The citric acid cycle, also known as the Krebs cycle, is a series of chemical reactions that occur in the mitochondria of cells. It plays a crucial role in cellular respiration, where it helps convert carbohydrates, fats, and proteins into energy. During the cycle, acetyl-CoA combines with oxaloacetate to form citric acid, which undergoes several transformations, releasing energy, carbon dioxide, and electron carriers like NADH and FADH2. These electron carriers are essential for the next stage of cellular respiration, the electron transport chain, where they help produce ATP, the energy currency of the cell. The cycle also regenerates oxaloacetate, allowing it to continue processing more acetyl-CoA. Overall, the citric acid cycle is vital for energy production and metabolic processes in living organisms.