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ATP sintasa
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Gradiente potencial
Concentration gradients are a key component of the biological world.
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The potential energy from these gradients is often used to perform biological work.
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Here we will focus on hydrogen ion concentration gradients.
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Hydrogen ions are also known as protons.
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A gradient exists when there is a higher concentration of a molecule in one compartment compared to a neighboring compartment.
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This animation will demonstrate how the potential energy that results from a hydrogen ion gradient
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uses ADP and inorganic phosphate, also known as PI, to synthesize ATP.
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This process involves an enzyme complex called ATP synthase.
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Gradients and the potential energy they create are key aspects of the biological world.
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A good example of the use of a gradient occurs in the mitochondria when ATP is synthesized.
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ATP is synthesized by ATP synthase, a large complex of membrane-bound protein.
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Here we see ATP synthase, along with other membrane-bound proteins.
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Notice the large difference in the number of hydrogen ions on the two sides of the membrane.
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This difference is a hydrogen ion, or proton, concentration gradient.
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The energy associated with this gradient is used to synthesize ATP from ADP and PI.
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This occurs at the ATP synthase complex.
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One hydrogen ion enters the ATP synthase complex from the intermembrane space, and a second
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hydrogen ion leaves it on the matrix space.
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The upper part of the ATP synthase complex rotates when a new hydrogen ion enters.
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Once three protons have entered the matrix space, there is enough energy in the ATP synthase
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complex to synthesize one ATP.
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In this way, the energy in the hydrogen ion gradient is used to make ATP.
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Now let's watch the process again.
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Notice how the proton enters the ATP synthase and exits into the matrix space.
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Once three more hydrogen ions have crossed the membrane, another molecule of ATP will
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be made.
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In this example, the hydrogen ion gradient is large enough to produce six ATP molecules.
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Please watch as the remaining ATP molecules are synthesized.
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The process has now completed and the result is an equal number of protons on each side
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of the inner membrane.
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Without a gradient, there is no more energy available to make ATP.
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In biological systems, however, a gradient is always maintained.
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The mitochondrial hydrogen ion gradient is generated as electrons pass through three
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membrane complexes.
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That process can be seen in the mitochondrial electron transport chain animation.
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- Idioma/s:
- Autor/es:
- Virtual Cell
- Subido por:
- Benito H.
- Licencia:
- Reconocimiento - No comercial - Compartir igual
- Visualizaciones:
- 1387
- Fecha:
- 7 de septiembre de 2010 - 10:32
- Visibilidad:
- Público
- Enlace Relacionado:
- Benito Hernández Giménez
- Centro:
- IES MORATALAZ
- Descripción ampliada:
- El gradiente electroquímico acopla el ritmo de la cadena de transporte electrónico con el ritmo de la síntesis de ATP. Debido a que el flujo electrónico necesita el bombeo de protones, el flujo electrónico no puede producirse más rápidamente que la utilización de los protones para síntesis de ATP ( fosforilación oxidativa acoplada), significando en una relación estrechamente acoplada entre la oxidación y la fosforilación.Esto conlleva a que los sustratos se oxidan, los electrones se transportan y el oxígeno se consumó tan sólo cuando se requiere la síntesis de ATP. Por lo tanto, las mitocondrias en reposo consumen oxígeno a una velocidad lenta, pero que puede incrementar enormemente en la presencia de ADP. El ADP es captado por las mitocondrias y estimula la ATP sintasa, que disminuye el gradiente de protones.
- Duración:
- 03′ 47″
- Relación de aspecto:
- 1.31:1
- Resolución:
- 1024x780 píxeles
- Tamaño:
- 19.14 MBytes
