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  2. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    Selenium, which is an essential element for animals and prokaryotes and is a beneficial element for many plants, is the least-common of all the elements essential to life. [ 3 ] [ 63 ] Selenium acts as the catalytic center of several antioxidant enzymes, such as glutathione peroxidase , [ 11 ] and plays a wide variety of other biological roles .

  3. Roles of chemical elements - Wikipedia

    en.wikipedia.org/wiki/Roles_of_chemical_elements

    See also: Carbon-based life: Fossil fuels: coal, methane and petroleum Textile industry: cellulose Metallurgy: alloys, especially carbon steel 7: N: Nitrogen 2: 15: Bacteria and archaea: nitrogen fixation by diazotrophs All forms of life on Earth: essential component of amino acids and of nucleic acids Earth's atmosphere, soil, and life forms ...

  4. Element collecting - Wikipedia

    en.wikipedia.org/wiki/Element_collecting

    A set of periodic-table elements, lacking several highly radioactive elements which are impractical or impossible to collect. An assortment of precious metals Hafnium samples for collectors. Element collecting is the hobby of collecting the chemical elements. Many element collectors simply enjoy finding peculiar uses of chemical elements.

  5. Matter - Wikipedia

    en.wikipedia.org/wiki/Matter

    All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, matter generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume.

  6. CHNOPS - Wikipedia

    en.wikipedia.org/wiki/CHNOPS

    Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. . "CHON" stands for carbon, hydrogen, oxygen, and nitrogen, which together make up more than 95 percent of the mass of biological system

  7. Carbon-based life - Wikipedia

    en.wikipedia.org/wiki/Carbon-based_life

    The carbon cycle is a biogeochemical cycle that is important in maintaining life on Earth over a long time span. The cycle includes carbon sequestration and carbon sinks. [4] [5] Plate tectonics are needed for life over a long time span, and carbon-based life is important in the plate tectonics process. [6]

  8. Carbon group - Wikipedia

    en.wikipedia.org/wiki/Carbon_group

    Carbon is a key element to all known life. It is in all organic compounds, for example, DNA, steroids, and proteins. [6] Carbon's importance to life is primarily due to its ability to form numerous bonds with other elements. [17] There are 16 kilograms of carbon in a typical 70-kilogram human. [18] Silicon-based life's

  9. Iron - Wikipedia

    en.wikipedia.org/wiki/Iron

    The iron and steel industry is thus very important economically, and iron is the cheapest metal, with a price of a few dollars per kilogram or pound. Pristine and smooth pure iron surfaces are a mirror-like silvery-gray. Iron reacts readily with oxygen and water to produce brown-to-black hydrated iron oxides, commonly known as rust.