The citric acid cycle (also known as the Krebs cycle or TCA cycle) is a series of chemical reactions in the mitochondria that breaks down acetate derived from carbohydrates, fats, and proteins into carbon dioxide to facilitate the production of ATP. Key steps include the condensation of acetyl-CoA with oxaloacetate to form citrate, oxidative decarboxylation reactions catalyzed by isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase, and the regeneration of oxaloacetate from succinate to complete the cycle. The cycle generates NADH and FADH2 that feed into oxidative phosphorylation to produce ATP.