Question

which of the following mechanisms removes nucleotides that are paired incorrectly during dna replication?
telomerase activity
chromosomal breakage repair
dna proofreading
nucleotide excision repair

Explanation:

• Telomerase activity is involved in maintaining telomere length, not in removing incorrect nucleotides during DNA replication.
• Chromosomal breakage repair deals with breaks in chromosomes, not with incorrect base - pairing during replication.
• DNA proofreading occurs during DNA replication. DNA polymerase has a proofreading function. When it detects an incorrectly paired nucleotide (e.g., a non - Watson - Crick base pair like A with C instead of A with T), it can backtrack (exonuclease activity) and remove the incorrect nucleotide.
• Nucleotide excision repair is a mechanism for repairing DNA damage (such as thymine dimers caused by UV light) in non - replicating DNA, not specifically for errors during replication.

Answer:

C. DNA proofreading