Question

Regarding regulation of the ara operon, what would be the effect of a mutation that removes the part of the AraC protein that binds to RNA Polymerase?
a. Transcription would not occur at high levels in either the presence or absence of arabinose.
b. Transcription would occur at high levels in both the presence and absence of arabinose.
c. Transcription would occur at high levels in the absence, but not the presence, of arabinose.
d. Transcription would occur at high levels in the presence, but not the absence, of arabinose. Submit

Answer 1

Answer:

The correct answer is option a. "Transcription would not occur at high levels in either the presence or absence of arabinose".

Explanation:

The ara operon, also known as the L-arabinose operon, is a series of related genes that are transcribed within the same transcript and are all related to the metabolism of L-arabinose. Among the proteins translated from the ara operon, the AraC protein that binds to RNA Polymerase is the one that recognizes L-arabinose and enhances ara operon transcription in its presence. Therefore, if a mutation removes the gene that encodes for the AraC protein, transcription would not occur at high levels in either the presence or absence of arabinose.