oxidative phosphorylation

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oxidative phosphorylation

chemical reaction

Also known as: respiratory-chain phosphorylation

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July 2, 2026

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Oxidative phosphorylation is the process by which cells synthesize ATP, the primary energy currency, using energy derived from the oxidation of nutrients. This crucial process occurs within the mitochondria of animal and plant cells.12

During oxidative phosphorylation, electrons are transferred through a series of protein complexes embedded in the inner mitochondrial membrane, known as the electron-transport chain. This electron flow releases energy, which is used to pump protons (H⁺ ions) across the membrane, creating an electrochemical gradient. This gradient represents stored potential energy, similar to water held behind a dam.23

An enzyme complex called ATP synthetase utilizes the energy from protons flowing back across the membrane to convert ADP and inorganic phosphate into ATP. This mechanism effectively converts electrical energy into chemical energy stored in ATP bonds. The reduced coenzymes NADH and FADH₂, formed during the breakdown of food molecules, are the initial electron donors in this process.2435

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metabolism
Oxidative, or respiratory-chain, phosphorylation
In oxidative phosphorylation the oxidation of catabolic intermediates by molecular oxygen occurs via a highly ordered series of substances that act as hydrogen and electron carriers. They constitute the electron transfer system, or respiratory chain. In most animals, plants, and fungi, the electron transfer system is…
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In oxidative phosphorylation the oxidation of catabolic intermediates by molecular oxygen occurs via a highly ordered series of substances that act as hydrogen and electron carriers. They constitute the electron transfer system, or respiratory chain. In most animals, plants, and fungi, the electron transfer system is…
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cell
ATP: fueling chemical reactions
…in the breakdown of sugars, oxidative phosphorylation, the high-energy hydrogen atoms are first separated into protons and high-energy electrons. The electrons are then passed from one electron carrier to another by means of an electron-transport chain. Each electron carrier in the chain has an increasing affinity for electrons, with the…
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…in the breakdown of sugars, oxidative phosphorylation, the high-energy hydrogen atoms are first separated into protons and high-energy electrons. The electrons are then passed from one electron carrier to another by means of an electron-transport chain. Each electron carrier in the chain has an increasing affinity for electrons, with the…
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cellular respiration
Oxidative phosphorylation
In the oxidative phosphorylation stage, each pair of hydrogen atoms removed from NADH and FADH₂ provides a pair of electrons that—through the action of a series of iron-containing hemoproteins, the cytochromes—eventually reduces one atom of oxygen to form water. In 1951 it was discovered that the
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In the oxidative phosphorylation stage, each pair of hydrogen atoms removed from NADH and FADH₂ provides a pair of electrons that—through the action of a series of iron-containing hemoproteins, the cytochromes—eventually reduces one atom of oxygen to form water. In 1951 it was discovered that the
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lipid
Oxidation of fatty acids
…by a process known as oxidative phosphorylation. All the participating enzymes are located inside the mitochondrial inner membrane—except one, which is trapped in the space between the inner and outer membranes. In order for the process to produce ATP, the inner membrane must be impermeable to hydrogen ions (H⁺). In…
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…by a process known as oxidative phosphorylation. All the participating enzymes are located inside the mitochondrial inner membrane—except one, which is trapped in the space between the inner and outer membranes. In order for the process to produce ATP, the inner membrane must be impermeable to hydrogen ions (H⁺). In…
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catabolism
…known as terminal respiration and oxidative phosphorylation (see cellular respiration).
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…known as terminal respiration and oxidative phosphorylation (see cellular respiration).
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phosphorylation
…to the cell is called oxidative phosphorylation (see cellular respiration). The process by which green plants convert light energy to chemical energy is called photophosphorylation (see photosynthesis).
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…to the cell is called oxidative phosphorylation (see cellular respiration). The process by which green plants convert light energy to chemical energy is called photophosphorylation (see photosynthesis).
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