ALT GIF shows the process of a Lac Operon that is present in some bacteria. There is a promoter region of the DNA, the operator region of the DNA, and there are three genes [labeled lacZ, lacY, and lacA] that code for enzymes that help in the process of breaking down lactose. If lactose is not present, then the repressor binds to the operator, which blocks RNA polymerase. The mRNA cannot be made. If lactose is around in the environment, it can change the repressor’s conformation. Now the repressor can’t bind to the operator. RNA polymerase finds its promoter, binds, and transcribes to make mRNA from the genes on the operon. That mRNA will be used to make enzymes to break down that lactose sugar.