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Assertion. When tryptophan is present th...

Assertion. When tryptophan is present the repressor is unable to bind to the operator.
Reason. Transcription of structural genes occurs.

A

If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion .

B

If both Assertion and Reason are true but Reason is not a correct explanations of the Assertion

C

If Assertion is true but the Reason is false .

D

If both Assertion and Reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the assertion and reason provided in the question, we need to understand the role of tryptophan in the regulation of the tryptophan operon, particularly in the context of the repressor and operator interaction. ### Step-by-Step Solution: 1. **Understanding the Assertion**: The assertion states that "When tryptophan is present, the repressor is unable to bind to the operator." This statement is incorrect. In fact, when tryptophan is present, it binds to the repressor protein, causing a conformational change that allows the repressor to bind to the operator. 2. **Understanding the Reason**: The reason states that "Transcription of structural genes occurs." This is true when the repressor is not bound to the operator. However, when tryptophan is present, the repressor binds to the operator, preventing transcription of the structural genes. 3. **Connecting Assertion and Reason**: The assertion and reason are related in that they both discuss the regulation of transcription in the presence of tryptophan. However, since the assertion is incorrect, the reason does not provide a valid explanation for the assertion. 4. **Conclusion**: Since the assertion is false (the repressor binds when tryptophan is present) and the reason is true (transcription does not occur when the repressor is bound), we conclude that both the assertion and reason are not in agreement. ### Final Answer: - The assertion is incorrect, and the reason is correct. Therefore, the statement "When tryptophan is present the repressor is unable to bind to the operator" is false, while "Transcription of structural genes occurs" is true, but does not explain the assertion.
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