How does lactose function with the lac operon?

In the promoter, the RNA polymerase binds and then begins transcription. The lac repressors in the operator binds to the O region.

Repressor Protiens

Because these genes must be expresses in order for the bacterium to be able to use the sugar lactose as food, they are called the lac operon.

The lac repressor protein has a binding site for lactose itself.

In the lac operon model, lactose acts as in inducer molecule. In the presence of lactose, the molecule binds to the repressor protein. This repressor-lactose complex is unable to bind to the...