Section III: Bioenergetics

Section III – Bioenergetics

Which one of the following statements about the free energy change (ΔG) in a biochemical reaction is CORRECT?

A. If ΔG is negative, the reaction proceeds spontaneously with a loss of free energy.

B. In an exergonic reaction, ΔG is positive.

C. The standard free energy change when reactants are present in concentrations of 1.0 mol/L and the pH is 7.0 is represented as ΔG⁰.

D. In an endergonic reaction there is a loss of free energy.

E. If a reaction is essentially irreversible, it has a high positive ΔG.

A reaction with a negative ΔG is exergonic, it proceeds spontaneously and free energy is released.

If the ΔG of a reaction is zero:

A. The reaction goes virtually to completion and is essentially irreversible.

B. The reaction is endergonic.

C. The reaction is exergonic.

D. The reaction proceeds only if free energy can be gained.

E. The system is at equilibrium and no net change occurs.

In an exergonic reaction ΔG is negative and in an endergonic reaction it is positive. When ΔG is zero, the reaction is at equilibrium.

ΔG^0’ is defined as the standard free energy charge when:

A. The reactants are present in concentrations of 1.0 mol/L.

B. The reactants are present in concentrations of 1.0 mol/L at pH 7.0.

C. The reactants are present in concentrations of 1.0 mmol/L at pH 7.0.

D. The reactants are present in concentrations of 1.0 μmol/L.

E. The reactants are present in concentrations of 1.0 mol/L at pH 7.4.

When the reactants are present in concentrations of 1.0 mol/L, ΔG⁰ is the standard free-energy change. For biochemical reaction, the pH (7.0) is also defined and this is ΔG^0′.

Which of the following statements about ATP is CORRECT?

A. It contains three high-energy phosphate bonds.

B. It is needed in the body to drive exergonic reactions.

C....