The electron transport chain refers to the transfer of
electrons from electron donors and electron acceptors. After the transfer of
electrons, these electrons then couple with protons (H+ ions) across a
membrane. In eukaryotic cells, electron transport chains occur within the
mitochondrial membrane where it serves as the site of oxidative phosphorylation
that uses ATP as its energy source.
The molecular oxygen is the final acceptor of electrons in an
electron transport chain. This type of transport is used by the cell in
extracting energy through redox reactions that occur during photosynthesis,
sugar oxidation, and cellular respiration.
