Search results
Results From The WOW.Com Content Network
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 ...
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.
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 therapy is the use of molecular hydrogen (H 2) for therapeutic purposes. H 2 has therapeutic benefits due to its antioxidant and anti-inflammatory effects, as well as due to its role as an inducer of gene expression , [ 1 ] H 2 is not cytotoxic or explosive below 4% concentration. [ 2 ]
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 is coupled to the oxidation of electron donors such as ferredoxin (FNR), and serves to dispose excess electrons in cells (essential in pyruvate fermentation).
A hydrogen carrier is an organic macromolecule that transports atoms of hydrogen from one place to another inside a cell or from cell to cell for use in various metabolical processes. [1] Examples include NADPH , NADH , and FADH .
The following articles relate to hydrogen in biology. Subcategories. This category has only the following subcategory. M ...