The main role of DNA polymerase III is

Options

A. addition and polymerization of nucleotides from 5' end to 3' end.
B. as major repair enzyme form 5' and to 3' end.
C. removal of DNA primer from 5' end.
D. addition and polymerization of nucleotides from 3' end to 5' end.

Answer

To answer the question regarding the main role of DNA polymerase III, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding DNA Polymerase III**:
- DNA polymerase III is a crucial enzyme in the process of DNA replication in prokaryotic cells.
- It is primarily responsible for synthesizing new DNA strands.

2. **Direction of Nucleotide Addition**:
- DNA polymerase III adds nucleotides to the growing DNA strand in a specific direction.
- The addition occurs from the 5' (five-prime) end to the 3' (three-prime) end of the new DNA strand.

3. **Polymerization Process**:
- The enzyme catalyzes the polymerization of nucleotides, which means it links nucleotides together to form a long DNA strand.
- This process is essential for duplicating the chromosomal DNA during cell division.

4. **Proofreading Activity**:
- DNA polymerase III also has proofreading capabilities, which means it can correct errors during DNA replication.
- It has a 3' to 5' exonuclease activity that allows it to remove incorrectly paired nucleotides.

5. **Role in DNA Repair**:
- While DNA polymerase III is mainly involved in DNA replication, other DNA polymerases are responsible for DNA repair mechanisms.

### Conclusion:
The main role of DNA polymerase III is the addition and polymerization of nucleotides from the 5' to the 3' direction during DNA replication.

### Final Answer:
**The main role of DNA polymerase III is the addition and polymerization of nucleotides from 5' to 3'.**

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