Biology - Genetics and Evolution

Question - 1

What does A and B represent in the given representation?

  • A A - Ribonucleoside, B - Deoxyribonucleoside
  • B A - Ribonucleotide, B - Deoxyribonucleotide
  • C A - Nucleoside, B - Nucleotide
  • D A - Nucleotide, B - Nucleoside

Question - 2

In DNA strand, the nucleotides are linked together by

  • A glycosidic bonds
  • B phosphodiester bonds
  • C peptide bonds
  • D hydrogen bonds.

Question - 3

In a DNA molecule, the phosphate group is attached to carbon __ of the sugar residue of its own nucleotide and carbon __ of the sugar residue of the next nucleotide by __ bonds.

  • A 5', 3', phosphodiester
  • B 3', 5', phosphodiester
  • C 5', 3', glycosidic
  • D 3', 5', glycosidic

Question - 4

Which of the following shows the correct positions of the phosphate (P), sugar (S) and base (B) molecules in the given line diagrams representing the structure of DNA?

  • A
  • B
  • C
  • D

Question - 5

DNA as an acidic substance present in nucleus was first identified by ____ in 1869; he named it as _____

  • A Meischer, nuclein
  • B Watson and Crick, DNA
  • C Chargaff, nuclein
  • D Wilkins and Franklin, double helix

Question - 6

Which of the following pairs is incorrectly matched?

  • A Purines - Adenine and Guanine
  • B Pyrimidines - Cytosine and Uracil
  • C Nucleosides - Adenosine and Thymidine
  • D DNA - Basic biomolecule

Question - 7

Watson and Crick (1953) proposed DNA double helix model and won the Nobel Prize; their model of DNA was based on (i) X-ray diffraction studies of DNA done by Wilkins and Franklin
(ii) Chargaff's base equivalence rule
(iii) Griffith's transformation experiment
(iv) Meselson and Stahl's experiment

  • A (i), (ii) and (iv)
  • B (i) and (ii)
  • C (iii) and (iv)
  • D (i), (ii), (iii) and (iv)

Question - 8

If a double stranded DNA has 20% of cytosine, what will be the percentage of adenine in it?

  • A 20%
  • B 40%
  • C 30%
  • D 60%

Question - 9

In one polynucleotide strand of a DNA molecule the ratio of A + T/G + C is 0.3. What is the A + G/T + C ratio of the entire DNA molecule?

  • A 0.3
  • B 0.6
  • C 1.2
  • D 1

Question - 10

If the sequence of bases in one strand of DNA is ATGCATGCA,what would be the sequence of bases on complementary strand?

  • A ATGCATGCA
  • B AUGCAUGCA
  • C TACGTACGT
  • D UACGUACG
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