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Chemiosmotic hypothesis

Definition

noun

A theory postulated by the biochemist Peter Mitchell in 1961 to describe ATP synthesis by way of a proton electrochemical coupling.

Accordingly, hydrogen ions (protons) are pumped from the mitochondrial matrix to the intermembrane space via the hydrogen carrier proteins while the electrons are transferred along the electron transport chain in the mitochondrial inner membrane. As the hydrogen ions accumulate in the intermembrane space, an energy-rich proton gradient is established. As the proton gradient becomes sufficiently intense the hydrogen ions tend to diffuse back to the matrix (where hydrogen ions are less) via the ATP synthase (a transport protein). As the hydrogen ions diffuse (through the ATP synthase) energy is released which is then used to drive the conversion of ADP to ATP (by phosphorylation).


Supplement

This theory was not previously well accepted until a great deal of evidence for proton pumping by the complexes of the electron transfer chain emerged. This began to favor the chemiosmotic hypothesis, and in 1978, Peter Mitchell was awarded the Nobel Prize in Chemistry.


Also called: chemiosmotic theory

See also: chemiosmosis


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Question-cellular respiration

... the generation of an electrochemical gradient across a membrane (chemiosmotic hypothesis) as shown in the schematic.. the picture is of a membrane with an ATP synthase with ...

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by biology_06er
Thu Jun 15, 2006 8:57 am
 
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Topic: Question-cellular respiration
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Views: 2640

Simple Diffusion`

... And I couldn't understand your point on chemiosmotic hypothesis. Can you explain please?

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by Poison
Fri Apr 21, 2006 11:09 pm
 
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whats ATP?

... than the single enzyme of substrate-level phosphorylation. Enzymes in chemiosmotic synthesis are arranged in an electron transport chain that is ... either the chloroplast or mitochondrion. According to the chemiosmosis hypothesis proposed by Peter Mitchell in 1961, a special ATP-synthesizing ...

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by CoolJay221
Thu Jan 05, 2006 5:20 pm
 
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Respiration and Kreb's Cycle

... me a while to get my head round it! Sorry I'm not really sure on the chemiosmotic hypothesis. :?

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by Jesskat14
Mon Apr 04, 2005 1:05 pm
 
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Respiration and Kreb's Cycle

... Krebs cycle and the electron transport chain and not forgetting the chemiosmotic hypothesis................ please need help........

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Mon Apr 04, 2005 7:58 am
 
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