Question

the lac operon is usually in the ________ position and is activated by a/an ________ molecule
multiple choice
57
off, inducer
off, repressor
on, repressor
on, inducer

Explanation:

The lac operon is a cluster of genes in E. coli that are involved in lactose metabolism. In the absence of lactose, the repressor protein binds to the operator region of the lac operon, preventing RNA polymerase from transcribing the genes. This keeps the operon "off." When lactose (or its analog, allolactose, which acts as an inducer) is present, it binds to the repressor, causing a conformational change that makes the repressor unable to bind to the operator. This allows RNA polymerase to transcribe the genes, effectively "activating" the operon. A repressor molecule would keep the operon off, not activate it. If the operon were "on" normally, there would be no need for an inducer to activate it in the context of lactose - related regulation.

Answer:

off, inducer