Question

A scientist randomly mutates the DNA of a bacterium. She then sequences the bacterium’s daughter cells, and finds that the daughters have many errors in their replicated DNA. The parent bacterium likely acquired a mutation in which enzyme?

a) DNA helicase
b) DNA ligase
c) DNA polymerase
d) Single-strand binding protein

Answer 1

The likely mutated enzyme causing many errors in the replicated DNA of a bacterium's daughter cells is DNA polymerase. This enzyme is responsible for synthesizing and proofreading the new DNA strands during replication.

Step-by-step explanation:

The bacterium that has acquired many errors in the replicated DNA of its daughter cells likely has a mutation in the enzyme responsible for DNA replication and proofreading. The correct enzyme in question is DNA polymerase, which not only synthesizes the new DNA strand but also has an essential proofreading activity that checks and corrects errors during DNA replication. If DNA polymerase is functioning incorrectly due to a mutation, this would lead to an increased number of errors in the replicated DNA of the daughter cells. Other enzymes like DNA helicase and DNA ligase are also involved in replication, with helicase unwinding the DNA strands and ligase joining Okazaki fragments on the lagging strand, but mutations in these enzymes would not cause an increased error rate in DNA synthesis itself. Therefore, the parent bacterium most likely has an issue with DNA polymerase.