What strategies do cells use to ensure that newly replicated DNA does not contai

Question

What strategies do cells use to ensure that newly replicated DNA does not contain errors? DNA polymerase replaces the newly replicated DNA on any chromosomes on which there are mistakes. Enzymes repair mistakes in the new DNA double helix after the new double helix separates from the original double helix. Enzymes find misshapen DNA sequences prior to replication and remove and resynthesize those sequences. As DNA polymerase synthesizes new DNA, the DNA polymerase finds and corrects misplaced nucleotides. Enzymes proofread the DNA after the DNA has been replicated and replace any mismatched nucleotides. Hint: Enzymes check newly replicated DNA for mistakes both during DNA synthesis and after the new strand is completed. How does an enzyme, such as DNA polymerase, determine that a nucleotide or sequence of nucleotides is incorrect and repair the mistake?

Explanation / Answer

DNA polymerase has two special qualities that greatly increase the accuracy of DNA replication. First, the enzyme carefully monitors the base-pairing between each incoming nucleotide and the template strand. Only when the match is correct does DNA polymerase catalyze the nucleotide addition reaction. Second, when DNA polymerase makes a rare mistake and adds the wrong nucleotide,it can correct the error through an activity called proofreading.
Proofreading takes place at the same time as DNA synthesis. Before the enzyme adds the next nucleotide to a growing DNA strand, it checks whether the previously added nucleotide is correctly base-paired to the template strand. If so, the polymerase adds the next nucleotide; if not,the polymerase clips off the mispaired nucleotide and tries again. fifth choice is the answer

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.