Questions and answers for exam Preparation

MCQs

Total Questions : 107 | Page 6 of 11 pages

Question 51. A five carbon sugar lacking a hydrogen at the number 2 carbon is found in

DNA
RNA
mRNA
rDNA

Discuss Question

Answer: Option A. -> DNA
Answer: (a).DNA

Question 52. A nucleotide consists of

a sugar, a base and a phosphate
a sugar and a phosphate
paired bases
a sugar, a base and three phosphates

Discuss Question

Answer: Option A. -> a sugar, a base and a phosphate
Answer: (a).a sugar, a base and a phosphate

Question 53. Which of the following amino acids interact with the DNA or RNA backbone (i.e. phosphate)?

Ile and Val
Lys and Arg
Leu and Ala
Cys and Met

Discuss Question

Answer: Option B. -> Lys and Arg
Answer: (b).Lys and Arg

Question 54. Cleavage of DNA by EcoRI endonuclease results in the formation of

two 3'-OH ends and two 5'-phosphate ends
one 3'-OH end and one 5'-phosphate end
two 3'-phosphate ends and two 3'-OH ends
one 3'-OH end and two 5'-phosphate end

Discuss Question

Answer: Option A. -> two 3'-OH ends and two 5'-phosphate ends
Answer: (a).two 3'-OH ends and two 5'-phosphate ends

Question 55. Reverse transcripase from HIV does not

uses RNA as a template
has a 5' to 3' polymerase activity
has a 3'- 5' exonuclease activity
requires a primer

Discuss Question

Answer: Option C. -> has a 3'- 5' exonuclease activity
Answer: (c).has a 3'- 5' exonuclease activity

Question 56. Which of the following amino acids can interact with the DNA or RNA nucleotide bases via hydrogen bonding?

Asn and Gln
Cys and Met
Lys and Leu
Ile and Val

Discuss Question

Answer: Option A. -> Asn and Gln
Answer: (a).Asn and Gln

Question 57. Which of the following is false about purine and pyrimidine bases?

They are hydrophobic and relatively insoluble in water at the near-neutral pH of the cell
At acidic or alkaline pH the bases become charged and their solubility in water increases
Purines have two rings in their structure, but pyrimidine bases have only one ring
At acidic or alkaline pH the bases become charged and their solubility in water decreases

Discuss Question

Answer: Option D. -> At acidic or alkaline pH the bases become charged and their solubility in water decreases
Answer: (d).At acidic or alkaline pH the bases become charged and their solubility in water decreases

Question 58. Building blocks of nucleic acids are ____________

Nucleotides
Nucleosides
Amino acids
Histones

Discuss Question

Answer: Option A. -> Nucleotides
Answer: (a).Nucleotides

Question 59. Which of the following is true about phosphodiester linkage?

5’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide
3’-phosphate group of one nucleotide unit is joined to the 5’-hydroxyl group of the next nucleotide
5’-phosphate group of one nucleotide unit is joined to the 5’-hydroxyl group of the next nucleotide
3’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide

Discuss Question

Answer: Option A. -> 5’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide
Answer: (a).5’-phosphate group of one nucleotide unit is joined to the 3’-hydroxyl group of the next nucleotide

Question 60. Number of hydrogen bonds between guanine and cytosine?

Discuss Question

Answer: Option C. -> 3
Answer: (c).3