Final answer:
In mismatch repair, incorrectly paired bases identified after DNA replication are excised by specialized enzymes and corrected by DNA polymerase. This process is vital for genetic stability and preventing mutations.
Step-by-step explanation:
In mismatch repair, DNA polymerase detects and replaces bases that were incorrectly paired during DNA synthesis. This process occurs when the proofreading function of DNA polymerase fails to catch an error. Mismatch repair enzymes then recognize the mispaired base after replication and initiate the correction process.
During mismatch repair, specific enzymes identify the incorrectly inserted nucleotide and excise it from the strand. The gap left behind is subsequently filled with the correct base by DNA polymerase. This correction mechanism is crucial for maintaining the stability of the genome and preventing mutations.
In the model organism E. coli, mismatch repair enzymes distinguish the parent DNA strand from the daughter strand by identifying the methylation pattern on the parent strand. Unmethylated daughter strands can then be targeted for repair where mismatches are detected, ensuring fidelity of the DNA replication process.