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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. [1] All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace ...

  3. Biomolecule - Wikipedia

    en.wikipedia.org/wiki/Biomolecule

    Most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human body's mass. But many other elements, such as the various biometals, are also present in small amounts.

  4. 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

  5. Biochemistry - Wikipedia

    en.wikipedia.org/wiki/Biochemistry

    Just six elements—carbon, hydrogen, nitrogen, oxygen, calcium and phosphorus—make up almost 99% of the mass of living cells, including those in the human body (see composition of the human body for a complete list). In addition to the six major elements that compose most of the human body, humans require smaller amounts of possibly 18 more.

  6. Biological roles of the elements - Wikipedia

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

    Some compounds may be carcinogenic; some forms are mildly toxic to humans. [11] selenium: 34: 4: 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.

  7. Carbon-based life - Wikipedia

    en.wikipedia.org/wiki/Carbon-based_life

    The branch of chemistry that studies organic compounds is known as organic chemistry. [ 15 ] Carbon is the 15th most abundant element in the Earth's crust , and the fourth most abundant element in the universe by mass, after hydrogen , helium , and oxygen .

  8. Organic chemistry - Wikipedia

    en.wikipedia.org/wiki/Organic_chemistry

    The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, [1] [2] [3] especially oxygen, nitrogen, sulfur, phosphorus (included in many biochemicals) and the halogens.

  9. Organic matter - Wikipedia

    en.wikipedia.org/wiki/Organic_matter

    Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals . [ 1 ]