| ribosome | <cell biology> A small particulate organelle found in prokaryotes and eukaryotes and also within mitochondria and chloroplasts, but differing in size and composition. Made of two subunits, each being an RNA protein complex. Ribosomes are responsible for the translation of mRNA which may occur in the cytoplasm (see polyribosomes) or on rough endoplasmic reticulum. Origin: Gr. Soma = body (18 Nov 1997) |
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| ribosome binding site | The region of a messenger RNA molecule that binds the ribosome to initiate translation. (09 Oct 1997) |
| ribosome-lamella complex | A cylindrical cytoplasmic inclusion composed of concentrically arranged sheets of membranes alternating with rows of ribosomes; characteristic of the hairy cell in leukaemic reticuloendotheliosis. (05 Mar 2000) |
| accelerator factor | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| acetate replacement factor | <biochemistry> 1,2 dithiolane 3 valeric acid. Regarded as a coenzyme in the oxoglutarate dehydrogenase complex of the citric acid cycle. Involved generally in oxidative decarboxylations of _ keto acids. A growth factor for some organisms. (18 Nov 1997) |
| adrenal weight factor | A postulated substance of adenohypophysial origin responsible for maintenance of the weight of the adrenal cortex. (05 Mar 2000) |
| adrenocorticotropic releasing factor | Hormone produced by hypothalamus that causes pituitary to secrete adrenocorticotropic hormone. (05 Mar 2000) |
| a-factor | <molecular biology> A protein which is found in the bacterial genus Streptomyces that helps start the production of streptomycin and the process of morphological differentiation. It is used in biotechnology to induce these functions in mutant strains of Streptomyces that cannot produce it themselves. (09 Feb 1998) |
| angiogenesis factor | Substance causing proliferation of new blood vessels. It is found in tissues with high metabolic requirements, such as the retina, and in certain cancers. The factor is also released by hypoxic macrophages at the edges or outer surfaces of wounds and initiates revascularization in wound healing. (12 Dec 1998) |
| animal protein factor | <biochemistry> Member of the water soluble B vitamin group, important in the proper function of the nervous system and important in proper carbohydrate, protein and fat metabolism. (27 Sep 1997) |
| antialopecia factor | A member of the vitamin B complex necessary for growth of yeast and of mice, absence from the diet causes hair loss and dermatitis in mice. (27 Sep 1997) |
| antianaemic factor | <biochemistry> Member of the water soluble B vitamin group, important in the proper function of the nervous system and important in proper carbohydrate, protein and fat metabolism. (27 Sep 1997) |
| antiberiberi factor | Synonym: thiamin. (05 Mar 2000) |
| anti-black-tongue factor | A precursor of NAD, that is a product of the oxidation of nicotine. (18 Nov 1997) |
| anticomplementary factor | A factor that interferes with the action or function of complement. (05 Mar 2000) |