Related topics: hydrogen · protein · cells · bacteria · carbon dioxide

Earth's lower mantle can be oxidized in the presence of water

If we took a journey from Earth's surface to the center, the midway point is roughly at 1900 km depth in the lower mantle. The lower mantle ranges from 660 to 2900 km depth and occupies 55% of our planet by volume. The chemical ...

Platinum-free catalysts could make cheaper hydrogen fuel cells

The high cost of platinum catalysts used in hydrogen fuel cells limits the commercialization of fuel cell electric vehicles. Scientists are studying alternative catalysts to increase cost-effectiveness and maintain efficiency ...

Untangling a key step in photosynthetic oxygen production

Photosystem II is a protein complex in plants, algae and cyanobacteria that is responsible for splitting water and producing the oxygen we breathe. Over the past few years, an international collaboration between scientists ...

Study the effect of long-term oxygen deficiency

Researchers at Luleå University of Technology have developed a method to study how muscle cells in the blood vessels of the lung permanently contract because of long-term oxygen deficiency. This phenomenon leads to increased ...

Researchers discover new and harmful copper-protein complexes

Copper is important for many processes in our body. It supports the production of red blood cells, metabolism, and the formation of connective tissue and bones, among other things. Copper is also known to play a role in diseases ...

'Water wires' may play bigger role in cellular function

Each of our cells is surrounded by a complex membrane that functions as a biological border, letting ions and nutrients such as salt, potassium and sugar in and out. The guards are membrane proteins, which do the hard work ...

Life might survive, and thrive, in a hydrogen world: study

As new and more powerful telescopes blink on in the next few years, astronomers will be able to aim the megascopes at nearby exoplanets, peering into their atmospheres to decipher their composition and to seek signs of extraterrestrial ...

Exoplanets: How we'll search for signs of life

Whether there is life elsewhere in the universe is a question people have pondered for millennia; and within the last few decades, great strides have been made in our search for signs of life outside of our solar system.

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Oxygen

Oxygen (pronounced /ˈɒksɨdʒɨn/, from the Greek roots ὀξύς (oxys) (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O. It is a member of the chalcogen group on the periodic table, and is a highly reactive nonmetallic period 2 element that readily forms compounds (notably oxides) with almost all other elements. At standard temperature and pressure two atoms of the element bind to form dioxygen, a colorless, odorless, tasteless diatomic gas with the formula O2. Oxygen is the third most abundant element in the universe by mass after hydrogen and helium and the most abundant element by mass in the Earth's crust. Diatomic oxygen gas constitutes 20.9% of the volume of air.

All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen in the form of O2 is produced from water by cyanobacteria, algae and plants during photosynthesis and is used in cellular respiration for all complex life. Oxygen is toxic to obligately anaerobic organisms, which were the dominant form of early life on Earth until O2 began to accumulate in the atmosphere 2.5 billion years ago. Another form (allotrope) of oxygen, ozone (O3), helps protect the biosphere from ultraviolet radiation with the high-altitude ozone layer, but is a pollutant near the surface where it is a by-product of smog. At even higher low earth orbit altitudes monatomic oxygen (O1) is a significant presence and a cause of erosion for spacecraft.

Oxygen was independently discovered by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his publication came out in print first. The name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Oxygen is produced industrially by fractional distillation of liquefied air, use of zeolites to remove carbon dioxide and nitrogen from air, electrolysis of water and other means. Uses of oxygen include the production of steel, plastics and textiles; rocket propellant; oxygen therapy; and life support in aircraft, submarines, spaceflight and diving.

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