Imagine That You Discover a Bacterial Operon Involved in the Synthesis

question 5

Multiple Choice

Imagine that you discover a bacterial operon involved in the synthesis of vitamin B₁₂. This operon is regulated by a repressor protein that binds to an operator sequence. Vitamin B₁₂ is the allosteric effector of the repressor
-the molecule that binds to the repressor to affect its activity. Predict how vitamin B₁₂ will influence repressor activity.

• A) When vitamin B₁₂ binds to the repressor, the repressor binds to the operator.
• B) When vitamin B₁₂ binds to the repressor, the repressor can bind to RNA polymerase.
• C) When vitamin B₁₂ binds to the repressor, the repressor cannot bind to RNA polymerase.
• D) When vitamin B₁₂ binds to the repressor, the repressor cannot bind to the operator.