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SAMPLE PAPER III-CLASS XII BIOLOGY

1.A haemophilic man marries a normal homozygous woman. What is the probability of their daughter will be haemophilic?
2.Due to an error during transcription, ATG of DNA formed UAG in mRNA. What would happen to the polypeptide chain during translation by this changed mRNA?
3.Why are Calotropis plants not browsed by herbivores?
4.Many tribes living in the high altitude of Himalayas show relatively more number of RBC in their blood. Give the probable reason for it.
5.Why does blood pressure rise after consuming tobacco?
6.What is meant by ‘Biolistics’?
7.What is ploidy of gametes produced by Cladophora and its parent body?
8.Mention the principle of natural methods of birth control.
9.A hypothetical sequence of transcriptional unit is represented below.3’-ATGCATGCATGCATGCATGCATGC-5’ template strand.5’ TACGTACGTACGTACGTACGTACG-3’ Coding strand. Write the sequence of mRNA transcribed from this unit. In which direction enzyme DNA-dependent RNA polymerase catalyse the process?
10.Rearrange the following stages of human evolution in an ascending evolutionary scale. Homoerectus, Australopithecus, Homosapiens, Homohabilis and Ramapithecus. Which was the common ancestor of apes and man?
11.What is the role of microbes in the production of antibiotics? Give any two examples.
12.What are the steps involved in the process by which pomato can be produced?
13.Give reasons why-(i) geitonogamy is genetically similar to autogamy. (ii) Xenogamy brings about genetic variation.
14.When a red flowered Antirrhinum plant was crossed with a white flowered Antirrhinum plant, the F1 offspring had pink flowers. Mention (a) the phenotype of F2 generation. (b) The reason why it did not bear the parental red or white colours?
15.A person injured in a road accident and requiring an urgent immune response was brought to a doctor. Why did the doctor do to develop immunity? What kind of immunity was he providing to the patient? Define this kind of immunity>
16.Differentiate between AMI and CMI with reference to their response to antigens.
17.Mention two uses of cloned genes in molecular diagnostics.
18.How does Mediterranean orchid ‘ophrys’ employ sexual deceit to get pollination?
19.Why are the number trophic levels in an ecosystem limited to 4 or 5? Explain with an example.
20.Represent diagrammatically various steps in the construction of recombinant DNA.
21.If your family owned a diary farm, what measures would you take to improve the quality and quantity of milk production?
22.In case of Bt cotton how does the toxic protein produced by bacterium kill the insect pest but not the cell of bacterium where the toxic protein is generated?
23.How does industrial melanism explain Darwin’s theory of natural selection? or Explain any three factors that would affect Hardy-Weinberg equilibrium.
24.A child has blood group ‘O’. If the father has blood group ‘A’ and mother has ‘B’, work out the possible phenotypes of other offspring.
25.What is the disadvantage of sowing seeds of a hybrid plant collected directly from the plants grown in the previous season? How can we make apomixis in the production of hybrids?
26.What are the salient features of theory of chemical evolution? Who proposed it?
27.Outline the salient features of carbon cycling in an ecosystem? or What are the features required by a vector to facilitate the process of cloning?
28.Describe the various steps in the process of decomposition of detritus or (a) what is eutrophication? How does it affect the aquatic life? (b) Describe Chipko movement.
29.(a) Correct the following statements with reasons- (i) surgical method of contraception prevent gamete formation (ii) Apple is a true fruit. (iii) Spermatozoa get nutrition from leydig cells. (b)Draw a neat diagram of male gametophyte of angiosperms and label any four parts. or (a) ) Correct the following statements with reasons (i) All sexually transmitted diseases are completely curable. (ii) Cross pollination occurs in cleistogamous flowers. (iii) Semen is the product of testes.(b) Draw a neat diagram of female gametophyte of angiosperm and label any four parts.
30.The police department observes some skin scrapings in the nails of a murdered man. There were two persons suspected in this offence. How will the forensic department give a clue to find out the culprit? Explain the technique. or. One chromosome contains one molecule of DNA. In eukaryotes the length of DNA molecule is enormously large. Explain how such a long molecule fits into the tiny chromosomes seen at metaphase.

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