New ! Biology MCQ Practise Tests

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

12th Standard

    Reg.No. :
  •  
  •  
  •  
  •  
  •  
  •  

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

    (a)

    AAA, proline

    (b)

    GGG, alanine

    (c)

    UUU, Phenylalanine

    (d)

    TTT, arginine

  3. When lactose is present in the culture medium:

    (a)

    Transcription of lac y, lac z, lac a genes occurs.

    (b)

    Repressor is unable to bind to the operator.

    (c)

    Repressor is able to bind to the operator.

    (d)

    Both (a) and (b) are correct.

  4. The term gene was coined by ________

    (a)

    Mendel

    (b)

    Lyon

    (c)

    Johannsen

    (d)

    Hershey

  5. Griffith's experiments proved that _________.

    (a)

    RNA is involved in protein synthesis

    (b)

    Bacteria undergoes asexual reproduction

    (c)

    DNA is the genetic material

    (d)

    DNA is made of two strands

  6. Human Genome was sequenced in ________.

    (a)

    1979

    (b)

    2015

    (c)

    1989

    (d)

    2001

  7. The codon _______ has dual function.

    (a)

    UAA

    (b)

    AUG

    (c)

    UGA

    (d)

    UUU

  8. Wobble hypothesis ________.

    (a)

    proves that many tRNAs are. needed to transport specific amino acids

    (b)

    proves that the bases in tRNA need not match with mRNA

    (c)

    helps in economic usage of tRNA

    (d)

    proves that one tRNA can carry many amino acids

  9. Escherichia coli fully labeled with N14 medium. The two strands of DNA molecules of the first generation bacteria have

    (a)

    Different density and do not resemble parent DNA

    (b)

    Different density but resemble parent DNA

    (c)

    Same density and resemble parent DNA

    (d)

    Same density but do not resemble parents DNA

  10. In Hershey - Chase experiment, the DNA of T2 phase was made radioactive by using__________

    (a)

    32p

    (b)

    35S

    (c)

    35p

    (d)

    32S

  11. Semi-conservative model of replication was proved by _________

    (a)

    Hershey and Chase

    (b)

    Griffith

    (c)

    Meselson and Stahl

    (d)

    Macleod and McCarty

  12. How many types of DNA polymerases does a eukaryotic cell possess?

    (a)

    two

    (b)

    three

    (c)

    four

    (d)

    five

  13. Capping of mRNA occurs using __________

    (a)

    Poly A residues

    (b)

    Methyl guanosine triphosphate

    (c)

    Deoxy ribonucleotide triphosphate

    (d)

    Ribonucleotide triphosphate

  14. The sequence of bases in coding strand of DNA is GAGTTAGCAGGC, then the sequence of codons in primary transcript is ___________

    (a)

    C U C A U A C G C C C G

    (b)

    C U C A A U C G U C C G

    (c)

    U C A G A U C U G C G C

    (d)

    U U C A A U C G U G C G

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

    (a)

    Eighth

    (b)

    Seventh

    (c)

    Sixth

    (d)

    Nineth

  16. 2 Marks

    10 x 2 = 20
  17. Differentiate - Leading stand and lagging strand

  18. Mention any two ways in which single nucleotide polymorphism (SNPs) identified in human genome can bring revolutionary change in biological and medical science

  19. 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.

  20. DNA acts as genetic material for the majority of living organisms and not the RNA. Give reasons to support the statement.

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

  22. What is TATA box? State its function

  23. Degeneracy of codon - comment.

  24. What are UTR's?

  25. Expand (a) ETS and (b) YAC.

  26. What are SNPs? Mention its uses.

  27. 3 Marks

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

  29. Why the human genome project is called a mega project?

  30. What are the three structural differences between RNA and DNA?

  31. State one gene one enzyme hypothesis

  32. Distinguish replication and transcription.

  33. Define a operon.

  34. State Chargaff's rule.

  35. Chemically DNA is more stable than RNA- Justify.

  36. What is a primer?

  37. Following is a DNA sequence representing a part of gene
    TAC TCG CCC TAT UAA CCC AAA ACC TCT
    using this derive
    (a) The RNA transcript
    (b) The spliced mRNA (consider all the codons with two Aderine bases are introns)
    (c) The total number of amino acids coded by the mRNA

  38. 5 Marks

    7 x 5 = 35
  39. How is the two stage process of protein synthesis advantageous?

  40. List the salient features of classical concept of gene.

  41. Explain the process of DNA replication in eukaryotes.

  42. List the salient features of genetic code.

  43. Explain the properties of DNA that makes it an ideal genetic material.

  44. Explain the transcription process in prokaryotes with needed diagram.

  45. Draw a flow chart depicting the steps of DNA fingerprinting technique.

*****************************************

TN 12th Standard Biology free Online practice tests

Reviews & Comments about 12th Standard Bio-Zoology English Medium Molecular Genetics Reduced Syllabus Important Questions With Answer Key 2021

Write your Comment