The lac operon is regulated by the binding of an enhancer to sequences just upstream of the promoter.

Question

Quizplus · Accepted Answer

The lac operon is regulated by the binding of a repressor protein to the operator region. The lac repressor protein binds to the operator in the absence of lactose, preventing RNA polymerase from binding to the promoter and transcribing the genes necessary for lactose metabolism. When lactose is present, it binds to the repressor protein, causing a conformational change that releases the repressor from the operator site and allows RNA polymerase to bind and initiate transcription. There is no enhancer involved in this regulation.

The Lac Operon Is Regulated by the Binding of an Enhancer