Question

What will prevent the binding of the molecules '$M$' with the operator gene? Mention the event that follows.

Answer 1

It has i region which synthesis the repressor which is represented by M. This repressor in absence of inducer i.e lactose binds to the operator region of the operon. So if lactose is present in the media then it will act as an inducer it will prevent the repressor from binding to the operator region. Then RNA polymerase with the camp molecule will bind to the operator and will start transcribing lac z, lac y and lac a gene giving beta-galactosidase, galactoside permease and trans-acetylase respectively.