Using your knowledge of DNA repair pathways, choose the pathway that would be used to repair the following types of DNA damage. Explain your reasoning.
A change in DNA sequence caused by a mistake made by DNA polymerase during replication

Verified step by step guidance

1. Step 1: Identify the type of DNA damage described in the problem. The damage is a change in the DNA sequence caused by a mistake made by DNA polymerase during replication. This type of error is typically referred to as a mismatch or replication error.
2. Step 2: Recall the DNA repair pathway responsible for fixing mismatches. The mismatch repair (MMR) pathway is specifically designed to correct errors introduced during DNA replication, such as base mismatches or small insertion/deletion loops.
3. Step 3: Understand the mechanism of the mismatch repair pathway. MMR detects the mismatch by recognizing distortions in the DNA helix caused by incorrect base pairing. It then excises the incorrect segment of DNA and replaces it with the correct sequence using the undamaged strand as a template.
4. Step 4: Explain why other repair pathways are not suitable for this type of damage. For example, nucleotide excision repair (NER) is used for bulky lesions like thymine dimers, and base excision repair (BER) is used for small, non-helix-distorting base modifications. Neither of these pathways is designed to address replication errors.
5. Step 5: Conclude that the mismatch repair pathway is the most appropriate mechanism for repairing the described DNA damage, as it specifically targets replication errors caused by DNA polymerase.

Key Concepts

DNA Replication

DNA replication is the process by which a cell duplicates its DNA before cell division. During this process, DNA polymerase synthesizes a new strand by adding nucleotides complementary to the template strand. However, errors can occur, leading to mismatches in the DNA sequence, which necessitate repair mechanisms to maintain genetic integrity.

DNA Repair Mechanisms

DNA repair mechanisms are cellular processes that correct damage to the DNA molecule. These mechanisms include various pathways such as base excision repair, nucleotide excision repair, and mismatch repair. Each pathway is specialized for different types of DNA damage, ensuring that errors introduced during replication or due to environmental factors are effectively repaired.

Mismatch Repair Pathway

The mismatch repair pathway is a specific DNA repair mechanism that corrects errors made during DNA replication, particularly those involving base pair mismatches. This pathway identifies and removes incorrectly paired nucleotides, followed by resynthesis of the correct sequence by DNA polymerase. It plays a crucial role in maintaining genomic stability and preventing mutations.