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  2. Biohydrogen - Wikipedia

    en.wikipedia.org/wiki/Biohydrogen

    Biological hydrogen production is also observed in nitrogen-fixing cyanobacteria. This microorganisms can grow forming filaments. This microorganisms can grow forming filaments. Under nitrogen-limited conditions some cells can specialize and form heterocysts , which ensures an anaerobic intracellular space to ease N 2 fixation by the ...

  3. Hydrogen production - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_production

    Electrohydrogenesis is used in microbial fuel cells to produce hydrogen from organic matter. [142] Biological hydrogen can be produced in an algae bioreactor. In the late 1990s it was discovered that if the algae is deprived of sulfur it will switch from the production of oxygen, i.e. normal photosynthesis, to the production of hydrogen. [143]

  4. Hydrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_cycle

    Many organic compounds also contain H atoms, such as hydrocarbons and organic matter. Given the ubiquity of hydrogen atoms in inorganic and organic chemical compounds, the hydrogen cycle is focused on molecular hydrogen, H 2. As a consequence of microbial metabolisms or naturally occurring rock-water interactions, hydrogen gas can be created.

  5. Photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Photosynthesis

    Photosynthesis (/ ˌ f oʊ t ə ˈ s ɪ n θ ə s ɪ s / FOH-tə-SINTH-ə-sis) [1] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.

  6. Light-dependent reactions - Wikipedia

    en.wikipedia.org/wiki/Light-dependent_reactions

    In oxygenic photosynthesis, the first electron donor is water, creating oxygen (O 2) as a by-product. In anoxygenic photosynthesis, various electron donors are used. Cytochrome b 6 f and ATP synthase work together to produce ATP (photophosphorylation) in two distinct ways.

  7. Amphoterism - Wikipedia

    en.wikipedia.org/wiki/Amphoterism

    In organic chemistry and biochemistry, important examples include amino acids and derivatives of citric acid. Although an amphiprotic species must be amphoteric, the converse is not true. For example, a metal oxide such as zinc oxide, ZnO, contains no hydrogen and so cannot donate a proton. Nevertheless, it can act as an acid by reacting with ...

  8. Water splitting - Wikipedia

    en.wikipedia.org/wiki/Water_splitting

    Other reaction products like H 2 O 2 or HO 2 remain minor. At the very high temperature of 3,000 °C (3,270 K; 5,430 °F) more than half of the water molecules are decomposed. At the very high temperature of 3,000 °C (3,270 K; 5,430 °F) more than half of the water molecules are decomposed.

  9. Photosynthetic efficiency - Wikipedia

    en.wikipedia.org/wiki/Photosynthetic_efficiency

    Photosynthesis is the only process that allows the conversion of atmospheric carbon (CO2) to organic (solid) carbon, and this process plays an essential role in climate models. This lead researchers to study the sun-induced chlorophyll fluorescence (i.e., chlorophyll fluorescence that uses the Sun as illumination source; the glow of a plant) as ...