| dicarboxylic acid cycle | That portion of the tricarboxylic acid cycle involving the dicarboxylic acids (succinic, fumaric, malic, and oxaloacetic acids), a cyclic scheme in which certain steps of the tricarboxylic acid cycle are used with the glyoxylate cycle; important in the utilization of glyoxylic acid in microorganisms. (05 Mar 2000) |
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| dicarboxylic acid-CoA oxidase | <enzyme> Oxidises dicarboxylic acid CoA esters using molecular oxygen and producing hydrogen peroxide, ultimately producing a dicarboxylic acid with 2 fewer carbon atoms Registry number: EC 1.3.3.- Synonym: dicarboxylyl-CoA oxidase, dicarboxylic acid-coenzyme a oxidase (26 Jun 1999) |
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| dicarboxylic acid-CoA synthetase | <enzyme> Converts dicarboxylic acids (c5-c16) into their mono-CoA esters in the presence of ATP Registry number: EC 6.2.1.- Synonym: dicarboxylyl-CoA ligase, dicarboxylic acid-coenzyme a synthetase (26 Jun 1999) |
| glyoxylic acid cycle | A catabolic cycle in plants and microorganisms like that of the tricarboxylic acid cycle in animals; its key reaction is the condensation of acetyl-CoA with glyoxylic acid to malic acid (analogous to the condensation of acetyl-CoA and oxaloacetic acid to form citric acid in the tricarboxylic acid cycle). Synonym: Krebs-Kornberg cycle. (05 Mar 2000) |
| citric acid cycle | <biochemistry> The central feaure of oxidative metabolism. Cyclic reactions whereby acetyl CoA is oxidized to carbon dioxide providing reducing equivalents (NADH or FADH2) to power the electron transport chain. Also provides intermediates for biosynthetic processes. (16 Dec 1997) |
| succinic acid cycle | A series of oxidation reduction reactions in which succinic acid and other 4-carbon atoms acids (fumaric, malic, oxaloacetic) take part in the oxidation of pyruvic acid as part of the tricarboxylic acid cycle. See: dicarboxylic acid cycle. (05 Mar 2000) |
| tricarboxylic acid cycle | <biochemistry> The central feaure of oxidative metabolism. Cyclic reactions whereby acetyl CoA is oxidized to carbon dioxide providing reducing equivalents (NADH or FADH2) to power the electron transport chain. Also provides intermediates for biosynthetic processes. (16 Dec 1997) |
| 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) |
| anovulatory cycle | A sexual cycle in which no ovum is discharged. (05 Mar 2000) |
| Born-Haber cycle | <physics> This is a mathematical description of the relationship between the electron affinity, heats of atomisation, ionisation energy and lattice energy of ionic compounds. (09 Oct 1997) |
| bottoming cycle | A cogeneration system in which steam is used first for process heat and then for electric power production. (05 Dec 1998) |
| brain wave cycle | The complete upward and downward excursion of a single wave, complex, or impulse as seen on an electroencephalogram. (05 Mar 2000) |
| c3 cycle | <biochemistry> The part of the photosynthesis process where carbon dioxide is converted into three-carbon compounds, which can then be turned into six-carbon sugars. (07 Nov 1997) |
| c4 cycle | <plant biology> An alternative, very efficient pathway used by plants living in areas with low levels of carbon dioxide, to convert carbon dioxide into a form usable by the plants during photosynthesis. (09 Oct 1997) |
| Calvin Benson cycle | <biochemistry, plant biology> Metabolic pathway responsible for photosynthetic carbon dioxide fixation in plants and bacteria. The enzyme that fixes carbon dioxide is RuDP carboxylase. The cycle is the only photosynthetic pathway in C3 plants and the secondary pathway in C4 plants. The enzymes of the pathway are present in the stroma of the chloroplast. (18 Nov 1997) |
| calvin cycle | In plants, a cyclical series of carbon-fixing, sugar-producing reactions in the chloroplasts. Some of the sugars (triose phosphates) are recycled, others are stored as carbohydrates. Light is not needed for these reactions, they use the carbon dioxide and energy produced in the light reactions of photosynthesis. (09 Oct 1997) |