Select Board & Class

Login

Board Paper of Class 12-Science 2013 Biology Delhi(SET 2) - Solutions

General Instructions:
(i) All questions are compulsory.
(ii) This 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 two 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 1

    Write the equation that helps in deriving the net primary productivity of an ecosystem. (1)

    VIEW SOLUTION
  • Question 2

    Name the type biodiversity represented by the following: (1)

    (a) 50,000 different strains of rice in India.

    (b) Estuaries and alpine meadows in India

    VIEW SOLUTION
  • Question 3

    Why is the enzyme cellulase needed for isolating genetic material from plant cells and not form the animal cells? (1)

    VIEW SOLUTION
  • Question 5

    Identify the examples of homologous structures from the following: (1)

    (i) Vertebrate hearts

    (ii) Thorns in Bougainvillea and tendrils of Cucurbita.

    (iii) Food storage organs in sweet potato and potato.

    VIEW SOLUTION
  • Question 6

    Name the enzyme and state its property that is responsible for continuous and discontinuous replication of the two strands of a DNA molecule. (1)

    VIEW SOLUTION
  • Question 7

    Why sharing of injection needles between two individuals is not recommended? (1)

    VIEW SOLUTION
  • Question 8

    An anther with malfunctioning tapetum often fails to produce viable male gametophytes. Give any one reason. (1)

    VIEW SOLUTION
  • Question 9

    Describe the gene therapy procedure for an ADA-deficient patient. (2)

    VIEW SOLUTION
  • Question 10

    Expand the following and mention one application of each:

    (i) PCR

    (ii) ELISA

    OR

    (a) Mention the difference in the mode of action of exonuclease and endonuclease.

    (b) How does restriction endonuclease function? (2)

    VIEW SOLUTION
  • Question 11

    Name any two sources of e-Wastes and write two difference ways of their disposal. (2)

    VIEW SOLUTION
  • Question 12

    Why the pyramid of energy is always upright? Explain. (2)

    VIEW SOLUTION
  • Question 13

    Explain why very small animals are rarely found in polar region. (2)

    VIEW SOLUTION
  • Question 14

    (a) How does cleistogamy ensure autogamy?

    (b) State one advantage and one disadvantage of cleistogamy to the plant. (2)

    VIEW SOLUTION
  • Question 15

    When and where do chorionic villi appear in humans? State their function. (2)

    VIEW SOLUTION
  • Question 16

    In a cross between two tall pea plants some of the offsprings produced were dwarf. Show with the help of Punett square how this is possible. (2)

    VIEW SOLUTION
  • Question 17

    A young boy when brought a pet dog home started to complain of watery eyes and running nose. The symptoms disappeared when the boy was kept away from the pet.

    (a) Name of type of antibody and the chemicals responsible for such a response in the boy.

    (b) Mention the name of any one drug that could be given to the boy for immediate relief from such a response. (2)

    VIEW SOLUTION
  • Question 18

    (a) Explain how to find whether an E. coli bacterium has transformed or not when a recombinant DNA bearing ampicillin resistant gene is transferred into it.

    (b) What does the ampicillin resistant gene act as in the above case? (2)

    VIEW SOLUTION
  • Question 19

    (a) Why are the fruit juices bought from market clearer as compared to those made at home?

    (b) Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus. (3)

    VIEW SOLUTION
  • Question 20

    (a) Why a transgenic animals so called?

    (b) Explain the role of transgenic animals in (i) Vaccine safety and (ii) Biological products with the help of an example each. (3)

    VIEW SOLUTION
  • Question 21

    How have human activities caused desertification? Explain.

    OR

    How does algal bloom destroy the quality of a fresh water body? Explain. (3)

    VIEW SOLUTION
  • Question 22

    (a) Explain how to overcome inbreeding depression in cattle.

    (b) List three advantages of inbreeding in cattle.

    (c) Name an improved breed of cattle.

    VIEW SOLUTION
  • Question 23

    Explain mutualism with the help of any two examples. How is it different from commensalism? (3)

    VIEW SOLUTION
  • Question 24

    Describe the structure of RNA polynucleotide chain having four different types of nucleotides. (3)

    VIEW SOLUTION
  • Question 25

    (a) Why is human ABO blood group gene considered a good example of multiple alleles?

    (b) Work out a cross up to F1 generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited. (3)

    VIEW SOLUTION
  • Question 26

    With the help of any two suitable examples explain the effect of anthropogenic actions on organic evolution. (3)

    VIEW SOLUTION
  • Question 27

    (a) Draw a diagram of the structure of a human ovum surrounded by corona radiate. Label the following parts:

    (i) Ovum

    (ii) Plasma Membrane

    (iii) State the function of Zona Pellucida. (3)

    VIEW SOLUTION
  • Question 28

    Describe the asexual and sexual phases of life cycle of Plasmodium that causes malaria in humans. (5)

    OR

    (a) What is plant breeding? List the two steps the classical plant breeding involves.

    (b) How has the mutation breeding helped in improving crop varieties? Give one example where this technique has helped.

    (c) How has the breeding programme helped in improving the public nutritional health? State two examples in support of your answer.

    VIEW SOLUTION
  • Question 29

    A child suffering from Thalassemia is born to a normal couple. But the mother is being blamed by the family for delivering a sick baby. (5)

    (a) What is Thalassemia?

    (b) How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.

    (c) List the values your counselling can propagate in the families.

    VIEW SOLUTION
  • Question 30

    (a) Draw a labeled schematic diagram of the transverse section of a mature anther of an angiosperm plant.

    (b) Describe the characteristic feature of an insect pollinated flower.

    OR

    (a) Describe the events of spermatogenesis with the help of a schematic representation.

    (b) Write two differences between spermatogenesis and oogenesis.

    VIEW SOLUTION
More Board Paper Solutions for Class 12 Science Biology
What are you looking for?

Syllabus