What is the prep reaction do?

The prep reaction, also known as the pyruvate decarboxylation or the link reaction, occurs in the mitochondria after glycolysis and before the citric acid cycle. In this process, each molecule of pyruvate generated from glycolysis is converted into acetyl-CoA, which involves the removal of a carbon atom (released as carbon dioxide) and the reduction of NAD+ to NADH. This reaction is crucial for linking glycolysis to the citric acid cycle, allowing for the further oxidation of glucose-derived substrates to generate energy.