Question

The product of the lacI gene is a(n) _________________ of a lac operon regardless of its chromosomal location.

a) Repressor
b) Activator
c) Suppressor
d) Initiator

Answer 1

The product of the lacI gene is a repressor of a lac operon regardless of its chromosomal location. In the presence of lactose and the absence of glucose, the repressor protein dissociates from the operator site, allowing transcription of the structural genes lacZ, lacY, and lacA.

Step-by-step explanation:

The product of the lacI gene is a repressor of a lac operon regardless of its chromosomal location. When glucose is present, the lac operon is typically silent, with the repressor protein bound to the operator site, blocking transcription of the lac operon. However, in the presence of lactose and the absence of glucose, the repressor protein dissociates from the operator site, allowing transcription of the three structural genes lacZ, lacY, and lacA.