Question

In the event of a mismatched nucleotide , which molecule is able to backtrack , "proofread , " and correct the nucleotide sequence ?
A. DNA Proofreadase
B. DNA Polymerase
C. DNA Helicase
D. DNA Primase

Answer 1

Answer:

The molecule that is able to go back and correct an error in the DNA nucleotide sequence is DNA polymerase (option B).

Explanation:

DNA polymerase is not only the enzyme that contributes to the polymerization of a new DNA strand during the replication process, but it can also correct errors in synthesis, such as when a mismatched nucleotide is placed.

Once an error has been detected during synthesis, the DNA polymerase —acting as a 3'-5'- exonuclease— reverses the process, the direction of synthesis, to correct the error which in this case is the mismatched nucleotide.

The other options are not correct because:

   A. DNA proofreadasa does not exist.

    C. Helicase breaks the hydrogen bridges that bind the nucleotides allowing the separation of the DNA strands. In some cases, it also acts as a DNA repairer

    D. DNA Primase is responsible for the synthesis of primers.