| glycine cleavage complex | A complex of several proteins that catalyze the reversible reaction of glycine with tetrahydrofolate to produce CO2, NH3, and N5,N10-methylenetetrahydrofolate; a deficiency of this enzyme (or one of its subunits) will result in nonketotic hyperglycinaemia. Synonym: glycine synthase. (05 Mar 2000) |
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| meridional cleavage | Cleavage in a plane through the axis of the zygote. (05 Mar 2000) |
| meroblastic cleavage | Incomplete separation of the blastomeres, with the divisions being limited to the nonyolked portion of the egg. Synonym: incomplete cleavage. (05 Mar 2000) |
| citrate cleavage enzyme | ATP citrate (pro-3S)-lyase |
| phosphoroclastic cleavage | <biochemistry> This reaction is an analogue to hydrolysis, except here a molecule is cleaved with phosphate as the attacking group. (09 Oct 1997) |
| cleavage | <cell biology> The early divisions of the fertilized egg to form blastomeres. The cleavage pattern is radial in some phyla, spiral in others. (18 Nov 1997) |
| cleavage cavity | The cavity in the blastula of a developing embryo. Synonym: blastocoele, cleavage cavity, segmentation cavity. Origin: blasto-+ G. Koilos, hollow (05 Mar 2000) |
| cleavage cell | One of the cells produced as the result of cell division, cleavage, in the fertilized egg. (18 Nov 1997) |
| cleavage division | The rapid mitotic division of the zygote with decrease in size of individual cells or blastomeres and the formation of a morula. See: cleavage. (05 Mar 2000) |
| cleavage lines | Lines which can be extrapolated by connecting linear openings made when a round pin is driven into the skin of a cadaver, resulting from the principal axis of orientation of the subcutaneous connective tissue (collagen) fibres of the dermis; they vary in direction with the region of the body surface. Synonym: Langer's lines. (05 Mar 2000) |
| cleavage product | A substance resulting from the splitting of a molecule into two or more simpler molecules. (05 Mar 2000) |
| cleavage site | A sequence in DNA that can be recognised and cut by a specific restriction enzyme. (12 Dec 1998) |
| cleavage stage, ovum | The embryo in its earliest stage, lasting from the first mitotic division of the fertilised ovum into two blastomeres to the formation of the morula, a compact mass of blastomeres. (12 Dec 1998) |
| complete cleavage | Cleavage in which the blastomeres are completely separated; the entire egg participates in cell division. Synonym: complete cleavage, total cleavage. (05 Mar 2000) |
| progressive cleavage | In fungi, a type of sporulation in which cleavage planes in the cytoplasm first produce protospores and then sporangiospores in a sporangium. (05 Mar 2000) |