Science-Class-12 Biology DPP Talent Search Examinations

Biology-XII 1. Biennials flower (1) Twice in a year (2) Once in every two years (3) First in second year and then every year (4) Only once after the completion of second season 2. The term Xenia denotes the effect of foreign pollen grain on the (1) Endosperm (2) Egg (3) Nucellus (4) Seed coat 3. The best example of polyembryony is seen in (1) Cocos (2) Citrus (3) Capsicum (4) Cycas 4. Formation of an embryo from unfertilised antipodals is (1) Apospory (2) Diplospory (3) Apogamy (4) Parthenogenesis 5. What is true about agamospermous apospory? (1) Formation of embryo from egg of embryo sac proliferated from a nucellar cell (2) Formation of embryo from egg of embryo sac formed directly from megaspore mother cell (3) Formation of embryo direct from nucellus (4) Formation of embryo direct from integument 6. The type of pollination found in Zostera is (1) Geitonogamy (2) Anemophily (3) Hydrophily (4) Entomophily 7. Mesogamy is found in (1) Cucurbita (2) Casuarina (3) Allium (4) Aster 8. For the formation of 50 embryos with 50 endosperms in a tobacco plant, minimum meiosis required will be (1) 12.5 (2) 50 (3) 62.5 (4) 63 9. Aleurone layer is present in (1) Cotyledons (2) The peripheral part of endosperm (3) The peripheral part of scutellum (4) The peripheral part of coleoptile 10. The pyramid of biomass, in a pond ecosystem, is generally (1) Inverted (2) Irregular (3) Upright (4) None of these 11. The closely related morphologically similar sympatric populations, but reproductivity isolated, are designated as (1) Clines (2) Clones (3) Demes (4) Sibling species - : Rough Space : - [2] Biology-XII 12. The two great industrial tragedies due to MIC and atomic power plant blast respectively occurred where and at which year ? (1) Bhopal 1980, Ukrain 1990 (2) Bhopal 1984, Ukrain 1986 (3) Bhopal 1986, Ukrain 1988 (4) Bhopal 1986, Russia 1988 13. The plant which can withstand narrow range of temperature tolerance, are called (1) Stenothermic (2) Monothermic (3) Eurythermic (4) Mesothermic 14. Rio De Janeiro conference held in 1992 was called (1) Earth summit (2) Wildlife conservation (3) Population control (4) Green house control 15. Which sector is the single-largest consumer of fresh water in India? (1) Agriculture (2) Industry (3) Domestic (4) Power 16. Forest area in India is about (1) 9 percent of geographical area (2) 19 percent of geographical area (3) 29 percent of geographical area (4) 37 percent of geographical area 17. Which of the following changes in a mRNA molecule is least likely to result in a deleterious effect ? (1) Insertion of a transposable element in a coding codon (2) Change of the first base of a codon of a coding region (3) Change of the second base of a codon (4) Change of the third base of a codon 18. A man and a woman who both appear normal have a child who has sickle cell anaemia. Sickele cell anaemia is an autosomal recessive trait. The woman becomes pregnant again and is told that she is carrying fraternal twins. What is the probability that both the twins will develop sickle cell anaemia ? (1) 1/16 (2) 1/4 (3) 1/2 (4) 9/16 19. Replication of DNA is (1) Unidirectional in prokaryotes and bidirectional in eukaryotes (2) Bidirectional in prokaryotes and unidirectional in eukaryotes (3) Unidirectional in both prokaryotes as well as in eukaryotes (4) Bidirectional in prokaryotes as well as eukaryotes - : Rough Space : - [3] Biology-XII 20. Proof-reading in a DNA strand during replication is due to (1) Endonuclease activity of DNA polymerase (2) DNA dependent exonuclease activity of DNA polymerases I, II as well as III in 3' to 5' direction (3) DNA dependent RNA polymerase activity of DNA polymerase II in 5´ to 3´ direction (4) RNA dependent DNA polymerase activity of DNA polymerase I in 5´ to 3´ direction 21. Which one of the following is correct about ribosome structure? (1) 50S subunit is made up of 23S rRNA, 5.8S rRNA and 21 proteins molecules (2) 30S subunit is made up of 16S rRNA and 32 proteins molecules (3) 60S subunit is made up of 28S rRNA, 5.8S rRNA, 5S rRNA and 50 protein molecules (4) None of the above 22. Which of the following is an incorrect statement? (1) In bacteria the translation starts only when transcription is completed (2) Translation on a mRNA begins while transcription is still going on (3) Capping occurs at the 5' end of the mRNA in eukaryotes only (4) The split genes occur in eukaryotes only 23. The theory that the strength of linkage between genes present on a chromosome is inversely proportional to the distance between them, was envisaged by (1) Bateson and Punnet (2) Morgan and Bateson (3) Bateson, Punnett and Morgan (4) Sturtevant and Morgan 24. A woman with two genes, one for haemophilia and one for colour-blindness on one of her X-chromosomes marries a normal man. The progeny will be (1) All sons haemophilic and colour-blind (2) 50% haemophilic and colour-blind sons and 50% normal sons (3) All daughters haemophilic and colour-blind (4) 50% haemophilic daughters and 50% colour-blind daughters 25. The formation of Barr body in human female is of (1) Maternal origin (2) Patertnal origin (3) Either maternal or paternal origin (4) None of these 26. Most of the cave paintings discovered are associated with :- (1) Cro-magnon man (2) Neanderthal man (3) Homo-erectus (4) Dryopithecus - : Rough Space : - [4] Biology-XII 27. How are the time of ovulation and the onest of menstruation related in the human menstrual cycle (1) Both are triggered by high luteinizing hormone “spikes” (sharp increase in concentration). (2) Ovulation occurs approximately 14 days before the first day of menstruation (3) Ovulation is triggered by copulation; menstruation is triggered by hormonal effect (4) Ovulation is triggered by hormonal effect; menstruation is triggered by copulation 28. Some of the following are the given diseases matched with either causative agent or vector. The correct match is (1) Filariasis – Wucheria bancrofti (2) Guinea worm disease – Trichinella spiralis (3) Sleeping sickness – Leishmania donovani (4) Kala azar – Glossina palpalis 29. If the fossil record has few or no intermediate forms, if there are long periods in which the fossils underwent no morphological change, and if new forms arose very quickly, then evolution of these new forms would be best described as (1) Punctuated equilibrium (2) Adaptive radiation (3) Convergent evolution (4) Stabilizing selection 30. Cohesive ends of DNA are produced by restriction endonuclease when (1) They cleave both strands of DNA so as to leave no unpaired bases on either end (2) Make staggered cuts on the two DNA strands leaving two to four nucleotides of one strand unpaired at each resulting end (3) They cut the methylated strand of host DNA by error (4) Enzymatic digestion of strand follows from one end after action of endonuclease 31. Following are some statements regarding the primary and secondary antibody response in humans. All the statement are correct except (1) Lag period (time between the introduction of antigen and appearance of antibodies in blood) in primary response is longer than that in secondary response (2) Predominantly produced in primary response is IgM while that in secondary response is IgG (3) Primary antibodies have a higher affinity for antigen as compared to secondary antibodies (4) IgM type of antibodies are produced in both primary and secondary response 32. Baculo viruses may be used as (1) Biofertilzer (2) Biopesticide (3) Biowar (4) All the above - : Rough Space : - [5] Biology-XII 33. HIV multiply in our body in which two type of cell (1) Monocyte and Lymphoblast (2) Neutrophil and Helper-T cells (3) Macrophages and TH cell (4) Macrophage and B–cell 34. Protein in silk thread is (1) Fibroin (2) Fibrinolysin (3) Fibrinase (4) Fibrin 35. Jurassic period of the Mesozoic era is characterised by (1) Dinosaurs became extinct and angiosperms appeared (2) Flowering plants and first dinosaurs appeared (3) Gymnosperms were dominant and first birds appeared (4) Radiation of reptiles and origin of mammal-like reptiles 36. If a person is severly injured and has not taken any tetanus vaccine then which type of immunity would protects immediately against tetanus (1) Active acquired immunity (2) Passive acquired immunity (3) Congenital immunity (4) Cellular immunity 37. Radioactive dating was performed on a rock to estimate its age. When the rock was analysed for its atomic content, it show presence of K40: Ar40 in the ratio of 1 : 7. If the half life of K40 is 1.25 billion years then the age of rock is (1) 1.25 billion years (2) 2.50 billion years (3) 8.75 billion years (4) 3.75 billion years 38. ZIFT-ET is usually applied for (1) If female is sterile and provide unfavourable environment for implantation (2) If female is fertile and provide unfavourable environment for implantation (3) If female is fertile and unfavourable environment for fertilization but favourable for implantation (4) Any of the conditions 39. Cyclosporin A is obtained from (1) Lactobaccilus (2) Saccharomyces cereviceae (3) Methanococcus (4) Trichoderma polysporum 40. Two populations of deer and mouse are found, one in the heart of the forest and the other in a nearby field habitat. The two populations show no interbreeding naturally but can interbreed in laboratory. This type of isolation is called :- (1) Seasonal isolation (2) Ecological isolation (3) Physiological isolation (4) Behavioural isolation - : Rough Space : - [6] Biology-XII 41. A plasmid occurs in the soil bacterium “Agrobacterium tumefaciens” infects all broad level agricultural crops such as tomato, soyabean, sunflower & cotton. It induces formation of cancerous growth called a “Crown gall tumor”. This is (1) F-plasmid (2) Ti-plasmid (3) R-Plasmid (4) Col – plasmid 42. Verhulst pearl logistic growth is described by following equation dN  rN dN  rN  N  K  (1) dt rt (2) dt dN       N  (3) (3) Nt  n0 e (4) dt rN 1     43. Which drug interferes with the transport of neuro-transmitter dopamine (1) Cannabinoid (2) Cocaine (3) Opioids (4) Heroin 44. Which of the following match is correct ? (1) Saccharomyces cerevisiae - Alcohol (2) Methanococcus - Vitamin B12 (3) Penicillium notatum - Neomycin (4) Trichoderma polysporum - Citric acid 45. G–6–P dehydrogenase deficiency is associated with haemolysis of (1) Leucocytes (2) Lymphocytes (3) Platelets (4) RBCs 46. The phase of menstrual cycle in humans that last for 7-8 days is (1) Follicular phase (2) Ovulatory phase (3) Luteal phase (4) Menstruation 47. Which one of the following is not correctly matched (1) Culex pipiens –– Filariasis (2) Aedes aegypti – Yellow fever (3) Anopheles culifacies – Leishmaniasis (4) Glossina palpalis – Sleeping sickness 48. Which of the following statements is incorrect regarding sewage treatment (1) The greater the BOD of waste water, more is its polluting potential hence BOD is a measure of the organic matter present in the water (2) Aerobic bacteria are used in primary treatment of sewage whereas anaerobic bacteria are used in secondary treatment of sewage (3) During sewage treatment bacteria produces a mixture of gases such as methane, hydrogen sulphide and carbondioxide, which forms biogas, used as a source of energy (4) None of these - : Rough Space : - [7] Biology-XII 49. ELISA is used to detect viruses, where (1) Southern blotting is done (2) Alkaline phosphatase is the key reagent (3) Catalase is the key reagent (4) DNA–probes are required 50. Following are given some trends/milestones in the evolution of plants I. Origin of vascular system II. Origin of rhizoids III. Origin of seeds The correct order of these events is IV. Origin of flowers (1) 1; 2; 4; 3 (2) 1; 2; 3; 4 (3) 2; 1; 3; 4 (4) 2; 1; 4; 3 🙤🙦🙥🙧 - : Rough Space : - [8] Biology-XII Biology Class-XII Answers 1. (4) 2. (1) 3. (2) 4. (3) 5. (1) 6. (3) 7. (1) 8. (4) 9. (2) 10. (1) 11. (4) 12. (2) 13. (1) 14. (1) 15. (1) 16. (2) 17. (4) 18. (1) 19. (4) 20. (2) 21. (3) 22. (1) 23. (4) 24. (2) 25. (3) 26. (1) 27. (2) 28. (1) 29. (1) 30. (2) 31. (3) 32. (2) 33. (3) 34. (1) 35. (3) 36. (2) 37. (4) 38. (3) 39. (4) 40. (2) 41. (2) 42. (4) 43. (2) 44. (1) 45. (4) 46. (1) 47. (3) 48. (2) 49. (2) 50. (3) - : Rough Space : - [9]