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PBBIOSET1AK1215 14/1/16 Pre-board (EEE Consortium) Examination 2015-16) Set-1 Biology (Answer Key) ANSWERS SN O MARKS SECTION A 1 1 2 Animals like whales, bats, cheetah and humans share similarities in the pattern of bones of forelimbs. In these animals, the same structure is developed along different directions due to adaptions to different needs. This is divergent evolution (b) Molluscs. (a) Insects 3 PD=N(Population)/S(area). Starvation and mass mortality + 4 In situation of natural or man made disturbances 1 5 6 7 - In haploids showing the haplontic life cycle gamete formation involves only mitosis whereas in diploids , the gamete formation requires meiosis SECTION B + 1 Introduction of sex education in schools is another step to disseminate *4 right information to the young minds about the reproductive organs ,accessory organs of reproduction, secondary sexual characters, adolescence and related changes ,safe and hygienic sexual practices ,STD s, birth control methods etc (any four) 1+1 (i) Vaccine safety- Transgenic mice are developed to test safety of polio vaccine before being used on humans. (ii) Human protein ( -1-antitrypsin) is used to treat emphysema. OR (a) insulin from other animal source cause allergy and other immune reaction. (b) in proinsulin C peptide joins polypeptide A and B but is processed later and isn t found in mature insulin. Page 1 of 6 1+1 8 2 9 (i) Tropical environments are less seasonal, relatively more constant and predictable than temperate environments. This promotes niche specialisation and results in greater diversity. (ii) There is more solar energy available in tropics which contributes to higher productivity and in turn greater biodiversity. 2 10 Secondary treatment includes aeration of primary effluent and biological treatment involving microbial treatment .The aerobic microbe grow and oxidize the organic matter. The major part of the organic matter is consumed by the microbes so that the BOD of the sewage is decreased. *4 SECTION C 11 12 Labelin g X4 Diag. 1 a) The endosperm development precedes embryo development. The developing embryo requires nutrition for its development that is provided by the endosperm b) Page 2 of 6 3 13 3 Page 3 of 6 (c) Law of independent assortment: This law states that the different factors or allelomorphic pair in gametes and zygotes assort themselves and segregate independently of one another. 14 15 16 17 18 19 (a) Salmonella typhi (b) Widal test (c) contaminated food and water (d) Symptoms are high fever , loss of appetite , stomach ache , headache and weakness , intestinal perforations OR (a)- When a person is infected with some deadly microbes. -Snake bite , passive immunisation Advantage: quick (b) Active immunity *3 + 1 1. Semen is injected into reproductive tract of selected female by breeder 2. Artificial insemination 3. To overcome the problem and low success of normal mating. (Refer NCERT text book page 148/Fig 8.1) a) Linkage genes occur in the same chromosome b) Strength of linkage between the two genes is inversely proportional to the distance between the two. c)Turner s syndrome in human females Short stature, under developed feminine characters. Females with these conditions are sterile as ovaries of rudimentary 1+1+1 a) Close the stomata in day and open in the night. b) Carrying capacity/ Limited resource availability c) Tundra and desert biomes have adverse conditions like very low precipitation. The tundra has also been referred to as a 'cold desert' due the limited precipitation. Plants that are commonly found in the tundra biome include dwarf shrubs, grasses, mosses and lichens. The theory of biogenesis states that a living organism arises from another living organisms. Experimental evidence of chemical evolution/Miller s experiment Experiment was performed by S.L. Miller and H.C. Urey in 1953. Experimental set-up: In a closed flask containing CH4, H2, NH3 and water vapour at 800 C, electric discharge was created. The conditions were similar to those in primitive atmosphere. Observations: After a week, they observed presence of amino acids and complex molecules like sugars, nitrogen bases, pigments and fats in the flask. Conclusions: (i) It provides experimental evidence for the theory of chemical origin. Page 4 of 6 2+1 *6 1+1+1 1+1+1 3 (ii) It showed that the first non-cellular form of life was created about 3 billion years ago. (iii) It showed that non-cellular biomolecules exist in the form of DNA, RNA, polysaccharides and protein. 20 (a) M.S. Swaminathan (b) The steps are: (i) Collection of variability. (ii) Evaluation and selection of parents. (iii) Cross hybridisation among the selected parents. (iv) Selection and testing of superior recombinants. (v) Testing, release and commercialisation of new cultivars 3 21 Mature insulin does not contain the polypeptide C . Draw the diagram to explain (a) DNA is hydrophilic and insoluble in lipid portion of membrane (b) Proteases are added (c) because presence of more sites makes the process complex by generating a number of fragments. SECTION D 1+2 Ans-a) Jeevan shows alertness, responsibility and firmness in tackling a problem. He expresses boldness towards environment consciousness. Ans-b) Height of the smoke emitted from exhaust pipe is closer to the height of the children. Ans-c) It indicates that the vehicles comply with the new auto fuel policy. At present vehicles complying Euro-IV or equivalent BS-IV norms are to ply in the identified 11 cities, rest of the country to follow Euro III / BS-III norms. 4 22 23 1+1+1 Ans-d) In these devices, platinum - palladium and Rhodium are used as catalysts. As the exhaust passes through the convertor, unburnt hydrocarbons are converted into CO2 and H2O. Carbon monoxide and nitric oxide are changed into CO2 and N2 gas respectively. Vehicles fitted with such equipment should run on unleaded petrol only since lead in petrol inactivates the catalysts. SECTION E 24 OR (a) Placenta develops after implantation of embryo in human female in the uterus. After implantation, finger-like projections called chorionic villi are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with eachother and together form a structural and functional unit between developing embryo and maternal body called placenta. (b) An umbilical cord connects placenta with the embryo. (c) The placenta also acts as an endocrine gland and secretes the following hormones: (i) Human chorionic gonadotropin (hCG), Page 5 of 6 5 (ii) Human placental lactogen (hPL), (iii) Progestogens, and (iv) Estrogens The hormone hCG and hPL and relaxin are only produced during pregnancy that maintains the pregnancy.The increased production of these hormones during pregnancy is essential for supporting the fetal growth and metabolic changes in the mother 25 Hershey and Chase experiment 5 Or (i) CGG ARGININE , UCC SERINE , CCC PROLINE , UAC TYROSINE (ii) If the first Adenine in the DNA segment is substituted by Guanine (a) CGG CCC CCC UAC (b) Arg Pro Pro - Tyro (c) GCC , GGG , GGG , AUG 26 5 Refer to fig 11.4 page 119 NCERT OR (i) A cloning vector must have the following characteristics: (a) ori or origin of replication (b) Selectable marker, genes encoding for an antibiotic resistance or genes encoding for -galactosidase. (c) Cloning site or recognition site for the restriction enzyme to recognise. (ii) DNA is a hydrophilic molecule, therefore it cannot pass through the cell membrane. The bacterial cells can be made competent by treating them with a specific concentration of a divalent ion like calcium. The cells are then incubated on ice followed by a heat shock by placing them briefly at 42 C and then putting back on ice. Page 6 of 6

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