Single Choice

Choose the correct answer from the alternatives given : In E. Coli, the lac operon gets switched on when

ALactose is present and it binds to the repressor
Correct Answer
BRepressor binds to operator
CRNA polymerase binds- to the operator
DLactose is present and it binds to RNA polymerase

Solution

The repressor of the operon is synthesized (all-the-time-constitutively) 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.
So, the correct answer is 'Lactose is present and it binds to the repressor'.

SIMILAR QUESTIONS

Genetics

Which of the following is required as inducer(s) for the expression of Lac operon?

Genetics

All of the following are part of an operon except

Genetics

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

Genetics

In the lac operon model, lactose molecules function as

Genetics

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down sometime after addition of lactose in the medium?

Genetics

Choose the correct answer from the alternatives given : The sequence of structural genes in lac operon is

Genetics

Choose the correct answer from the alternatives given : In E. Coli, the lac operon gets switched on when

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