Question

the lac operon is normally in an off mode and does not initiate enzyme synthesis when the appropriate substrate is absent.

true or false

true
false

Explanation:

Analyze the default state of the lac operon

The lac operon is an inducible operon. In the absence of lactose (the substrate), the active repressor protein binds to the operator, blocking RNA polymerase and keeping transcription turned off.

Evaluate the statement

The statement asserts that the lac operon is normally in an "off" mode and does not initiate enzyme synthesis when the substrate (lactose) is absent. This matches the biological mechanism of inducible operons.

Answer:

• True (Correct answer)
• False