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Determine the correctness or otherwise of the following Assertion (a) and Reason (r):
Assertion (a): IPTG (Isopropylthiogalactoside) is a gratuitous inducer of lac operon.
Reason (r) : IPTG is an efficient inducer, but not a substrate of lac operon
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- Both (a) and (r) are true and (r) is the correct reason for (a)
- Both (a) and (r) are true but (r) is not the correct reason for (a)
- (a) is true but (r) is false
- (a) is false but (r) is true
Correct Option: B
IPTG (I-8000, I-8050) is an artificial inducer of the lac operon. IPTG binds to the lac repressor and inactivates it, preventing its binding to the lac operator and thus inducing the expression of beta-galactosidase. IPTG cannot be hydrolyzed and broken down by the cell and is therefore called a “gratuitous” inducer.
