Final answer:
Cells require a specialized system to repair G-T mismatches to prevent permanent damage. Mismatch repair is a mechanism that recognizes and corrects incorrectly added nucleotides. Enzymes involved in mismatch repair help maintain the integrity of DNA and prevent mutations.
Step-by-step explanation:
Cells require a specialized system to repair G-T mismatches because these mismatches can lead to permanent damage if left uncorrected. Mismatch repair is a mechanism that recognizes and excises the incorrectly added nucleotide and replaces it with the correct base. The enzymes involved in mismatch repair play a crucial role in maintaining the integrity of DNA and preventing mutations.