What is NOT a likely repair system used if a strand of DNA has a pyrimidine dimer?
A) mismatch repair
B) direct repair pathway
C) base excision
D) nucleotide excision

Question

Quizplus · Accepted Answer

Mismatch repair is used to correct errors during DNA replication, not to repair damaged DNA such as a pyrimidine dimer.

Answer: B) direct repair pathway 
 Direct repair pathway is not a likely repair system used to repair a pyrimidine dimer. Direct repair pathway is used to repair specific types of damage such as alkylated bases or UV-induced photoproducts.

Answer: C) base excision 
 Base excision repair is used to repair damage to a single DNA base, not to repair pyrimidine dimers which involve damage to adjacent bases.

Answer: D) nucleotide excision 
 Nucleotide excision repair is the correct repair system used to repair pyrimidine dimers. It removes a section of DNA around the damage and fills in the gap with new nucleotides.

What Is NOT a Likely Repair System Used If a Strand