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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Focus Forming Assay, Forming Face
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Focal atelectasis Alveolar collapse and failure of oxygenation caused by a deficiency of surfactant.
Focus formation The ability of transformed eukaryotic cells to grow in clusters piled one on top of the other.
Focus forming assay A test for the oncogenic activity of DNA. The test DNA is transfected into animal cells that normally show contact inhibition. If the test DNA has oncogenic activity, the recipient cells lose contact inhibition and form areas of dense packing (foci).
Focus forming unit (ffu) A quantitative measure of focus formation
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Foetus The unborn child. The prenatal stage of a viviparous animal, between the embryonic stage and parturition.
Foetal calf serum (FCS) Serum from the blood of embryonic calves. FCS is an essential component of tissue culture media.
Foetoscopy A technique that permits direct inspection of the foetus with a fibre optic endoscope. The test can be done in the second trimester of pregnancy ad foetal blood sample obtained at the same time by cordocentesis can be analysed.
Folate antagonist A compound such as methotrexate that blocks reactions in nucleotide synthesis that require folic acid. Folate antagonists are used as cancer chemotherapeutic agents.
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Fold The basic tertiary structure of a protein that includes secondary structure elements, their sequential connections and relative spatial positions.
Fold-back DNA A class of DNA with palindromic or inverted repeat sequences that reanneal rapidly when duplex DNA is denatured. The repeat sequence allows the formation of a double-stranded region within each of the separated strands of the original molecule.
Fold recognition The prediction of protein structure by detection of very remote structural relationships or homologies.
Folded genome The condensed state of the DNA in the bacterial nucleoid. The DNA is separated into domains, each of which is negatively supercoiled
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Folding pathway Stages in which a newly synthesised protein chain acquires its final 3D shape.
Folding problem The problem of determining the folding of a protein into its final 3-dimensional structure from the information encoded in its primary structure.
Foldome The population of gene products classified through their tertiary structure.
Folic acid A water-soluble vitamin and member of the B-complex vitamins. Folic acid is made up of a pteridine nucleus, p-aminobenzoic acid (PABA) and glutamate. Folate plays an important role in 1-carbon metabolism via the active form of the vitamin-tetrahydrofolate. Folate deficiency causes megaloblastic anaemia. 
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Follicle 1. An enclosed cluster of cells such as an ovarian follicle that contains a developing egg cell or a hair follicle that envelops the hair root. The follicle protects and nourishes a cell or structure within. 2. In immunology, an area of the spleen or lymph node occupied by B cell and follicular dendritic cells.
Follicle stimulating hormone (FSH) A hormone, secreted by the anterior pituitary gland in mammals. In females, FSH stimulates the maturation of specialised structures in the ovary (Graafian follicles) that produce ova. In males the hormone stimulates the formation of sperm in the hormone with the receptor results in the activation of adenylate cyclase, generation of c-AMP and stimulation of protein kinases.
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Follicular (proliferative) phase The first half of the menstrual cycle in which FSH stimulates the development of the follicle with resulting increase in oestrogen secretion. One of the follicles, which becomes sensitive to FSH develops. Proliferative changes occur in the uterine and vaginal epithelium
Follicular dendritic cell (FDC) A cell found in the secondary lymphoid organs that participates in B ell activation.
Follicular hyperkeratosis Hyperkeratinisation of the epithelium lining the hair follicle. This occurs in vitamin A deficiency.
Food preservation Technique to prevent or delay microbial growth in food. These include pickling, salting, smoking, pasteurization, refrigeration, canning, freeze-drying, ad radiation. Several chemical agents such as benzoic acid are also used I food preservation.
Food processing enzyme An enzyme that is used to control food texture, flavour, appearance and nutritional value. For example, proteases tenderize meat proteins.
Footprinting A technique used for identifying protein-binding sites of DNA. These sites are protected from attack by DNase I.
Forced cloning The insertion of foreign DNA (DNA insert) into a cloning vector in a predetermined orientation.
Foreign DNA A DNA molecule that is incorporated into a cloning vector or a chromosomal site. Also termed DNA insert.
Forensic science The science developed by Edmund Locard to establish the identity of a criminal based on trace evidence found at the scene of crime. This involves use of blood, semen, saliva and hair found at the scene of crime and analysis of blood groups. With the advent of DNA technology, PCR-based DNA fingerprinting is increasingly used which requires only trace amounts of sample. See DNA fingerprinting.
Formamide A commonly used chemical (CONH2) for denaturing nucleic acid in hybridization techniques.
Formed elements The solid parts of the blood that include the red blood ells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Forming face That side of the Golgi stack where the vesicles that have bedded off from the rough endoplasmic reticulum fuse with the Golgi apparatus. Also called the cis face.
Formol labile ACP Erythrocyte acid phosphates that is inhibited by formaldehyde.
Formulation 1. The method by which a therapeutic agent is delivered to its site of action. 2. For tissue culture, see medium; medium formulation.
Formycin B A purine derivative that inhibits use of salvaged nucleotides from the extracellular medium for nucleic acid synthesis. It is used as an antiprasitic agent.
Fortification The addition of nutrients to foods to prevent or correct a nutritional deficiency, to balance the total nutrient profile of food, or to restore nutrients lost I processing.
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