body length around 8 metres. • Colour olive green with black spots or bands. • Aggressive, dangerous to man. Alligator American alligator • Found in North America and China. mississipiensis • Less aggressive. • Snout short, broad and rounded. • Body length around 3 metres. • Colour steel grey. Gavialis Gharial • Found in India, Myanmar, Pakistan and Nepal. gangeticus • Eats only fish because of narrow throat. • Snout very long and slender. • Body length around 6 metres. • Colour dark olive green.

Economic importance of reptiles Reasons for success of reptiles on land As food • Four factors have made reptiles true land animals • Of all reptiles, turtles are most heavily exploited for human independent of moist environment : consumption. − Horny scales which check loss of water. • Crocodiles, snakes and lizards are locally important food − Internal fertilisation as gametes cannot survive on sources. land. For pest control − Shell around the egg to check desiccation. • Reptiles eat insects and rodents that are pests of crops. − Fluid-filled amnion around the embryo to provide • Reptiles are also economically important for medicinal aquatic environment for its development on land. products, leather goods and pet trade.

MTBIOLOGY TODAY | JANUARY ‘16 63 some important facts • Mesozoic era is known as the golden age of reptiles. • Snake has both an exoskeleton as well as an endoskeleton. • Foramen of Panizzae is an aperture in the heart of lizards and crocodiles. It is located at the point where right and left aorta cross each other and are in contact. • Study of lizards is known as saurology. • Cloacal respiration occurs in turtles. • Hemidactylus shows autotomy by breaking off its tail when threatened. • Chameleon is ovoviviparous lizard. • Heloderma suspectum is the only poisonous lizard of the world. • Study of snakes is called ophiology or serpentology. • Hoffkin’s Institute, Mumbai is well known for the production of anti-venom injections.

1. Reptiles represents the first group of vertebrates fully adapted to live on land. Discuss some features that eventually lead to success of reptiles on land. 2. Give a small note on origin of reptiles. 3. Give some examples of poisonous and non-poisonous snakes.

ClAss AvEs • Body is covered by feathers. • The Class Aves include birds. The birds are unique in having a • Skin is dry and without glands except for the presence of coat of feathers and in resting on the hindlimbs alone. an oil or preen gland or uropygeal gland at the base of • Birds exhibit great variety of colours and behaviours such as short tail or uropygium. The secretion of this gland is used courtship, nest building, parental care and migration. for dressing the feathers. • Oil gland is absent in flightless birds, parrots, pigeons, • Birds are often described as “glorified reptiles” because of doves and woodpeckers. their resemblance with the reptiles. • Sweat glands are absent. General characters • The endoskeleton is ossified, but light and strong. Many bones • The body is spindle-shaped and streamlined. It is are fused to acquire strength. Endoskeleton is represented by divisible into head, neck, trunk and tail. (i) feathers (ii) scales on legs, similar to those of reptiles, (iii) • Head is small and rounded. Neck is long, vertical and flexible. claws on the toes (iv) sheaths on beaks. Trunk is compact. Tail is short. • The feathers are highly modified reptilian scales. They • The upper and lower jaws are prolonged and covered with conserve body heat, help in flight and provide colouration horny sheath modified into beak, which lacks teeth. to the bird. • Beaks are adapted to many ways of feeding; seed-crushing, • Skull is monocondylic, i.e., has a single occipital condyle. fruit-scooping, flesh-tearing, nectar-sipping, wood-chiselling The last 3 or 4 fused tail vertebrae form a structure called and so on. pygostyle. • There are two pairs of limbs. The forelimbs are modified • The forked bone furcula formed by the fusion of two clavicles into wings for flight. The wings are supplied energy by and single interclavicle is called wish bone. Synsacrum is powerful flight, or breast muscles attached to a large formed by the fusion of posterior thoracic, lumbar, sacral and sternum, or breast bone. anterior caudal vertebrae. • Sternum is large with a mid-ventral keel for attachment of • Alimentary canal contains crop (modified oesophagus) flight muscles. for storing and softening of food and gizzard (grinding part • The hindlimbs or legs are large and variously adapted for of stomach, the other glandular part being proventriculus) perching, walking, hopping, wading or swimming. for crushing it.

64 MTBIOLOGY TODAY | JANUARY ‘16 • Cloacal aperture is present. • The voice is produced by the vibrations of the tympaniform • Gall bladder is absent in some seed-eating birds membranes of syrinx as the air is forcibly expelled from the (graminivorous) such as pigeons. lungs during expiration. • Respiration takes place only by lungs. The latter are spongy Bird milk and inelastic and are associated with thin-walled air sacs. • Like mammals, the young ones of some birds are fed on • Most of the birds have 9 major air sacs. They are special secretions from parents. named according to their location in the body such as • Unlike mammals, however, both sexes produce it. The interclavicular, cervical, anterior thoracic, posterior best known of these secretions is the “crop milk” that thoracic and abdominal. Air sacs are paired in origin but pigeons feed to squabs. the two interclavicular air sacs fuse early in development. Larynx Glottis • The milk is produced by a sloughing of fluid-filled cells from the lining of the crop, a thin-walled, sac-like food- Syrinx Trachea storage chamber that projects outward from the bottom Bronchus Cervical air sac Clavicular air sac of the oesophagus. Inter-clavicular Extraclavicular air sac • Crops are presumably a device for permitting birds to air sac Humeral air sac gather and store food rapidly, minimizing the time that in cavity of they are exposed to predators. humerus • Crops tend to be especially well developed in pigeons and Anterior thoracic game birds. air sac Bronchus • Crop milk is extremely nutritious. Posterior thoracic • The pigeon milk which contains more protein and fat Right lung air sac than does cow or human milk, is the exclusive food of the Abdominal Left lung nestlings for several days after hatching, and both adults air sac feed it to the squabs for more than two weeks. Fig.: Respiratory system of a bird • The heart is relatively large and fast beating for quick • The arrangement and presence of air sacs brings several supply of adequate amount of blood during flight. It is advantages in respiration : 4-chambered, having two auricles and two ventricles. − At each breath lungs of birds are completely emptied. There is neither sinus venosus nor truncus arteriosus. Only Residual air restricted to air sacs only. right aortic arch (systemic) persists in adults. − Air of lungs is renewed twice at each breath. During • Renal portal system is greatly reduced. inspiration much of air reaches directly into the air sacs through the secondary bronchi then back to the lungs • Red blood corpuscles are oval, biconvex and nucleated. through separate ducts and the recurrent bronchi. • The brain is large with well developed optic lobes and cerebellum and reduced olfactory bulbs. There are 12 pairs of cranial nerves. • The olfactory sacs open by internal nares into the buccal cavity. Sense of smell is usually poor. • Eyes possess a comb-like structure or pecten. It is present in all birds except Kiwi. Pecten is well developed in diurnal birds than nocturnal. It helps in accommodation and nutrition of eye ball. It may cast a shadow on retina and thus helps in the perception of movements. It also regulates the fluid pressure in the eye. Birds have keen eyesight. • Each ear consists of three parts : external, middle and internal. Pinnae are absent. • Kidneys are metanephric and 3-lobed. Ureters open into cloaca. Excretory matter is chieflyuric acid (uricotelism). Urinary bladder is absent. • Well marked sexual dimorphism is present. Testes • Voice box lies at the junction of the trachea and bronchi. It are paired. Female has a single functional left ovary and is called syrinx (characteristic feature). The larynx (without oviduct. cords) does not act as a sound box.

MTBIOLOGY TODAY | JANUARY ‘16 65 • Fertilisation is internal. Males generally lack copulatory keep themselves warm. Therefore, they must feed more often organs. Copulation occurs by cloacal apposition. than most reptiles. • All birds are oviparous. Eggs are large with much yolk • The birds show advancement over the reptiles in having: (marcolecithal) and hard, calcareous shell, and need regulated body temperature; light insulating coat of feathers; incubation at a constant body temperature by the parents. aeration of blood in the lungs during both inspiration and expiration; complete separation of oxygenated and • Ninety-five percent of bird species are socially deoxygenated blood in the heart; highly developed brain; monogamous. more efficient eyes and ears; and active life due to high rate • Development is direct. Embryonic membranes (amnion, of metabolism. chorion, allantois, yolk sac) are formed as in reptiles. Classification • Bursa fabricii is a lymphoid tissue attached to cloaca • Birds show less diversification than any other group of of some young birds which takes part in formation of vertebrate animals. About 9,000 living species of birds are lymphocytes and probably it produces antibodies and known at present. protects against local infection but it atrophies in the adult • The Class Aves is divided into two subclasses: before sexual maturity. It is also called cloacal thymus. Archaeornithes and Neornithes. It is given in details in • The birds are homoiotherms, and spend a lot of energy to the following flow chart.

. J J -

– , green parrot (,Psittacula krameriPpeafowl ( avo cristatus), cuckoo () Cuculus canorus ,Swan ()Cygnus , White breasted kingfisher (Halcyon smyrnensis), hoopoe () Upupa epops ,Pelicans ()Pelecanus , Sand piper ()Tr inga glariola , gull present. ()Larus, flamingo () Phonicopterus , saruus crane ()Antegone antegone , common pariah kite (Milvus migrans), king vulture ()Sarcogyps calvus , peregrine falcon ()Falco peregrinus , eagle ()Aquila , Indian swift ()Micropodus .

, female has clitoris

Giant elephant bird

66 MTBIOLOGY TODAY | JANUARY ‘16 Feathers Barbs

• Feathers of bird are light, strong, elastic, waterproof and Rachis show many colours due to presence of pigments. Rachis (Shaft) Vane • Feathery exoskeleton is characteristic of bird. Calamus • Feathers are variously modified to serve different functions : − Due to light weight, impervious, flexible, durable and Barbules waterproof body covering, it protects the underlying

tender skin from all kinds of mechanical, chemical, Calamus Calamus pathological and environmental injuries. Umbilicus − The feathers serve the most important function of retention of heat. Fig.:A. Contour feather;B. Down feather or plumule; − The feathers hold a considerable blanket of enveloping C. Structure of a typical flight feather (Remex) air around the body and add much to its buoyancy. Down feathers or plumules − Feathers provide many secondary sexual characters to • It is without shaft and bear fluffy tuft of barbules. both sexes of most birds which help in recognition of • In young one, down feathers, cover the body and are called sexes and sexual selection. as nestling down feathers. − They are also used as natal covering in those birds that • Other types are Tactile feathers/vibrissae at the root of are born in an advanced state of development and as beak (in owl and nocturnal birds), ornamental plumes of dense undercoat in many aquatic birds. many birds, bristles around the base of bill (rachis) of fly − They are also used in the formation of nest. catchers, goat suckers etc, and powder down feathers which occur in many birds usually aggregated into patches, Types of feather such as paired pectoral and pelvic yellowish patches on the • Feathers are characteristic feature of birds since no other skin of herons and sometimes in scattered tracts and tufts group of animal kingdom has ever developed them. Various as in parrots, etc. types of feathers are: • The arrangement or distribution of feathers on the body is Quill (flight) feather called pterylosis. • In majority of birds, except penguins, the feathers are not • Quill feathers have a strong shaft (or rachis) and barbules uniformly distributed over the whole body but are arranged with an interlocking arrangement. They are further classified in distinct patches or tracts called pterylae. into following types: • The pterylae are followed by featherless areas or apteria. − Remiges are the wing-quills used for flight. − Rectrices are tail-quills that act as a brake and help in Aerial or flight adaptations in birds steering the flight. • The following modifications are present in birds that help − Covert cover the base of wing-quills. They are smaller in them fly :- size and oppose the buoyancy of the air. − The spindle-shaped body of a bird is designed to Contour feathers (pennae) • Contour feathers form general covering of the body having poorly developed barbules. • Contour feathers provides a smooth surface to body, reduces To easily remember the six hormones secreted by the anterior drag or frictional resistance to motion through air, give pituitary gland, the mnemonic “FLAT PiG” can be used as shape by overlapping of the vanes and make a good heat follows: conserving layer. F (sH) : Follicle Stimulating Hormone Filoplumes l (H) : Luteinizing Hormone • These are small, delicate and hair-like feathers sparsely A (CTH) : Adrenocorticotropic Hormone T (sH) : Thyroid Stimulating Hormone distributed over the body. P (rolactin) : Milk Stimulating Hormone • Also known as space filling feathers. i : ignore • Probably help keep the other feathers in their place. G (H) : Growth Hormone

MTBIOLOGY TODAY | JANUARY ‘16 67 offer minimum resistance to the wind and hence easily Types of beaks in birds propelled through the air. • Birds exhibit indefinite variations in shape, size and structure − Presence of feathers make the body streamlined and of beaks. The diversity of forms of beaks is related to the type further helps its passing through the air by reducing of food eaten and manner of feeding. The most common friction to the minimum. types of beaks are: − Forelimbs are modified into wings, which help during • Seed-eating beak – Short, stout, peg-like and conical flight. The conversion of forelimbs into wings is duly beaks are characteristic of small granivorous or seed-eating compensated by the presence of a bill or beak. birds, such as sparrows, finches and cardinals. − Besides procurement of food, beak is also used for nest • Cutting beaks – Birds such as crows, possess long building. and slender beaks with cutting edges which can be used − The flight muscles on the breast are greatly developed variously. which help in flight. • Fruit-eating beak – In parrots, the beak is sharp, massive, − Most of the bones are pneumatic and filled with air deeply hooked and extremely strong. It is well adapted for instead of bone marrow. It makes the body light. gnawing or breaking open hard seeds and nuts, which form − Birds are warm blooded animals which is responsible for their staple diet. high temperature of the body (40°C - 46°C), a necessity for flight. • Insectivorous beak – In swallows and swifts, the beak − Urinary bladder is absent. Excreta is passed out is small, wide and delicate to scoop-up their living insect

at once. These features help in reducing the weight of prey while on wing. In hoopoe, the beak is long, slender body. and slightly curved and meant for turning the leaves or − Presence of a single functional ovary on the left probing into the soil for insect grubs and pupae, etc. side in the female bird also leads to reduction of weight • Wood-chiselling beak – Woodpeckers have elongated, which is essential for flight. straight and stout chisel-like beaks for drilling into the barks or wood for insect larvae or for nest construction. Modes of flight • Tearing and piercing beak – Carrion-feeding and flesh- • There are four chief kinds of flight in birds, and all the eating birds, such as vultures, hawks, eagles, owls, kinds may be used at different times by the same bird. Also, kites, etc., have short, pointed, sharp-edged and powerful, in all types of flight, the tail helps to support and balance the hooked beaks for tearing flesh which are operated by well- body, serving as a rudder. developed mandibular muscles. Gliding or skimming • Mud-probing beak – Familiar examples of mud-probing beaks are found in snipe, stilt, sand-piper, lapwing, etc. • The simplest and probably the most primitive mode of flight Their beaks are extremely long and slender and are used as is gliding. a probe for thrusting far down into water and mud in search • Birds hold their wings spread, motionless and glide for a of worms and larvae. considerable distance without flapping them. • Water and mud-straining beak – In ducks and geese • Gliding flight can be readily observed in shore-birds coming the beak is broad and flat. in for a landing; in ducks, gulls and herons over water. • Fish-catching beak – Storks, herons and kingfishers soaring or sailing have long, powerful and sharply-pointed, spearing beaks to • It is the most remarkable and highly specialised mode of capture fish, frogs, tadpoles and similar aquatic animals. flight, illustrated by birds with a large wing-span, such as • Flower-probing beak – The long, pointed and rapier- albatross, vulture, falcon, stork, crow, etc. like probing beak of tropical humming birds dive down the • The bird, usually at a high level, describes great circles corollas of flowers for sucking honey and insects. without any movement of wings. Types of feet or claws in birds Flapping • Cursorial or running feet – In running birds, the legs are powerful and the number of toes is reduced. The hind toe • It is the most common or ordinary mode of flight. All birds fly

by flapping their wings up-and-down. may be elevated, reduced or absent. In bustards and ratites such as emu, rhea and cassowary, only 3 toes, directed Hovering forward are present. • It is a peculiar variant of flapping flight. In hovering, found • Perching feet – The birds hold the twig or perch firmly by in humming birds, the body is kept vertical, while the bird flexing their toes around it. The majority of birds belong to remains poised in the air before a flower or above an object the category of perching birds or passers, such as sparrows, upon the ground, the tips of its wings apparently describes crows, bulbuls, robins, mynahs, etc. a figure of eight. • Scratching feet – The feet of fowls, quails, pheasants,

68 MTBIOLOGY TODAY | JANUARY ‘16 etc. are stout, with strongly-developed claws and well • It is merely a dispersal or short journey from the bleaker adapted for running as well as scratching the earth. slopes to the more protected valley and has been called • Raptorial feet – Predatory or carnivorous birds, such as altitudinal or vertical migration. eagles, kites, vultures, owls, etc. have strongly taloned • It occurs in the grebes and coots of Andes in Argentina. feet for striking and grasping their prey. The toes have seasonal migration strongly-developed, sharp and curved claws. • Field observers in temperate countries have grouped • Wading feet – The legs and toes are exceptionally long migrating birds according to seasons. and slender in wading or marshy birds such as herons, • In Britain, swifts, swallows, nightingales and cuckoos are snipes, jacana, lapwing, etc. These serve to walk over summer visitors, for they arrive in spring from the south, e.g. aquatic vegetation or marshes , ducks, pelicans. remain to breed and leave for the south in autumn. • Swimming feet – In swimming birds, the toes are webbed, • Some birds like fieldfare, snow bunting and redwing are partially or completely. winter visitors, as they arrive in autumn, chiefly from the • Climbing feet – In parrots and woodpeckers the feet north, stay throughout the winter and fly northwards again are used as grasping organs and especially adapted for in spring. climbing vertical surfaces. • Some birds like snipes and sandpipers are the birds of • Clinging feet – In swifts, martinets and humming- passage, seen for a short time twice a year on their way to birds, all the four toes point forward and serve to cling. colder or warmer countries in spring and autumn. Migration Communication • It may be defined as regular and periodical movements • Birds communicate using both visual and auditory signals. of birds between their summer and winter homes or it is Signals can be interspecific (between species) and a periodic swing from a breeding and nesting place to a intraspecific (within species). feeding and resting place. • Birds sometimes use plumage to assess and assert social Kinds of migration dominance, to display breeding condition in sexually selected species, or to make threatening displays. latitudinal migration • Visual communication among birds may also involve ritualised • The most familiar migrations are latitudinal that is, north to displays, which have developed from non-signalling actions south and vice versa. such as preening, the adjustments of feather position, • These are pronounced in the Northern Hemisphere, having pecking, or other behaviour. larger land masses. • Bird calls and songs, which are produced in the syrinx, are • Birds move during summer over the temperate and sub- the major means by which birds communicate. arctic regions of Northern Hemisphere, where there are • Calls are used for a variety of purposes, including mate facilities for feeding and nesting. attraction, evaluation of potential mates, bond formation, • The birds return to the south for shelter during winter, when the claiming and maintenance of territories, the identification north is covered with ice and snow. of other individuals (such as when parents look for chicks • E.g., Some birds of Siberia visit the plains of Himalayas in in colonies or when mates reunite at the start of breeding India. season), and the warning of other birds of potential longitudinal migration predators, sometimes with specific information about the • Some birds make migrations that are longitudinal rather nature of the threat. than latitudinal, that is, east to west and vice versa. Parental care • E.g., Starling moves from a breeding area in east Europe or • At the time of their hatching, chicks may be helpless or Asia towards the Atlantic coast, to avoid the independent, depending on their species. continental winter. • Helpless chicks are termed Altitudinal migration altricial, and tend to be born small, • Wherever large mountains are blind, immobile and naked; chicks found in temperate regions, that are mobile and feathered upon the birds migrate regularly hatching are termed precocial. up and down their slopes, as • Altricial chicks need thermo- the weather changes. regulation and must be brooded for • The birds pass the summer in longer than precocial chicks. the mountainous regions, but • Chicks at neither of these extremes return to the lowlands in winter. can be semi-precocial or semi-altricial.

MTBIOLOGY TODAY | JANUARY ‘16 69 Table : Important examples of birds Scientific name Common name Important notes Flightless birds Struthio African Ostrich • Largest living flightless bird, prominent eyes, can run at the speed of 60 km per (Shutarmurg) hour. • Foot bear two unequal toes provided with pads, which help the bird in running fast. • Lays largest egg produced by any living bird. • Eyes are largest of any land animal. Apteryx Kiwi • It is a New Zealand’s emblem bird. It is the smallest flightless bird. • Good sense of smell and acute hearing, most sensitive beak among birds. • Poor eyesight, male bird builds the nest and incubates sitting on one or more eggs. Aptenodytes Penguin • Gregarious flightless birds and live in cold sea waters of the South Pole specially in Antarctica. • Feeds on fishes, wings are modified into swimming flippers. • Male penguin alone incubates the egg without feeding for two months. Rhea South American • Smaller than ostrich but its habits are quite similar to ostrich. Ostrich • Head and neck are feathered, not naked as in ostrich. • Male is polygamous. Dromaius Emu • Next to ostrich, emu is the largest living bird. • It is confined to Australia, invariably monogamous though seen in small parties after breeding. • Male digs the nest and sits over the first brood of eggs, females sit over the second brood. Casuarius Cassowary • World’s third largest flightless bird. • Lives in Australia, New-Guinea and adjacent islands. • Shy and nocturnal. • Foot has 3-clawed toes. • Old males may even attack human beings if disturbed. Flying birds Choriotis Great Indian • Inhabitant of the semi-arid areas of Rajasthan, Gujarat and Maharashtra. nigriceps Bustard • State bird of Rajasthan. • Hunting for its flesh has reduced its population.Highly endangered bird. Eudynamis Koel, kokila • The male sounds like kuoo-kuoo-kuoo, female is generally heard during breeding scolopaceus season and has a short and sharp call kik-kik-kik, otherwise she is mostly silent. • It does not make any nest but lays eggs in the crow’s nest. Known as the Indian nightingale because of its pleasant call. Corvus splendens House crow • It is abundantly found throughout the peninsula of India. • Both sexes are similar. • Crows are intelligent and cunning birds. • Omnivorous. Psittacula Parrot • It is common in India, Bangladesh, Sri Lanka and Burma. eupatria • The beak is short but stout, sharp edged, deeply hooked and coral red. • The female is green all over, but the male has a rose pink collar and a black throat. • Parrots can copy and speak some words like man. • Popular domestic cage birds. • It carries the germs of the disease called psittacosis, which can be fatal.

70 MTBIOLOGY TODAY | JANUARY ‘16 Anas Duck • Well adapted for swimming, eats mosquito larvae, small fishes, grains and vegetables. • Male duck (drake) bears a characteristic copulatory organ. Columba livia Pigeon • Pigeons are gregarious, omnivorous. • The cavity of the gizzard of the pigeon always contains small pieces of stones and bricks swallowed by the bird. These pieces of stones and bricks helps the gizzard in grinding up the food. • Monogamous. • Young ones are fed upon by both male and female on ‘pigeon milk’. Gallus gallus Red jungle fowl • Exhibit sexual dimorphism. • Fowl (common word for cock and hen) provides good food for human beings. • Their eggs have good food value and are hence commonly eaten by men. Pseudogyps White rumped • Flies very high in the sky for hours together. bengalensis vulture (Gidh) . • Acts as a natural scavenger. • Parental care is offered by either sex. Bubo bubo Great horned owl • Distributed worldwide. (Ghughu) • Two prominent feather tufts above head look like ears, hence the name great horned owl. • Fully feathered legs are characteristic of horned owl. • It is a nocturnal bird. • It is of great economic value to agriculture as it feeds on harmful rodents. Ketupa Brown fish owl • Common throughout India. zeylonensi (Ulloo) • Similar to the horned owl in all respects, but its legs are unfeathered. Milvus migrans Common pariah • It is found throughout India, Pakistan, Bangladesh, Sri Lanka and Burma. kite (Cheel) • True scavenger, feeds largely on flesh. • Beak can tear flesh into pieces. • Are destructive to chicks, young turkeys and ducklings. Pavo cristatus Peacock (Mor) • Polygamous, usually one male lives in the company of four or five females. • Before copulation male exhibits sexual display, male has the bright blue neck, breast and long beautiful tail. • Indian peacock is the National bird of India.

Economic importance • Colourful birds, such as parrots and mynas, are bred in • Chickens account for much of human poultry consumption, captivity or kept as pets, a practice that has led to the illegal though turkeys, ducks, and geese are also relatively trafficking of some endangered species. common. • Falcons and cormorants have long been used for hunting • Many species of birds are also hunted for meat. and fishing, respectively. • Bird hunting is primarily a recreational activity except in • Today, such activities are more common either as hobbies, extremely undeveloped areas. for entertainment and tourism, or for sports such as pigeon racing. • The most important birds hunted in North and South America are waterfowl; other widely hunted birds include pheasants, • Birds can act as vectors for spreading diseases such wild turkeys, quail, doves, partridge, grouse, snipe, and as psittacosis, salmonellosis, campylobacteriosis, avian woodcock. tuberculosis, avian influenza (bird flu), giardiasis, and cryptosporidiosis over long distances. Some of these can • Other commercially valuable products from birds include also be transmitted to humans. feathers (especially the down feathers of geese and ducks), which are used as insulation in clothing and bedding, and Conservation seabird faeces (guano), which is a valuable source of • The most commonly cited human threat to birds is habitat phosphorus and nitrogen. loss. Other threats include overhunting, accidental mortality • Birds have been domesticated by humans both as pets and due to structural collisions or long-line fishing bycatch, for practical purposes. pollution (including oil spills and pesticide use), competition

MTBIOLOGY TODAY | JANUARY ‘16 71 and predation from non-native invasive species, and climate • Such projects have produced some successes; one study change. estimated that conservation efforts saved 16 species of birds • Governments and conservation groups work to protect birds, that would otherwise have gone extinct between 1994 and either by passing laws that preserve and restore bird habitat 2004, including the California Condor and Norfolk Island or by establishing captive populations for reintroductions. Green Parrot. Some important facts • Study of birds is called ornithology. • Modern birds appeared in Cretaceous period. • T. H. Huxley called birds to be glorified reptiles. • Archaeopteryx lithographica was discovered in 1861 by Andreas Wanger at Bavaria of Germany. • Birds are the only amniotes whose bodies are highly specialised for aerial mode of life. • Marine birds have salt-glands. • Bee Humming Birds (Cuba) Mellisuga helenae is the smallest bird (length 5.5 cm) which can fly in both direction, forward and backward. • Dodo Raphus cucullatus is a flightless bird of Mauritius which is now extinct. • Famous Indian ornithologist is Dr. Salim Ali (Bird Man of India). • Nidology is study of bird’s nests. • Poisonous bird, Pitohui dichrous (hooded pitohui) ofPapua, New Guinea, possesses toxins in its skin and feathers. • Hornbill is emblem of BNHS (Bombay Natural History Society).

4. Discuss various aerial or flight adaptations present in birds. 5. What do you mean by migration in case of birds? Discuss various types of migration that are observed in birds. 6. What are the different types of feathers present in birds? Discuss some important functions of feathers.

1. Kidney of adult reptile is (c) T-shaped (d) A-shaped. (a) metanephric (b) mesonephric 6. Heart in crocodiles is (c) protonephric (d) all of these (a) completely 4 chambered 2. The ‘Golden age of reptiles’ is (b) incompletely 4 chambered (a) palaeozoic era (b) carboniferous era (c) 3 chambered (d) 2 chambered. (c) mesozoic era (d) archezoic era. 7. The identifying character of cobra is 3. Mammal like reptiles belong to (a) round tail (b) small scales on head (a) anapsid line of evolution (c) presence of hood (b) euryapsid line of evolution (d) third supralabial touches eye and nostril. (c) parapsid line of evolution (d) synapsid line of evolution. 8. Which one of the following in birds, indicates their reptilian ancestry? 4. Turtles are included in the order (a) Two special chambers crop and gizzard in their digestive (a) Chelonia (b) Rhynchocephalia tract (c) Squamata (d) Crocodilia. (b) Eggs with a calcareous shell 5. Interclavicle in repitle is (c) Scales on their hind limbs (a) H-shaped (b) W-shaped (d) Four-chambered heart

72 MTBIOLOGY TODAY | JANUARY ‘16 9. The scientist, who described the birds as glorified reptiles, 13. Raptorial feet are found in was (a) vulture (b) crow (a) Romer (b) Mendel (c) mynah (d) lapwing. (c) Huxley (d) Robert Hooke. 14. Some vertebrae in birds fuses to form 10. Flightless birds are included in (a) sacrum (b) synsacrum (a) odontognathae (b) impennae (c) coccyx (d) none of these (c) ratitae (d) carinatae. 15. Flight muscles of birds are attached to 11. The character of living birds without exception is (a) keel of sternum (b) clavicle (a) omnivorous (b) beak without teeth (c) pelvic girdle (d) humerus. (c) flying wings (d) monogamous. ANSWER KEY 12. The special sound producing organ in birds is 1. (a) 2. (c) 3. (d) 4. (a) 5. (c) (a) larynx (b) syrinx 6. (a) 7. (c) 8. (c) 9. (c) 10. (c) (c) oesophagus (d) glottis. 11. (b) 12. (b) 13. (a) 14. (b) 15. (a)  CENTRAL BOARD OF SECONDARY EDUCATION EXAM ALERT! ALL INDIA PRE-MEDICAL/PRE-DENTAL ENTRANCE TEST- 2016

nline applications are invited for All India Pre-Medical/Pre-Dental Entrance categories must have obtained a minimum of 50% marks taken together in OTest -2016 to be held on 1st May, 2016 (Sunday) for admission to MBBS/ Physics, Chemistry and Biology/Bio-technology at the qualifying examination BDS Courses under 15% All India Quota seats as per the directives of Hon’ble and candidates belonging to Scheduled Caste/Scheduled Tribes or Other Supreme Court of India and also for seats under the control of participating Backward Classes, must have obtained 40% instead of 50%. Further, for States/Universities/Institutions in the academic session 2016-17. persons for locomotory disability of lower limbs, the minimum of 45% marks PATTERN OF EXAMINATION for General-PH and 40% marks for SC-PH/ST-PH/OBC-PH are required. Those The AIPMT Examination shall consist of one paper containing 180 objective who are appearing in class XII examination in 2016 may also appear for the type questions (four options with single correct answer) from Physics, Chemistry entrance test provisionally subject to their fulfilling the conditions later. and Biology (Botany & Zoology). The duration of paper would be 03 hours from (vi) Candidates from the States of Andhra Pradesh, Telangana and J & K are 10.00 a.m. to 01.00 p.m. not eligible for 15% All India Quota seats as these states had opted out of All ELIGIBILITY CRITERIA India Scheme since its inception. However, they are eligible to appear in AIPMT (i) Indian Nationals and Overseas Citizens of India are eligible for appearing for admission in AFMC, Pune. in the All India Pre-Medical/Pre-Dental Entrance Test (AIPMT). PARTICIPATING STATE GOVERNMENTS / uNIVERSITIES/ INSTITuTIONS (ii) The candidate must have completed age of 17 years at the time of The states of Haryana, Himachal Pradesh, Madhya Pradesh, Manipur, admission on or before 31st December, 2016. Meghalaya*, Odisha, Rajasthan, UT of Chandigarh, University of Delhi, Armed (iii) The upper age limit for candidates seeking admission under 15% All India Forces Medical College, Banaras Hindu University and Hamdard University, Quota Seats is 25 years as on 31st December, 2016 relaxable by a period of New Delhi have decided to voluntarily use the merit list of AIPMT-2016 for 5(five)years for SCs/STs/OBCs. admission in the Medical Colleges/Dental Colleges for seats under their control. (iv) The upper age limit for candidates seeking admission in MBBS/BDS seats Candidates who wish to seek admission in these State/University/Institution(s) under the control of participating States/Universities/Institutions shall be as per may confirm eligibility conditions from the respective States/University/ the rules of the State/University/Institution concerned. Institutions concerned in advance. (v) The candidate must have passed in the subjects of Physics, Chemistry, *Subject to confirmation from state government. Biology/Bio-technology and English individually. The candidates from the other For more details visit the website www.aipmt.nic.in

SCHEDuLE WITHOuT LATE FEE Schedule for on-line submission of application For fee through e-challan For fee through other e-modes forms 15.12.2015 (Tuesday) to 08.01.2016 (Friday) 15.12.2015(Tuesday) to 12.01.2016 (Tuesday) Last date for successful final transaction of fee 12.01.2016 (Tuesday) 12.01.2016 (Tuesday) WITH LATE FEE Schedule for on-line submission of application For fee through e-challan For fee through other e-modes forms 13.01.2016 (Wednesday) to 06.02.2016 (Saturday) 13.01.2016 (Wednesday) to 10.02.2016 (Wednesday) Last date for successful transaction of fee 10.02.2016 (Wednesday) 10.02.2016 (Wednesday)

MTBIOLOGY TODAY | JANUARY ‘16 73 WHITEFLY RESISTANT TRANSGENIC PLANT Developed by NBRI hiteflies are small hemipterans that typically feed on the underside of plant leaves. It is a common pest which affects 30 plant varieties including cotton, brinjal, Wpapaya, tomato, okra, cucurbits. It sucks all nutrients from leaves and excretes on the leaf’s surface, thus causing fungal infection. Crops infested with whitefly remain stunted. Once the pest spreads, it can destroy the crop quickly. This year, it has affected about two-third of standing cotton crop in Punjab thus, leading to huge economic loss. Large number of farmers committed suicide due to this. Whitefly cannot be controlled by spraying pesticides as canopy formed by grown up plants may not let pesticide to act on each and every leaf and whiteflies lay their eggs on the lower region of the plants. In this regard, NBRI, Lucknow, has developed a new transgenic variety of cotton which is resistant to this pest. ‘Coker’ variety of cotton was used for this purpose. In this variety, a gene derived from a vegetable (which remains undisclosed) was introduced. The gene makes whitefly sterile, thus controlling the reproduction of the pest. The protein formed by the gene was safe and also easily digestible in laboratory trials. The technology is now ready for field trials. NBRI has applied for patent for the technology in eight countries.

GHATIXALUS MAGNUS A Novel Third Species of the Western Ghats’ Endemic Genus Ghatixalus new species of rhacophorid tree frog is discovered by a team of researchers comprising of Robin Abraham (a researcher from the University of Kansas, USA), A Anil Zachariah (a batrachologist from Wayanad) and Vivek Philip Cyriac (a researcher of the IISER, Thiruvananthpuram) in the Western Ghats in Kadalar High Ranges of Idukki district, Kerala. The discovery has been published in the latest issue of International Taxonomic Journal, Zootaxa. The Western Ghats biodiversity hotspot is a recognised centre of rhacophorid diversity as demonstrated by several recent studies. The Family Rhacophoridae consists predominantly of arboreal tree frogs. The endemic genus Ghatixalus is represented by two species from two separate high-elevation regions within the Ghats. The new species of rhacophorid tree frog is ascribed to the genus Ghatixalus based on “a unique combination of molecular, morphological and larval characteristics”. It has been named Ghatixalus magnus after its large size, making it the biggest known tree frog from the Western Ghats. With this, there are now three nominal species of the Western Ghats’ endemic genus Ghatixalus. The team has also rediscovered a species of bush frog, Raorchestes flaviventris that had been evading for the past few decades. It was first described from Western Ghats by George Albert Boulenger in 1882. Since then, this had never been sighted. The frog has been rediscovered after 132 years.

74 MTBIOLOGY TODAY | january ‘16 Contd. from page no. 30 (iv) Prostate, testis, seminal vesicles, Cowper’s gland PRACTICE PAPER (i) (ii) (iii) (iv) (iii) 1st menstruation at puberty in female is called (a) Vas deferens Vagina Cervix Cowper’s gland capacitation. (b) Rete testis Ovary Graafian follicle Prostate (iv) If human sperm cut in T.S. and seen under light microscope (c) Scrotum Uterus Corpus luteum Seminal vesicles its axoneme will have 9 + 2 arrangement of fibrils, outer 9 (d) Fallopian tube Ejaculatory duct Acrosome Testis fibrils will be triplets. 128. Repair of endometrium is undertaken by (v) 80 secondary spermatocytes produces 160 sperms in case (a) LH (b) FSH of human. (c) estrogen (d) prolactin. (a) (ii), (iii) and (iv) (b) (ii) and (iii) (c) (iii) and (iv) (d) All except (v) 129. The following graph shows the levels of pituitary hormones during a menstrual cycle. What do 1 and 2 represent? 122. Signal for parturition originates from (a) hypothalamus, which stimulates release of oxytocin from its neurons

(b) fully developed foetus and regressing corpus luteum levels

(c) hypothalamus and placenta Pituitary hormone (d) fully developed foetus and placenta. Days

123. Spermatid is converted into sperm by the process named 1 2 (a) spermatogenesis (b) spermiogenesis (a) LH FSH (c) spermiation (d) insemination. (b) Estrogen Progesterone 124. Which of the following is a correct sequence? (c) FSH LH (a) Seminiferous tubule → Rete testis → Vasa deferentia (d) Progesterone Estrogen → Epididymis → Vasa efferentia → Ejaculatory duct → 130. Withdrawal of which of the following hormones is the Urethra. immediate cause of menstruation? (b) Germinal epithelium → Spermatogonia → Primary (a) Progesterone (b) Estrogen spermatocyte → Secondary spermatocyte → Spermatid (c) FSH (d) FSH-RH → Sperm. (c) Corona radiata → Zona pellucida → Perivitelline space 131. Which of the following is a wrong match w.r.t. menstrual → Cortical granules → Plasma membrane. cycle? (d) Oogonium → Primary oocyte (at female child birth (a) Follicular growth – FSH and LH. at dictyotene) → Secondary oocyte (ovulated at 1st (b) Thickening of endometrium – Progesterone and metaphase) → Ovum (after release of second polar estradiol. body). (c) Trigger for ovulation – LH surge. (d) Menstruation trigger – Increased oestrogen. 125. Which of the following is a true statement? (a) Male sex accessory ducts include seminiferous tubules, rete 132. Modification in sperm after insemination, within female testis, vasa efferentia, epididymis and vas deferens. reproductive tract, so as to make it capable of penetration into (b) Normal temperature for sperm development in human is female’s developing gamete is about 34.5° – 35°C. (a) spermarche (b) cortical reaction (c) capacitation (d) menarche. (c) Leydig’s cells of seminiferous tubules secretes testosterone. 133. In a normal pregnant woman, the amount of total gonadotropin (d) Mammary glands of human are one typed sebaceous activity was assessed. The result expected was glands. (a) high level of circulating FSH and LH in the uterus to stimulate implantation of the embryo. 126. Which of the following hormone is not secreted by human (b) high level of circulating hCG to stimulate endometrial placenta? thickening directly. (a) hCG (b) hCS (c) high levels of FSH and LH in uterus to stimulate endometrial (c) Progesterone (d) Luteinising thickening. 127. Pick the odd one out from each series given below and select (d) high level of circulating hCG to stimulate estrogen and the correct option. progesterone synthesis. (i) Scrotum, rete testis, Fallopian tube, vas deferens 134. Milk produced during initial few days of lactation is called (ii) Ovary, uterus, vagina, ejaculatory duct colostrum which contains several chemicals essential for (iii) Acrosome, Graafian follicle, corpus luteum, cervix development of child. Some of them are

MTBIOLOGY TODAY | JANUARY ‘16 75 (a) high Fe and lipid contents 142. Vegetative propagule of Agave is (b) high proteins and high vitamin C contents (a) leaf buds (c) high protein content and IgA (b) offset with two groups of rosset leaves (d) all of the above (c) slips or sets 135. Human placenta is haemochorial type, which of the following (d) bulbils. is correct about it? 143. How many of the following organisms are monoecious? (a) There are 3 barriers between foetal and mother’s blood, as endothelium, connective tissue and epithelium of Chara, Papaya, Leech, Marchantia, Maize, Date palm, maternal placental part. Tapeworm, Funaria, Earthworm and Common roundworm. (b) There are two barriers between foetal and mother’s blood (a) 7 (b) 5 (c) 6 (d) 9 as endothelium and connective tissue of foetal part of placenta. 144. Oestrous cycle takes place during reproductive life in (c) There are two barriers between foetal and mother’s blood (a) apes (b) rat as endothelium and connective tissue of mother’s part of (c) monkey (d) human. placenta. 145. Which of the following is true w.r.t. grafting? (d) There are three barriers between foetal and mother’s (a) Very commonly practised in monocot plants. blood as endothelium, connective tissue and epithelium i.e., of foetal placental part. (b) In air layering one typed grafting uses auxin to induce rooting. 136. Regressed corpus luteum towards the end of menstrual cycle is (c) Stock is shoot piece which is used in grafting. called (d) New plant produced after grafting produces fruits similar (a) corpus haemorhoegicum (b) corpus albicans to scion source. (c) atristic follicle (d) corpus callosum 146. Zygospore differs from zoospore by 137. Male accessory gland, lubricating penis during cohabitation, by A. being diploid B. being actively motile its secretion is C. being sexual spore D. helps in dispersal of species (a) prostate gland (b) Cowper’s gland (c) Bartholin's glands (d) both (b) and (c). E. does not undergo meiosis before germination. (a) A, C and D only (b) B, D and E 138. Which of the following is a true statement w.r.t. human (c) A and C only (d) all except ‘B’ reproduction? (a) Egg is cledoic and alecithal. 147. To produce 16 male gametes from MMCs how many mitosis (b) Cleavages are equal and determinate. and meiosis are required in angiosperms? (c) Human placenta is chorionic, metadiscoidal and deciduate. (a) 8 and 2 respectively (b) 4 and 2 respectively (d) Corona radiate, in released secondary oocyte is a tertiary (c) 1 and 4 respectively (d) 16 and 2 respectively egg membrane. 148. Rafflesia like foul smelling flowers are pollinated by 139. Which of the following is incorrect match? (a) beetles and moths (b) moths and flies (a) Enamel of tooth – ectodermal (c) flies and beetles (d) moths, beetles and flies. (b) Eye lens – mesodermal 149. Sunscreen lotions may have added pollen products due to (c) Lungs – endodermal (d) Spleen – mesodermal (a) presence of saturated fats and carbohydrates 140. Which of the following is a wrong match? (b) presence of saturated fats and smaller oligosaccharides (a) Birth canal – Vagina only. (c) presence of unsaturated fats (b) Clitoris – Homologous to human penis. (d) none of these. (c) Myometrium – Middle layer of tissue in uterine wall. (d) Spermiation – Sperms released from seminiferous tubule 150. Translator mechanism commonly found in by this process. (a) Calotropis (b) Zeuxin, an orchid (c) Salvia (d) Fig. 141. In the following pedigree find phenotype of individual indicated as X, if dominant gene is F and recessive allele is f 151. How many of the following statements are true w.r.t. sickle cell anaemia? A. It is an example of point mutation, as well as, missense mutation. B. It is a sex-linked recessive trait. C. 6th amino acid of b-chain glutamate is replaced by valine. D. Example of transition type of mutation. E. In an individual with HbA HbS genotype, some RBCs become sickle shaped under the effect of low O2 (a) FF (b) Ff availability. (c) ff (d) either (a) or (b) (a) 4 (b) 5 (c) 2 (d) 3

76 MTBIOLOGY TODAY | JANUARY ‘16 152. shown symbol of pedigree indicates other and their parents by about 0.1 nucleotide sequence (a) illicit couple (b) inbreeding of their genome. (c) increased hybrid vigour in their progeny (iii) Chromosome number 1 has maximum number of gene, (d) all of the above. whereas, chromosome Y has least number of genes. (iv) Largest gene being dystrophin with 3.4 million bp’s. 153. Which of the following are correct matches? (v) Satellite DNA is inert but shed light on chromosome Pisum sativum A. Green colour of pod in – Dominant trait. structure, dynamics and evolution. B. Has no father, still has a grandfather – Drone. (a) (ii), (iii) and (iv) only (b) (iii), (iv) and (v) only C. Female heterogametic w.r.t. sex chromosome – Fowl. (c) (i), (ii) and (iii) only (d) all except (iv) D. Gene with multiple phenotypes – Polygene E. Mendel’s work was republished, in year 1901 – Journal 161. Which of the following is true statement? Flora (a) Pribnow box lies in mRNA in upstream stream sequence. (a) C and D (b) C, D and E (b) In clover leaf model of tRNA, amino acid is attached to 5′ (c) B, C and D (d) all except ‘D’ by ester bond, if it is a charged one. (c) Translation is initiated by s factor, formed of γ-chain, of 154. Seed produced by selfing of true breeding tall plant, was RNA polymerase enzyme. grown in a barren soil, plant grows as dwarf. It was crossed to (d) Sn RNA, 5S RNA and tRNA are transcribed with the help another tall plant, then which of the following is true about its of RNA polymerase III in eukaryotes. progeny (a) all tall with genotype TT 162. Which of the following statement is true w.r.t. structure of DNA (b) all tall with genotype either TT or Tt (Watson and Crick Model)? (c) all tall with genotype Tt (a) Base pair rise 34 Å (b) Pitch of DNA 3.4 Å (d) either (a) or (b). (c) Two strand antiparallel due to formation hydrogen bonds. (d) Two strands are coiled upon one another to form right 155. A, B, C and D lies on same chromosome with given distances handed helices. between them, as AD = 60 morgan, AB = 38 morgan, DB = 22 morgan and 163. DNA with one strand labelled with radioactive thymidine. AC = 18 morgan. Find the sequence of four genes on the Allowed to replicate in normal nutrient medium for three chromosome. generations. Then proportion of DNA molecules showing (a) A, C, B and D (b) C, A, B and D radioactivity is (c) D, B, A and C (d) any of these. (a) 12.5% only (b) 25% 156. In Drosophila melanogaster eye colour is controlled by 15 (c) 6.25% (d) 50%. different alleles. How many possible genotypes it may have in 164. ‘Myotonic dystrophy’ in human is controlled by the population? (a) X-linked recessive gene (a) 120 (b) 45 (c) 450 (d) 150 (b) X-linked dominant gene 157. An Individual has genotype PPQqRrSSTtUUVv. How many (c) autosomal dominant gene different genotype it may have in it gametes? (d) autosomal recessive gene. (a) 34 (b) (24)2 (c) 16 (d) 128 165. How many of the listed characters are not indicative Down’s syndrome? 158. Thalassemia differs from sickle cell anaemia as (a) former is due to qualitative problem of synthesising an Big and wrinkled tongue, Gynaecomastia, Simple palm incorrectly functioning globin. crease, Under developed feminine characters, Broad flat (b) later is due to quantitative synthesising too few globin face, Azoospermia, Congenital heart disease molecule. (a) 2 (b) 1 (c) 3 (d) 4 (c) thalassaemia is controlled by autosomal gene, but, sickle cell anaemia is controlled by X linked recessive gene. 166. Match the following column-I with column-II and find the right (d) none of these. match. Column-I Column-II 159. From following listed molecules, how many are nucleosides? A. Down’s syndrome (i) Trisomy of 13th Thymidylate, Guanosine, Uridine, Cytosine, chromosome Guanilic acid, Adenosine, Adenylate B. Turner's syndrome (ii) Trisomy of sex chromosome C. Patau’s syndrome (iii) Autosomal dominant (a) 4 (b) 3 (c) 2 (d) 6 character 160. Which of the following statements are true w.r.t. human D. Klinefelter's syndrome(iv) Monosomy of sex genome? chromosome (i) Human genome has 1.4 million SNPs in it. E. Huntington's chorea (v) Non disjunction of (ii) Poonam and Sumit are siblings, which differs from each autosomes

MTBIOLOGY TODAY | JANUARY ‘16 77 (a) A-(iii), B-(iv), C-(i), D-(ii), E-(v) (c) 32P and 35S isotops (d) none of these (b) A-(v), B-(iv), C-(i), D-(iii), E-(ii) 175. Match the following column-I with column-II and find the right (c) A-(v), B-(iv), C-(i), D-(ii), E-(iii) match. (d) A-(iii), B-(i), C-(iv), D-(ii), E-(v) Column-I Column-II 167. Diagram shown below is schematic structure of “transcription A. Non-parental gene (i) Crossing over unit”. Which of the following is true w.r.t. shown diagram? combination Promoter Strand A B. Non-sister chromatids (ii) Z and W 3 5 C. Sex chromosomes (iii) Sex-linked recessive disease 5 3 D. Haemophilia (iv) Recombination (a) A-(II), B-(IV), C-(I), D-(III) (b) A-(IV), B-(I), C-(II), D-(III) Strand B Terminator (c) A-(II), B-(IV), C-(III), D-(I) (d) A-(II), B-(I), C-(IV), D-(III) (a) If strand A is antisense it will have 5′ towards left side in 176. Multiple alleles controlling which of the following characters diagram. A. Eye colour in Drosophila (b) If strand B is coding, it will have 5′ towards left side in B. ABO blood groups in human diagram. C. Skin colour in human D. Sickle cell anaemia (c) If strand B is –ve strand, it will have 3′ towards right E. Thalassaemia side. (a) B and C (b) A and D (d) Both (a) and (c). (c) A and B (d) all except D. 168. Which of the following is a wrong match? 177. In the diagram amino acid ‘Ala’ at the tail of arrow ‘X’ contribute (a) 3′UAG5′ – Non sense codon (i) group and amino acid val at head of arrow ‘X’ contribute (b) UGG – Codes for tryptophan (ii) group for formation of bond between these two amino (c) s Factor – initiates transcription acids. (d) None of these Gly Leu Tyr 169. How many of the following statements are incorrect statements? ‘X’ rd Ser A. 3 base of anticodon is wobble base. Growing polypeptide chain Leu Asn B. Most abundant RNA in the cell is rRNA. Gly C. Coding part of split gene is intron. tRNA RNA Ser D. Z-gene of lac-operon produces hydrolytic enzyme. t Ala Val E. 23S rRNA in eukaryotic ribosome is a ribozyme catalysing the formation of peptide bond. tRNA tRNA (a) 3 (b) 2 (c) 4 (d) 1 CG U CAA 170. One codon can undergo how many transitions? (a) 9 (b) 6 (c) 3 (d) 549 5  mRNA Ribosome 171. DNA base sequence is polymeric if (a) (i) – P – H and (ii) – COOH (a) it is present in more than 1000 genes (b) (i) – NH and (ii) – COOH (b) a variant sequence exist in at least 1% of population 2 (c) (i) – P – OH and (ii) – NH (c) it can’t be cut by exonuclease and endonuclease enzyme 2 (d) (i) – COOH and (ii) – NH Ser (d) the carrier frequency is between 2-8%. 2 172. Which of the following statements is false? 178. In the given clover leaf t ‘z’ (a) 2 turns of Z-DNA has 48 nucleotides. model of RNA recognised (b) 5′AUG GAC GGG GCG GCC UAG AAC3′ segment of the labelled part as Z. mRNA will not be translated fully. (a) T y C loop (c) 3-D model of tRNA, where it has inverted L-shaped (b) DHU loop structure was given by Rich and Klug. (c) D-loop (d) To form 1st peptide bond during protein synthesis four (d) CCA terminus U CA phosphate bonds are used. 179. 10% crossing over leads to 173. Tailoring of hnRNA to produce tRNA is carried out by (a) 10% recombination (b) 20% recombination (a) scrup (b) Intron (c) 5% recombination (c) 18 S rRNA (d) Snurp. (d) statement of question is wrong because %age 174. Uniequivocal proof that DNA is a genetic material, made use of recombination has no relation to %age crossing over. (a) Streptococcus and T2 180. Mechanism of sex determination in honey bee is (b) 15N as ammonium chloride and density gradient equilibrium (a) XX – XO (b) 2n – n technique (c) arrhenotoky (d) thelotoky.

78 MTBIOLOGY TODAY | JANUARY ‘16 sOLuTIOns 1. (c) : Refer to 1st paragraph page number 19 NCERT +1; refer to 14. (d) : Bacterial cell wall contains N-acetyl glucosamine (NAG) in page number 20; 3rd paragraph which indicates mycoplasma can carbohydrate part of cell wall and chitin is a polymer of NAG. survive without oxygen, so, facultative aerobic, for methanogen 15. (c) : Refer to table 3.1 indicating differences among different refers to page number 19 article 2.1.1. NCERT +1. classes of algae, page number 33 NCERT +1. 2. (d) : Citrus canker disease is caused by Xanthomonas citri. 16. (c) : In algae, vegetative reproduction mainly takes place by 3. (a) : For size of bacteria (1-2 mm) refer to diagram 8.2 page fragmentation not by any asexual or sexual spore. number 128 NCERT +1; refer to 2nd paragraph under article 17. (a) : For (i) refer to last line page number 30 NCERT +1; (ii) refer 8.4.1 page number 128 for glycocalyx; for fimbriae refer to rd3 to page number 32, 1st paragraph +1 NCERT; (iii) Sphagnum is paragraph on page number 129. Folds of mesosomes contain a bryophyte where sporophyte is parasite on gametophyte; Refer component of ETC so helps in aerobic respiration. mRNA (not to diagram 3.2 page number 34 NCERT +1. SCP mean single cell rRNA) attached to many ribosomes is a polysome. protein i.e., protein of microbial origin, like Chlorella and Spirullina 4. (c) : 8 Bacteria divides repeatedly, three times to produce 64 are good source of SCP. bacteria, so, time consumed for one binary fission cycle is total 18. (c) : Prothallus is a gametophyte; strobilus is another name of time divided by 3 i.e., 120/3 = 40 m. cone; inducium is a protective covering of sorus. 5. (a) : Whole body of fungus produced from one spore is mycelium, 19. (a) : 2 × 10 × 4 × 5 × 6 × 4 = 9600 is the total number of whereas one thread like structure in it is hypha acting as building spores produced on 2 sporophylls. block of fungal body; exchange of gases in lichens takes place 20. (a) : Floridean starch has structure similar to amylopectin and through cyphella, oospore is diploid. Trichonympha in the intestine glycogen (refer to page number 33 NCERT +1). Sphagnum bears of termite digests cellulose and provides food to it. both male and female sex organs on same plant, so monoecious. 6. (a) : For dikaryon refer to 2nd paragraph on page number 23 It bears male and female sex organs on different branches so NCERT +1; Sooty mass of spore production is characteristic of autoecious, but, Marchantia bears male and female sex organs smut, which is caused by Ustilago mainly, not by Puccinia; for on different plants so dioecious; sphenopsids contain brown, choice number (iv) refer to last two lines of page number 24 NCERT nonphotosynthetic scale leaves so photosynthesis is carried out +1; Morchella is an edible morel member of Class Ascomycetes, by green stem. not Basidiomycetes. 21. (d) : Protonema is found only in mosses not in liverworts. 7. (d) : Bracket fungi like Polyporus damage our timber resource. 22. (a) : Only fern zygote is diploid; all other cells listed here are For Neurospora refer to last two lines of 1st paragraph page haploid. number 24 NCERT +1; for Albugo refer to page number 23, article 23. (c) : Heterospory originated in lycopods like Selaginella. 2.3.1 NCERT +1; Conidiospores are characteristic spores of both 24. (d) : Endosperm in gymnosperms is haploid structure. Endosperm the Classes Ascomycetes and Deuteromycetes. contains 16 chromosomes. It is a ‘n’ number of chromosome; leaf 8. (b) : Agaricus, puff balls, Ustilago and Puccinia are members and MMC being 2n contain 32 chromosomes; pollens being ‘n’ of Basidiomycetes i.e., 4 members only whereas Aspergillus, contain 16 chromosomes. Claviceps and edible morels belong to Ascomycetes; Albugo 25. (a) : Because, only, in bryophytes sporophyte is parasite on belongs to Phycomycetes; Alternaria and Trichoderma belong to gametophyte. Deuteromycetes. rd 26. (a) : Salvinia is a heterosporus fern. Selaginella is also 9. (d) : Refer to 3 paragraph page number 23 NCERT +1, these heterosporus, but, it is a lycopod not a fern. three criteria are used in classification. 27. (c) : Refer to diagram 3.4 (c) on page number 39 NCERT +1. 10. (c) : Diagram 2.5 (c) shows the labelled parts, your tutor might have explained it (gap in NCERT). Label 1 is hypha producing 28. (c) : Walking fern is Adiantum caudatum because of apical fruiting body, it is dikaryotic; Label-2 stipe is edible, formed of reproductive buds on leaves which after coming in contact with secondary mycelium; Label-3 Annulus is remains of velum which the soil help in spreading on ground; bog moss is Sphagnum, protects young developing gills; Label 4 gills help in production of Cycas living fossil because of ciliated sperms; maiden hair tree is basidiospores from its hymenium part. Ginkgo. 11. (c) : Cyanobacteria always lack flagella and fimbriae, but, bacteria 29. (d) : Refer to article 3.4 on page number 38 NCERT +1. may contain it; in both the bacteria and cyano-bacteria, DNA lacks 30. (c) : Indicated feature is of bryophyte and Marchantia is a histones, so, it is a similarity; anoxygenic photosynthesis found bryophyte. in bacteria, but, cyanobacteria have oxygenic photosynthesis; stored food in bacteria is glycogen but cyanobacteria mainly have 31. (a) : Peat is an inferior quality coal, carbonised dead body cyanophycean starch; bacteria lack heterocyst but cyanobacteria of Sphagnum used as a fuel, bryophytes are highly important contain heterocysts. ecologically as they help in soil formation and ecological succession; Male cone of Pinus equivalent to angiospermic 12. (b) : X- is Nitrosomonas and Y- is Nitrobacter; Gram -ve bacteria flower for being axillary in position; Endosperm ofCycas is a pre- are resistant to most of the antibiotics; Frankia fixes N in non- 2 fertilisation product derived from female gametophyte. leguminous root nodules. 32. (b) : Refer to figure 3.1 page number 31 and figure 3.3 page 13. (a) : As fungi grow in dark, warm and humid conditions. number 37 NCERT +1.

MTBIOLOGY TODAY | JANUARY ‘16 79 33. (c) : Bryophytes differ from pteridophytes by lacking vascular gizzard found both in birds and cockroach, collar cell is found tissue not by containing vascular tissue. in canal system, colloblast attaching cells on tentacles of 34. (d) : Refer to last four lines of page number 38 NCERT +1. ctenophores, tornaria larva found in phylum Hemichordata, like 35. (a) : During forest fire rhizomes survive below the surface of soil, Balanoglossus. after forest fire they regenerate new plants; chilgoza nut is a seed 57. (b) : Echinodermata is the only phylum that contains bilaterally not a fruit, ovuliferous scales are equivalent to carpels. symmetrical larva and radially symmetrical adult. 36. (c) : Refer to last paragraph on page number 35 NCERT +1. 58. (a) : Taenia and dog tapeworms lack alimentary canal; Fasciola 37. (a) : (i), (ii) and (iii) are features of gymnosperms, according to contains incomplete alimentary canal; so, lacks anus, Amphioxus NCERT life cycle of gymnosperm is diplontic; all gymnosperms are being chordate contains complete alimentary canal. heterosporus. 59. (d) : Filaria is caused by Wuchereria bancrofti, a round worm. 38. (c) : Life of sporophyte starts with zygote, so first cell in life of Culex mosquito is vector not a cause of disease. sporophyte is zygote, whereas, gametes fuse to form zygote, so 60. (a) : Excretory organ of hemichordata is proboscis gland refer to gametes are last cells in the life of gametophyte. article 4.2.10 page number 54 NCERT +1. Amphioxus contain 39. (c) : Marchantia being a liverwort has unicellular rhizoids; flame cell and prawn has green gland as excretory organ. Sphagnum contains water storing retort cells in the ‘stem’. 61. (b) : All the listed characters pertains to Aschelminthes and 40. (c) : Thallophytes contain non jacketed unicellular sex organs, Ascaris is its member. commonly. 62. (b) : Sea fan is Gorgonia, a Cnidarian. th 41. (d) : Gymnosperms contain archegonia but lack antheridia. 63. (d) : Refer to article 4.2.2, 3rd and 4 line on page number 50 42. (d) : Refer to 2nd paragraph on page 38 NCERT +1. NCERT +1. 43. (d) : Archegonium of gymnosperm contains highly reduced neck, 64. (a) : Vector for Wuchereria is a female culex, Peripatus is without neck canal cell (N.C.C.). connecting link of annelida and arthropoda, chloragozen cells of earthworm are equivalent to human liver because both can store 44. (d) : Funaria and Pinus both lack fruit so similarity, but, Funaria glycogen. produces antheridium and archegonia, Pinus contains archegonia but lacks antheridium, but, Pinus produces seeds but Funaria 65. (b) : Locust is a gregarious animal, instead of colonial. lacks seeds. 66. (d) : Female Aedes mosquito acts as a vector of Dengue. 45. (d) : Prothallus of fern is a gametophyte which produces gametes. 67. (b) : Tornaria larva – Balanoglossus; Brachiolaria – Starfish; Strobilus, sporangia and sorus are found on sporophyte, not on Axolotl – Salamander; Trochophore – Nereis. prothallus. 68. (c) : Osphradium of Pila is a chemoreceptor which is a leaf like 46. (b) : Both are terrestrial and have main body as gametophyte, structure checks chemical nature of water which enter the pallial Pila bryophytes contain sterile jacket around sex organs; gametes are complex of . not multiflagellated. 69. (b) : Neophron written in italics is a biological name of vulture. It is not a functional unit of kidney, which is a "nephron". 47. (b) : In Funaria, sporophyte is a parasite, all the three contain archegonia; vascular tissue absent in Funaria; in Ginkgo 70. (c) : Refer to diagram 4.21 and 4.22 on page number 57 and 58 gametophyte highly reduced in comparison to sporophyte and of NCERT +1. parasite on sporophyte. 71. (b) : Doliolium is a hemichordate one typed protochordate; 48. (d) : They live on damp, cool and shady place and need water for Ichthyophis is a limbless amphibian; Ornithorhyncus (duck billed fertilisation so have limited geographical distribution. platypus) is an egg laying mammal; Delphinus (Dolphin) is an 49. (c) : Presence of seeds and flagellated sperms together is aquatic mammal; Myxine (Hag fish) is a jawless fish. unusual in plant kingdom, as found in some lower gymnosperms 72. (c) : Study comparison of cyclostomes, chondrichthyes and like cycads. osteichthyes from NCERT pages 56 and 57 NCERT +1. 50. (c) : Double fertilisation is found in all angiosperms. 73. (a) : Some crustaceans, aquatic amphibians and amphibians are 51. (d) : Unique features to mammals are mammary glands and hair not uricotelic. (refer to last two lines on page number 61 NCERT +1); 74. (b) : All sponges have high regeneration power due to presence of protochordates do not include hemichordates. All vertebrates are chordates. archaeocytes in their body wall. Some sponges may contain silicious spicules; mostly found in warm water, Spongilla is a fresh water 52. (a) : (ii) and (v) are wrong. Echinoderms contain water vascular system, not canal system; reptiles are amniotes. sponge, mostly they are asymmetrical. 53. (d) : Body of hemichordates like Balanoglossus is divisible into 75. (d) : Both (C) and (D) have true coelom as schizocoelom. proboscis, collar and trunk. 76. (a) : Scorpion, spider and cockroach all have ventral solid nerve 54. (c) : Collar cells are characteristic to sponges; uropygeal gland cord, for being invertebrates. found in birds; Struthio flightless bird, so, lacks well developed 77. (a) : Diagram A-true coelom – Annelids; B-pseudocoelom – keel. Swim bladder not found in Chondrichthyes like Scoliodon. Aschelminthes; C-Acoelomate – Platyhelminthes. 55. (d) : Metameric segmentation found in all the listed three phyla. 78. (d) : Nereis, housefly and roundworms are unisexual organisms. 56. (d) : Amphioxus, a chordate contain flame cells; crop and 79. (b) : Listed characters pertain to phylum Arthropoda.

80 MTBIOLOGY TODAY | JANUARY ‘16 80. (c) : Post anal tail is a feature of chordates, only, snake in the 101.(c) : Read line number four from end of page number 29 NCERT choices is a chordate. +2. 81. (a) : Deuteromycetes are called imperfect fungi because they 102.(d) : Bending of pollen tube towards synergid is chemotropic lack perfect stage i.e., sexual stage or this stage has not yet been movement, not a chemotactic one. reported. 103.(a) : Aleurone grain layer is a part of endosperm. 82. (c) : Cell wall of diatoms is indestructible and embedded with 104. (a) : In angiosperms pollens are commonly released at 2 celled silica. stage (page number 23, 2nd paragraph NCERT +2). 83. (c) : In higher fungi (Ascomycetes and Basidiomycetes) distinct 105. (b) : Page number 35, figure 2.14(a) (check labelling carefully) dikaryophase is present during sexual life because there is a time NCERT +2. gap between plasmogamy and karyogamy. 106.(d) 84. (a) : Due to complimentary chromatic adaptations red algae show 107. (c) : Maize grain is a single seeded fruit cryopsis, so, using change in colour from top to bottom of sea water. formula n × 1.25 (where n is seeds to be produced), the answer 85. (b) : Sporophyte of bryophytes is parasite or dependent on should be 125. gametophyte; sporophyte lack root like structures to absorb 108. (c) nutrition from damp soil, both statements are true without direct relation. 109. (d) : Palynology is study of all aspects of pollen grain, canthrophily is pollination by beetle and papaya is a dioecious plant. 86. (b) : Assertion and reason are two independent true statements. 110. (d) : Page number 38, read last sentence of NCERT +2. 87. (b) : Both statements are true without any direct relation. 111. (a) : All sentences are taken from NCERT +2 Chapter 4. 88. (b) : Both are independently true statements. 112. (c) : LNG-20 is a hormone releasing IUD so makes uterus 89. (d) : Polyp produces medusae asexually and medusae for polyp unsuitable for implantation (read last paragraph of page number sexually so, A is a wrong statement. Polyp and medusa are not, 60 NCERT +2). common, to different group of cnidarians. 113. (a) : All sentences are taken from chapter number 4, NCERT +2. 90. (a) : As in platyhelminthes blastopore develops into mouth, all of rd them are protostomes. 114. (b) : Please refer to page number 64 read 3 paragraph NCERT 91. (d) : Fruits produced from ovaries without the act of fertilisation +2. rd are parthenocarpic not parthenogenetic, ovary wall mature into 115.(b) : Refer to page number 64 read 3 paragraph NCERT +2. pericarp not testa. In angiosperms endosperm development 116.(b) : Page number 61, based upon figure 4.4a NCERT +2. preceeds not proceeds the development of embryo. 117.(a) : Read article 4.2 from page number 59-60 of NCERT +2 and 92. (c) : One meiosis produces 4 pollen and each pollen produces match the columns. 2 male gametes, so, one meiosis produces 8 male gametes, so 118. (a) 96 =12 meiosis are required to produce 96 male gametes. 119. (c) : Totally based upon article 3.4 page number 49, 50 & 51 8 NCERT +2. 93. (c) 120.(d) : Read last five lines from summary of chapter Human 94. (a) : Tassels you see are nothing but stigma and style which Reproduction at page number 55 NCERT +2. wave in wind to trap pollens; (page number 29 NCERT +2 last 121.(c) : All sentences are based upon NCERT taken from articles st but one sentence of 1 paragraph) cleistogamy is one typed self menstrual cycle and gametogenesis. pollination i.e., inbreeding leads to inbreeding depression, so, loss 122.(d) : Read 5th and 6th line under article 3.7 page number 54 of hybrid vigour; read Geitonogamy at page number 28 NCERT NCERT +2. +2. In Eichhornia flowers are above the water level and purple in nd st colour, so, pollinated by bees, dioecy is unisexuality of plant, so, no 123. (b) : Read 2 last sentence of 1 paragraph under the article 3.3 possibility of self pollination. gametogenesis page number 47 NCERT +2. 95. (a) : Page number 22, NCERT +2 Ist paragraph. 124. (b) 96. (c) : Double fertilisation was discovered by Nawaschin in Lilium, 125. (b) : Seminiferous tubule produces sperms so, not an accessory and Fritillaria but, in Monotropa plant fertilisation was discovered duct in male reproductive system, Leydig’s cells lies outside the by Strasburger. Polygonum type of embryosac is monosporic seminiferous tubule, human mammary glands are modified sweat typed. glands, human sperms, develop at temperature 2-2.5°C less than 97. (d) : C-of shown diagram is a zygote, not an embryo, as it is human body temperature (37°C). unicellular. A-produces 3n endosperm (based upon figure 2.13(a) 126. (d) : LH is produced by anterior pituitary, not by placenta. page number 34 NCERT +2). 127.(d) : All sentences from male and female reproductive systems 98. (a) : Carpel is modified megasporophyll and mega-sporangium given in Chapter 3rd of NCERT +2. modifies to form ovule. 128.(c) 99. (b) 129.(c) : Look at Fig. 3.9 page number 50 NCERT +2. 100. (d) : Orchid are monocot producing non endospermic seeds, 130. (a) : In absence of fertilisation, corpus luteum degenerates leading groundnut, pea and mustard are non endospermic dicots. Castor to decrease level of progesterone which causes disintegration of is endospermic dicot, barley, maize and wheat are endospermic endometrium. monocots.

MTBIOLOGY TODAY | JANUARY ‘16 81 131.(d) : Menstruation trigger is decrease level of progesterone due 159. (b): Guanosine, uridine and adenosine are nucleosides here to degeneration of corpus luteum. cytosine is a nitrogenous base. 132. (c) 133.(d) 160. (d) : Largest gene dystrophin contain 2.4 bp’s. All sentences 134. (c) : Colostrum does not contain Fe and vitamin C, but, colostrum taken from article salient features of human genome project page is rich in IgA and protein. number 120 NCERT +2. 135. (d) 136. (b) 137. (b) 161. (d): Pribnow box lies in coding strand of DNA; amino acid binds at 3′ of tRNA by ester bond; Translation initiated by AUG codon 138. (c): Human egg is alecithal, noncledoic. Cleavage in human are where as s factor initiates transcription. taken as equal and indeterminate; corona radiata is a secondary membrane. Human placenta produced from chorion, so chorionic; 162. (c): Two strands of DNA are antiparallel as phosphodiester in the early embryonic stage vili are uniformly distributed over linkage is reversed to make H-bonding between A = T & C ≡ G. Reverse order of phosphodiester is the consequence of blastocyst and later on remain restricted to discoidal area so H-bonding. metadiscoidal; all extra embryonic membrane are shed from female body, so, deciduate. 163. (a) : Based upon article 6.4.1 page number 104-105 NCERT+2. 139. (b) : Eye lens is ectodermal in origin. 164. (c) : Refer to page number 88, figure 5.14 read the label of the figure, NCERT +2. 140. (a) : Birth canal is formed of both cervical canal and vagina. (Read 2nd paragraph on page number 46 NCERT +2). 165. (c) : Gynaecomastia, under developed feminine characters and azoospermia are not the symptoms of down’s syndrome. 141. (d) : Character is controlled by autosomal recessive gene. 166.(c) 142. (d) : Read label of figure 1.4 on page number 7 of NCERT +2. 167. (b) : Based upon understanding of figure 6.9 page number 108 143. (c) : Chara, Leech, Maize, Tapeworm, Funaria and earthworm NCERT +2. are monoecious mean bisexual. 168. (a) : As codons are read from 5′→ 3′ so given codon 3′UAG5′ is 144.(b) 145. (d) 146. (c) GAU not a non sense codon. 147. (d) : Two meiosis because meiosis leads to formation of 8 169. (a) : 3rd base of codon is wobble base, Z-gene of lac operon microspores (pollen). Microspores (pollen) 16 mitosis because one produces b-galactosidase which digests lactose to glucose and pollen produces 2 male gametes by 2 mitosis during development galactose, so, it is a hydrolytic enzyme, 23S rRNA is a ribozyme, of male gametophyte. found in prokaryotic ribosome. 148. (c) : Plants with foul odours are pollinated by flies and beetle, 170. (c) : As transition is replacement of purine by purine or pyrimidine page number 30 NCERT +2. by pyrimidine so one codon contain three nitrogenous bases it can 149. (c) : Unsaturated fats protects skin from UV rays. undergo only three transitions. 150. (a) 171. (b) st 151. (d) : Based upon article Sickle Cell anaemia and figure 5.15 172. (d): To form 1 peptide bond 7 phosphate bonds are required (4 given on page number 89 NCERT +2. from ATP and 3 from GTP). 152. (b) : Inbreeding because marriage between closely related 173. (d) : Tailoring means processing which is carried out by snurp individuals is one type of inbreeding. (i.e., splicing only). 32 35 153. (d) 154. (d) 174.(c) : Unequivocal proof used P and S because it was Hershey and Chase Experiment. 155. (d) : 175.(b) : Based upon basics of genetics, all given in chapter 5 NCERT +2. 176.(c) : Based upon examples given in chapter 5 NCERT +2. 177. (d) : Ala lies on P-site it will contribute –COOH group and Val lies on A-site will contribute –NH2 group. 178. (a): T y C loop because minor loop or loop III always lies between As relation of gene C with respect to B and D is not given it can anticodon and T y C loop. be on either side of A. If C is on left side of A, sequence may be 179.(c) : If 100 meiosis are being studied. They lead to formation CABD or if on right side of A then, the sequence may be ACBD or of 400 gametes and 10% crossing over lead to formation of DBAC. So, the answer is any of these. 20 recombinant gametes, so, percentage recombination will be 20 156. (a) : To find number of genotypes in a population for given ×=100 5% . number of multiple allele for a character, formula used is 400 n ()n +1 where n is number of allele controlling a character so 180.(b) : Based upon article sex determination in honey bee on page 2 15 number 288 NCERT +2. here, the number of genotypes ==()15 +=1 120 .  2 157. (c) : Number of gametic genotypes produced by a hybrid is given by formula 2n, where n is number of hybrid pair of factors in the ANSWERS WHO AM I ... individual, so 24 = 16. 1. Mycoplasma Pg. 51 158. (d) : Refer to last sentence of paragraph under heading 2. Mesosome Pg. 56 thalassemia on page number 289 NCERT +2. 3. Pecten Pg. 69

82 MTBIOLOGY TODAY | JANUARY ‘16 Readers can send their responses at [email protected] or post us with complete address by 25th of every month to win exciting prizes. Winners' name will be published in next issue. ACROSS 7. A protein which forms principal component of bacterial flagella. (9) 132 4 5 6 12. The highly resistant glycoprotein particles formed 789 10 due to mutation in gene PRNP. (6) 11 12 15. A protein which forms the bacterial appendages which are not used in locomotion. (5) 13

18. A collection of secretions from the male accessory 14 15 16 17 glands and sperms from testes. (5) 20. An iron containing molecule that binds to protein to form haemoproteins. (4) 18 19 22. A condition in which the dissolved oxygen is below 20 21 the necessary level to sustain animal life. (7) 23. An attachment point in seed through which it

attached to the funicle. (5) 22 24. A somatic hybrid formed as a result of somatic hybridisation. (6) 23 24

25. The simplest and the smallest free-living prokar- 25 26 yotes. (9) 27 27. A poisonous substance produced by Paramecium. (9) 28. The zygote of cellular slime moulds is called 28 29

______. (9) 30 29. A fertile male in a colony of honeybee. (5) 30. A type of asexual reproduction in protozoa. (10) 10. A flat, broad and leaf-like mycophycomycetes which is attached DOWN to the substratum at one or few places. (7) 1. Unicellular green algae which act as indicators of clean 11. A disease caused by Trichomonas vaginalis in human water. (7) females (11) 2. The outermost mucilage layer of the bacterial cell which consists 13. A drug which is derived from opium and used in medicine for of non-cellulosic polysaccharides. (10) inducing sleep. (6) 3. The smallest self replicating particles. (7) 14. A soluble carbohydrate found in the root tubers of Dahlia. (6) 4. An ingrowth of plasma membrane in bacteria which contains 16. A dual entities having association between fungus and an respiratory enzymes. (8) alga. (6) 5. A disease in silkworm caused by Nosema bombycis. (7) 17. A glue obtained from red algae; used as adhesive in textiles. (6) 6. A vesicle present in Aquaspirillum magnetotacticum having 19. A unit prefix in the metric system denoting a factor ofone magnetite. (11) million. (4) 8. A slender pseudopodia with axial support found in amoeboid 21. A branch of science which deals with the study of various causes protozoans. (8) of the disease. (8) 9. A mass of nervous tissue containing many cell bodies and 26. A highly condensed and specialised underground stem. (4) synapses. (8) 

MTBIOLOGY TODAY | JANUARY ‘16 83 All the Best for your Exam. Show your best, MTG is with you for all kind of assistance. Success is waiting for you. YUASK Q. 2.Why the inner portion of some guavas is of red colour? –Akanksha Deshmukh Ans. The guava fruit grows on a small tree with a wide, short WE ANSWER canopy and a sturdy single to multi-stemmed trunk. The guava Do you have a question that you just can’t get answered? tree is an interesting plant with mottled greenish bark and Use the vast expertise of our MTg team to get to the bottom simple, elliptic to ovate leaves. Guava trees produce white of the question. From the serious to the silly, the controversial flowers that yield to small round, oval or pear shaped fruits. to the trivial, the team will tackle the questions, easy and These are more accurately berries and have soft flesh, which tough. Few questions and their solutions are printed in this may be white, pink, yellow or even red and varies in taste from column. For more queries and their answers, please visit acidic, sour to sweet, and nutrient content varies depending www.mtg.in upon variety. Readers can send their queries at [email protected] or post to us. There are many different varieties such as Blitch (pink inside), Q.1. I am appearing for Class 12th Boards this year. Can you Mexican Cream (creamy-white), Ruby (red inside) and Supreme suggest me how should I plan my studies to get good (white inside.) marks? Pink guava contains naturally occurring organic pigment – Nishtha Garg, New Delhi lycopene which is a carotenoid, that imparts pink colour to Ans. It is already January, so the syllabus has almost completed its pulp. The concentration of carotenoid varies from species in the schools. Thus, your focus should be more on revision to species depending upon which guavas range from light and practice. You should keep the following in mind while pink to deep pink. The carotenoid content of white guava is preparing: insufficient to impart colour to its pericarp (pulp). (i) Vision and Revision : Though there is no one method of revising that works for everyone, but it is important to cover Q. 3.If Apple is cut in pieces, after sometime its colour the whole syllabus on time, so that you have enough time becomes brownish. What is the reason behind it? for last revision before an exam. Leaving everything until the –Sibat Sidiq, Kashmir last minute reduces chances of success, and leads to stress. Ans. The outer skin of an apple acts to protect the inner pulp (a) Plan your revision timetable and do strictly follow it. against injury. But if this layer is damaged, the cells in the (b) Keep track of your progress, topics that you have pulp release enzymes which react with oxygen to oxidise the covered. damaged cells and form a protective layer against infection. (c) Make short notes and highlight the text for faster Thus, the brown colouration in an apple occurs in response revision. to damage caused to the apple. (d) Do as many practice questions as you can. It will help to Apples contain an enzyme called polyphenol oxidase that make concept clear. You can use - “MTG-Excel in Biology” reacts with oxygen and iron-containing phenols that are found which is very helpful for final revision and would help you in the apple. The oxidation reaction basically forms a sort of to achieve peak performance in board examination. Theory rust on the surface of the fruit. Browning of the fruit is seen covers all topics and is presented in a manner that you when it is cut or bruised because these actions damage the can master on each topic. Practice papers and previous cells in the fruit, allowing oxygen in the air to react with the year’s board papers would help you to get deep insight enzyme and other chemicals, as oxygen present in air is an about examination. extremely reactive gas. (ii) Learn the key words : Write the solution according to question When oxygen enters in the cell, polyphenol oxidase (PPO) only. Use key words in your answers like name, definition, enzymes in the chloroplasts rapidly oxidise phenolic description, explanation. compounds, present in the apple tissues to o-quinones, colourless precursors to brown-coloured secondary products. (iii) In the examination : Keep yourself calm and relaxed when O-quinones then produce the well documented brown colour you receive question paper and carefully fill your details in by reacting to form compounds with amino acids or proteins, response sheet. or they self-assemble to make polymers.Thus, the brown colour (a) Do not panic if you are not able to answer any question of apple is due to rusting. and do not waste too much time on particular question. (b) Manage your time from beginning, so that you can attempt If we cut a browned apple into two again, we will notice that the insides are still white. That’s because the cells inside were all questions. intact, and did not let oxygen enter right inside. (c) Use ‘left over’ time for revision and highlighting important points. 

84 MTBIOLOGY TODAY | JANUARY‘16 BIOLOGY TODAY 2015 AT A GLANCE

HIGH YIELD FACTS MONTHS PMT ESSENTIAL PMT FOUNDATION CONCEPT MAP BOTANY ZOOLOGY

JAN Biotic Interactions ...... Excretion and Osmoregulation Human Physiology Nitrogen Nutrition in Plants

Human Male Reproductive FEB Chromosomal Mutations Immunology Transport in Plants - I Reproduction System

Human Female Reproductive MARCH ...... Sensory Receptors Transport in Plants - II Genetics and Evolution System

APRIL Photosynthesis-I Animal Kingdom - I Ecological Succession Biology in Human Welfare Gametogenesis

Breathing and Exchange of MAY Photosynthesis-II ...... Biotechnology Five Kingdom Classification Gases

JUNE ...... Animal Kingdom - II Origin of Life Ecology Metabolism

Sexual Reproduction in Flowering JULY Animal Kingdom - III Microbes in Human Welfare Diversity in the Living World Cellular Respiration Plants-I Sexual Reproduction in Flowering Structural Organisation in Plants AUG Animal Kingdom - IV Animal Husbandry Synapse Plants-II and Animals SEPT Plant Tissue Culture Animal Kingdom - V Biological Classification Cell: Structure and Functions Morphology of Roots OCT Biodiversity and Conservation Animal Kingdom - VI Plant Breeding Plant Physiology Morphology of Stem NOV Environmental Issues - I Animal Kingdom - VII Human Heart Human Physiology - Part-I Morphology of Leaf Pre-Mendelian and Mendelian Human Physiology - Part-II DEC Environmental Issues-II Animal Kingdom - VIII Inflorescence Genetics

SOLVED PAPER NCERT XTRACT PRACTICE PAPER SPECIAL FEATURES (2015)

You Ask We Answer, Biology Olympiad Problems, Concept Booster, JAN Plant Growth and Development ...... CBSE Board Unit-V Crossword

Biotechnology-Principles and FEB ...... CBSE Board 2015 Concept Booster, Crossword Processes

Target PMTs, Biology Olympiad Problems, You Ask We Answer, MARCH ...... CBSE Board 2015 Concept Booster, Crossword

APRIL ...... Target AIPMT You Ask We Answer, Target PMTs, Crossword, AIIMS Special

Target PMTs, AIIMS Special, You Ask We Answer, Bio Bulletin, MAY ...... CBSE Board Target AIIMS Crossword

AIPMT, WBJEE, JUNE ...... Target PMTs, Crossword Kerala PMT

MH-CET, COMEDK, JULY ...... *Mind Bogglers, *Unscramble Me, Crossword KCET

AIIMS’ 15 Toppers Talk, Mind Bogglers, You Ask We Answer, AUG Biotechnology and its Application J & K CET ...... *Spellathon, Unscramble Me, Concept Booster, Crossword

Mind Bogglers, AIIMS Special, You Ask We Answer, Spellathon, SEPT Mineral Nutrition AIPMT (Re-Exam) CBSE Board Unit-I Unscramble Me, Crossword

AIIMS Special, Mind Bogglers, You Ask We Answer, Spellathon, OCT ...... Bihar CECE CBSE Board Unit-II Unscramble Me, Crossword

Topper’s Talk, AIIMS Special, *Glance Around, Nobel Prize 2015, NOV Transport in Plants ...... CBSE Board Unit-III Spellathon, Unscramble Me, Crossword You Ask We Answer, Glance Around, AIIMS Special, *Bio-gram, DEC Evolution ...... CBSE Board Unit-IV *Bio-Reporter, Crossword, Unscramble Me, Spellathon

*New features introduced MTBIOLOGY TODAY | JANUARY ‘16 85 86 MTBIOLOGY TODAY | JANUARY ‘16