Cellular respiration is formally an electrochemical process: the overall oxidation of glucose by molecular oxygen to carbon dioxide and water is a redox reaction in which glucose is oxidized (losing electron density) and oxygen, the terminal electron acceptor, is reduced, so electrons flow from fuel to oxidant exactly as they flow from anode to cathode species in a galvanic cell. In the biological case oxidation state must be assessed by electron density and electronegativity rather than by formal ionic charge, since carbon bonded to oxygen retains far less electron density than carbon bonded to hydrogen. The cell realizes the functional elements of an electrochemical cell — a conductive path in the electron transport chain, and spatial separation of oxidation from reduction through mitochondrial compartmentalization — so that the electron flow can be harnessed to phosphorylate ADP to ATP rather than to drive an external electrical load; glucose is oxidized stepwise, with progressively oxidized metabolites passing electrons to electron carrier molecules that are the species actually feeding the transport chain. The topic integrates general-chemistry electrochemistry with metabolism/bioenergetics.
Cellular respiration is formally an electrochemical process: the overall oxidation of glucose by molecular oxygen to carbon dioxide and water is a redox reaction in which glucose is oxidized (losing …