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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Fos Related Antigens (FRA), Freeze Fracture Electron Microscopy
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Fortify The addition of strengthening components or beneficial ingredients to a nutrient medium.
Forward template The template for the leading strand during replication.
Fos The oncogene carried by FBJ murine osteosarcoma retrovirus. The product of fos gene together with jun functions to alter the rates of transcription of certain genes.
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Fosfomycin (fosfonomycin) An antibiotic which is a structural analogue of phosphoenol pyruvate (PEP) that blocks bacterial cell wall synthesis at a step that requires PEP.
Fosmid library A library of ‘F’ plasmids.
Fouling The coating or plugging of equipment that prevents it from proper functioning. This may be caused by materials or microorganisms.
Founder animal An organism carrying a transgene in its germ line that an be used to breed pure transgenic lines, or one that acts as a breeding stock for transgenic animals.
Founder effect The presence in a population consisting of many individuals all with the same chromosomes or region of a chromosome, derived from single, common ancestor.
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Founder principle The probability that a new, small, isolated population may be genetically different from the parent population, this may be because the founding individuals (who constitute a small, random sample from the large, parent population) may differ significantly from typical members of the parent population.
Four-base cuter A type II restriction endonuclease that recognises a sequence of four nucleotide pairs and cleaves within that sequence. Since a four base pair sequence occurs more frequently by chance than a six base pair sequence, four-base cutters cleave more frequently than do six-base cutters. As a result, four-base cutters create smaller fragments than six-base cutters. Also known as four-base-pair-cutter; four-cutter.
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Four-strand crossing over Crossing over between two sister chromatids that involves breaking of both DNA strands on both the chromosomes.
Fourier synthesis A method of summing waves such as scattered x-rays to obtain a periodic function such as the electron density in a crystal.
Fps The oncogene carried by the fujinami sarcoma virus that encodes tyrosine kinases. The fps is a homologue from chicken.
Fragile site The sites on chromosomes showing a higher probability of breakage and a common site of chromosomal translocation.
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Fragile X syndrome A common neurological disease, and the first reported genetic disorder with microsatellite expansion. It occurs as a result of DNA polymerase slippage during DNA replication. It is inherited as an X-linked dominant trait and presents with mental retardation and chromosome breakages at specific sites. It is characterised by expansion of the microsatellite trincleotide repeat CGG in the 5’untranslated region of the FMR1 gene resulting in hypermethylation and downregulation of gene expression. The severity of the disease increases with the number of repeats.
Fragment See restriction fragment.
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Forward mutations Mutations that inactivate a wild-type gene.
Four-helix bundle A complex supersecondary structure in proteins in which four antiparallel α-helices are packed together to form a hydrophobic core with hydrophilic residual groups exposed. This is found in many α-helical proteins such as ferritin
Fragmentins An enzyme present in the granules of cytotoxic T cell and NK cells that induces apoptosis in the target cells. Also called granzymes.
Fragmentome Low molecular weight metabolite, protein and peptide fragments being explored as potential cancer biomarkers.
Frameshift A mutation caused by insertion or deletion of nucleotides other than in multiples of three that alters the reading frame of the codons beyond that point
Fos-related Antigens (FRA) Nuclear phosphoproteins that are similar in structure to the fos oncogene product
Frameshift mutation A mutation that alters the reading frame of an mRNA, either by insertion or deletion of nucleotides.
Framework region Regions of the antibody molecule that do not bind antigen but whose structure permits folding of the antibody so that all the contact regions bind antigen.
Franklin, Rosalind (1920-1958) A physical chemist whose X-ray diffraction data enabled Watson and Crick to deduce the double helical structure for DNA for which they were awarded the Noble Prize.
FRAP An acronym for Fluorescence Recovery After Photobleaching. This technique is used in analyzing cell membrane synthesis and fluidity. This involves bleaching of fluorescent molecules located in specific cellular structure such as the nucleus or cell membrane by a microscopic light beam. The bleached area is examined at various time intervals after photobleaching to determine how fast the cellular structure regenerates the material in the bleached area.
Fraternal twins Siblings born at the same time same the result of fertilisation of two ova by two sperm. They share the same genetic relationship with each other as other siblings.
Free energy That part of the total energy of a system that is available for doing useful work at constant temperature and pressure. ΔG=ΔH - TΔS, where ΔH= change in chemical bond energy and ΔS= change in entropy. IfΔG is negative, the reaction proceeds in the forward direction, if it is positive, it moves in the reverse direction and if it is zero, the reaction is at equilibrium.
Free energy of activation See Activation energy.
Free fatty acids (FFA) Fatty acids that are not esterified.
Free radical Any species containing one or more unpaired electrons and capable of independent existence. The free radicals in biological systems are derivatives of oxygen and are referred (HO2), superoxide radical (O2), hydrogen peroxide (H2O2) and hydroxyl radical (OH). The products of metabolism or deliberate during phagocytosis.
Free-energy change (ΔG) The amount of free energy that is released (negative ΔG) or absorbed (positive ΔG) in a reaction at constant temperature and pressure.
Freeze etch A technique for analyzing cell structure by electron microscopy. The frozen cell sample is cracked with a knife to reveal the cell contents, freeze dried, shadowed and examined under the electron microscopes.
Freeze preservation See cryobiological preservation.
Freeze-drying The technique of drying a tissue or an organ in a frozen state under vacuum. Tissues are freeze-dried in order to measure their dry weight or to preserve them for future analysis. Freeze-drying is the standard method for the long-term preservation of microorganisms. See lyophilisation.
Freeze-fracture electron microscopy A technique for analyzing membrane structure. Here the membrane of a frozen cell is fractured along the interior of the bilayer, separating it into two monolayers with the inner surface exposed.
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