Where does the Krebs cycle take place within the cell?

The Krebs cycle, also known as the citric acid cycle or TCA cycle, occurs in the mitochondrial matrix of eukaryotic cells. The mitochondrial matrix is the space enclosed by the inner membrane of the mitochondria, where enzymes and substrates for the Krebs cycle are present. This environment is optimal for the series of chemical reactions that convert acetyl-CoA into energy-carrying molecules, such as NADH and FADH2, while also releasing carbon dioxide as a waste product.

The mitochondrial matrix's pH and ion concentration are tightly regulated, providing an ideal environment for the enzymes involved in the Krebs cycle. For instance, the presence of various coenzymes and the compartmentalization of metabolic processes enhance the efficiency of energy production within the mitochondria. Hence, the Krebs cycle is crucial for aerobic respiration, linking glycolysis, which occurs in the cytoplasm, and oxidative phosphorylation in the inner mitochondrial membrane, enabling cells to produce ATP effectively.