In E. coli, the lac operon gets switched on when\

Question

Professor PC Thomas Classes · Answer

(a) : The repressor of the operon is synthesised (all-the-timeconstitutively) from the $i$ gene. The repressor protein binds to the operator region of the operon and prevents RNA polymerase from transcribing the operon. In the presence of an inducer, such as lactose or allolactose, the repressor is inactivated by interaction with the inducer. This allows RNA polymerase access to the promoter and transcription proceeds. Thus, the lac operon gets switched on.