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Chemiosmosis

Definition

noun

The subsequent movement of ions from an area of higher concentration to an area of lower concentration through transport proteins on the selectively-permeable membrane as a result of a proton gradient that forms across the membrane that is not readily permeable to ions.

More specifically, chemiosmosis is the diffusion of hydrogen ions (protons) across the biological membrane via the ATP synthase (a transport protein) due to a proton gradient that forms on the other side of the membrane. The proton gradient forms when the hydrogen ions accumulate as they are forcibly moved to the other side of the membrane by carrier proteins while the electrons pass through the electron transport chain in the membrane. Since more hydrogen ions are on the other side they tend to move back across the membrane via the ATP synthase. As they flow through energy is released which is then used to convert ADP to ATP (by a process called phosphorylation).


Supplement

Chemiosmosis is one of the processes by which ATP is synthesized. In eukaryotes, it takes place in the mitochondria during cellular respiration and in the chloroplasts during photosynthesis. In prokaryotes, it occurs in the cell membrane.

This process is called chemiosmosis because the chemical ions move from an area of higher concentration to an area of lower concentration across a semipermeable membrane, similar to the movement of water molecules by osmosis.


Word origin: chem- (chemical) + osmosis.

Variant: chemosmosis

See also: chemiosmotic theory


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Chemiosmosis

Chemiosmosis is relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration.It will diffuse from an area of high proton concentration to an area of lower proton concentration. ...

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by MarkHolland
Wed Dec 05, 2012 7:34 am
 
Forum: Cell Biology
Topic: Chemiosmosis
Replies: 5
Views: 4281

Chemiosmosis

... concentration. I'm not sure how this proceeds, as it was always covered in lectures simply as increase of Mg2+ ions, but it could be related to chemiosmosis http://en.wikipedia.org/wiki/RuBisCO#Regulation_of_its_enzymatic_activity

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by JackBean
Thu Nov 29, 2012 1:56 pm
 
Forum: Cell Biology
Topic: Chemiosmosis
Replies: 5
Views: 4281

Chemiosmosis

I'm so lost on chemiosmosis...can anyone explain how chemiosmosis occurs in a Chloroplast?

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by ChinchillaChic
Sun Nov 04, 2012 11:22 pm
 
Forum: Cell Biology
Topic: Chemiosmosis
Replies: 5
Views: 4281

Role of membranes in synthesis of ATP in cellular respiratio

... not make ATP directly, but uses the flow of electrons generated from its reactions to regulate hydrogen levels. ATP production occurs because of chemiosmosis, the diffusion of hydrogen ions across the membrane using the ATP synthase (a transport protein). This protein uses the power of hydrogen ...

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by mkbeast99
Wed Aug 15, 2012 11:12 pm
 
Forum: Molecular Biology
Topic: Role of membranes in synthesis of ATP in cellular respiratio
Replies: 1
Views: 11403

Chemiosmosis, the movement of hydrogen ions to make ATP, was

... B. Protons diffuse from high concentrations to low concentrations. C. A fewer number of molecules of ATP are formed in cellular respiration due to chemiosmosis D. Hydrogen ions build up as a result of the electron transport chain E. Phosphorylation (the addition of phosphate to ADP) occurs as a ...

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by rurutashy
Thu May 31, 2012 12:17 am
 
Forum: Cell Biology
Topic: Chemiosmosis, the movement of hydrogen ions to make ATP, was
Replies: 1
Views: 5624
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