This page discusses gene expression regulation in E. coli, focusing on the lac operon, which metabolizes lactose through a repressor mechanism. When lactose is present, it enables transcription by det...This page discusses gene expression regulation in E. coli, focusing on the lac operon, which metabolizes lactose through a repressor mechanism. When lactose is present, it enables transcription by detaching the repressor. The page also covers the dual control by Catabolite Activator Protein (CAP), which requires cAMP for DNA binding, allowing prioritization of glucose over lactose.