| Tc | cytotoxic T-cell; the generation time of a cell cycle; tricuspid closure |
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| tG1 | the time required to complete the G1 phase of the cell cycle |
| tG2 | the time required to complete the G2 phase of the cell cycle |
| tM | the time required to complete the M phase of the cell cycle |
| tS | time required to complete the S phase of the cell cycle |
| latent heat | The amount of heat that a substance may absorb without an increase in temperature, as in conversion from solid to liquid state (ice to water at 0캜), or from liquid to gaseous state (water to steam at 100캜). Compare: sensible heat. (05 Mar 2000) |
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| 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) |
| carbon dioxide cycle | First, an organism which can photosynthesise (such as a plant or some bacteria) will absorb carbon dioxide (CO2) from the air and incorporate it into its body or turn it into organic matter. Then, other organisms which cannot photosynthesise will eat the organic matter, or the photosynthesising organism, and release carbon dioxide gas as a waste product back into the air. (09 Oct 1997) |
| cardiac cycle | The complete round of cardiac systole and diastole with the intervals between, or commencing with, any event in the heart's action to the moment when that same event is repeated. (05 Mar 2000) |
| gamma-glutamyl cycle | A proposed pathway for the glutathione-dependent transport of certain amino acids (most notably l-cystine, l-methionine, and l-glutamine) and dipeptides into certain cells; this cycle requires the formation of gamma-glutamyl amino acids and gamma-glutamyl dipeptides as well as a protein for the translocation of these di-and triisopeptides into the cells. (05 Mar 2000) |
| genesial cycle | The reproductive period of a woman's life. (05 Mar 2000) |
| visual cycle | The transformation of carotenoids involved in the bleaching and regeneration of the visual pigment. (05 Mar 2000) |
| cell cycle | <cell biology, molecular biology> The sequence of events between mitotic divisions. The cycle is conventionally divided into G0, G1, (G standing for gap), S (synthesis phase during which the DNA is replicated), G2 and M (mitosis). Cells that will not divide again are considered to be in G0 and the transition from G0 to G1 is thought to commit the cell to completing the cycle and dividing. (26 Mar 1998) |