Question

Inducible operons differ from repressible operons in that ______.

Options

• the operator of inducible operons is switched off by a repressor protein.

• inducible operons have an operator that controls binding of RNA polymerase to the promoter region.

• inducible operons use activators and positive control to regulate their transcription.

• inducible operons usually include structural genes that function in catabolic pathways.

Answer 1

Inducible operons differ from repressible operons in that inducible operons usually include structural genes that function in catabolic pathways.

Explanation:

Inducible operons (like the lac operon) are usually “off” and only turn “on” to break down (catabolize) a specific nutrient when it's available. In contrast, repressible operons (like the trp operon) are usually “on” and stay active to build (anabolize) essential molecules until there is enough of them to signal a shutdown.