When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Biological roles of the elements - Wikipedia

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

    Ubiquitous, essential for all forms of life; all proteins and nucleic acids contain substantial amounts of nitrogen. [11] Toxic in some forms. [11] osmium: 76: 1a: None known. [11] Osmium is very rare, substantially more so than any element essential to life. [3] The oxide is toxic to humans. [11] oxygen: 8: 5

  3. Nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_cycle

    The nitrogen cycle is an important process in the ocean as well. While the overall cycle is similar, there are different players [40] and modes of transfer for nitrogen in the ocean. Nitrogen enters the water through the precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N

  4. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    The elements listed below as "Essential in humans" are those listed by the US Food and Drug Administration as essential nutrients, [9] as well as six additional elements: oxygen, carbon, hydrogen, and nitrogen (the fundamental building blocks of life on Earth), sulfur (essential to all cells) and cobalt (a necessary component of vitamin B 12).

  5. Nitrogen balance - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_balance

    Nitrogen is a fundamental chemical component of amino acids, the molecular building blocks of protein. As such, nitrogen balance may be used as an index of protein metabolism. [1] When more nitrogen is gained than lost by an individual, they are considered to have a positive nitrogen balance and be in a state of overall protein anabolism.

  6. Discovering how to make 'synthetic nitrogen' became life's ...

    www.aol.com/news/discovering-synthetic-nitrogen...

    Carbon, nitrogen, and oxygen. None is more important than the other but if there's a first among equals it would be nitrogen. Carbon, nitrogen, and oxygen. None is more important than the other ...

  7. Human impact on the nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Human_impact_on_the...

    Human activities account for over one-third of N 2 O emissions, most of which are due to the agricultural sector. [2] This article is intended to give a brief review of the history of anthropogenic N inputs, and reported impacts of nitrogen inputs on selected terrestrial and aquatic ecosystems.

  8. Biogeochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Biogeochemical_cycle

    The six aforementioned elements are used by organisms in a variety of ways. Hydrogen and oxygen are found in water and organic molecules, both of which are essential to life. Carbon is found in all organic molecules, whereas nitrogen is an important component of nucleic acids and proteins.

  9. Nitrogen - Wikipedia

    en.wikipedia.org/wiki/Nitrogen

    [41] [42] Given the half-life difference, 13 N is the most important nitrogen radioisotope, being relatively long-lived enough to use in positron emission tomography (PET), although its half-life is still short and thus it must be produced at the venue of the PET, for example in a cyclotron via proton bombardment of 16 O producing 13 N and an ...