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

Durante la cadena de transporte de electrones, los electrones de alta energía de NADH y FADH₂ pasan a través de los complejos de proteínas que impulsan el bombeo de protones a través de la membrana. Los electrones del NADH entran en el Complejo I y se mueven a través de los complejos, bombeando aproximadamente diez protones a través de los complejos I, III y IV. Los electrones de FADH₂ entran en el Complejo II, que no bombea protones. Como resultado, FADH2 contribuye a bombear solo seis protones a través de la membrana. El movimiento del protón crea tanto un gradiente de concentración como un gradiente eléctrico, generando colectivamente la fuerza motriz del protón. Los protones fluyen de regreso a través de la membrana a través de la ATP sintasa, un complejo enzimático unido a la membrana que utiliza la fuerza motriz del protón para fosforilar el ADP en ATP, un proceso llamado quimiosmosis. La ATP sintasa utiliza aproximadamente cuatro protones para sintetizar una molécula de ATP. Como resultado, se generan alrededor de 2,5 moléculas de ATP por NADH, y alrededor de 1,5 moléculas de ATP por FADH₂.

quimiosmosis

Chemiosmosis and ATP Synthesis

La cadena de transporte de electrones es un componente fundamental de la respiraci&#243;n celular y tiene lugar en la membrana mitocondrial interna. Facilita la transferencia de electrones de alta energ&#237;a desde cofactores reducidos, como NADH y FADH_ 2, hasta el ox&#237;geno molecular, el aceptor final de electrones. Esta transferencia de electrones a trav&#233;s de una serie de complejos proteicos est&#225; estrechamente acoplada a la translocaci&#243;n de protones a trav&#233;s de la membrana, generando un gradiente de protones esencial para la s&#237;ntesis de ATP.
Flujo de electrones y bombeo de protones
Los electrones procedentes del NADH ingresan en la ETC a trav&#233;s del Complejo I (NADH: ubiquinona oxidorreductasa). En procariotas, a medida que los electrones pasan por el Complejo I, impulsan el bombeo de protones desde el citoplasma hacia el espacio extracelular. Posteriormente, los electrones se transfieren a la ubiquinona (coenzima Q), que los transporta hasta el Complejo III (complejo citocromo bc1). El Complejo III facilita una transferencia adicional de electrones al citocromo c, al mismo tiempo que bombea m&#225;s protones. Finalmente, los electrones alcanzan el Complejo IV (citocromo c oxidasa), donde se reduce el ox&#237;geno molecular a agua. Este complejo tambi&#233;n contribuye a la translocaci&#243;n de protones. En conjunto, el paso de electrones desde el NADH conlleva el bombeo de aproximadamente diez protones a trav&#233;s de la membrana.
En cambio, los electrones procedentes del FADH_ 2 ingresan en la ETC a trav&#233;s del Complejo II (succinato deshidrogenasa), eludiendo el Complejo I. El Complejo II no posee capacidad de bombeo de protones. Los electrones del FADH_ 2 se transfieren a la ubiquinona y siguen un recorrido similar a trav&#233;s de los Complejos III y IV. El FADH_ 2 contribuye a la translocaci&#243;n de s&#243;lo seis protones a trav&#233;s de la membrana.
Fuerza prot&#243;n-motriz y s&#237;ntesis de ATP
El bombeo diferencial de protones genera tanto un gradiente qu&#237;mico (de concentraci&#243;n) como un gradiente el&#233;ctrico (de voltaje) a trav&#233;s de la membrana mitocondrial interna, conjunto conocido como fuerza prot&#243;n-motriz. Este gradiente electroqu&#237;mico impulsa el regreso de los protones a la matriz mitocondrial a trav&#233;s de la ATP sintasa, un complejo enzim&#225;tico unido a la membrana. El proceso de utilizaci&#243;n de la fuerza prot&#243;n-motriz para fosforilar ADP en ATP se conoce como quimi&#243;smosis.
La ATP sintasa requiere aproximadamente cuatro protones para sintetizar una mol&#233;cula de ATP. Debido a las diferencias en la eficiencia de translocaci&#243;n de protones, la oxidaci&#243;n de una mol&#233;cula de NADH produce aproximadamente 2,5 mol&#233;culas de ATP, mientras que una mol&#233;cula de FADH_ 2 genera cerca de 1,5 mol&#233;culas de ATP. Esta eficiencia resalta el papel esencial de la cadena de transporte de electrones y la fuerza prot&#243;n-motriz en el metabolismo energ&#233;tico celular.

Quimiosmosis

La cadena de transporte de electrones es un componente fundamental de la respiraci&#243;n celular y tiene lugar en la membrana mitocondrial interna. ...

Education

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JoVE Core

Microbiology

Microbiología

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Microbial Metabolism

Metabolismo microbiano

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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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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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