The arabinose operon (ara) provides a particularly interesting example of ________ in that when arabinose is present in the environment, the operon is transcribed.
A) positive control
B) negative control
C) push forward control
D) reverse transcription
E) positive translation

Question

Quizplus · Accepted Answer

The arabinose operon is under positive control because the presence of arabinose activates the transcription of the operon. This is accomplished through the binding of the arabinose operon regulatory protein (AraC) to the arabinose sugar, which then helps RNA polymerase bind to the promoter region of the operon. When there is no arabinose in the environment, the operon is not transcribed, as is the case with most inducible operons, making negative control an incorrect answer choice. The other answer choices are not related to the regulation of gene expression.

The Arabinose Operon (Ara) Provides a Particularly Interesting Example of ________