Concept explainers
How does the lac operon regulate lactose digestion in bacteria?
a. The repressor protein becomes a lactose-digesting enzyme only when lactose is present.
b. The repressor protein binds to the lac operon when lactose is present, blocking transcription.
c. When lactose is present, it binds to the operator region of the lac operon, activating transcription of the repressor protein gene.
d. The repressor protein falls off the lac operon when lactose is present, and lactose-digesting genes are expressed.
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