Final answer:
Mismatch repair corrects mismatched bases after DNA replication, while nucleotide excision repair (NER) addresses bulky DNA damage like thymine dimers and single-strand breaks that distort the DNA helix.
Step-by-step explanation:
A primary difference between mismatch repair and nucleotide excision repair (NER) with respect to the type of damage repaired is that mismatch repair will repair errors that occurred during DNA replication by identifying and correcting mismatched bases, while NER will repair damaged bases that cause large distortions in the DNA helix, such as thymine dimers, as well as single-strand breaks.
Mismatch repair works post-replication to identify and replace incorrectly paired nucleotides that could lead to more permanent DNA damage if left uncorrected. Nucleotide excision repair, however, has a broader reach in that it is capable of recognizing and removing larger, bulky lesions created by ultraviolet (UV) radiation or chemicals that disrupt the double helix, making it essential in maintaining DNA integrity. The repair mechanism of NER involves making cuts on both sides of the damaged DNA, removing a short segment, and synthesizing new DNA to fill the gap.