Answer:
Explanation:
Lactose operon or lac operon (includes lacZ, lacY and lacA genes) is found in some bacteria and the products of its genes are involved in lactose metabolism. So, this operon is active (genes are transcribed) when lactose is present and glucose is absent (or at low level). The operon is regulated by the lac repressor which acts as a lactose sensor and catabolite activator protein (CAP) which acts as a glucose sensor.
When there is lactose (in the form of allolactose) lac repressor detects it and stops being repressor. This enables transcription.
CAP detects glucose (via cAMP) and activates transcription when glucose levels are low.