The trp operon is controlled by:
A)Trp repressor.
B)attenuation.
C)catabolite activator protein (CAP).
D)Trp repressor and catabolite activator protein (CAP).
E)Trp repressor and attenuation.

Question

Quizplus · Accepted Answer

The trp operon is regulated by both the trp repressor and attenuation mechanisms. The trp repressor is a protein that binds to the operator region of the trp operon in the presence of tryptophan and prevents RNA polymerase from transcribing the genes. Attenuation occurs during transcription and is dependent on the levels of charged tRNA molecules in the cell. If tryptophan levels are high, charged tRNA molecules will be abundant and transcription will be attenuated, stopping the synthesis of the trp operon genes. Therefore, the trp operon is not regulated by the catabolite activator protein (CAP), which is involved in the control of genes involved in glucose metabolism.

The Trp Operon Is Controlled By