Question

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

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

Answer 1

Answer: (B)

In negative regulation, a repressor molecule binds to the operator of an operon and terminates transcription. The lac operon is a negatively controlled inducible operon, where the inducer molecule is allolactose.