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12th Standard Biology English Medium Reduced Syllabus Model Question paper with answer key - 2021 Part - 1

12th Standard

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Biology

Time : 02:45:00 Hrs
Total Marks : 70

      Part I

      Answer all the questions.

      Choose the most suitable answer from the given four alternatives and write the option code with the corresponding answer.


    15 x 1 = 15
  1. Assertion and reasoning questions:
    In each of the following questions there are two statements. One is assertion (A) and other is reasoning (R). Mark the correct answer as
    Assertion: In bee society, all the members are diploid except drones.
    Reason: Drones are produced by parthenogenesis

    (a)

    If both A and R are true and R is correct explanation for A

    (b)

    If both A and R are true but R is not the correct explanation for A

    (c)

    If A is true but R is false

    (d)

    If both A and R are false

  2. In _____ types of natural parthenogenesis only females are produced.

    (a)

    Thelytoky

    (b)

    Arrhenotoky

    (c)

    Amphitoky

    (d)

    Arrhenotoky

  3. Assertion (A): Syngamy refers to the fusion of two haploid gametes.
    Reason (R): Syngamy leads to zygote formation.

    (a)

    A and R are correct.

    (b)

    A and R are incorrect.

    (c)

    R is not the right explanation for A

    (d)

    A is correct but R is incorrect

  4. A – In human male, testes are extra abdominal and lie in scrotal sacs.
    R – Scrotum acts as thermoregulator and keeps temperature lower by 2oC for normal sperm production
     

    (a)

    A and R are true, R is the correct explanation of A

    (b)

    A and R are true, R is not the correct explanation of A

    (c)

    A is true, R is false

    (d)

    Both A and R are false

  5. Three children of a family have blood groups A, AB and B. What could be the genotypes of their parents?

    (a)

    IA IB and ii

    (b)

    IA Io and IBIo

    (c)

    IB IB and IA IA

    (d)

    IA IA and ii

  6. Pataus’ syndrome is also referred to as

    (a)

    13-Trisomy

    (b)

    18-Trisormy

    (c)

    21-Trisormy

    (d)

    None of these

  7. An operon is a:

    (a)

    Protein that suppresses gene expression

    (b)

    Protein that accelerates gene expression

    (c)

    Cluster of structural genes with related function

    (d)

    Gene that switched other genes on or off

  8. Exo-erythrocytic schizogony of Plasmodium takes place in _______

    (a)

    RBC

    (b)

    Leucocytes

    (c)

    Stomach

    (d)

    Liver

  9. The gases produced in anaerobic sludge digesters are

    (a)

    Methane, oxygen and hydrogen sulphide

    (b)

    Hydrogen sulphide, methane and sulphur dioxide

    (c)

    Hydrogen sulphide, nitrogen and methane

    (d)

    Methane, hydrogen sulphide and CO2.

  10. The figure given below is a diagrammatic representation of response of organisms to abiotic factors. What do A, B and C represent respectively.

    (a)
    A B C
    Conformer Regulator Partial Regulator
    (b)
       A     B     C
    Regulatorr Partial Regulator Conformer
    (c)
    A B C
    Partial Regulatorr Regulator Conformer
    (d)
    A B C
    Regulatorr Conformerr Partial Regulatorr
  11. Which among the following is the most abundant Green-House-Gas (GHG) in the earth’s atmosphere?

    (a)

    Carbon dioxide

    (b)

    Water Vapour

    (c)

    Sulphur Dioxide

    (d)

    Tropospheric Ozone

  12. Which one of the following is an example of polygenic inheritance?

    (a)

    Flower colour in Mirabilis Jalapa

    (b)

    Production of male honey bee

    (c)

    Pod shape in garden pea

    (d)

    Skin Colour in humans

  13. The process of recombinant DNA technology has the following steps
    I. amplication of the gene
    II. Insertion of recombinant DNA into the host cells
    III. Cutting of DNA at specific location using restriction enzyme .
    IV. Isolation of genetic material (DNA) Pick out the correct sequence of step for recombinant DNA technology.

    (a)

    ii, iii, iv, and i

    (b)

    iv, ii, iii, and i

    (c)

    i, ii, iii, and iv

    (d)

    iv, iii, i, and ii

  14. Which of the following statement is correct

    (a)

    Agar is not extracted from marine algae such as seaweeds

    (b)

    Callus undergoes differentiation and produces somatic embryoids.

    (c)

    Surface sterilization of explants is done by using mercuric bromide

    (d)

    PH of the culture medium is 5.0 to 6.0

  15. Which of the following would most likely help to slow down the greenhouse effect.

    (a)

    Converting tropical forests into grazing land for cattle.

    (b)

    Ensuring that all excess paper packaging is buried to ashes.

    (c)

    Redesigning landfill dumps to allow methane to be collected.

    (d)

    Promoting the use of private rather than public transport.

    1. Part II

      Answer any 6 questions. Question no. 21 is compulsory.


    6 x 2 = 12
  16. What happens to the following floral parts, after the fertilization process?
    (a) Ovary
    (b) Secondary nucleus
    (c) Outer integument of ovule
    (d) Funicle

  17. Name any four greenhouse gases.

  18. What is Dobson unit?

  19. Where did Montreal Protocol was held? State its objectives.

  20. Mutagens are the substances that induces mutation. Name any two physical and chemical mutagens.

  21. Name the insect resistant varieties developed in the following crops.
    (a) Okra (b) Rapeseed mustard.

    1. Part III

      Answer any 6 questions. Question no. 27 is compulsory.


    6 x 3 = 18
  22. Complete the table.

      Natural Parthenogenesis Sex of developing organism
    i. Arrhenotoky A
    ii. Thelytoky B
    iii. Amphitoky C
  23. Brief about female heterogamety

  24. What is vaccine? What are its types?

  25. Give the diagnostic characters features of a Biome

  26. “Endothecium is associated with dehiscence of anther” Justify the statement

  27. What is vivipary? Name a plant group which exhibits vivipary.

    1. Part IV

      Answer all the questions.
    5 x 5 = 25
  28. Differentiate between the following:
    (a) Binary fission in amoeba and multiple fission in Plasmodium
    (b) Budding in yeast and budding in Hydra
    (c) Regeneration in lizard and Planaria

  29. What is the difference between syngamy and fertilization?

  30. Amnicentesis, the foetal sex determination test, is banned in our country, Is it necessary? comment

  31. (i) Write the scientific name of the filarial worm that causes filariasis.
    (ii) Write the symptoms of filariasis.
    (iii) How is this disease transmitted?

  32. Give a concise account on steps involved in fertilization of an angiosperm plant.

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