Of the various oxidation reactions in glycolysis and the citric acid cycle, the only one that does not involve NAD+ is the succinate dehydrogenase reaction. What would ∆G°′ be for an enzyme that oxidizes succinate with NAD+ instead of FAD? If the intramitochondrial concentration of succinate was 10-fold higher than that of fumarate, what minimum [NAD+] / [NADH] ratio in mitochondria would be needed to make this reaction exergonic at 37° C?