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Molecular Genetics Model Question Paper

12th Standard

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Biology

Time : 01:00:00 Hrs
Total Marks : 50
    5 x 1 = 5
  1. What is the basis for the difference in the synthesis of the leading and lagging strand of DNA molecules?

    (a)

    Origin of replication occurs only at the 5' end of the molecules

    (b)

    DNA ligase works only in the 3' → 5' direction

    (c)

    DNA polymerase can join new nucleotides only to the 3' end of the growing stand.

    (d)

    Helicases and single-strand binding proteins that work at the 5' end

  2. Which of the following is the correct sequence of event with reference to the central dogma?

    (a)

    Transcription, Translation, Replication

    (b)

    Transcription, Replication, Translation

    (c)

    Duplication, Translation, Transcription

    (d)

    Replication, Transcription, Translation

  3. Meselson and Stahl’s experiment proved

    (a)

    Transduction

    (b)

    Transformation

    (c)

    DNA is the genetic material

    (d)

    Semi-conservative nature of DNA replication

  4. One gene one enzyme hypothesis was proposed by Beadle and Tatum based on ________

    (a)

    Yeast

    (b)

    Drosophila

    (c)

    E. coli

    (d)

    Neurospora

  5. The experiment conducted by Griffith was based on_________.

    (a)

    Transduction

    (b)

    Replication

    (c)

    Transformation

    (d)

    Conjucation

  6. 5 x 2 = 10
  7. Give reasons: ‘Genetic code is universal’.

  8. Differentiate - Leading stand and lagging strand

  9. In E.coli, three enzymes β- galactosidase, permease and transacetylase are produced in the presence of lactose. Explain why the enzymes are not synthesized in the absence of lactose.

  10. What makes the DNA and RNA as acidic molecules?

  11. What is nucleosome? How many base pairs are there in a typical nucleosome?

  12. 5 x 3 = 15
  13. Why the human genome project is called a mega project?

  14. Why tRNA is called an adapter molecule?

  15. State one gene one enzyme hypothesis

  16. What is initiation complex in transcription?

  17. Define termination in protein synthesis.

  18. 4 x 5 = 20
  19. How is the two stage process of protein synthesis advantageous?

  20. Explain the formation of a nucleosome.

  21. Describe the steps involved in DNA finger printing.

  22. Give a detailed account of a transcription unit.

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