Question

Which of the following acts as an inducer in the lac operon?

• A. glucose
• B. tryptophan
• C. lactose
• D. galactose

Answer 1

Answer:

C. lactose

• When lactose is present in the medium, it binds to the repressor protein changing its conformation while preventing the former’s binding at the operator region.

• Thus the structural genes are transcribed and lactose is catabolized, therefore lactose acts as an inducer in the lac operon.