The obvious advantage of the lactose operon is that
A) it allows bacteria to survive in the presence of lactose.
B) lactose-metabolizing enzymes need not be made when lactose is not present.
C) it enables bacteria to make lactose only in the presence of the proper enzymes.
D) it negates the need for milk in the diet of adult humans.
E) it enables glucose to substitute for lactose in the diet of lactose intolerant persons.

Question

Quizplus · Accepted Answer

The lactose operon allows bacteria to regulate the expression of lactose-metabolizing enzymes based on the presence or absence of lactose. When lactose is not present, the genes for these enzymes are not expressed, conserving cellular resources. When lactose is present, the genes are activated and the enzymes are made, enabling the bacteria to utilize lactose as a food source. This provides an energy-efficient way for bacteria to survive in environments where lactose may be present intermittently.

The Obvious Advantage of the Lactose Operon Is That