How does extracellular 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

Extracellular glucose reduces the levels of intracellular cAMP, which in turn decreases the binding of the cAMP-CAP complex to the promoter, thereby inhibiting transcription of the lac operon.

How Does Extracellular Glucose Inhibit Transcription of the Lac Operon