Which molecule is released during the conversion of pyruvic acid to acetyl CoA?

During the conversion of pyruvic acid to acetyl CoA, carbon dioxide (CO2) is released as a byproduct. This process occurs in the mitochondrial matrix and is part of the link reaction that connects glycolysis to the citric acid cycle (Krebs cycle).

In this reaction, pyruvic acid, which is a three-carbon molecule produced during glycolysis, undergoes decarboxylation, wherein one carbon atom is removed in the form of CO2. The remaining two-carbons are then attached to coenzyme A, forming acetyl CoA, which is crucial for entering the citric acid cycle. This release of CO2 is a significant aspect of cellular respiration, as it contributes to the overall carbon balance in metabolic processes.

The other molecules mentioned, such as water, NADH, and ATP, are involved in different stages of cellular respiration. For instance, NADH is generated during glycolysis and is used later in the electron transport chain, while ATP is produced in various stages, including during glycolysis and oxidative phosphorylation, but neither are directly released from the conversion of pyruvic acid to acetyl CoA.