elektróntransportkeðjunni

The electron transport chain, or elektrónflutningskeðjan in Icelandic, is a series of protein complexes embedded in the inner mitochondrial membrane of eukaryotic cells. It is the final stage of aerobic respiration, where the majority of ATP, the cell's energy currency, is produced. This process utilizes the energy released from the stepwise transfer of electrons from electron carriers, NADH and FADH2, to molecular oxygen.

These electron carriers are generated during earlier stages of cellular respiration, such as glycolysis and the Krebs cycle. Within the electron transport chain, electrons are passed from one protein complex to another, moving down an electrochemical gradient. As electrons move through the chain, energy is released and used to pump protons (H+) from the mitochondrial matrix into the intermembrane space. This creates a proton gradient across the inner mitochondrial membrane.

The potential energy stored in this proton gradient is then harnessed by an enzyme called ATP synthase. As protons flow back into the matrix through ATP synthase, the enzyme catalyzes the synthesis of ATP from ADP and inorganic phosphate. This process is known as chemiosmosis. The final electron acceptor in the chain is oxygen, which combines with electrons and protons to form water. The electron transport chain is therefore crucial for aerobic metabolism, efficiently converting the chemical energy stored in glucose into usable cellular energy in the form of ATP.