Regulation of the Lac Operon

Professor Miesfeld at the University of Arizona

This Online Biochemistry Course is based on Miesfeld’s Biochemistry (3rd Edition)

The E. coli lac operon is the classic model of prokaryotic gene regulation: bacteria turn on the lactose genes only when lactose is present and glucose is absent. This video covers the lac repressor and operator, allolactose induction, and CRP-cAMP activation with glucose (catabolite) repression.

Key concepts covered: operons, coordinated transcription, lac repressor and operator, allolactose induction, beta-galactosidase and lac permease, CRP-cAMP activation, catabolite repression, phosphotransferase system (PTS), positive and negative gene regulation.