A : Kornberg enzyme is asscoitated with the removal of primers and thymine dimer.
R: DNA polymersase I does exonuclease activity in `5 to 3` and `3 to 5` directions.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark
B. If both Assertion & Reason are true and the reason is not the correct explanation of the assertion , then mark
C. If Assertion is true statement but Reason is false, then mark.
D. If both Assertion and Reason are false statements, then mark.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion (A):**
- The assertion states that "Kornberg enzyme is associated with the removal of primers and thymine dimer."
- The Kornberg enzyme refers to DNA polymerase I, which is indeed involved in the removal of RNA primers during DNA replication and can also participate in the repair of thymine dimers.

2. **Understanding the Reason (R):**
- The reason states that "DNA polymerase I does exonuclease activity in 5' to 3' and 3' to 5' directions."
- DNA polymerase I has exonuclease activity in both directions, but it is important to clarify that it primarily exhibits 5' to 3' exonuclease activity for the removal of primers and 3' to 5' exonuclease activity for proofreading.

3. **Evaluating the Assertion:**
- The assertion is correct because DNA polymerase I is indeed responsible for the removal of RNA primers and can also help in repairing thymine dimers.

4. **Evaluating the Reason:**
- The reason is partially correct; however, it is misleading. While DNA polymerase I does have exonuclease activity in both directions, the statement implies that it is equally effective in both, which is not entirely accurate. The primary function for primer removal is through its 5' to 3' exonuclease activity.

5. **Conclusion:**
- The assertion is true, but the reason is misleading and not a correct explanation of the assertion. Therefore, we conclude that the assertion is true and the reason is false.

**Final Answer:**
- Assertion (A) is true, and Reason (R) is false.

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