The lac operon in E. coli is
- A
Activated only when glucose is abundant, allowing efficient catabolism of sugars
- B
Repressed when lactose is present (the corepressor activates the repressor protein)
- Ccheck_circle
Induced when lactose is present (and glucose absent), allowing the cell to digest lactose
- D
Constitutively expressed regardless of lactose or glucose concentrations in the medium
Explanation
Allolactose binds the LacI repressor, releasing it from the operator so transcription proceeds. Catabolite activator protein (CAP) further amplifies transcription when glucose is low.