How does breakdown of glucose inhibit transcription of the lac operon?
A) by strengthening the binding of the repressor to the operator
B) by weakening the binding of the repressor to the operator
C) by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription
D) by reducing the levels of intracellular cAMP

Question

Quizplus · Accepted Answer

The breakdown of glucose reduces the levels of intracellular cAMP, which is necessary for the activation of CAP (catabolite activator protein). CAP, when bound to cAMP, facilitates the binding of RNA polymerase to the lac operon promoter, enhancing transcription. Low cAMP levels due to glucose presence result in reduced transcription of the lac operon.

How Does Breakdown of Glucose Inhibit Transcription of the Lac