Question

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

• A. Feedback inhibition because excess of $\beta$-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



In lac operon, the operon is switched OFF when the repressor protein is present. Thus, the lac operon is a negatively controlled system.
In lac operon, the presence of the metabolite or lactose switches ON the operon. Hence, the lac operon is an inducible system.