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12th Standard Bio-Zoology English Medium Molecular Genetics Reduced Syllabus Important Questions 2021

12th Standard

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Biology

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

    Multiple Choice Questions

    15 x 1 = 15
  1. DNA and RNA are similar with respect to

    (a)

    Thymine as a nitrogen base

    (b)

    A single-stranded helix shape

    (c)

    Nucleotide containing sugars, nitrogen bases and phosphates

    (d)

    The same sequence of nucleotides for the amino acid phenyl alanine

  2. A mRNA molecule is produced by

    (a)

    Replication

    (b)

    Transcription

    (c)

    Duplication

    (d)

    Translation

  3. Which of the following statements is not true about DNA replication in eukaryotes?

    (a)

    Replication begins at a single origin of replication.

    (b)

    Replication is bidirectional from the origins.

    (c)

    Replication occurs at about 1 million base pairs per minute

    (d)

    There are numerous different bacterial chromosomes, with replication ocurring in each at the same time.

  4. The first codon to be deciphered was __________ which codes for ________.

    (a)

    AAA, proline

    (b)

    GGG, alanine

    (c)

    UUU, Phenylalanine

    (d)

    TTT, arginine

  5. Chromosomes were first observed by ________.

    (a)

    Miescher

    (b)

    Hofmeister

    (c)

    Avery

    (d)

    Griffith

  6. The term nucleic acid was coined by ________.

    (a)

    Miescher

    (b)

    Hofmeister

    (c)

    Altman

    (d)

    Mcleod

  7. _______demonstrated that RNA is the genetic material in RNA containing viruses.

    (a)

    Avery

    (b)

    Conrat and Singer

    (c)

    Griffith

    (d)

    Watson and Crick

  8. The concept of RNA world was independently proposed by __________

    (a)

    Orgel, Brick and Carl woese

    (b)

    Brick, Griffith and Crick

    (c)

    Wilkins and Franklin

    (d)

    Walter Gilbert

  9. Chromosome __________ has 231 genes only.

    (a)

    X

    (b)

    19

    (c)

    Y

    (d)

    22

  10. The association of histone H1 with a nudeosome indicates

    (a)

    Transcription is occurring

    (b)

    DNA replication is occurring

    (c)

    The DNA is condensed into chromatin fiber

    (d)

    The DNA double helix is exposed

  11. The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A.to C.
       A                    B                   C
    DNA ⟶ mRNA ⟶ protein⟶ proposed by__________

    (a)

    A - trancscription, B-replication, C- James Watson

    (b)

    A - trancscription, B-trancscriptioii, C-Erwin

    (c)

    A - transcription, B - translation, C - Francis Crick

    (d)

    A- trancscription, B- extension, C-Rosalind Frankin

  12. Select the two statements out of the four (I -IV) given below about lac operon,
    i. Glucose or galactose may bind with the repressor and inactive it.
    ii. In the absence of lactose, the repressor binds with the operator region
    iii. The z-gene codes for permease.
    iv. This was elucidated by Francois Jacob and Jacques Monod.
    The correct statements are

    (a)

    i and ii

    (b)

    ii and iii

    (c)

    ii and iv

    (d)

    i and ii

  13. In sickle cell anaemia, the __________ codon of \(\beta \) - globin gene is modified

    (a)

    Eighth

    (b)

    Seventh

    (c)

    Sixth

    (d)

    Nineth

  14. Lac Z gene codes for _______________

    (a)

    Permease

    (b)

    transacetylase

    (c)

    \(\beta \)-galactosidase

    (d)

    Aminoacyl transferase

  15. SNP stands for

    (a)

    Single nucleotide Polymorphism

    (b)

    Single Nucleoside Polypeptide

    (c)

    Single nucleotide Polymorphism

    (d)

    Single nucleotide polymer

  16. 2 Marks

    10 x 2 = 20
  17. Differentiate between purines and pyrimidines.

  18. Why is the term nucleic acid used for DNA and RNA?

  19. What does 'RNA world' refer to?

  20. What is genophore?

  21. Which type of bond is formed
    (a) between a purine and pyrimidine base?
    (b) between the pentose sugar and adjacent nucleotide?

  22. Expand and define NHC

  23. Which is the widely accepted model of DNA replication? Who has proved it?

  24. Name the various types of prokaryotic DNA polymerase. State their role in replication process.

  25. Given below are some events of eukaryotic replication. Name the enzymes involved in the process.
    (a) Unwinding of DNA (b) Joining of Okazaki fragments
    c) Addition of nucleotides to new strand (d) Correcting the repair

  26. Distinguish between exons and introns

  27. 3 Marks

    10 x 3 = 30
  28. Distinguish between structural gene, regulatory gene and operator gene

  29. Why tRNA is called an adapter molecule?

  30. Name the anticodon required to recognize the following codons: AAU, CGA, UAU, and GCA.

  31. Mention any 3 rules as defined by classical concept of gene

  32. Differentiate DNA and RNA.

  33. What is initiation complex in transcription?

  34. Distinguish monocistronic and polycistronic gene.

  35. What is S-D Sequence?

  36. How 5' of DNA differ from its 3'?

  37. Write in simple about semi-conservative mode of DNA replication.

  38. 5 Marks

    7 x 5 = 35
  39. a) Identify the figure given below
    b) Redraw the structure as a replicating fork and label the parts
    c) Write the source of energy for this replication and name the enzyme involved in this process.
    d) Mention the differences in the synthesis of protein, based on the polarity of the two template strands.

  40. Explain the properties of genetic material.

  41. Explain how mutation can impact genetic code with an example

  42. Explain the negative control of transcription initiation as described by Jacob and Monod.

  43. Describe the steps involved in DNA finger printing.

  44. Meselson and Stahl's experiment proved the semi-conservation mode of DNA replication. Explain.

  45. Explain the mechanism of lac-operon of the E-coli.

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