When E. coli is grown on glucose, and there is no lactose available
a. lactose molecules bind to the lac repressor.
b. the lac repressor binds to the operator of the lac operon.
c. RNA polymerase binds to the promoter of the lac operon.
d. the lac genes are transcribed into messenger RNA.
Answer: b. the lac repressor binds to the operator of the lac operon.