Answer:
Electron transport chain
Explanation:
In all eukaryotes electron transport chain is located in the inner mitochondrial membrane where it serves as the site of oxidative phosphorylation (production of ATP) through the action of ATP synthase.
Electron transport chain consists of protein complexes that transfer electrons from donors to acceptors via redox reactions. As a result of electron transport, protons (H+ ions) are pumped across a membrane and electrochemical proton gradient is formed. Proton gradiend is used for the ATP synthesis.
Cells
tissue
organs
organ systems
organisms.
