What is the role of acetyl-CoA in the Citric Acid Cycle?

Acetyl-CoA plays a critical role in the Citric Acid Cycle as it functions as a substrate that combines with oxaloacetate to initiate the cycle. When acetyl-CoA enters the cycle, it reacts with oxaloacetate, forming citrate. This step marks the transition from glycolysis and the conversion of pyruvate into a usable form of energy. The formation of citrate from acetyl-CoA and oxaloacetate is essential because it sets off a series of enzymatic reactions that lead to the production of energy-carrying molecules such as NADH, FADH2, and ATP.

This central role of acetyl-CoA ensures that the cycle continues to process and extract energy from carbon-containing compounds. Understanding this function of acetyl-CoA is crucial for grasping how metabolic pathways are interconnected and how energy production takes place in cells.