The continued oxidation of acetyl CoA via the TCA cycle requires the continued replenishment of:

At how many points in the TCA cycle is ${\mathrm{NAD}}^{+}$ reduced to NADH + ${\mathrm{H}}^{+}$?

During the conversion of succinyl CoA to succinic acid in TCA cycle:
1. One molecule of ATP is directly synthesized
2. ${\mathrm{NAD}}^{+}$ is reduced
3. FAD is reduced
4. One molecule of GTP is synthesized

Oxidative decarboxylation of pyruvate produces: