Final answer:
The decarboxylation of pyruvate to acetyl-CoA conserves energy by reducing NAD+ to NADH and through the formation of a high-energy thioester bond in acetyl-CoA, which is later used in the Krebs cycle.
Step-by-step explanation:
The energy released from the decarboxylation of pyruvate to acetyl-CoA is conserved in animals and plants through the formation of high-energy compounds. During this highly exergonic reaction, pyruvate is oxidatively decarboxylated to acetyl-CoA by the enzyme complex pyruvate dehydrogenase. Simultaneously, a molecule of NAD+ is reduced to NADH, capturing some of the energy released during this process. Furthermore, the acetyl group forms a high-energy thioester linkage with coenzyme A (acetyl-CoA), which is then used in the Krebs cycle to produce additional ATP and reduced electron carriers. The regulation of this reaction ensures that it occurs when more energy is needed and conserves energy appropriately within the cell.