| morphologic element | Any anatomical unit, such as a cell. Synonym: morphologic element. (05 Mar 2000) |
|---|---|
| control element | Generic term for a region of DNA, such as a promoter or enhancer adjacent to (or within) a gene that allows the regulation of gene expression by the binding of transcription factors. (18 Nov 1997) |
| controlling element | A transposon which, when inserted into or removed from a gene, breaks the chromosome and/or causes mutations. (09 Oct 1997) |
| copia element | A group of transposons whose base sequences are closely related to each other, found in the genome of the fruit fly genus Drosophila. (09 Oct 1997) |
| polarizing element | <microscopy> A general term for a device for producing or analysing plane-polarized light. It may be a Nicol prism, some other form of calcite prism, a reflecting surface, or a polarizing filter. (05 Aug 1998) |
| heat-shock response element | <cell biology, protein> The nucleotide sequence, CNNGAANNTCCNG, which is in the promoter region of the heat-shock genes. When the animal is exposed to certain types of stress such as a sudden rise in temperature, the first thing that happens to activate these genes is the binding of the HSE by a transcriptional enhancer protein. (09 Oct 1997) |
| serum response element | Dyad symmetry element bound by serum response factor to control the expression of c fos. (18 Nov 1997) |
| neutral element | An element of the zero group of the periodic system comprising the rare gases, He, Ne, Ar, Kr, Xe, Rn. Synonym: noble element. (05 Mar 2000) |
| noble element | A metal that cannot be oxidised by heat alone, nor readily dissolved by acid; e.g., gold, platinum. Synonym: noble element. (05 Mar 2000) |
| dyad symmetry element | Dyad symmetry element bound by serum response factor to control the expression of c fos. (18 Nov 1997) |
| Is element | Mobile nucleotide sequences that occur naturally in the genomes of bacterial populations. When inserted into bacterial DNA, they inactivate the gene concerned, when they are removed the gene regains its activity. Closely related to transposons and range in size from a few hundred to a few thousand bases, but are usually less than 1500 bases. (18 Nov 1997) |
| electronegative element | An element whose atoms have a tendency to accept electrons and form negative ions (e.g., oxygen, sulfur, chlorine, etc.). (05 Mar 2000) |
| electropositive element | <chemistry> An element whose atoms have a tendency to lose electrons and form positive ions (e.g., sodium). (05 Mar 2000) |
| element | <chemistry> One of the 103 known chemical substances that cannot be divided into simpler substances by chemical means. A substance whose atoms all have the same atomic number. Examples: hydrogen, lead, uranium.(See atom, matter, nuclide.) (16 Dec 1997) |
| trace element | Any chemical element that an organism needs very small quantities of tosurvive. (09 Oct 1997) |