Questions: Part A In nucleotide excision repair, damaged DNA is excised by what enzyme(s)? View Available Hint(s) ligase nuclease helicase DNA polymerases primase Submit

The answer is the second one: nuclease.

Explanation for each option:

1. Ligase: This enzyme is responsible for joining DNA fragments together by forming phosphodiester bonds. It is not involved in excising damaged DNA.

2. Nuclease: This enzyme is responsible for cutting out damaged sections of DNA during nucleotide excision repair. It recognizes and excises the damaged nucleotides.

3. Helicase: This enzyme unwinds the DNA double helix, but it does not excise damaged DNA. It is involved in processes like DNA replication and repair to separate the strands.

4. DNA polymerases: These enzymes synthesize new DNA strands by adding nucleotides complementary to the template strand. They are involved in filling in the gap after the damaged DNA has been excised but do not perform the excision themselves.

5. Primase: This enzyme synthesizes RNA primers needed for DNA replication. It is not involved in the excision of damaged DNA.

In summary, the enzyme responsible for excising damaged DNA in nucleotide excision repair is nuclease.