| species group | <zoology> The taxonomic categories species and subspecies. (09 Jan 1998) |
|---|---|
| nitrogen group | Five trivalent or quinquivalent elements whose hydrogen compounds are basic and whose oxyacids vary from monobasic to tetrabasic: nitrogen, phosphorus, arsenic, antimony, and bismuth. (05 Mar 2000) |
| nitrogenous group transferases | <enzyme> Enzymes that catalyze the transfer of nitrogenous groups, primarily amino groups, from a donor, generally an amino acid, to an acceptor, usually a 2-oxoacid. Registry number: EC 2.6 (12 Dec 1998) |
| nocardioform group | A group of actinomycetes that forms mycelia that break up into rod-shaped or coccoid elements. Certain genera in this group are pathogenic to man. (12 Dec 1998) |
| subscapular group of axillary lymph nodes | Node's of the axillary region located along the subscapular vein and its tributaries; they receive afferent vessels from the dorsal surface of the thorax and scapular region, and send efferent vessels to the central group of lymph nodes. Synonym: nodi lymphatici axillares subscapulares, posterior group of axillary lymph nodes. (05 Mar 2000) |
| nonpolar group | <chemistry> Group in which the electronic charge density is essentially uniform and that cannot therefore interact with other groups by forming hydrogen bonds or by strong dipole dipole interactions. In an aqueous environment, nonpolar groups tend to cluster together, providing a major force for the folding of macromolecules and formation of membranes. Clusters are formed chiefly because they cause a smaller increase in water structure (decrease in entropy) than dispersed groups. Nonpolar groups interact with each other only by the relatively weak London van der Waals forces. (12 Mar 1998) |
| dakota group | <geology> A subdivision at the base of the cretaceous formation in Western North America; so named from the region where the strata were first studied. Source: Websters Dictionary (01 Mar 1998) |
| sulfur group | The elements sulfur, selenium, and tellurium; they form dibasic acids with hydrogen, and their oxyacids are also dibasic. (05 Mar 2000) |
| sulfur group transferases | <enzyme> Enzymes that catalyze the transfer of sulfur atoms (2.8.1), sulfur groups (2.8.2) or coenzyme a (2.8.3). Registry number: EC 2.8 (12 Dec 1998) |
| symptom group | See: syndrome, complex. (05 Mar 2000) |
| synechococcus group | Unicellular, coccoid to rod-shaped cyanobacteria that divide by binary fission in a single plane. Their cells lack structured sheaths and range in diameter from 0.3 to 2.3 microns. These organisms are isolated from freshwater, marine, and hot spring environments. By examining morphological, physiological, and chemical properties it has been possible to subdivide this group into six "strain clusters". These clusters are equivalent to genera but have not been formalised. (12 Dec 1998) |
| synechocystis group | Unicellular cyanobacteria that divide by binary fission in two or three successive planes at right angles to one another. Typically, the cells occur singly or in pairs. These organisms are isolated from freshwater and seawater environments. By examining morphological, physiological, and chemical properties it has been possible to subdivide this group into four "strain clusters". These clusters are equivalent to genera but have not been formalised. (12 Dec 1998) |
| determinant group | That part of an antigenic molecule against which a particular immune response is directed. For instance a tetra to penta peptide sequence in a protein, a tri to penta glycoside sequence in a polysaccharide. In the animal most antigens will present several or even many antigenic determinants simultaneously. See: hapten. (18 Nov 1997) |
| difarnesyl group | A 30-carbon open chain hexaisoprenoid hydrocarbon radical; occurs as a side chain in vitamin K2. (05 Mar 2000) |
| Dombrock blood group | See Blood Groups appendix. (05 Mar 2000) |