Food Biotechnology terms starting with P

364 terms

Poly(A) polymerase Catalyzes the addition of adenine residues to the 3' end of pre-mRNAs to form the poly(A) tail. (See Polymerase.)
poly-(A) tail See: polyadenylation.
polyacrylamide gel Inert electrophoresis matrix, formed by the polymerization of acrylamide monomer in the presence of the cross-linker N,N'-methylene-bis-acrylamide.
Polyacrylamide gel electrophoresis Electrophoresis through a matrix composed of a synthetic polymer, used to separate proteins, small DNA, or RNA molecules of up to 1000 nucleotides.
polyadenylation Post-transcription al addition of multiple adenine residues to the 3' end of eukaryotic mRNA. Also called poly-(A) tailing.
polycistronic A single mRNA that contains the information necessary for the production of more than one polypeptide. Particularly characteristic of prokaryotic mRNA s.
Polyclonal antibodies A mixture of immunoglobulin molecules secreted against a specific antigen, each recognizing a different epitope.
polyclonal antibody A serum sample that contains a mixture of distinct immunoglobulin molecules, each recognizing a different antigenic determinant of a given antigen.
polycloning site See: polylinker.
polyembryony The production of more than one embryo from a single egg cell (in animals) or from a range of embryogenic cell types (in plants).
polyethylene glycol (Abbreviation: PEG). A polymer having the general formula HOCH2(CH2OCH2)nCH2OH and available in a range of molecular weights.
polygalacturonase (Abbreviation: PG). An enzyme which catalyses the breakdown of pectin. A tomato engineered to contain an antisense-PG gene succeeded in delaying the onset…
polygene One of a number of genes, each of small effect, which together act to determine the phenotype of a quantitative trait.
Polygenic Controlled by or associated with more than one gene.
polyhydroxybutyrate (Abbreviation: PHB). A biopolymer, with physical properties similar to polystyrene, originally discovered in the bacterium Alcaligenes eutropus.
Polylinker A short DNA sequence containing several re- striction enzyme recognition sites that is contained in cloning vectors.
polymer (PAH-lih-mer) A molecule made up of small identical molecules called monomers. The monomers are joined together in a repeating pattern.
polymerase An enzyme that catalyses the formation of polymers from monomers . A DNA polymerase synthesizes DNA from deoxynucleoside triphosphates using a…
Polymerase (DNA) Synthesizes a double-stranded DNA molecule using a primer and DNA as a template.
polymerase chain reaction (puh-LIM-eh-rayz ...) A laboratory method used to make many copies of a specific DNA sequence. Also called PCR.
polymerase chain reaction (PCR) A procedure that en- zymatically amplifies a DNA polymerase. (See Polymerase.)
polymerization The chemical fusion of a number of identical or similar monomers to form a polymer.
polymery The phenomenon whereby a number of genes at different loci (which may be polygenes ) can act together to produce a single effect.
polymorphism (PAH-lee-MOR-fih-zum) A common variation or mutation in DNA.
Polymorphisms Variant forms of a particular gene that occur simultaneously in a population.
Polynucleotide A DNA polymer composed of multiple nucleotides. (See Nucleotide.)
Polypeptide A linear polymer composed of covalently linked amino acids. Each link is formed by a single peptide bond.
Polypeptide (protein) A polymer composed of multiple amino acid units linked by peptide bonds.
Polyploid A multiple of the haploid chromosome number that results from chromosome replication without nuclear division.
polysaccharide (PAH-lee-SA-kuh-ride) A large carbohydrate molecule. It contains many small sugar molecules that are joined chemically. Also called glycan.
polysaccharide capsule See: capsule.
polysome A multi-ribosomal structure representing a linear array of ribosomes held together by mRNA.
polyspermy The entry of several sperm nuclei into the egg during fertilization, although only one actually fuses with the egg nucleus.
polytene chromosome Giant chromosomes produced by interphase replication without division, and consisting of many identical chromatid s arranged side by side.
polyunsaturates Oils in which some of the carbon-carbon bonds are not fully hydrogenated - i.e. of the form -CH=CH-, rather than -CH2-CH2-.
Polyvalent vaccine A recombinant organism into which has been cloned antigenic determinants from a number of different disease-causing organisms. (See Vaccine.)
polyvinylpyrrolidone (Abbreviation: PVP). An occasional constituent of plant tissue culture isolation media.
Population the totality of items or units of material under consideration.
Population density Number of cells or individuals per unit. The unit could be an area, or a volume of medium.
Population genetics The branch of genetics that deals with frequencies of alleles and genotypes in breeding populations.
porcine endogenous retrovirus (Abbreviation: PERV). The provirus of a porcine retrovirus. The possibility that PERVs could be activated after xenotransplantation of pig organs into…
position effect The influence of the location of a gene (particularly a transgene ) on its expression and hence its effect on phenotype.
positional candidate gene A gene known to be located in the same region as a DNA marker that has been shown to be linked to a single-locus trait or to a QTL, and whose deduced…
positional cloning A strategy for gene cloning that relies on the identification of closely linked markers to the target trait, and then uses chromosome walking to identify…
positive control system A mechanism in which a regulatory protein (s) is required to turn on gene expression.
positive selectable marker See: dominant selectable marker.
positive selection A method by which cells that carry a DNA insert integrated at a specific chromosomal location can be selected, since this integration confers a…
post-replication repair A recombination-dependent mechanism for repairing damaged DNA.
post-translational modification The addition of specific chemical residues to a protein after it has been translated.
potentiometric See: enzyme electrode.
PPA See U.S. Department of Agriculture.
PPF Abbreviation for photosynthetic photon flux.
PPM Abbreviation for parts per million.
PR protein Abbreviation for pathogenesis related protein.
pre-filter A coarse filter used to screen out large particles from a fluid or gas, before it is passed through a much finer filter.
pre-mRNA See: primary transcript.
pre-transplant A stage in micropropagation - the rooting and hardening process prior to transfer to soil.
precautionary principle The approach whereby any possible risk associated with the introduction of a new technology is avoided, until a full understanding of its impact on…
precocious germination Early germination of a seed or embryo, prior to the full maturation of the embryo.
pressure potential The pressure generated within a cell, being the net difference between the cell's osmotic potential and the water potential of the external environment.
preventive immunization Infection with an antigen to elicit an antibody response that will protect the organism against future infections. Synonym: vaccination.
Pribnow box Consensus sequence near the mRNA start-point of prokaryotic genes. See: TATA box.
primary First in order of time or development.
primary antibody In an ELISA or other immunological assay, the antibody that binds to the target molecule.
Primary cell A cell or cell line taken directly from a living organism, which is not immortalized.
primary cell wall The cell wall layer formed during cell expansion. Plant cells possessing only primary walls may divide or undergo differentiation.
primary culture A culture started from cells, tissues or organs taken directly from organisms. A primary culture may be regarded as such until it is sub-cultured for the…
Primary germ layers See: germ layer.
primary growth 1. Apical meristem -derived growth; the tissues of a young plant. 2. Explant growth during the initial culture period.
primary immune response The immune response that occurs during the first encounter of a mammal with a given antigen.
primary meristem Meristem of the shoot or root tip giving rise to the primary plant body.
primary structure The linear sequence of residues making up a polymer such as a nucleic acid, polysaccharide or protein.
primary tissue A tissue that has differentiated from a primary meristem.
primary transcript The RNA molecule produced by transcription prior to any post-transcriptional modifications; also called a pre-mRNA in eukaryotes.
Primer A short DNA or RNA fragment annealed to single-stranded DNA, from which DNA polymerase extends a new DNA strand to produce a duplex molecule.
primer walking A method for sequencing long (>1 kbp) cloned pieces of DNA. The initial sequencing reaction reveals the sequence of the first few hundred nucleotides of…
primordium A group of cells which gives rise to an organ.
primosome A protein -replication complex that catalyses the initiation of synthesis of Okazaki fragments during discontinuous replication of DNA.
Prion See Proteinaceous infectious particle.
Prion-related protein (PrP) A normal protein, expressed in the nervous system of animals, whose structure when altered (by interaction with altered copies of itself) is the cause of…
pro-embryo A group of cells arising from the division of the fertilized egg cell or somatic embryo before those cells which are to become the embryo are recognizable.
pro-meristem The embryonic meristem that is the source of organ initials or foundation cells.
pro-nuclear micro-injection An early, low success-rate method to achieve transgenesis in animals, involving the micro-injection of many gene copies into one of the two pro-nuclei of…
pro-nucleus Either one of the two haploid gamete nuclei, just prior to their fusion in the fertilized egg.
pro-phage The genome of a bacteriophage integrated into the chromosome of a lysogenic bacterial cell, and replicated along with its host chromosome.
pro-toxin A latent, non-active precursor form of a toxin.
Probability The chance that an event occurs. It is usually expressed as a percent. Zero percent denotes impossibility, while 100% denotes certainty.
proband The individual in a family in whom an inherited trait is first identified.
Probe A sequence of DNA or RNA, labeled or marked with a radioactive isotope, used to detect the presence of complementary nucleotide sequences. See Nucleotide.
procambium A primary meristem that gives rise to primary vascular tissues and, in most woody plants, to the vascular cambium.
procaryote See: prokaryote, prokaryotic.
procaryotic (adj.) See: procaryote.
processed pseudo-gene A copy of a functional gene which has no promoter, no introns and which, consequently, is not itself transcribed.
production environment All input-output relationships, over time, at a particular location. The relationships include biological, climatic, economic, social, cultural and…
production traits Characteristics of animals, such as the quantity or quality of the milk, meat, fibre, eggs, work, etc.
productivity The amount of economically significant product generated within a given period of time from a specified quantity of resource.
progeny Offspring; the product of reproduction or replication.
progeny testing With respect to discrete loci, the inference of the allelic state of an individual from the pattern of segregation among its offspring.
progesterone (proh-JES-tuh-RONE) A type of hormone made by the body that plays a role in the menstrual cycle and pregnancy.
programmed cell death A type of cell death in which a series of molecular steps in a cell leads to its death.