Question

The lac I gene product is involved in gene control regulating the lactose operon of E.coli.

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

Answer 1

The correct option is C

Negative and inducible because repressor protein prevents transcription

The correct option is C.

Explanation of the correct option:

1. The lac operon has no control over gene expression since it is generally switched off owing to repressor binding to the operator region.
2. The presence of inducers such as lactose allolactose causes it to be inducible.
3. Because the inducer attaches to the repressor, RNA polymerase is now able to enter the promoter region and begin transcription.

Final Answer: The lac I gene product is involved in gene control regulating the lactose operon of E.coli is negative and inducible because repressor protein prevents transcription.