Which is incorrect with respect to DNA polymerase III?

Options

A. It requires ATP for polymerase action.
B. It is required for PCR.
C. It is more active than DNA polymerases I and II.
D. It is requires a pre-formed DNA template to work on.

Answer

To determine which statement is incorrect with respect to DNA polymerase III, we can analyze the characteristics and functions of this enzyme step by step.

### Step-by-Step Solution:

1. **Understanding DNA Polymerase III**:
- DNA polymerase III is a holoenzyme that plays a crucial role in prokaryotic DNA replication. It synthesizes new DNA strands by adding nucleotides complementary to the template strand.

2. **Evaluating the Options**:
- **Option 1**: "It requires ATP for polymerase action."
- This statement is correct. DNA polymerase III does not require ATP; it utilizes the energy from the dNTPs (deoxynucleotide triphosphates) that it incorporates into the growing DNA strand.

- **Option 2**: "It is required for PCR."
- This statement is incorrect. While DNA polymerase is necessary for PCR (Polymerase Chain Reaction), the specific enzyme used in PCR is often Taq polymerase, not DNA polymerase III. Therefore, this option is the one that is incorrect.

- **Option 3**: "It is more active than DNA polymerase I & II."
- This statement is correct. DNA polymerase III is indeed more active and is the primary enzyme involved in DNA replication, while DNA polymerase I and II are involved in DNA repair processes.

- **Option 4**: "It requires a preformed DNA template to work on."
- This statement is also correct. DNA polymerase III requires a template strand to synthesize a new DNA strand.

3. **Conclusion**:
- After evaluating all the options, the incorrect statement regarding DNA polymerase III is that "it is required for PCR."

### Final Answer:
The incorrect statement with respect to DNA polymerase III is: **"It is required for PCR."**