The Standard Reduction Potentials (E'°) for the Following Half Reactions $\rightarrow$

Multiple Choice

The standard reduction potentials (E'°) for the following half reactions are given. Fumarate + 2H⁺ + 2e^- $\rightarrow$ succinate
E'° = +0.031 V
FAD + 2H⁺ + 2e^- $\rightarrow$ FADH₂
E'° = -0.219 V
If succinate, fumarate, FAD, and FADH₂, all at l M concentrations, were mixed together in the presence of succinate dehydrogenase, which of the following would happen initially?

A) Fumarate and succinate would become oxidized; FAD and FADH₂ would become reduced.
B) Fumarate would become reduced; FADH₂ would become oxidized.
C) No reaction would occur because all reactants and products are already at their standard concentrations.
D) Succinate would become oxidized; FAD would become reduced.
E) Succinate would become oxidized; FADH₂ would be unchanged because it is a cofactor, not a substrate.