In the lac operon how would gene expression be affected if o

In the lac operon, how would gene expression be affected if one of the following segments were missing?

                A. lac operon promoter

                B. Operator site

                C. lacA gene

Solution

A. lac operon promoter: If  lac operon promoter is missed, there is no site for RNA polymerase to bind. Hence it effects the expresson.

B. Operator Site : It is the main gateway for operon. In the absence of operator site, the RNA polymerase continously movies on functional genes,so it expresses continously.

C. LacA gene: It affects the lactose conversion, not the operon function. Becuase the product of lac A is -galactoside transacetylase, which transfers an acetyl group from acetyl-CoA to -galactosides.