diffusible
91chemoattraction — Non committal description of cellular response to a diffusible chemical not necessarily by a tactic response. Term preferable to chemotaxis when the mechanism is unknown …
92chemotaxis — A response of motile cells or organisms in which the direction of movement is affected by the gradient of a diffusible substance. Differs from chemokinesis in that the gradient alters probability of motion in one direction only, rather than rate… …
93cis- activation — Activation of a gene by an activator located on the same chromosome ie. not by a diffusible product …
94equilibrium dialysis — Technique used to measure the binding of a small molecule ligand to a larger binding partner. The macromolecule is contained within a dialysis chamber and the diffusible ligand added to the exterior: once equilibrium is reached an excess of… …
95French flag problem — The French flag (tricolor) is used to illustrate a problem in the determination of pattern in a tissue, that of specifying three sharp bands of cells with discrete properties that do not have blurred edges using, for example, a gradient of a… …
96gradient perception — Problem faced by a cell that is to respond directionally to a gradient of, for example, a diffusible attractant chemical. In a spatial mechanism the cell would compare receptor occupancy at different sites on the cell surface; a temporal… …
97NAD — (= nicotinamide adenine dinucleotide; NAD+ ; formerly DPN) Coenzyme in which the nicotine ring undergoes cyclic reduction to NADH and oxidation to NAD. Acts as a diffusible substrate for dehydrogenases etc. NADH+ is one source of reducing… …
98nuclear receptor — Receptor for a diffusible signal molecule that can enter the nucleus, particularly receptors for steroid hormones …
99pattern formation — One of the classic problems in developmental biology is the way in which complex patterns are formed from an apparently uniform field of cells. Various hypotheses have been put forward, and there is now evidence for the existence of gradients of… …
100pseudospatial gradient sensing — Mechanism for sensing a gradient of a diffusible chemical in which the cell sends protrusions out at random; up gradient protrusions are stabilized by positive feedback (because receptor occupancy is rising with time) and others are transitory… …
