試題詳解

32.Which enzyme is commonly added when using a single restriction enzyme
in cloning, and what is its purpose?
(A) T4 DNA polymerase, to fill in 5' overhangs and generate blunt ends to
increase ligation efficiency.
(B) Reverse transcriptase, to synthesize cDNA from RNA prior to cloning.
(C) Exonuclease, to degrade the unwanted DNA after restriction enzyme
digestion.
(D) Alkaline phosphatase, to prevent the vector from self-ligating by removing5' phosphate groups.

(E) Topoisomerase, to relieve supercoiling in the DNA fragment during cloning.