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12th Standard Biology English Medium Reduced Syllabus Important Questions - 2021 Part - 2

12th Standard

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Biology

Time : 02:45:00 Hrs
Total Marks : 165

    Multiple Choice Questions

    15 x 1 = 15
  1. In which type of parthenogenesis are only males produced?

    (a)

    Arrhenotoky

    (b)

    Thelytoky

    (c)

    Amphitoky

    (d)

    Both a and b

  2. The mode of reproduction in bacteria is by

    (a)

    Formation of gametes

    (b)

    Endospore formation

    (c)

    Conjugation

    (d)

    Zoospore formation

  3. The mature sperms are stored in the

    (a)

    Seminiferous tubules

    (b)

    Vas deferens

    (c)

    Epididymis

    (d)

    Seminal vesicle

  4. The milk secreted by the mammary glands soon after child birth is called

    (a)

    Mucous

    (b)

    Colostrum

    (c)

    Lactose

    (d)

    Sucrose

  5. Assertion: Head of the sperm consists of acrosome and mitochondria.
    Reason: Acrosome contains spiral rows of mitochondria.
    Codes:
    (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.

    (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

  6. Select the incorrect action of hormonal contraceptive pills from the following

    (a)

    Inhibition of spermatogenesis.

    (b)

    Inhibition of ovulation

    (c)

    Changes in cervical mucus impairing its ability to allow passage and transport of sperms

    (d)

    Alteration in uterine endometrium to make it unsuitable for implantation

  7. Klinefelters’ syndrome is characterized by a karyotype of

    (a)

    XYY

    (b)

    XO

    (c)

    XXX

    (d)

    XXY

  8. E. coli cell grown on 15N medium are transferred to 14N medium and allowed to grow for two generations. DNA extracted from these cells is ultracentrifuged in a cesium chloride density gradient. What density distribution of DNA would you expect in this experiment?

    (a)

    One high and one low density band

    (b)

    One intermediate density band.

    (c)

    One intermediate density band.

    (d)

    One low and one intermediate density band

  9. Darwin’s finches are an excellent example of

    (a)

    connecting links

    (b)

    seasonal migration

    (c)

    adaptive radiation

    (d)

    parasitism

  10. Allergy involves

    (a)

    IgE

    (b)

    IgG

    (c)

    lgA

    (d)

    IgM

  11. PCR proceeds in three distinct steps governed by temperature, they are in order of

    (a)

    Denaturation, Annealing, Synthesis

    (b)

    Synthesis, Annealing, Denaturation

    (c)

    Annealing, Synthesis, Denaturation

    (d)

    Denaturation, Synthesis, Annealing

  12. Match the following and choose the correct combination from the options given below.

    Column I Column II
    A. Mutalism 1. Lion and deer
    B. Commensalism 2. Round worm and man
    C. Parasitism 3. Birds compete with squirrels for nuts
    D. Competition 4. Sea anemone on hermit crab
    E. Predation 5. Bernacles attached to Whales.
    (a)

    A- 4, B-5, C-2, D –3, E-1

    (b)

    A- 3, B-1, C-4, D – 2, E-5

    (c)

    A- 2, B-3, C-1, D – 5, E-4

    (d)

    A- 5, B-4, C-2, D – 3, E-1

  13. What type of human population is represented by the following age pyramid?

    (a)

    Vanishing population

    (b)

    Stable population

    (c)

    Declining population

    (d)

    Expanding population

  14. Which one of the following are at high risk extinction due to habitat destruction

    (a)

    Mammals

    (b)

    Birds

    (c)

    Amphibians

    (d)

    Echinoderms

  15. In Haplopappus gracilis, number of chromosomes in cells of nucellus is 4. What will be the chromosome number in Primary endosperm cell?

    (a)

    8

    (b)

    12

    (c)

    6

    (d)

    2

  16. 2 Marks

    15 x 2 = 30
  17. Compare point mutation with chromosomal mutation.

  18. Given below are the gene sequences on the chromosome. Compare them with the normal  chromosome and identify the type of structural chromosomal aberrations.
    Normal Chromosome : A - B - C - D - E- F - G - H - I.
    Chromosome 1 : A - B - C - B .C - D - E - F - G - H - I.
    Chromosome 2 : A - B - C - D - F - G - H - I

  19. Write an palindrome sequence of DNA.

  20. Name any four vectors that you know?

  21. What are polylinkers?

  22. Write the composition of vitamins used in MS medium.

  23. What does ELSI represents to?

  24. Heliophytes differ from Sciophytes. How?

  25. Compare Euryhaline organisms with stenohaline organisms.

  26. Mention any four topographic factors that affect vegetation.

  27. Define mutualism with an example

  28. What is standing crop?

  29. Compare Deforestation and Afforestation

  30. Write the health benefits of Kodo millet.

  31. Name the plant species used for making paper pulp.

  32. 3 Marks

    15 x 3 = 45
  33. Give reasons for the following:
    (a) Some organisms like honey bees are called parthenogenetic animals
    (b) A male honey bee has 16 chromosomes where as its female has 32 chromosomes

  34. What is inhibin? State its functions

  35. Define gametogenesis.

  36. Why tRNA is called an adapter molecule?

  37. What is vaccine? What are its types?

  38. What are DNA vaccines?

  39. One of the applications of biotechnology is ‘gene therapy” to treat a person born with a hereditary disease
    i) What does “gene therapy” mean?
    ii) Name the hereditary disease for which the first clinical gene therapy was used.
    iii) Mention the steps involved in gene therapy to treat this disease.

  40. What are the ways by which organisms respond to abiotic factors?

  41. Why do we find a decrease in biodiversity distribution, if we move from the tropics towards the poles?

  42. Why is biodiversity so important and worthy of protection?

  43. List any two strategy adopted by bisexual flowers to prevent self-pollination.

  44. Explain the law of dominance in monohybrid cross.

  45. Explain the mechanism of crossing over.

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

  47. Explain the best suited type followed by plant breeders at present?

  48. 5 Marks

    15 x 5 = 75
  49. How is juvenile phase different from reproductive phase?

  50. The procedure of GIFT involves the transfer of female gametes into the fallopain tube, can gametes be transferred to the uterus to achieve the same result? Explain.

  51. Open Book Assessment
    ‘Healthy reproduction, legally checked birth control measures and proper family planning programmes are essential for the survival of mankind’ Justify

  52. Explain the mode of sex determination in honeybees.

  53. Explain the inheritance of sex linked characters in human being.

  54. How is the two stage process of protein synthesis advantageous?

  55. Mention any three similarities found common in Neanderthal man and Homo sapiens.

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

  57. List the common withdrawal symptoms of drugs and alcohol abuse.

  58. List the advantages of biogas plants in rural areas.

  59. PCR is a useful tool for early diagnosis of an Infectious disease. Elaborate

  60. Explain why cloning of Dolly, the sheep was such a major scientific breakthrough?

  61. Give an account of the properties of soil.

  62. In north eastern states, the jhum culture is a major threat to biodiversity – substantiate.

  63. Write a note on
    i) Protected areas,
    ii) Wild life sanctuaries,
    iii) WWF.

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