An E. coli cell without a functional lacI gene is expected to
A) be unable to metabolize lactose within the cell.
B) always produce fi- galactosidase.
C) never produce fi- galactosidase.
D) be unable to transport lactose into the cell.

Question

Quizplus · Accepted Answer

The lacI gene encodes the lac repressor, which inhibits the expression of the lac operon genes (including the gene for β-galactosidase) in the absence of lactose. Without a functional lacI gene, the cell cannot produce the repressor, leading to constant expression of β-galactosidase regardless of lactose presence.

An E Coli Cell Without a Functional LacI Gene Is Expected