| G1 | presynthetic gap [phase of cells prior to DNA synthesis] |
|---|---|
| G2 | postsynthetic gap [phase of cells following DNA synthesis] |
| IDS | iduronate sulfatase; immune deficiency state; inhibitor of DNA synthesis; integrated delivery system... |
| IRDP | insulin-related DNA polymorphism |
| ras | retrovirus-associated DNA sequence |
| indeterminate cleavage | Cleavage resulting in blastomeres of similar developmental potencies, each capable, when isolated, of producing an entire embryonic body. (05 Mar 2000) |
|---|---|
| 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) |
| A-DNA | A form of DNA in which the helix is right-handed and the overall appearance is short and broad. (05 Mar 2000) |
| a-form DNA | <molecular biology> One of several forms that can be assumed by a double helix. A-DNA is stable in dehydrated conditions. This form is less common than the dominant form found under physiological conditions -- beta-DNA. This form is also assumed by DNA-RNA hybrid helices and by regions of double-stranded RNA. It is a right-handed helix and is a more compact form than beta-DNA. (09 Oct 1997) |
| antisense DNA | <molecular biology> A synthetic DNA strand that is complementary to a particular strand of target DNA with a complementary sequence of bases. This results in preventing expression of the gene encoded. These proteins can be used to selectively turn off production of certain proteins or block viral genetic instructions, by marking them for destruction by cellular enzymes, in order to prevent the building of new virus or the infection of new cells. (14 Nov 1997) |
| apurinic DNA | <molecular biology> A DNA molecule that has lost adenine and guanine, its purine bases. Apurinic DNA can be produced by treating the DNA with acid. (09 Oct 1997) |
| ATP-dependent DNA strand transferase | <enzyme> From human cell nuclei; catalyses strand exchange between homologous DNA sequences; magnesium dependent, requires ATP hydrolysis Registry number: EC 2.7.7.- Synonym: ATP-dep-DNA-str trnsfase (26 Jun 1999) |
| bacteriophage T7 induced DNA polymerase | <enzyme> Complex of two proteins, phage gene 5 protein and E coli thioredoxin Registry number: EC 2.7.7.- Synonym: t7 phage DNA polymerase, sequenase, t7 DNA polymerase, thermo sequenase (26 Jun 1999) |