The wrong base if added, is removed and proper base is usually added during DNA replication by

Options

A. DNA polymerase I
B. Ligase
C. DNA polymerase III
D. RNA primer

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Replication**: DNA replication is the process by which a cell makes an identical copy of its DNA. This is crucial for cell division and the transmission of genetic information.

2. **Identifying the Role of Enzymes**: During DNA replication, various enzymes play specific roles. The question asks about the removal of incorrect bases and the addition of the correct ones.

3. **Analyzing the Options**:
- **DNA Polymerase I**: This enzyme is primarily involved in removing RNA primers and replacing them with DNA nucleotides. It also has proofreading capabilities, which means it can remove incorrectly paired bases and replace them with the correct ones.
- **Ligase**: This enzyme's main function is to join DNA fragments together, particularly during the lagging strand synthesis. It does not directly remove or replace bases.
- **DNA Polymerase III**: This is the main enzyme responsible for synthesizing new DNA strands during replication. It adds nucleotides to the growing DNA strand but does not have the primary role in removing incorrect bases.
- **RNA Primer**: The RNA primer is necessary for initiating DNA synthesis but does not play a role in the removal or replacement of bases.

4. **Conclusion**: Based on the functions of the enzymes, the correct answer to the question is **DNA Polymerase I**, as it is responsible for removing incorrect bases and adding the correct ones during DNA replication.

**Final Answer**: DNA Polymerase I

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