Question

If DNA polymerase is observed to pause as it is synthesizing genetic material from a template strand, this is likely the result of:(A) DNA polymerase encountering a "bulky lesion" on the template strand.(B) DNA polymerase recognizing a "mismatched" base pair, like adenine and guanine.(C) DNA polymerase running into a TATA box located in the middle of one of the gene’s exons.(D) DNA polymerase pausing to remove an RNA primer it encounters.

Answer 1

Answer:

(B) DNA polymerase recognizing a "mismatched" base pair, like adenine and guanine.

Explanation:

In DNA, adenine is always paired with thymine and guanine with cytosine. The DNA polymerase has 3' to 5' exonuclease activity which is also called proofreading activity. If a DNA polymerase adds the wrong nucleotide, it can not be translocated post the mismatched nucleotide. The pause allows the 3' to 5' exonuclease activity of DNA polymerase to remove the mismatched nucleotide followed by the addition of a correct nucleotide.