The lac operon controls the production of the enzyme beta-galactosidase in bacterial cells. In the presence of lactose, thousands of molecules of beta-galactosidase are produced to break down lactose into glucose and galactose. When no lactose is present, fewer beta-galactosidase enzymes are produced.

1. LAC OPERON PRESENCE INDUCES BACTERIAL CELLS TO MAKE ENZYMES DISACCHARIDES FOUND IN MILK LACTOSE IF MORE LACTOSE IS PRESENT, THOUSANDS OF MOLECULES OF BETA- GALACTOSIDASE WILL BE FOUND. BROKEN DOWN INTO GLUCOSE AND GALACTOSE BYTHE ENZYME BETA-GALACTOSIDASE IF NO LACTOSE IS PRESENT, FEWER BATE- GALACTOSIDASE ENZYME IS FOUND.

2. WHEN THERE IS NO LACTOSE

4. WHEN THERE IS LACTOSE PRESENT

6. SUMMARY OF LAC OPERON WITH AND WITHOUT THE PRESENCE OF LACTOSE