| oxidation-reduction indicator | A substance that undergoes a definite colour change at a specific oxidation potential. Synonym: redox indicator. (05 Mar 2000) |
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| oxidation-reduction potential | <chemistry, physics> The potential in volts of an inert metallic electrode measured in a system of an arbitrarily chosen ratio of [oxidant] to [reductant] and referred to the normal hydrogen electrode at absolute temperature. It is calculated from the following equation: where R is the gas constant expressed in electrical units, T the absolute temperature (Kelvin), n the number of electrons transferred, F the faraday and E0 the normal symbol for the potential of the system at pH 0; for biological systems E0' is often used (in which pH = 7). Compare: Nernst's equation. Synonym: redox potential. (05 Mar 2000) |
| oxidation-reduction reaction | <chemistry> Any reaction in which electrons are removed from one molecule or atom and given to another molecule or atom. (09 Oct 1997) |
| oxidation-reduction system | <enzyme> An enzyme system in the tissues by which oxidation and reduction proceed simultaneously through the transference of hydrogen or of one or more electrons from one metabolite to another. See: oxidation-reduction. Synonym: redox system. (05 Mar 2000) |
| terminal oxidation | <biochemistry> The last oxidation step in a catabolic pathway. Synonym: terminal oxidation. (05 Mar 2000) |
| end oxidation | <biochemistry> The last oxidation step in a catabolic pathway. Synonym: terminal oxidation. (05 Mar 2000) |
| fatty acid oxidation cycle | A series of reactions involving acyl-coenzyme A compounds, whereby these undergo beta oxidation and thioclastic cleavage, with the formation of acetyl-coenzyme A; the major pathway of fatty acid catabolism in living tissue. (05 Mar 2000) |
| biological | Pertaining to biology. (18 Nov 1997) |
| biological agent | <microbiology> A disease-causing microorganism or virus, or other toxic biological matter, which is used as a weapon during war. (21 Mar 1998) |
| biological assay | <technique> Once a pharmaceutical protein is isolated from the cells in which it was grown, researchers perform tests to measure the protein's biological activity. It must maintain a certain minimal level of biological activity to be used for animal or clinical testing or, later, for market. Researchers also test to confirm that the isolated protein is identical to the desired protein. (21 Mar 1998) |
| biological assessment | A specific process required as part of an environmental assessment. An evaluation of potential effects of a proposed project on proposed, endangered, threatened, and sensitive animal and plant species and their habitats. (05 Dec 1998) |
| biological availability | The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action. (12 Dec 1998) |
| biological chemistry | The scientific study of the chemistry of living cells, tissues, organs and organisms. (09 Oct 1997) |
| biological clock | <biology, physiology> An internal biological mechanism which controls certain biological rhythms and biocycles, such as metabolism, sleep cycles, photosynthesis. (21 Mar 1998) |
| biological clocks | The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioural phenomena in plants and animals. The pineal gland, which receives input from the optic nerves and connects to the hypothalamus, may be the biological clock in humans. (12 Dec 1998) |