| 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) |
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| 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) |
| 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) |
| cell cycle proteins | Proteins that control the cell division cycle. This family of proteins includes a wide variety of classes, including cyclin-dependent kinases, mitogen-activated kinases, cyclins, and phosphoprotein phosphatases (phosphoprotein phosphatase) as well as their putative substrates such as chromatin-associated proteins, cytoskeletal proteins, and transcription factors. (12 Dec 1998) |
| cell cycle restriction point | <cell biology, molecular biology> A point, late in G1, after which the cell must, normally, proceed through to division at its standard rate. (26 Mar 1998) |
| cell division cycle gene | Genes which control the yeast cell cycle. There are around 50 different genes which do this. (09 Oct 1997) |
| cell division cycle mutant | A yeast cell which has cell division cycle genes that have mutated to become sensitive to temperature, at certain temperatures (usually high ones), various parts of the normal yeast cell cycle become abnormal, and in some strains the yeast cell does not survive at all. (09 Oct 1997) |
| reproductive cycle | The cycle which begins with conception and extends through gestation and parturition. (05 Mar 2000) |
| glycine-succinate cycle | A series of metabolic steps in which glycine is condensed with succinyl-CoA and is then oxidised to CO2 and H2O with regeneration of the succinyl-CoA; important in the synthesis of d-aminolevulinic acid and in the metabolism of red blood cells. Synonym: Shemin cycle. (05 Mar 2000) |