Final answer:
Base excision repair is beneficial for its high specificity but limited to small, non-helix-distorting lesions. Nucleotide excision repair handles bulkier DNA damages that BER can't, such as pyrimidine dimers caused by UV light. BER and NER are two distinct DNA repair mechanisms with their respective strengths and limitations.
Step-by-step explanation:
Base excision repair (BER) is a critical DNA repair mechanism that deals with damage to a single nucleotide due to various causes such as oxidation, alkylation, hydrolysis, or deamination. In BER, the affected base is removed by a glycosylase, and the site is then restored to its correct sequence with the aid of repair synthesis and DNA ligase.
An advantage of BER is its high specificity for damaged bases, which permits the repair of DNA without disrupting the double helix significantly. This precision helps maintain genetic stability. However, a disadvantage is that BER has a limited capacity for error detection, primarily focusing on small, non-helix-distorting lesions, which could leave more significant damages, like those caused by UV light resulting in pyrimidine dimers, unaddressed.
Comparatively, nucleotide excision repair (NER) is more suited for repairing bulkier, helix-distorting damages that BER cannot handle, including thymine dimers caused by UV exposure. NER involves removing a longer oligonucleotide segment surrounding the damage and filling in the gap using DNA polymerase and DNA ligase.