Which one of the following activities would LEAST likely be found in a topoisomerase?

(A) cutting a phosphodiester linkage

(B) inducing or relaxing twists in double-stranded DNA

(C) Topoisomerases are equally likely to perform all of these functions.

(D) adding nucleotides to the end of a DNA strand

(E) reforming phosphodiester linkages

Adding nucleotides to the end of a DNA strand

Explanation:

Topoisomerases are enzymes that participate in the or underwinding / inducing or relaxing twists in double-stranded DNA. During DNA replication or trancription, the twist are generated ahead of the replication fork so the topo-isomerases removes these twists. In case of bacteria, topoisomerse is known as gyrase.

Topoisomerases are very important in DNA replication and transcription.