One interesting and surprising finding regarding the regulation of the ara operon is that it is under both positive and negative control. What protein is responsible for the dual action of this operon?
A) AraC is responsible for both the positive and negative control of the ara operon.
B) RNA polymerase is responsible for both the positive and negative control of the ara operon.
C) AraD is responsible for both the positive and negative control of the ara operon.
D) DNA polymerase is responsible for both the positive and negative control of the ara operon.
E) AraBAD is responsible for both the positive and negative control of the ara operon.

Question

Quizplus · Accepted Answer

The protein responsible for the dual action of the ara operon is AraC. It acts as both an activator and a repressor depending on the presence or absence of arabinose in the environment. When arabinose is present, it binds to AraC and causes a conformational change that allows it to bind to the DNA and activate the transcription of the ara operon. When arabinose is absent, AraC binds to the DNA in a different location and blocks the transcription of the ara operon by preventing RNA polymerase from accessing the promoter. Therefore, AraC is responsible for both the positive and negative control of the ara operon.

One Interesting and Surprising Finding Regarding the Regulation of the Ara