Question

Which one of the following accurately describes the Lac operon?

A. The repressor is freed from the operator when lactose is present.
B. RNA polymerase transcribes the lac genes when lactose isn't present.
C. The repressor protein binds to the operator when lactose is present.
D. RNA polymerase is prevented from transcribing the lac genes when lactose is present.


es the Lac operon?

Answer 1

The Answer Is :

A. The repressor is freed from the operator when lactose is present.

Answer 2

Answer: The correct option is A) The repressor is freed from the operator when lactose is present.

Lac operon is an example of inducible operon in bacteria. It is used for the metabolism and transport of lactose. It consists of three structural gene, an operator, a promotor, and a regulatory element. Regulatory element produces active repressor, which binds to operator and turns off the operon.

In the presence of lactose, repressor becomes inactive and operon is turned on as transcription and translation of the structural genes takes place. Therefore, repressor can not bind to the operator in presence of lactose. Thus, repressor is freed from the operator when lactose is present.

Thus, the statement A) accurately describes Lac operon.