| thioclastic cleavage | The splitting of a bond in fashion analogous to hydrolysis or phosphorolysis except that the elements of a substituted hydrogen sulfide (usually coenzyme A) are added across the break. (05 Mar 2000) |
|---|---|
| total cleavage | Cleavage in which the blastomeres are completely separated; the entire egg participates in cell division. Synonym: complete cleavage, total cleavage. (05 Mar 2000) |
| enamel cleavage | The splitting of enamel in a plane parallel to the direction of the enamel rods. (05 Mar 2000) |
| equal cleavage | Cleavage producing blastomeres of like size. (05 Mar 2000) |
| equatorial cleavage | Cleavage in which the plane of cytoplasmic division is at right angles to the axis of the ovum. (05 Mar 2000) |
| yolk cleavage | Segmentation of the vitellus. (05 Mar 2000) |
| unequal cleavage | Cleavage producing blastomeres of different sizes at the two poles. (05 Mar 2000) |
| freeze cleavage | Method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers and it is therefore possible to get en face views of membranes that reveal the pattern of Integral membrane proteins. The E face is the outer lamella of the plasma membrane viewed as if from within the cell, the P face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation. (18 Nov 1997) |
| activated partial thromboplastin time | The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system. (05 Mar 2000) |
| reaction of partial identity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| partial | 1. Of, pertaining to, or affecting, a part only; not general or universal; not total or entire; as, a partial eclipse of the moon. "Partial dissolutions of the earth." 2. Inclined to favor one party in a cause, or one side of a question, more then the other; baised; not indifferent; as, a judge should not be partial. "Ye have been partial in the law." (Mal. Ii. 9) 3. Having a predelection for; inclined to favor unreasonably; foolishly fond. "A partial parent." "Not partial to an ostentatious display." (Sir W. Scott) 4. <botany> Pertaining to a subordinate portion; as, a compound umbel is made up of a several partial umbels; a leaflet is often supported by a partial petiole. Partial differentials, Partial differential coefficients, Partial differentiation, etc. (of a function of two or more variables), the differentials, differential coefficients, differentiation etc, of the function, upon the hypothesis that some of the variables are for the time constant. <mathematics> Partial fractions, the simple tones which in combination form an ordinary tone; the overtones, or harmonics, which, blending with a fundamental tone, cause its special quality of sound, or timbre, or tone colour. See, also, Tone. Origin: F, fr. LL. Partials, fr. L. Pars, gen. Partis, a part; cf. (for sense 1) F. Partiel. See Part. Source: Websters Dictionary (01 Mar 1998) |
| partial adrenocortical insufficiency | Normal basal adrenocortical function with failure of adrenocortical reserve to respond to ACTH stimulation. (05 Mar 2000) |
| partial agglutinin | Immune agglutinin present in an antiserum in lesser concentration than the major agglutinin. Synonym: partial agglutinin. (05 Mar 2000) |
| partial anencephaly | Congenital failure of the cerebrum to develop normally; usually the cerebellum and basal ganglia are represented at least in rudimentary form. Synonym: partial anencephaly. Origin: hemi-+ G. Kephale, head (05 Mar 2000) |
| partial aneuploidy | A type of mosaicism in which some cells have a normal number of chromosomes and some have an abnormal number. (05 Mar 2000) |