Question

Gene regulation governing lactose operon of E.coli that involves the lacI gene product is:

• A. Feedback inhibition because excess of β -galactosidase can switch off transcription
• B. Positive and inducible because it can be induced by lactose
• C. negative and inducible because repressor protein prevents transcription
• D. negative and repressible because repressor protein prevents transcription

Answer 1

The correct option is C

negative and inducible because repressor protein prevents transcription

The lac operon is a negative inducible operon. Basically, when lactose is absent, the regulator protein (a repressor) binds to the operator, inhibiting transcription.