Skip to main content

The lac Operon: Inducible Regulation

This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.

State

The lac operon is inducible: when lactose is present, its metabolite binds the lac repressor, releasing it from the operator and permitting transcription.

Show

Allolactose binds the lac repressor, changing its shape so it can no longer bind the operator, letting polymerase transcribe the lactose genes.

Watch for

Repressor release only permits transcription — full activity needs glucose scarce, reverse from the trp operon's shutoff.