Question

Why does the lac operon shut down some time after the addition of lactose in the medium where E.coli was growing? Why low level expression of lac operon is always required?

Answer 1

Answer:

I have attached solution to your question. I hope it will help you.

Answer 2

Answer:

Lac operon is controlled by the existence of lactose in the growing medium. When Lactose is present in the medium, it binds to the repressor particle. This averts the repressor molecule from binding to the operator area of the operon. In the nonappearance of lactose the repressor molecule gets free and can bind to the operator region again, thus averting the transcript of the genes, and closing down the operon.