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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.
In a certain rat model of Parkinson's disease, the brain's hydrogen sulfide concentration was found to be reduced, and administering hydrogen sulfide alleviated the condition. [14] In trisomy 21 (Down syndrome) the body produces an excess of hydrogen sulfide. [3] Hydrogen sulfide is also involved in the disease process of type 1 diabetes.
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 ...
The chemistry of the environment is, of course, relevant to survival, and detection of chemical input from the outside may well articulate directly with cell chemicals. [ citation needed ] Chemoreception is important for the detection of food, habitat, conspecifics including mates, and predators.
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% ...
Hydrogen is able to penetrate narrow channels in the enzyme that oxygen molecules cannot enter. This allows bacteria such as Mycobacterium smegmatis to utilize the small amount of hydrogen in the atmosphere as a source of energy when other sources are lacking.
Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. (Image not to scale) A hydrogen atom is an atom of the chemical element hydrogen.The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb force.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...