Navigation Links
Oxidative phosphorylation


Oxidative phosphorylation is a biochemical process in cells. It is the final metabolic pathway of cellular respiration, after glycolysis and the citric acid cycle.

The process takes place at a biological membrane. In prokaryotes this is the plasma membrane, and in eukaryotes it is the inner of the two mitochondrial membranes. NADH and FADH2, electron carrier molecules that were "loaded" during the citric acid cycle, are used in an intricate mechanism (involving NADH-Q reductase, cytochrome c oxidase, and cytochrome reductase) to pump H+ across the membrane against a proton gradient.


A large protein complex called ATP synthase is embedded in that membrane and enables protons to pass through in both directions; it generates ATP when the proton moves with (down) the gradient, and it costs ATP to pump a proton against (up) the gradient. Because protons have already been pumped into the intermembrane space against the gradient, they now can flow back into the mitochondrial matrix via the ATP synthase, generating ATP in the process. The reaction is:


ADP3- + H+ + Pi ↔ ATP4- + H2O


Each NADH molecule contributes enough proton motive force to generate 3 ATP. Each FADH2 molecule is worth 2 ATP. All together, the 10 NADH and 2 FADH2 molecules contributed through oxidation of glucose (glycolysis, conversion of pyruvate to acetyl-CoA, and the Krebs cycle) account for 34 of the 38 total ATP energy carrier molecules. It is worth noting that these ATP values are maximums, in reality each NADH molecule contributes between 2 and 3 ATP, while each FADH2 contributes a maximum of 2 ATP.

Reactive oxygen species

Several highly reactive, transient oxygen derivatives can be formed during this process:

  1. Hydrogen peroxide
  2. Superoxide anion
  3. Hydroxyl radical



'"/>


(Date:4/23/2014)... domestic heating may contribute to early fetal death according ... Research Institute of Children,s Hospital Los Angeles and Ulaanbaatar, ... , In a paper published today in the journal ... strong statistical correlations" between seasonal ambient air pollutants and ... has one of the highest levels of air pollution ...
(Date:4/23/2014)... hungry diner ripping open a dinner roll, a fuel ... open a hydrogen molecule. Now researchers have captured a ... halves of its hydrogen feast. The view confirms previous ... catalyst work better for alternative energy uses. , This ... where the hydrogen halves end up in the structure ...
(Date:4/23/2014)... shows that male black widow spiders prefer their female ... of mate preference by male spiders. , ... Maydianne Andrade, a professor in UTSC,s Department of Biological ... wild that males overwhelmingly chose to mate with well-fed, ... tell whether a potential mate is well-fed and unmated ...
Breaking Biology News(10 mins):Pollutants from coal-burning stoves strongly associated with miscarriages in Mongolia 2Halving hydrogen 2Halving hydrogen 3Halving hydrogen 4Picky male black widow spiders prefer well-fed virgins 2
... research team has tested the utility of the short version ... disability in patients with depression, "which in the case of ... of the instrument." In Spain, more than 10% of ... is usually the first to screen an individual who feels ...
... today by ESA,s Envisat satellite, shows the vast cloud of ... Iceland, more than 1000 km away. Carried by winds ... the eruption of the Eyjafjallajoekull glacier in southwest Iceland has ... Scandinavia, with further disruption in northern Europe expected later today. ...
... This press release is available in French . ... of the 20th century, but new research shows initiatives of ... dollars as people might think. McGill University Biologist Dr. Jonathan ... most affected by them is a far more effective and ...
Cached Biology News:It takes only 5 minutes to assess disability in patients with depression 2Trying to eradicate a disease is a waste of money: researcher 2
Other biology definitionOther Tags