Final answer:
Mismatch repair is a process that corrects DNA replication errors by excising incorrect nucleotides and replacing them with the correct ones, thus preventing permanent damage to the DNA.
Step-by-step explanation:
A third process called mismatch repair corrects errors after replication is complete.
In the process of mismatch repair, the enzymes involved recognize the mismatched or incorrectly added nucleotide after DNA replication has occurred. They excise this nucleotide and replace it with the correct base. If a nucleotide mismatch is not corrected, this may lead to more permanent damage to the DNA. In prokaryotes such as E. coli, the methyl-directed mismatch repair system identifies the newly synthesized strand by the lack of methylation and corrects errors there, as the parental strand will be methylated.