Assertion: Amber codon is a terminating codon.
Reason: If in a mRNA, a termination codon is present, the protein synthesis stops abruptly whether the protein synthesis is complete or not.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.
C. If Assertion is true but the Reason is false.
D. If both Assertion and Reasom are false.

Answer

To analyze the given question, we need to evaluate both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Amber codon is a terminating codon."
- In molecular biology, the amber codon refers specifically to the stop codon UAG. This codon signals the termination of protein synthesis during translation.

2. **Evaluating the Assertion**:
- The statement is true because UAG is indeed one of the three stop codons (the others being UAA and UGA) that signal the end of translation.

3. **Understanding the Reason**:
- The reason states that "If in an mRNA, a termination codon is present, the protein synthesis stops abruptly whether the protein synthesis is complete or not."
- This statement is also true. When a ribosome encounters a stop codon during translation, it halts the synthesis of the polypeptide chain immediately, regardless of whether the protein is fully synthesized or not.

4. **Analyzing the Relationship**:
- While both the assertion and the reason are true, the reason does not adequately explain why the amber codon is classified as a termination codon. The reason describes the general function of termination codons but does not specifically address the unique characteristics of the amber codon.

5. **Conclusion**:
- The assertion is true, and the reason is also true, but the reason is not the correct explanation for the assertion.

### Final Answer:
- **Assertion**: True
- **Reason**: True
- **Explanation**: The reason does not correctly explain the assertion.