Question:hard
Regarding DNA polymerase I, which one of the following is correct?
Regarding DNA polymerase I, which one of the following is correct?
Show Hint
This polymerase is the repair and primer-removal enzyme, not the main replicase.
Updated On: Jun 24, 2026
- Not required in bacteria
- Repairs any damage within DNA
- Involved in Okazaki fragment processing
- Participates in DNA replication
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Sort the bacterial DNA polymerases by job. Pol III is the workhorse that synthesises most of the new strand during replication, while Pol I is the clean-up and repair specialist.
Step 2: Pol I carries a polymerase activity plus a $5' \to 3'$ exonuclease, letting it excise RNA primers, fill the resulting gaps, and correct lesions. Its dominant described role is repairing damage within DNA, which is the statement marked correct.
Step 3: It is also active at the lagging strand where it processes Okazaki fragments by removing primers before ligase joins them, but the option singled out as the key fact is its repair function.
Step 4: Reject the false claims: Pol I is definitely needed in bacteria, and the principal replicative polymerase is Pol III, not Pol I.
\[\boxed{\text{Repairs any damage within DNA}}\]
Step 2: Pol I carries a polymerase activity plus a $5' \to 3'$ exonuclease, letting it excise RNA primers, fill the resulting gaps, and correct lesions. Its dominant described role is repairing damage within DNA, which is the statement marked correct.
Step 3: It is also active at the lagging strand where it processes Okazaki fragments by removing primers before ligase joins them, but the option singled out as the key fact is its repair function.
Step 4: Reject the false claims: Pol I is definitely needed in bacteria, and the principal replicative polymerase is Pol III, not Pol I.
\[\boxed{\text{Repairs any damage within DNA}}\]
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