Name: electron transport chain powers atp output
Uploaded: 2025-06-12T09:34:38.000Z
Duration: 1 min 22 s
Channel: JoVE

During the electron transport chain, high-energy electrons from NADH and FADH&#8322; pass through the protein complexes driving the pumping of protons across the membrane.Electrons from NADH enter Complex I and move through the complexes, pumping approximately ten protons through complexes I, III and IV.Electrons from FADH&#8322; enter Complex II, which does not pump protons. As a result, FADH2 contributes to pumping only six protons across the membrane.The proton movement creates both a concentration gradient and an electrical gradient, collectively generating the proton motive force.Protons flow back across the membrane through ATP synthase, a membrane-bound enzyme complex that uses the proton motive force to phosphorylate ADP into ATP &#8212; a process called chemiosmosis.ATP synthase utilizes approximately four protons to synthesize one ATP molecule. As a result, about 2.5 ATP molecules are generated per NADH, and around 1.5 ATP molecules are produced per FADH&#8322;.

chemiosmose

Chemiosmosis and ATP Synthesis

De elektronentransportketen is een cruciaal onderdeel van de cellulaire ademhaling en vindt plaats in de binnenmembraan van het mitochondrion. Deze keten ondersteunt de overdracht van hoogenergetische elektronen van de gereduceerde cofactoren NADH en FADH_2 naar moleculaire zuurstof, de uiteindelijke elektronacceptor. Deze elektronenoverdracht via een reeks eiwitcomplexen is nauw gekoppeld aan het transport van protonen over het membraan, waardoor een protonengradi&#235;nt wordt opgebouwd die noodzakelijk is voor de ATP-synthese.
Elektronentransport en protonenpompen
Elektronen afkomstig van NADH komen in de ETC binnen bij Complex I (NADH:ubiquinon oxidoreductase). In prokaryoten drijft de elektronenstroom door Complex I de protonenpomp aan, waarbij protonen vanuit het cytoplasma naar de extracellulaire ruimte worden getransporteerd. De elektronen worden vervolgens overgedragen aan ubiquinon (co-enzym Q), dat ze transporteert naar Complex III (cytochroom bc1-complex). Complex III faciliteert verdere elektronoverdracht naar cytochroom c en pompt tegelijkertijd extra protonen. Ten slotte bereiken de elektronen Complex IV (cytochroom-c-oxidase), waar moleculaire zuurstof wordt gereduceerd tot water. Dit complex draagt eveneens bij aan het protonentransport. Gezamenlijk resulteert de elektronenoverdracht van NADH in het pompen van ongeveer tien protonen over het membraan.
Daarentegen komen elektronen van FADH_2 de ETC binnen bij Complex II (succinaatdehydrogenase), waarmee Complex I wordt omzeild. Complex II beschikt niet over protonenpompende eigenschappen. Elektronen van FADH_2 worden overgedragen aan ubiquinon en volgen een vergelijkbaar traject via Complex III en IV. FADH_2 draagt bij aan de translocatie van slechts zes protonen over het membraan.
Protonmotorkracht en ATP-synthese
Door het netto ongelijke protonentransport ontstaat zowel een chemische (concentratie)gradi&#235;nt als een elektrische (spannings)gradi&#235;nt over de binnenmembraan van het mitochondrion, gezamenlijk aangeduid als de protonmotorkracht. Dit elektrochemische gradi&#235;nt drijft protonen terug de mitochondriale matrix in via ATP-synthase, een membraan-gebonden enzymcomplex. Het proces waarbij de protonmotorkracht wordt gebruikt om ADP te fosforyleren tot ATP staat bekend als chemiosmose.
ATP-synthase vereist ongeveer vier protonen voor de synthese van &#233;&#233;n ATP-molecuul. Dankzij dit verschil in rendement van de protonmotorkracht levert de oxidatie van &#233;&#233;n NADH-molecuul ongeveer 2,5 ATP-moleculen op, terwijl &#233;&#233;n FADH_2-molecuul ongeveer 1,5 ATP-moleculen genereert. Dit rendement benadrukt de essenti&#235;le rol van de elektronentransportketen en de protonmotorkracht in cellulaire energiemetabolisme.

Chemiosmose

De elektronentransportketen is een cruciaal onderdeel van de cellulaire ademhaling en vindt plaats in de binnenmembraan van het mitochondrion. Deze keten ...

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electron transport chain powers atp output

The electron transport chain powers ATP production during cellular respiration. It sits in the inner mitochondrial membrane and moves high-energy electrons from NADH and FADH2 to molecular oxygen, the final electron acceptor. As electrons move through the chain, protons are pushed across the membrane to build the gradient needed for ATP synthesis.

Electrons from NADH enter the chain at Complex I, also called NADH: ubiquinone oxidoreductase. In prokaryotes, this step helps pump protons from the cytoplasm into the extracellular space. The electrons then move to ubiquinone, or coenzyme Q, which carries them to Complex III, where more protons are pumped and electrons are passed to cytochrome c.

From Complex III, the electrons reach Complex IV, or cytochrome c oxidase. Here, molecular oxygen is reduced to water. Complex IV also helps move protons across the membrane. Overall, electrons that start with NADH lead to the pumping of about ten protons.

FADH2 follows a different route. Its electrons enter at Complex II, also called succinate dehydrogenase, which bypasses Complex I and does not pump protons. The electrons then move to ubiquinone and continue through Complex III and Complex IV. Because of this shorter path, FADH2 contributes only six protons to membrane transport.

The proton pumping creates a proton motive force. This force includes both a concentration gradient and a voltage gradient across the inner mitochondrial membrane. Protons flow back into the mitochondrial matrix through ATP synthase, a membrane enzyme that uses this energy to make ATP from ADP. This use of the proton motive force is called chemiosmosis.

ATP synthase needs about four protons to produce one ATP molecule. Because NADH and FADH2 move different numbers of protons, they yield different ATP amounts. One NADH molecule produces about 2.5 ATP, while one FADH2 molecule produces about 1.5 ATP. These values show how the electron transport chain links electron flow, proton movement, and cellular energy production.

Electron Transport Chain Powers ATP Output

electron-transport-chain-powers-atp-output

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chemiosmosis and atp synthesis

The electron transport chain powers ATP production during cellular respiration. It sits in the inner mitochondrial membrane and moves high-energy electrons from NADH and FADH2 to molecular oxygen, the final electron acceptor. As electrons move through the chain, protons are pushed across the membrane to build the gradient needed for ATP synthesis. Electrons from NADH enter the chain at Complex I, also called NADH: ubiquinone oxidoreductase. In prokaryotes, this step helps pump protons from the...

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key terms and concepts

Learn how the electron transport chain moves electrons, pumps protons, and drives ATP synthase to make ATP from NADH and FADH2 in cellular respiration.

Electron Transport Chain Powers ATP Output | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Electron Transport Chain Powers ATP Output

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