Chapter 11, Problem 13PS

Study the depiction of the lac operon in Figure 11.2. Normally, the genes are turned off when lactose is not present. Lactose activates the genes, which code for enzymes that enable the cell to use lactose. Mutations can alter the function of this operon. Predict how the following mutations would affect the function of the operon in the presence and absence of lactose:

1. a. mutation of regulatory gene; repressor will not bind to lactose
2. b. mutation of operator; repressor will not bind to operator
3. c. mutation of regulatory gene; repressor will not bind to operator
4. d. mutation of promoter; RNA polymerase will not attach to promoter