öndunarkeðjan

Öndunarkeðjan, also known as the electron transport chain, is a series of protein complexes and electron carrier molecules embedded in the inner mitochondrial membrane. This crucial process is the final stage of cellular respiration, where the majority of ATP, the cell's energy currency, is generated. The chain begins with the transfer of high-energy electrons from electron carriers like NADH and FADH2, which were produced during earlier stages of respiration. These electrons move sequentially through a series of protein complexes, releasing energy at each step. This energy is then used to pump protons (H+) from the mitochondrial matrix into the intermembrane space, creating an electrochemical gradient. Oxygen acts as the final electron acceptor at the end of the chain, combining with electrons and protons to form water. The accumulated proton gradient drives the synthesis of ATP through a process called chemiosmosis, where protons flow back into the matrix through an enzyme called ATP synthase. This efficient mechanism allows cells to harness energy from food molecules to power their essential functions.