Question

You are looking at two fragments of DNA. Both have the sequence CATTCTG on one strand and GTAAGAC on the other. One of the fragments is exposed to UV light, and the other is not. What will happen to the fragments, and how might these mutations be repaired?

Answer 1

Answer:

The fragment exposed to UV light contains two thymine base pair. When this strand is exposed to UV light Thymine lying adjacent to each other can form thymine dimers . This mutation can be repaired by nucleotide excision.

Explanation:

Nucleotide excision repair (NER), is a mechanism where damaged bases are cut out within a string of nucleotides, and are replaced by DNA as per the information decoded from the template strand. This mechanism removes pyrimidine dimers formed by UV radiation.