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CBSE Class 12 Pre Board 2020 : Biology (Kendriya Vidyalaya (KV), Lucknow Region)

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KENDRIYA VIDYALAYA SANGATHAN, LUCKNOW REGION FIRST PRE - BOARD EXAMINATION (2019-20) SET-I CLASS: XII SUBJECT: BIOLOGY (044) THEORY Time Allowed: 3 hours MaximumMarks: 70 General Instructions:1. 2. 3. There are a total of 27 questions and five sections in the question paper. All questions are compulsory. Section A contains question numbers1 to 5, multiple choice questions of one mark each. Section B contains question numbers 6 to 12, short answer type I questions of two mark each. Section C contains question numbers 13 to 21, short answer type II questions of three marks each. Section D contains question numbers 22 to 24, case-based short answer type questions of three marks each. Section E contains question numbers 25 to 27, long answer type questions of five marks each. There is no overall choice in the question paper. However, internal choices are provided in two questions of one mark, one question of two marks, two questions of three marks and all three questions of five marks. An examinee is to attempt any one of the questions out of the two given in the question paper with the same question number. SECTION-A 1. Which of the following plant is found in hilly tract of Kerala and Karnataka and flower once in twelve years: (a) (b) Mangifera indica Rosa indica (b) (d) Strobilanthus kunthiana Eucalyptus (b) (d) Apes Monkeys 1 OR Oestrus cycle occurs in: (a) Rats (c) Humans 2. The Chromosomal Theory of Inheritance was proposed by: (a) G.J.Mendel (b) Morgan (c) Sutton & Bovery (d) Griffith OR 1 1 Enzyme responsible for joining of deoxyribonucleotide into polynuceotide chain is: (a) DNA Ligase (b) DNA Polymerase (c) Endonuclease (d) Amylase 3. Human Immunodeficiency Virus (HIV) does not spread by: (a) Sharing food (b) Unprotected sexual behavior (c) Infected blood transfusion (d) Sharing infected needles 1 4. Multiple copies of a desired gene is synthesized by which process: (a) DNA fingerprinting (b) Gel electrophoresis (c) PCR (d) Bioreactor 1 5. Nodal Agency for validating GM research in India is(a) CPCB (b) IUCN (c) IARI (d) GEAC SECTION-B 6. Name the vegetative propagules in the following: (a) Agave (b) (c) Potato (d) 2 Bryophyllum Water hyacinth OR Name the organic material of which Exine of pollen grains made of? How is this material advantageous to pollen grain? Give reasons. 7. Why are humans testes located outside the abdominal cavity? Name any one hormone produced from testes? 2 8. Why is it that the father never passes on the gene for Haemophilia to his sons? Explain. 2 9. DNA is considered better hereditary material than RNA. Give reasons. 2 10. What is meant by germ plasm collection? Give its any two significance? 2 11. What is multiple allelism? Give an example. 2 12. Name the deficiency disease for which first clinical Gene Therapy was given? Mention the cause and one cure for this disease. 2 2 SECTION-C 13. Draw a diagram of a mature human sperm. Label any three parts and write their functions. 3 14. Explain the mechanism of sex determination in Birds. How does it differ from that of human beings? 3 15. Why do Lepidopterans die when they feed on Bt cotton plant? Explain how it happens? 16. How do snails, seeds, bears, zooplanktons, fungi and bacteria adapt to conditions unfavorable to their survival? 3 17. 3 (a) Construct a Grazing food chain and Detritus food chain using the following with five links each. Earthworm, Bird, Snake, Vulture, Grass, Grasshopper, Frog, Decaying plant matter. 3 (b) The pitcher plant is a producer as well as a consumer. Do you agree with this statement? Justify by giving reasons. 18. Draw a well labeled sketch of a typical Biogas Plant. State its one application. 3 19. (a) Briefly explain the process of double fertilization in angiosperms? 3 (b) Why does the development of endosperm precedes that of embryo? OR (a) (b) 20. Draw a diagram of L.S of Maize seed and label any four parts. What is Apomixis? Appearance of Melanised moth post industrialization in England is a classic example of evolution by natural selection. Explain. 3 OR What is DNA finger printing? Mention any two of its applications. 21. Describe the process of amplification of Gene of interest using PCR technique. 3 3 SECTION-D 22. With reference to the above schematic representation of (a) Spermatogenesis and (b) Oogenesis, answer the following questions: (i) (ii) About 300 million spermatozoa may be present in a human male ejaculation at one time. Calculate how many Spermatocytes will be involved to produce 300 spermatozoa. How many Chromatids are found during Oogenesis in (a) Primary Oocyte and (b) First polar body in a human female? 23. Study the following molecule of an antibody and answer the questions that follows: - 3 (i) (ii) (iii) Identify A, B, and C in the diagram of an antibody molecule. What are the antigens and antibodies? What is the chemical composition of an antibody? 4 (24) Observe the above diagram and answer the following questions: (i) (ii) (iii) 3 Why is the Pyramid of energy always upright? Can a given species occupy more than one trophic level in the same ecosystem at the same time? State any two limitations of Ecological Pyramids. 5 SECTION-E 25. (a) Why are colorblindness and thalassemia categorized as Mendelian disorders? How thalassemia differ from sickle cell anaemia? 5 (b) About 8% of human male population suffers from colour blindness whereas only about 0.4 % of human female population suffers from this disease. Write an explanation to this statement with cross. OR Answer the following question based on Hershey and Chase s experiment:(a) Name the type of virus they worked with and why? (b) Why did they used two types of culture media to grow viruses? Explain. (c) What was the need for using a blender and later a centrifuge during their experiments? State the conclusion drawn by them after the experiment. (d) 26. (a) Baculoviruses are excellent candidates for Integrated Pest Management in an ecologically sensitive areas. Explain giving two reasons. 5 (b) What is Organic farming? Why is it suggested to switch over to organic farming? How crops are protected from pests in Organic farming? OR (a) Name the source from which insulin was extracted earlier. Why is this insulin no more in use by diabetic people? (b) Explain the process of synthesis of insulin by Eli Lilly Company. Name the technique used by the company. How is the insulin produced by human body different from the insulin produced by the above mentioned company? (c) 27. Study the answer the graph given below and questions that follow: 5 6 (i) (ii) (iii) What does BOD stand for? Explain the term. What is the relationship between dissolved oxygen and BOD? Mention their effect on aquatic life in the river. OR Observe the following diagram and answer the questions that follow: - (i) Name the gases depicted in the above diagram. (ii) Comment on the consequences of increase in the level of each gas. (Any Three). -------------------------------------------------- 7

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