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Welcome to Wikipedia,the free encyclopedia that anyone can edit.2,434,772 articles in EnglishArtsBiographyGeographyHistoryMathematicsScienceSocietyTechnologyAll portalsOverview · Editing · Questions · HelpContents · Categories · Featured content · A–Z indexToday’s featured articleOxidative phosphorylation is a metabolic pathway that uses energy released by the oxidation of nutrients to produce adenosine triphosphate (ATP). Although the many forms of life on Earth use a range of different nutrients, almost all carry out oxidative phosphorylation to produce ATP, the molecule that supplies energy to metabolism. This pathway is probably so pervasive because it is a highly efficient way of releasing energy, compared to alternative fermentation processes such as glycolysis. During oxidative phosphorylation, electrons are transferred from electron donors to electron acceptors such as oxygen, in redox reactions. These redox reactions release energy, which is used to form ATP. In eukaryotes, these reactions are carried out by a series of protein complexes within mitochondria, whereas in prokaryotes, these proteins are in the cells’ inner membranes. These linked sets of enzymes are called electron transport chains. Although oxidative phosphorylation is a vital part of metabolism, it produces reactive oxygen species such as superoxide, hydrogen peroxide and free radicals, damaging cells and contributing to aging and disease. The enzymes carrying out this metabolic pathway are also the target of many drugs and poisons that inhibit their activities. (more…)Recently featured: The General in His Labyrinth – Imperial Trans-Antarctic Expedition – Moe BergArchive – By email – More featured articles…Did you know…From Wikipedia’s newest articles:… that as part of Operation Noble Eagle (service badge pictured), Canada provided air defense protection for the Super Bowl XL?… that Marie Studholme, one of the most popular postcard beauties of Edwardian musical comedy, was wooed by her wealthy second husband under an assumed name?… that Norsk Transport has operated four railway ferries on Lake Tinnsjå in Norway?… that in 1885, Bug Holliday became the first baseball player to make his Major League debut in post-season play?… that American actress Kim Stanley was cast in the starring role of the 1964 British film Séance on a Wet Afternoon after Deborah Kerr and Simone Signoret turned down the part?… that Rupprecht Gerngroß is considered to be the leader of the only successful putsch against Adolf Hitler in Nazi Germany?… that the Vadigo, a species of carangid fish, is believed to be expanding its range in the Mediterranean Sea?… that William D. Washington became the first faculty member of the Virginia Military Institute to die during his tenure there?Archive – Start a new article…In the newsRobert Mugabe (pictured) is sworn in for his sixth term as President of Zimbabwe after a controversial run-off presidential election in which opposition leader Morgan Tsvangirai withdrew his candidacy due to election-related violence.Spain wins the European Football Championship, defeating Germany 1-0 in the final through a goal by Fernando Torres.Serbian President Boris Tadić names Mirko Cvetković as the new Prime Minister following the parliamentary election held in May.Pakistan holds by-elections, with the contest for one seat delayed by the Supreme Court until it can handle the appeal of disqualified candidate Nawaz Sharif, former Prime Minister and leader of the Pakistan Muslim League (N).In District of Columbia v. Heller, the United States Supreme Court rules that the Second Amendment to the U.S. Constitution protects an individual’s right to bear arms, with possible consequences for existing gun control laws.Wikinews – Recent deaths – More current events…On this day…June 30: Independence Day in the Democratic Republic of the Congo (1960)1758 – Seven Years’ War: Austria defeated Prussia at the Battle of Domstadtl, forcing Frederick the Great to leave Moravia.1894 – London’s Tower Bridge (pictured), a combined bascule and suspension bridge over the River Thames, opened.1905 – The Annalen der Physik scientific journal published Albert Einstein’s article “On the Electrodynamics of Moving Bodies”, the third of his Annus Mirabilis Papers, introducing the theory of special relativity.1908 – A massive explosion occurred near the Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia, knocking over 80 million trees over 2,150 square kilometres (830 sq mi).1934 – Adolf Hitler violently purged members of the Sturmabteilung, its leader Ernst Röhm, and other political rivals on the Night of the Long Knives, executing at least eighty-five people.More events: June 29 – June 30 – July 1Archive – By email – More anniversaries…It is now 12:59, June 30, 2008 (UTC) – Refresh this pageToday’s featured pictureThe “Double O Arch”, a natural sandstone arch in Arches National Park in Utah, United States. This is one of over 2,000 natural arches found in the park and is so named because there are two arches that form circular holes: The easily visible large one, and the smaller hole underneath it.Photo credit: FlickaRecently featured: “The Two Platforms” – Buffalo Soldiers – Mice GalaxiesArchive – More featured pictures…