Biotechnology and Genetics — page 12 of 40

Biotechnology and Genetics terms

1101. embryo sac The mature female gametophyte in angiosperms. Generally a seven-celled structure - two synergids, one egg cell, three antipodal cells (each with a single…
1102. embryo sexing The determination of the sex of an embryo prior to birth. Typically achieved by the polymerase chain reaction -mediated amplification of DNA extracted…
1103. embryo splitting The splitting of young embryos into several sections, each of which develops into an animal. A form of animal cloning, i.e.
1104. embryo storage Cryogenic preservation of animal embryos, allowing inembryonation or other manipulations long after embryo formation.
1105. embryo technology Generic name for any modification of mammalian embryos. It encompasses embryo cloning, embryo splitting, embryo storage, and in vitro fertilization.
1106. embryo transfer (Abbreviation: ET). See: embryo multiplication and transfer, multiple ovulation and embryo transfer.
1107. embryogenesis 1. (General) Development of an embryo. 2. (In plants) In vitro formation of plants from plant tissues, through a pathway closely resembling normal…
1108. embryoid Plant biotechnology term no longer commonly used. An embryo-like body developing in vitro, forming a complete, self-contained plantlet with no vascular…
1109. Embryoid bodies (EBs) Spheroid colonies seen in culture produced by the growth of embryonic stem cells in suspension.
1110. Embryonal carcinoma (EC) cells A type of pluripotent stem cell derived from teratocarcinoma (usually a testis tumor).
1111. Embryonic disk A group of cells derived from the inner cell mass of the blastocyst, which later develops into an embryo.
1112. Embryonic germ (EG) cells Cells found in a specific part of the embryo/fetus called the gonadal ridge that normally develop into mature gametes.
1113. Embryonic germline cells Embryonic germline cells, also called EG cells, are pluripotent stem cells derived from the primitive germline cells (those cells that give rise to eggs…
1114. Embryonic stem (ES) cells Cell lines derived from early embryos that have the potential to differentiate into all types of somatic cells as well as to form germ line cells, and…
1115. Embryonic stem cell Also called ES cells, embryonic stem cells are cells derived from the inner cell mass of developing blastocysts.
1116. Embryonic stem cell line Embryonic stem cells, which have been cultured under in vitro conditions that allow proliferation without differentiation for months to years.
1117. Embryonic stem cells (Abbreviation: ES cells). Cells of the early embryo that can give rise to all differentiated cells, including germ line cells.
1118. emission wavelength The specific wavelength of light emitted by a fluorescent molecule, such as a labelled probe, upon absorption of light at the (higher) excitation…
1119. EMT See: embryo multiplication and transfer.
1120. Encapsidation Process by which a virus' nucleic acid is enclosed in a capsid. See Coat protein.
1121. encapsulating agents Anything which forms a shell around an enzyme or bacterium, common agents being polysaccharides such as alginate or agar.
1122. encapsulation Any method packaging an enzyme or bacterium and maintaining its normal functions. Used to immobilize cells in a bioreactor.
1123. encode The gene product specified by a particular nucleic acid sequence. See: genetic code.
1124. end-labelling The introduction of a readily-visualized tag at the end of a DNA or RNA molecule.
1125. end-product inhibition The inhibition of an enzyme by a metabolite. Typically, the enzyme is the first enzyme in a biosynthetic pathway, and the metabolite the product of the…
1126. Endangered species A plant or animal species in immediate danger of extinction because its population number has reached a critical level, or its habitat has been…
1127. Endemic Where disease occurs on a consistent basis.
1128. endocrine gland Any gland in an animal that manufactures hormones and secretes them directly into the bloodstream to act at distant sites in the body, known as target…
1129. endocrine interference Interference with the normal balance of hormones.
1130. endocytosis The process by which materials enter a cell without passing through the cell membrane.
1131. Endoderm The internal layer of cells of the gastrula, which develops into the alimentary canal (gut) and digestive glands of the adult.
1132. endodermis The layer of living cells, with various characteristically thickened walls and no intercellular spaces, which surrounds the of certain plants and occurs…
1133. endogamy See: inbreeding.
1134. endogenous Produced inside an organism or cell. The opposite is external (exogenous) production.
1135. Endogenous retrovirus Integrated retrovirus DNA (provirus) derived from infection of the germline of an ancestral animal.
1136. Endogenous stem cells Stem cells that are already present in the body.
1137. Endometrium (en-do-MEE-tree-um) The layer of tissue that lines the uterus.
1138. endomitosis Duplication of chromosomes without division of the nucleus, resulting in a doubling (or more) in the chromosome number within a cell.
1139. Endonuclease See Nuclease.
1140. Endophyte An organism that lives inside another.
1141. endoplasmic reticulum (Abbreviation: ER). A cytoplasmic net of membranes, adjacent to the nucleus, visible under the electron microscope. The sites of protein synthesis.
1142. endopolyploidy The net result of endomitoses. The somatic chromosome number has doubled (or more), forming a polyploid cell line.
1143. endoprotease An enzyme that cleaves internal peptide bonds within a polypeptide molecule. Site of cleavage is usually specific to certain amino acid residues.
1144. endoreduplication Chromosome reproduction during interphase. Four-chromatid chromosomes (diplochromosomes) are seen during this phase.
1145. endosperm The nutritive tissue that develops in the seed of most angiosperms, containing varying proportions of carbohydrate (usually starch), protein and lipid.
1146. endosperm mother cell One of the seven cells of the mature plant embryo sac, containing the two polar nuclei and, which, following fertilization, gives rise to the primary…
1147. Endothelial relating to a flat layer of cells lining the heart, for example, or blood vessels.
1148. endotoxin A component of the cell wall of gram-negative bacteria that elicits, in mammals, an inflammatory response and fever.
1149. Engraftment The process in which transplanted stem cells or bone marrow cells migrate to the bone marrow and begin producing healthy red blood cells, white blood…
1150. enhancer 1. A substance or object that increases a chemical activity or a physiological process. 2.
1151. enhancer element See: enhancer.
1152. enhancer sequence See: enhancer.
1153. enolpyruvyl-shikimate-3-phosphate synthase (Abbreviation EPSP synthase or EPSPS). An enzyme produced by virtually all plants, which is essential for normal metabolism, and for the biosynthesis of…
1154. enterotoxin A bacterial protein that, following release into the intestine, causes cramps, diarrhoea and nausea.
1155. Enucleated A cell with its nucleus removed.
1156. Enucleated oocyte (cytoplast) An egg cell from which the nucleus has been removed mechanically.
1157. enucleated ovum Egg cell from which the nucleus has been removed, usually as a preparatory step for nuclear transfer.
1158. Environmental Protection Agency (EPA) (EPA) Environmental Protection Agency (EPA) was established as an independent agency on December 2, 1970 during President Nixon's term in office.
1159. enzyme A protein that speeds up chemical reactions in the body.
1160. enzyme bioreactor A reactor in which a chemical conversion reaction is catalysed by an enzyme.
1161. Enzyme Commission number (Abbreviation: EC number). Systematic label which identifies an enzyme in the technical literature.
1162. enzyme electrode A type of biosensor, in which an enzyme is immobilized onto the surface of an electrode.
1163. enzyme immunoassay A range of immunoassay techniques employing enzymes, which includes ELISA.
1164. enzyme kinetics The quantitative characteristics of enzyme reactions.
1165. enzyme stabilization Maintaining the active conformation of an enzyme. This can be achieved in vitro by providing the appropriate chemical environment and cofactors.
1166. enzyme-linked immunosorbent assay See: ELISA.
1167. Enzymes Proteins that control the various steps in all chemical reactions.
1168. EPA See Environmental Protection Agency.
1169. EPD See: expected progeny difference.
1170. Epiblast Gives rise to the ectoderm and mesoderm. The mesoderm then displaces the hypoblast cells and forms the entodermal cell layer on its inner surface.
1171. epicotyl The upper portion of the axis of a plant embryo or seedling, above the cotyledons.
1172. Epidermal growth factor (EGF) A cell messenger protein that has effects including stimulation of epidermal development, in newborn animals it hastens eyelid-opening and tooth-eruption
1173. epidermis (ep-i-DER-mis) The upper or outer layer of the two main layers of tissue that make up the skin.
1174. epigenesis Describes the developmental process whereby each successive stage of normal development is built up on the foundations created by the preceding stages of…
1175. epigenetic variation Non-hereditary and reversible variation; often the result of a change in gene expression due to methylation of DNA.
1176. epinasty A process by which the growth of branches or petioles is abnormally pointing downward.
1177. epiphyte A plant that grows upon another plant, but is neither parasitic on it nor rooted in the ground.
1178. episome A genetic extrachromosomal element (e.g. the F factor in Escherichia coli) which replicates within a cell independently of the chromosome and is able to…
1179. Epistasis Interaction between genes at different loci, e.g. one gene suppresses the effect of another gene that is situated at a different locus.
1180. Epithelium (EP-ih-THEE-lee-um) A thin layer of tissue that covers organs, glands, and other structures within the body.
1181. epitope (EP-i-tope) A part of a molecule that an antibody will recognize and bind to.
1182. epizootic A disease simultaneously affecting a large number of animals.
1183. EPSP synthase Abbreviation for enolpyruvyl-shikimate 3-phosphate synthase.
1184. EPSPS Abbreviation for enolpyruvyl-shikimate 3-phosphate synthase.
1185. equational division A chromosome division in which the two chromatids of each duplicated chromosome separate longitudinally, prior to being incorporated into two daughter…
1186. equilibrium density gradient centrifugation A procedure used to separate macromolecules based on their density (mass per unit volume).
1187. ER Describes cells that do not have a protein to which the hormone estrogen will bind.
1188. Erlenmeyer flask A conical flat-bottomed laboratory flask with a narrow neck, widely used for culturing micro-organisms.
1189. Erythrocyte (eh-RITH-roh-site) A cell that carries oxygen to all parts of the body. Also called RBC and red blood cell.
1190. Erythroid cell Red blood cells.
1191. ES cells See: embryonic stem cells.
1192. Escherichia coli A commensal bacterium inhabiting the human colon that is widely used in biology, both as a simple model of cell biochemical function and as a host for…
1193. essential amino acid An amino acid required for normal metabolism, but which cannot be synthesized by an organism. It therefore has to be supplied via feed or food.
1194. essential derivation of varieties (Abbreviation: EDV). Genotypes very similar to an originating cultivar, obtained, for example, by the selection of a mutant or a variant individual from…
1195. Essential element Any of a number of elements required by living organisms to ensure normal growth, development and maintenance.
1196. essential nutrient Any substance required by living organisms to ensure normal growth, development and maintenance.
1197. essential requirement In plant cell tissue culture, comprises inorganic salts, including all of the elements necessary for plant metabolism; organic factors (amino acids…
1198. EST See: expressed sequence tag.
1199. established culture 1. An aseptic viable explant (See: micropropagation ). 2. A suspension culture subjected to several passages with a constant cell number per unit time.
1200. estimated breeding value (Abbreviation: EBV). Twice the expected progeny difference. The difference is doubled because breeding value is a reflection of all the genes of an…