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12th Standard Biology English Medium Chromosomal Basis of Inheritance Reduced Syllabus Important Questions With Answer Key 2021

12th Standard

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Biology

Time : 01:00:00 Hrs
Total Marks : 100

    Multiple Choice Questions

    15 x 1 = 15
  1. An allohexaploidy contains

    (a)

    Six different genomes

    (b)

    Six copies of three different genomes

    (c)

    Two copies of three different genomes

    (d)

    Six copies of one genome

  2. Match list I with list II
     

    List I list II
    A. A pair of chromosomes extra with diploid i) monosomy
    B. One chromosome extra to the diploid ii) tetrasomy
    C. One chromosome loses from diploid iii) trisomy
    D.Two individual chromosomes lose from diploid

    iv) double monosomy

    (a)

    A-i, B-iii, C-ii, D-iv

    (b)

    A-ii, B-iii, C-iv, D-i

    (c)

    A-ii, B-iii, C-i, D-iv

    (d)

    A-iii, B-ii, C-i, D-iv

  3. Accurate mapping of genes can be done by three point test cross because increases

    (a)

    Possibility of single cross over

    (b)

    Possibility of double cross over

    (c)

    Possibility of multiple cross over

    (d)

    Possibility of recombination frequency

  4. Genes G S L H are located on same chromosome. The recombination percentage is between L and G is 15%, S and L is 50%, H and S are 20%. The correct order of genes is

    (a)

    GHSL

    (b)

    SHGL

    (c)

    SGHL

    (d)

    HSLG

  5. If haploid number in a cell is 18. The double monosomic and trisomic number will be

    (a)

    35 and 37

    (b)

    34 and 37

    (c)

    37 and 35

    (d)

    17 and 19

  6. Assertion (A): Gamma rays are generally use to induce mutation in wheat varieties.
    Reason (R): Because they carry lower energy to non-ionize electrons from atom

    (a)

    A is correct. R is correct explanation of A

    (b)

    A is correct. R is not correct explanation of A

    (c)

    A is correct. R is wrong explanation of A

    (d)

    A and R is wrong

  7. Which is not a feature of the chromosomal theory of inheritance?

    (a)

    Somatic cells of organisms are derived from zygote by repeated meiosis.

    (b)

    Chromosomes retain their structural uniqueness throughout the life of an organism.

    (c)

    Mendelian factors are located in chromosomes

    (d)

    Sutton and Boveri independently proposed the theory.

  8. Number of chromosomes (2n) in Ophioglossum is _________

    (a)

    1226

    (b)

    1622

    (c)

    1262

    (d)

    2126

  9. Incomplete linkage was reported by Hutchinson in ___________

    (a)

    Drosophila

    (b)

    Maize

    (c)

    Neurospora

    (d)

    Lathyrus odoratus

  10. During cross over, chiasma occurs between

    (a)

    Sister chromatids of non-homologous chromosomes

    (b)

    Non-sister chromatids of non- homologous chromosomes

    (c)

    Non-sister chromatids of homologous chromosomes

    (d)

    Sister chromatids of homologous chromosomes

  11. At which stage of meiosis, does the chromosomes undergo recombination process

    (a)

    Leptotene stage of prophase I

    (b)

    Zygotene stage of prophase I

    (c)

    Diplotene stage of prophase I

    (d)

    Pachytene stage of prophase I

  12. Mutation theory was proposed by____________

    (a)

    T. H. Morgan

    (b)

    Hugo de Vries

    (c)

    Alfred Sturtevant

    (d)

    Sutton and Boveri

  13. Which one of the following ploidy is irrelevant to others?

    (a)

    Monosomy

    (b)

    Trisomy

    (c)

    Tetrasomy

    (d)

    Pentasomy

  14. One of the following is not the kind of euploidy

    (a)

    Diploidy

    (b)

    Polyploidy

    (c)

    Hyperploidy

    (d)

    Autoploidy

  15. Observe the gene sequence and identify the types of aberration ABC BCD E F?

    (a)

    Tandem duplication

    (b)

    Simple duplication

    (c)

    Reverse tandem duplication

    (d)

    Displaced tandem duplication

  16. 2 Marks

    10 x 2 = 20
  17. If you cross dominant genotype PV/PV male Drosophila with double recessive female and obtain F1 hybrid. Now you cross F1 male with double recessive female.
    i) What type of linkage is seen?
    ii) Draw the cross with correct genotype.
    iii) What is the possible genotype in F2 generation?

  18. s.no gamete types Number of progenies
    1 ABC 349
    2 Abc 114
    3 abC 124
    4 AbC 5
    5 aBc 4
    6 aBC 116
    7 ABc 128
    8 abc 360

    i) What is the name of this test cross?
    ii) How will you construct gene mapping from the above given data?
    iii) Find out the correct order of genes.

  19. Define linkage. Mention its types.

  20. Crossing over occurs only in germinal cells. Yes or no. Support your answer.

  21. Define terminalization.

  22. Define the terms
    (a) locus
    (b) centimorgan.

  23. What are multiple alleles?

  24. How Sharbati Sonora was developed by Dr. M.S. Swaminathan et. al?

  25. Differentiate Aneuploidy from Euploidy.

  26. 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

  27. 3 Marks

    10 x 3 = 30
  28. Write the salient features of Sutton and Boveri concept.

  29. Write the steps involved in molecular mechanism of DNA recombination with diagram.

  30. Point out any three salient features of chromosomal theory of inheritance.

  31. Give a short note on incomplete linkage.

  32. How and where chiasma is formed?

  33. What is recombination? Which is the widely accepted model of DNA recombination

  34. List any three characteristic features of multiple allele.

  35. Explain co-mutagens with examples.

  36. Give an account on colchicine.

  37. Study the figures given below and answer the questions.

    Which type of cross produces higher recombinant percentage? Give reason in support
    of your answer.

  38. 5 Marks

    7 x 5 = 35
  39. How is Nicotiana exhibit self-incompatibility. Explain its mechanism.

  40. Draw the diagram of different types of aneuploidy.

  41. Mention the name of man-made cereal. How it is formed?

  42. Why crossing over is important?

  43. Explain hyperploidy with its types.

  44. List out the significance of ploidy.

  45. Explain the Translocation type of chromosomal aberration.

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