Chap. X: Mitochondria_2026_English

The mitochondrion is a double-membrane cellular organelle essential for the production of energy in the form of ATP through aerobic cellular respiration. Its smooth outer membrane, permeable to small molecules, surrounds a cristae-pleated inner membrane that contains the respiratory chain complexes and ATP synthase. Between the two lies the intermembrane space, rich in protons (H⁺), and at the center, the mitochondrial matrix, containing mitochondrial DNA, ribosomes, enzymes of the Krebs cycle, and metabolic pathways such as β-oxidation of fatty acids. Thanks to its compartmentalized structure and its own genetic material, the mitochondrion is considered a semi-autonomous organelle. It also plays a key role in apoptosis, calcium regulation, and the synthesis of certain molecules.