Imagine That You Discover a Bacterial Operon Involved in the Synthesis

question 10

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

---

Definitions:

Acetone

A volatile, colorless liquid with the formula (CH3)2CO, used as a solvent and in the production of various chemicals.

Electrophile

A chemical species that accepts an electron pair in order to bond to a nucleophile during a chemical reaction.

Lewis Acid

A compound or ionic species that can accept an electron pair from a donor molecule, often functioning as a catalyst in chemical reactions.

Nucleophile

A chemical species that donates an electron pair to form a chemical bond in relation to a reaction.