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1 BIOLOGY (Theory) Time allowed : 3 hours Maximum Marks : 70 General Instructions: (i) (ii) All questions are compulsory. The question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C is of 9 questions of three marks each and Section D is of 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. QUESTION PAPER CODE 57/1/1 SECTION A 1. Mention the unique flowering phenomenon exhibited by Strobilanthus kunthiana (neelakuranaji) How does smoking tobacco in human lead to oxygen deficiency in their body? 1 3. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same species produced constricted green pods. Identify the dominant traits Why is Eichhornia crassipes nicknamed as "Terror of Bengal"? 1 5. Write the location and function of the sertoli cells in humans Name the following: 1 The semi-dwarf variety of wheat which is high-yielding and disease-resistant. Any one inter-specific hybrid mammal. 215

2 7. Write the similarity between the wing of a butterfly and the wing of a bat. What do you infer from the above with reference to evolution? 1 8. Write what do phytophagous insects feed on. 1 SECTION - B 9. Draw a neat labelled sketch of a replicating fork of DNA Where is sporopollenin present in plants? State its significance with reference to its chemical nature Highlight the role of thymus as a lymphoid organ. 2 Name the cells that are released from the above mentioned gland. Mention how they help in immunity. 12. Explain the work carried out by Cohen and Boyer that contributed immensely in biotechnology Why do clown fish and sea anemone pair up? What is this relationship called? State the difference between meiocyte and gamete with respect to chromosome number. 2 Why is a whiptail lizard referred to as parthenogenetic? 15. Name the plant source of the drug popularly called "smack". How does it affect the body of the abuser? 2 Why is Rhizobium categorized as a 'symbiotic bacterium'? How does it act as a biofertiliser? 16. State the role of DNA ligase in biotechnology. 2 What happens when Meloidegyne incognitia consumes cells with RNAi gene? 17. Some organisms suspend their metabolic activities to survive in unfavourable conditions. Explain with the help of any four examples

3 18. Name the Protozoan parasite that causes amoebic dysentery in humans. Mention two diagnostic symptoms of the disease. How is this disease transmitted to others? SECTION - C 19. It is established that RNA is the first genetic material. Explain giving three reasons. 3 Name the enzyme responsible for the transcription of trna and the amino acid the initiator trna gets linked with. Explain the role of initiator trna in initiation of protein synthesis. 20. State the theory of Biogenesis. How does Miller's experiment support this theory? Name the two different categories of microbes naturally occurring in sewage water. Explain their role in cleaning sewage water into usable water Write the function of each one of the following: (Oviducal) Fimbriae Coleoptile Oxytocin 23. Name the genes responsible for making Bt cotton plants resistant to bollworm attack. How do such plants attain resistance against bollworm attacks? Explain Study a part of the life cycle of malarial parasite given below. Answer the questions that follows: 3 217

4 Mention the roles of 'A' in the life cycle of the malarial parasite. Name the event 'C' and the organ where this event occurs. Identify the organ 'B' and name the cells being released from it. 25. Given below is the representation of amino acid composition of the relevant translated portion of β-chain of haemoglobin, related to the shape of human red blood cells. 3 Is this representation indicating a normal human or a sufferer from certain related genetic disease? Give reason in support of your answer. What difference would be noticed in the phenotype of the normal and the sufferer related to this gene? Who are likely to suffer more from the defect related to the gene represented the males, the females or both males and females equally? And why? 26. By the end of 2002 the public transport of Delhi switched over to a new fuel. Name the fuel. Why is this fuel considered better? Explain Draw a schematic sketch of pbr 322 plasmid and label the following in it : Any two restriction sites. Ori and rop genes. An antibiotic resistant gene. 218

5 SECTION - D 28. Explain the carbon cycle with the help of a simplified model. 5 Explain how does: a primary succession start on a bare rock and reach a climax community? the algal bloom eventually choke the waterbody in an industrial area? 29. The following is the illustration of the sequence of ovarian events (a i) in a human female. 5 (i) (ii) (iii) (iv) (v) Identify the figure that illustrates ovulation and mention the stage of oogenesis it represents. Name the ovarian hormone and the pituitary hormone that have caused the above mentioned event. Explain the changes that occur in the uterus simultaneously in anticipation. Write the difference between 'c' and 'h'. Draw a labelled sketch of the structure of a human ovum prior to fertilization. How does the megaspore mother cell develop into 7-celled, 8 nucleate embryo sac in an angiosperm? Draw a labelled diagram of a mature embryo sac. 30. What is the inheritance pattern observed in the size of starch grains and seed shape of Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of inheritance deviate from that of Mendelian law of dominance? 5 State the aim and describe Messelson and Stahl's experiment. 219

6 QUESTION PAPER CODE 57/1 SECTION A 1. Why is banana considered a good example of parthenocarpy? 1 2. State two different roles of spleen in the human body A garden pea plant produced axial white flowers. Another of. the same species produced terminal violet flowers. Identify the dominant traits Why is it desirable to use unleaded petrol in vehicles fitted with catalytic converters? 1 5. Where is acrosome present in humans? Write its function Write the name of the following: 1 The most common species of bees suitable for apiculture An improved breed of chicken 7. Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above, with reference to evolution? 1 8. Mention the role of cyanobacteria as a biofertiliser. 1 SECTION B 9. Draw a neat labelled diagram of a nucleosome. 2 Mention what enables histones to acquire a positive charge. 10. State one advantage and one disadvantage of cleistogamy Where do the signals for parturition originate from in humans? 2 Why is it important to feed the newborn babies on colostrum? 12. A recombinant vector with a gene of interest inserted within the gene of α-galactosidase enzyme, is introduced into a bacterium. Explain the method that would help in selection of recombinant colonies from non-recombinant ones. Why is this method of selection referred to as "insertional inactivation"? 2 220

7 13. Explain brood parasitism with the help of an example Give reasons for the following: 2 The human testes are located outside the abdominal cavity.. Some organisms like honey-bees are called parthenogenetic animals. 15. Name the plant source of ganja. How does it affect the body of the abuser? 2 Name the two special types of lymphocytes in humans. How do they differ in their roles in immune response? 16. Mention the cause and the body system affected by ADA deficiency in humans. 2 Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the recipient cells. 17. How did Ahmed Khan, plastic sacks manufacturer from Bangalore, solve the everincreasing problem of accumulating plastic waste? Name the bacterium that causes typhoid. Mention two diagnostic symptoms. How is this disease transmitted to others? 2 SECTION C 19. Explain the phenomena of multiple allelism and co-dominance taking ABO blood group as an example. What is the phenotype of the following: (i) I A i (ii) i i How does industrial melanism support Darwin's theory of Natural Selection? Explain What is the programme called that is involved in improving success rate of production of desired hybrid and herd size of cattle? Explain the method used for carrying this programme for cows

8 22. Explain the function of each of the following: 3 Coleorhiza Umbilical cord Germ pores 23. How is the amplification of a gene sample of interest carried out using Polymerase Chain Reaction (PCR)? Trace the life-cycle of malarial parasite in the human body when bitten by an infected female Anopheles List the salient features of double helix structure of DNA. 3 How are the structural genes activated in the lac operon in E. coli? 26. Alien species are highly invasive and are a threat to indigenous species. Substantiate this statement with any three examples Tobacco plants are damaged severely when infested with Meloidegyne incognitia. Name and explain the strategy that is adopted to stop this infestation. Name the vector used for introducing the nematode specific gene in tobacco plant. 3 SECTION D 28. Taking one example each of habitat loss and fragmentation, explain how are the two responsible for biodiversity loss. Explain two different ways of biodiversity conservation. 5 What depletes ozone in the stratosphere? How does this affect human life? Explain biomagnification of DDT in an aquatic food chain. How does it affect the bird population? 222

9 29. The following is the illustration of the sequence of ovarian events "a" to "i" in a human female: Identify the figure that illustrates corpus luteum and name the pituitary hormone that influences its formation. Specify the endocrine function of corpus luteum. How does it influence the uterus? Why is it essential? What is the difference between "d" and "e"? (d) Draw a neat labelled sketch of Graafian follicle. 5 Why is fertilisation in an angiosperm referred to as double fertilisation? Mention the ploidy of the cells involved. Draw a neat labelled sketch of L.S. of an endospermous monocot seed. 30. Describe Frederick Griffith's experiment on Streptococcus pneumoniae. Discuss the conclusion he arrived at. 5 Explain a monohybrid cross taking seed coat colour as a trait in Pisum sativum. Work out the cross up to F 2 generation. State the laws of inheritance that can be derived from such a cross. How is the phenotypic ratio of F 2 generation different in a dihybrid cross? 223