Which one is involved in DNA repair?

Options

A. Ligase
B. Primase
C. DNA polymerase III
D. DNA polymerase I

Answer

To answer the question "Which one is involved in DNA repair?", we will analyze the options provided: ligase, primase, DNA polymerase III, and DNA polymerase I.

### Step-by-Step Solution:

1. **Understanding DNA Repair**:
- DNA repair refers to the processes that correct damage to the DNA molecules that encode an organism's genome. This can involve replacing damaged sections of DNA or fixing errors that occurred during DNA replication.

2. **Identifying the Options**:
- **Ligase**: This enzyme is responsible for joining DNA fragments together, particularly during DNA replication and repair, but it does not directly repair DNA.
- **Primase**: This enzyme synthesizes RNA primers needed for DNA replication. It does not play a role in repairing DNA.
- **DNA Polymerase III**: This enzyme is primarily involved in DNA synthesis during replication. It extends the DNA strand but is not primarily responsible for repairing DNA.
- **DNA Polymerase I**: This enzyme has a key role in DNA repair. It removes RNA primers from the Okazaki fragments and replaces them with DNA. It also has exonuclease activity, allowing it to remove damaged DNA and replace it.

3. **Conclusion**:
- Among the options, DNA Polymerase I is specifically involved in the DNA repair process by removing RNA primers and replacing them with DNA, thus repairing the DNA strand.

### Final Answer:
**DNA Polymerase I is involved in DNA repair.**