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

在电子传递链过程中，来自NADH和FADH₂的高能电子通过蛋白质复合体，驱动质子跨膜泵送。NADH中的电子进入复合体I，并通过各复合体传递，在复合体I、III和IV中总共泵出约十个质子。来自FADH₂的电子进入复合体II，该复合体不泵送质子。因此，FADH₂2 仅对膜外泵送六个质子有贡献。质子的移动形成了浓度梯度和电势梯度，共同产生了质子驱动力。质子通过ATP合酶顺着浓度梯度跨膜回流，ATP合酶是一种膜结合的酶复合体，利用质子动力势将ADP磷酸化为ATP——这一过程称为化学渗透。ATP合酶利用约4个质子合成1个ATP分子。因此，每分子NADH可产生约2.5个ATP分子，每分子FADH₂可产生约1.5个ATP分子。

化学渗透作用

Chemiosmosis and ATP Synthesis

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Education

教育

JoVE Core

Microbiology

微生物学

Unit

单元

Microbial Metabolism

微生物代谢

KEY TERMS AND CONCEPTS

关键术语与概念

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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How Plants Make Oxygen and ATP

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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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