Which type of repair mechanism addresses base errors due to DNA polymerase mistakes after replication is complete?

Which type of repair mechanism addresses base errors due to DNA polymerase mistakes after replication is complete?

• A. Base excision repair
• B. Nucleotide excision repair
• C. Mismatch repair
• D. Homologous recombination

Answer: (C)

Mismatch repair is the mechanism that specifically addresses base errors resulting from DNA polymerase mistakes after DNA replication has been completed. DNA replication is a highly precise process, but it is not infallible and can lead to mismatches where incorrect nucleotides are incorporated into the newly synthesized strand. Mismatch repair functions by recognizing these incorrect pairings of nucleotides and correcting them. This is crucial for maintaining genetic fidelity, as these errors can lead to mutations if they are not repaired. The process involves several steps: the recognition of the mismatch, the removal of the erroneous segment of DNA, and the resynthesis of the correct sequence using the complementary strand as a template. This system is vital in preventing the propagation of errors during cell division. Base excision repair and nucleotide excision repair operate on different types of DNA damage, such as single-base lesions or bulky DNA adducts, rather than directly addressing mismatches caused by polymerase errors. Homologous recombination, on the other hand, primarily functions in the repair of double-strand breaks rather than corrections of base-pair mismatches. Thus, mismatch repair specifically targets and corrects errors that arise during replication, making it the appropriate choice for this question.

Mismatch repair is the mechanism that specifically addresses base errors resulting from DNA polymerase mistakes after DNA replication has been completed. DNA replication is a highly precise process, but it is not infallible and can lead to mismatches where incorrect nucleotides are incorporated into the newly synthesized strand.

Mismatch repair functions by recognizing these incorrect pairings of nucleotides and correcting them. This is crucial for maintaining genetic fidelity, as these errors can lead to mutations if they are not repaired. The process involves several steps: the recognition of the mismatch, the removal of the erroneous segment of DNA, and the resynthesis of the correct sequence using the complementary strand as a template. This system is vital in preventing the propagation of errors during cell division.

Base excision repair and nucleotide excision repair operate on different types of DNA damage, such as single-base lesions or bulky DNA adducts, rather than directly addressing mismatches caused by polymerase errors. Homologous recombination, on the other hand, primarily functions in the repair of double-strand breaks rather than corrections of base-pair mismatches. Thus, mismatch repair specifically targets and corrects errors that arise during replication, making it the appropriate choice for this question.