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Hydrogen breath tests are based on the fact that there is no source for hydrogen gas in humans other than bacterial metabolism of carbohydrates. [4] Even though the test is normally known as a "hydrogen" breath test, some physicians may also test for methane in addition to hydrogen. Many studies have shown that some patients (approximately 35% ...
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 ...
Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H 2, sometimes called dihydrogen, [11] hydrogen gas, molecular hydrogen, or simply hydrogen. It is colorless, odorless, [12] non-toxic, and highly combustible.
The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds. Hydrogen (H) is the most abundant element in the universe. [1] On Earth, common H-containing inorganic molecules include water (H 2 O), hydrogen gas (H 2), hydrogen sulfide (H 2 S), and ammonia ...
Hydrogen oxidation is coupled to the reduction of electron acceptors such as oxygen, nitrate, ferric ion, sulfate, carbon dioxide (CO 2), and fumarate. On the other hand, proton reduction ( 2 ) is coupled to the oxidation of electron donors such as ferredoxin (FNR), and serves to dispose excess electrons in cells (essential in pyruvate ...
Hydrogen is the most widespread element in the universe, representing around three-quarters of all atoms. [4] In the atmosphere, the concentration of molecular hydrogen (H 2) gas is about 0.5–0.6 ppm, and so it represents the second-most-abundant trace gas after methane. [3]
Hydrogen compounds are compounds containing the element hydrogen. In these compounds, hydrogen can form in the +1 and -1 oxidation states. Hydrogen can form compounds both ionically and in covalent substances. It is a part of many organic compounds such as hydrocarbons as well as water and other organic substances.
Pages in category "Hydrogen biology" The following 15 pages are in this category, out of 15 total. This list may not reflect recent changes. A. Acetogenesis; B.