Ni
| cell nucleolus | Within most types of eukaryotic cell nucleus, a distinct region, not delimited by a membrane, in which some species of rrna (RNA, ribosomal) are synthesised and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rrna is transcribed from a nucleolar organiser, i.e., a group of tandemly repeated chromosomal genes which encode rrna and which are transcribed by RNA polymerase I. (12 Dec 1998) |
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| cell nucleus | Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. (12 Dec 1998) |
| P cell | A characteristic specialised cell, with probable pacemaker function, found in the S-A node and A-V junction. (05 Mar 2000) |
| cell organelle | <cell biology> A structurally discrete component of a cell. (18 Nov 1997) |
| cell physiology | Characteristics and physiological processes of cells from cell division to cell death. (12 Dec 1998) |
| cell plate | <plant biology> Region in which the new cell wall forms after the division of a plant cell. In the plane of the equator of the spindle a disc like structure, the phragmoplast forms, into which are inserted pole derived microtubules. Golgi derived vesicles containing pectin come together and fuse at the plate which develops from the centre outwards and eventually fuses with the plasma membrane thereby separating the daughter cells. (26 Mar 1998) |
| cell polarity | 1. <cell biology> In epithelial cells the differentiation of apical and basal specialisations. In many epithelia the apical and baso lateral regions of plasma membrane differ in lipid and protein composition and are isolated from one another by tight junctions. The apical membrane may, for example: be the only region where secretory vesicles fuse or have a particular ionic pumping system. 2. A motile cell must have some internal polarity in order to move in one direction at a time: a region in which protrusion will occur (the front) must be defined. Locomotory polarity may be associated with the pericentriolar microtubule organising centre and can be perturbed by drugs that interfere with microtubule dynamics. (26 Mar 1998) |
| cell potential | <cell biology, physiology> The voltage of an electrochemical cell, the larger the cell potential, the greater the extent of reaction when equilibrium is reached. (26 Mar 1998) |
| cell proliferation | <cell biology> Increase in cell number by division. (26 Mar 1998) |
| cell recognition | <cell biology> Interaction between cells that is possibly dependent upon specific adhesion. Since the mechanism is not entirely clear in most cases, the term should be used with caution. (26 Mar 1998) |
| cell renewal | <cell biology> Replacement of cells, for example those in the skin, by the proliferative activity of basal stem cells. (26 Mar 1998) |
| cell respiration | The exergonic metabolic processes in living cells, animal or plant, by which molecular oxygen is taken in, organic substances are oxidised, free energy is released, and carbon dioxide, water, and other oxidised products are given off by the cell. (12 Dec 1998) |
| cell sap | <cell biology> Effectively equivalent to the term cytosol. (26 Mar 1998) |
| cell signalling | <cell biology> Release by one cell of substances that transmit information to other cells. (26 Mar 1998) |
| cell size | The physical dimensions of a cell. It refers mainly to changes in dimensions correlated with physiological or pathological changes in cells. (12 Dec 1998) |