Which structural gene of the lac operon can be mutated without affecting the cell's ability to break down lactose?
A)lacZ
B)lacY
C)lacA
D)lacP
E)lacO

Question

Quizplus · Accepted Answer

lacA encodes for a transacetylase enzyme that is not directly involved in lactose breakdown. Therefore, mutating lacA would not affect the cell's ability to break down lactose. The other genes in the lac operon (lacZ, lacY, and lacP) are directly involved in lactose metabolism and mutations in these genes would affect lactose breakdown. lacO is the operator site and mutations in this region would affect the binding of the lac repressor and regulation of the operon.

Which Structural Gene of the Lac Operon Can Be Mutated