MITOCHONDRIAL OXIDATIVE PHOSPHORYLATION, REACTIVE OXYGEN SPECIES, AND CELLULAR ENERGY HOMEOSTASIS: MOLECULAR MECHANISMS AND BIOLOGICAL SIGNIFICANCE

Mitochondria play a central role in cellular ATP production, redox balance maintenance, calcium signaling regulation, and stress response management. The mitochondrial electron transport chain and oxidative phosphorylation constitute the primary molecular basis of these processes. Electrons carried by NADH2 and FADH2 enter the respiratory chain, and their transfer to oxygen drives the formation of a proton electrochemical gradient. This gradient drives ATP synthesis via ATP synthase.

However, the flow of electrons through the mitochondrial respiratory chain is also associated with the generation of reactive oxygen species (ROS). At low levels, ROS can act as signaling molecules, whereas high levels lead to oxidative stress and cellular damage.

This review examines the molecular mechanisms of mitochondrial biological oxidation, the electron transport chain, oxidative phosphorylation, ROS generation, and reverse electron transport. Additionally, the biological and clinical significance of mitochondrial oxidation along with current research directions in this field are discussed.