Which of the Following Accounts for the Negative Control of Operons

Question

Which of the following accounts for the negative control of operons?  
A) Promoters
B) Repressors
C) Structural genes
D) Operators
E) Deactivators

Accepted Answer

Repressors are proteins that bind to specific regions of DNA called operators and prevent RNA polymerase from binding to the promoter and transcribing the structural genes. This is a form of negative control because it inhibits gene expression. Operators, promoters, and structural genes all play a role in regulating gene expression, but they do not account for the negative control of operons. Deactivators are not a known component of operon regulation.