Having been transcribed and translated, it is
time for the proteins coded for by the Z and Y genes to play their roles. The
two proteins, ß-galactosidase (Z) and permease (Y), can now help bring
the lac operon cycle to completion. Clicking on each of the
thumbnail images will bring up a larger, labeled version of the described scene.
see the Flash movie for the following sequence of images,
Once the permease has become embedded in
the membrane, it allows lactose to flood into the cell at an elevated rate.
After entering the cell, the lactose is then broken down
by ß-galactosidase into the simple sugars glucose and galactose. These
simple sugars are used by the cell as food.