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Home >> Biotechnology Dictionary >> F factor - Fusion gene
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F factor -
a bacterial episome that confers the ability to function as a genetic donor in conjugation; the fertility factor in bacteria.
F1 - the first filial generation in a cross between any two parents; the first generation of descent from a given mating.
Feedback inhibition - the process by which the accumulated end product of a biochemical pathway stops synthesis of that product. A late metabolite of a synthetic pathway regulates synthesis at an earlier step of the pathway. if end-product inhibition.
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F2 - the second filial generation, produced by crossing two members of the F1 or by self pollinating the F1. The: grandchildren of a given mating.
Factorial mating - a mating scheme in which each male parent is mated with each female parent. Made possible in animals by means of in vitro embryo production (q.v.). Such a mating: scheme substantially reduces the rate of inbreeding in a selection programme.
FAD - flavin adenine dinucleotide. A : co-enzyme important in various biochemical reactions. It comprises a phosphorylated vitamin B2 (riboflavin) molecule linked to the nucleotide adenine monophosphate (AMP). It functions as a hydrogen acceptor in dehydrogenation reactions, being reduced to FADH2. This in turn is oxidised to FAD by the electron transport chain, thereby generating ATP (two molecules of ATP per molecule of FADH2.
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Fed-batch fermentation - culture of cells or micro-organisms where nutrients are added periodically to the bioreactor.
Fermentation substrates - materials used as food for growing micro-organism. The fermentation substrates and the trace materials needed, together with chemicals added to make the fermentation easier, form the culture medium.
False-negative - a negative assay result that should have been positive.
False-positive - a positive assay result that should have been negative.
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Fertile - of an organism: capable of breeding and reproduction.
Fouling - the coating or plugging (by materials or micro-organisms) of equipment, thus prevening it from functioning properly.
Founder animal - in transgenesis research, an organism that carries a transgene in its germ line and can be used in matings to establish a pure-breeding transgenic line, or one that acts as a breeding stock for transgenic animals.
Founder principle - the possibility that a new, small, isolated population may be genetically different from the parent population, because the founding individuals (being a small, random: sample from the large, parent population) could be quite different from typical. members of the parent population.
Four-base cutter - a type II restriction endonuclease that binds (and subsequently cleaves) DNA at sites that contain a sequence of four nucleotide pairs that is uniquely recognised by that enzyme. Because any sequence of four bases occurs more frequently by chance than any sequence of six bases, four-base cutters cleave more frequently than do six-base cutters. Thus, four-base cutters create smaller fragments than six-base cutters.
Fractionation - separation.
Frameshift mutation - a mutation that changes the reading frame of an mRNA, either by inserting or deleting nucleotides.
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Farm animal genetic resources (AnGR) - in AnGR: those animal species that are used, or may be used, for the production of food and agriculture, and the populations within each of them. These populations within each species can be classified as wild and feral populations, landraces and: primary populations, standardized breeds, selected: lines, and any conserved genetic material. (Source: F AO,1999).
Fermentation - the anaerobic breakdown by micro-organisms of complex organic substances, especially carbohydrates like glucose. The process is energy-yielding. Fermentation is often misused to describe large scale aerobic cell culture in specialised vessels (fermenters, bioreactors) for secondary product synthesis.
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Free water -
water released by a cell when freezing occurs in intercellular spaces. If bound water.
Free-living conditions -
natural or greenhouse conditions where the plantlets are transferred from in vitro conditions to soil mixtures. In such instances, plantlets must manufacture their own food supply for survival.
Freeze-drying - the process of drying a tissue or an organ in a frozen state under vacuum. Tissues are freeze-dried to measure their dry weight or to preserve them for future analysis. Freeze-drying is the standard way of preserving microorganisms for long periods of time. cf lyophilisation.
Frequency distribution - a graph showing either the relative or absolute incidence of classes in a population. The classes may be defined by either a discrete or a continuous variable; in the latter case, each class represents a different interval on the scale of measurement.
Fresh weight -
the weight, including the water content, of a plant or plant part at the time of harvest. cf: wet weight.
Friable -
a term commonly used to describe a crumbling or fragmenting callus. A friable callus is easily dissected and readily dispersed into single cells or clumps of cells in solution.
Fungicide -
an agent, such as a chemical, that kills fungi.
Furfuraldehyde -
used industrially as a solvent and as a raw material for synthetic resin.
Fusion gene -
a hybrid gene created by joining portions of two different genes (to produce a new protein) or by joining a gene to a different promoter (to alter or regulate gene transcription).
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