Question

Which of the following statements is true?

(a) Exonuclease III removes nucleotide residues from the 3’ ends of a DNA strand

(b) Bacteriophage lambda exonuclease removes terminal phosphates

(c) Alkaline phosphatase removes nucleotides from 5‘ends

(d) Kinase adds homopolymer tails to the 3’ –OH ends of a linear duplex

I had been asked this question during an online interview.

Origin of the question is DNA Cloning: The Basics-1 in chapter DNA-Based Information Technologies of Biochemistry

Answer 1

Correct answer is (a) Exonuclease III removes nucleotide residues from the 3’ ends of a DNA strand

Explanation: Bacteriophage lambda exonuclease removes nucleotides from 5‘ends.

Alkaline phosphatase removes terminal phosphates

Terminal transferase adds homopolymer tails to the 3’ –OH ends of a linear duplex.