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CHON is a mnemonic acronym for the four most common elements in living organisms: carbon, hydrogen, oxygen, and nitrogen. The acronym CHNOPS, which stands for ''c''arbon, ''h''ydrogen, ''n''itrogen, ''o''xygen, ''p''hosphorus, ''s''ulfur, represents the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.〔The acronym S.P. Cohn was also used in high school biology classes to represent the six chemical elements. 〕 Sulfur is used in the amino acids cysteine and methionine. Phosphorus is an essential element in the formation of phospholipids, a class of lipids that are a major component of all cell membranes, as they can form lipid bilayers, which keep ions, proteins, and other molecules where they are needed for cell function, and prevent them from diffusing into areas where they should not be. Phosphate groups are also an essential component of the backbone of nucleic acids and are required to form ATP – the main molecule used as energy powering the cell in all living creatures. Carbonaceous asteroids are rich in CHON elements.〔 (Water vs. Rocks: Resources for Earth or for Exploration? ) SSI-TV video archive, recorded on 30 October 2010, 66:07, four talks and Q&A given during Session 2: ''Extraterrestrial Prospecting'' of the Space Studies Institute’s Space Manufacturing 14 conference in California. Prof. Michael A'Hearn (University of Maryland) @ 7:10 in the video. ''The video also includes Brad Blair, Space Studies Institute, and Prof. Leslie Gertsch, University of Missouri-Rolla: ''Mining Concepts Development for Accessing Asteroid Resources''; Mark Sonter, Asteroid Enterprises Pty Ltd Resources: ''Asteroids: What We Can Expect From What We Know Now''; Dr. Faith Vilas, University of Arizona, Department of Astronomy and Steward Observatory'', accessed 2011-01-07.〕 These asteroids are the most common type, and frequently collide with Earth as meteorites. Such collisions were especially common early in Earth's history, and these impactors may have been crucial in the formation of the planet's oceans.〔 == See also == * Abundance of the chemical elements * Carbon-based life 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「CHON」の詳細全文を読む スポンサード リンク
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