| anomalous complex | A complex in the electrocardiogram differing significantly from the physiologic type in the same lead. (05 Mar 2000) |
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| antennal complex | <cell biology> Light harvesting complexes (LHC) of protein and pigment in or on photosynthetic membranes of bacteria are organised into arrays, called antennae. They transfer photon energy to reaction centres. (18 Nov 1997) |
| antennapedia complex | A set of mutations that cause developmental defects in the limbs and appendages of the fruit fly Drosophila melanogaster, such as the development of legs (-pedia) in the places where antennae are supposed to be. (09 Oct 1997) |
| antigen-antibody complex | The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes immune complex diseases. If the antigen is polyvalent the complex may be insoluble. Immune complexes activate complement through the classical pathway. See: glomerulonephritis, Arthus reaction, type III hypersensitivity. (12 Dec 1998) |
| antigenic complex | A composite of different antigenic structures, such as a cell or a bacterium, or, by extension, a molecule containing two or more determinant groups of different antigenic specificities. (05 Mar 2000) |
| apical complex | A set of anterior structures that characterise one or several developmental stages of members of the protozoan phylum Apicomplexa; includes the following structures, visible by electron microscopy: polar ring, conoid, rhoptries, micronemes, and subpellicular tubules. (05 Mar 2000) |
| atrial complex | P wave in the electrocardiogram. Synonym: auricular complex. (05 Mar 2000) |
| auricular complex | P wave in the electrocardiogram. Synonym: auricular complex. (05 Mar 2000) |
| avian leukaemia-sarcoma complex | A term applied to a group of transmissible virus-induced diseases of chickens causing sarcoma, myeloblastosis, erythroblastosis, leukosis, osteopetrosis, and lymphomatosis. These agents are closely related viruses (avian leukosis-sarcoma virus) causing prolferation of immature erythroid, myeloid, or lymphoid cells, a division of the RNA tumour viruses (subfamily Oncovirinae) causing the avian leukosis-sarcoma complex of diseases; the viruses are subgrouped according to antigenic characteristics and growth in defined types of tissue culture cells. Synonym: avian erythroblastosis virus, avian leukosis-sarcoma virus, avian lymphomatosis virus, avian myeloblastosis virus, avian sarcoma virus, fowl erythroblastosis virus, fowl lymphomatosis virus, fowl myeloblastosis virus. (05 Mar 2000) |
| b c1 complex | <biochemistry> A part of the mitochondrial electron transport chain that accepts electrons from ubiquinone and passes them on to cytochrome C. The b/c1 complex consists of 2 cytochromes. (18 Nov 1997) |
| b-complex vitamin | <biochemistry> A group of vitamins that includes: B1(thiamin), B2 riboflavin), B3 (niacin), B6(pyridoxine), B12 (cobalamin) and folate. (24 Mar 1998) |
| binary complex | A noncovalent complex of two molecules; often referring to the enzyme-substrate complex in an enzyme-catalyzed reaction. Compare: central complex, Michaelis complex. Synonym: enzyme-substrate complex. (05 Mar 2000) |
| bithorax complex | <genetics, molecular biology> A group of homeotic mutations of Drosophila that map to the bithorax region on chromosome III. The mutations all cause the third thoracic segment to develop like the second thoracic segment to varying extents. The genes of the bithorax complex are thought to determine the differentiation of the posterior thoracic segments and the abdominal segments. (18 Nov 1997) |
| brain wave complex | A specific combination of fast and slow electroencephalographic activity that recurs frequently enough to be identified as a discrete phenomenon. (05 Mar 2000) |
| brother complex | Extreme envy or jealousy of a brother, leading to hatred. Synonym: brother complex. Origin: Cain, biblical personage (05 Mar 2000) |