The trp operon in E.coli is regulated in such a manner as to allow expression of the genes only when cellular levels of tryptophan are low.When tryptophan levels are adequate,the secondary structure of the mRNA halts translation.This form of regulation is known as
A)attenuation.
B)transcriptional regulation.
C)positive regulatory control.
D)negative regulatory control.
E)repression.

Question

Quizplus · Accepted Answer

The described form of regulation is known as attenuation, where the secondary structure of the mRNA halts translation when levels of a particular substance (in this case, tryptophan) are adequate. This is a post-transcriptional form of control. Transcriptional regulation (B) involves control of gene expression at the level of transcription, while positive regulatory control (C) and negative regulatory control (D) describe processes involving activators and repressors that affect transcription. Repression (E) specifically refers to the inhibition of gene expression.

The Trp Operon in E