Biotechnology and Genetics terms starting with P

399 terms

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…
Primitive streak The initial band of cells from which the embryo begins to develop. The primitive streak establishes and reveals the embryo's head-tail and left-right…
Primordial germ cell A gamete, that is, a sperm or egg, OR a primordial cell that can mature into a sperm or egg.
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…
Privacy In genetics, the right of people to restrict access to their genetic information.
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.
Progenitor cell A progenitor cell, often confused with stem cell, is an early descendant of a stem cell that can only differentiate, but it cannot renew itself anymore.
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.
Prokaryote A bacterial cell lacking a true nucleus; its DNA is usually in one long strand. See Eukaryote.
prolactin (proh-LAK-tin) A hormone that is made by the pituitary gland (a pea-sized organ in the center of the brain).
Proliferation Increase by frequent and repeated reproduction; growth by cell division.
Promoter Any person who, directly or indirectly, organizes or assists in the organization of a tax shelter or who participates in the sale of any interests in a…
promoter sequence See: promoter (1).
Pronuclear injection The use of a fine needle to inject DNA into the nucleus of an unfertilized egg.
Pronucleus Either of the two haploid gamete nuclei just prior to their fusion in the fertilized ovum.
proofreading The scanning of newly-synthesized DNA for structural defects, such as mis-matched base pairs. A functional activity of most DNA polymerase s.
propagation The duplication of a whole plant from a range of vegetative materials; adapted for in vitro culture as micropropagation.
propagule Any structure capable of giving rise to a new plant by asexual or sexual reproduction, including bulbils, leafbuds, etc.
prophase The first stage of nuclear division. The stage during which occurs in the first division of meiosis (see: leptonema, zygonema, pachynema, diplonema…
prostate cancer (PROS-tayt KAN-ser) Cancer that forms in tissues of the prostate (a gland in the male reproductive system found below the bladder and in front of the…
protamine A class of small basic proteins that replace the histones in the chromosomes of some sperm cells.
protease An enzyme that cleaves peptide bonds that link amino acids in protein molecules.
protein (PRO-teen) A molecule made up of amino acids that are needed for the body to function properly.
protein crystallization The production of a pure preparation of a protein. In this form, the three-dimensional structure of the molecule can be determined.
protein drug See: therapeutic agent.
protein engineering Generating proteins with modified structures that confer novel properties such as higher catalytic specificity or thermal stability.
Protein kinase An enzyme that adds phosphate groups to a protein molecule at serine, threonine, or tyrosine residues.
protein metabolic step One step in the chain of reactions that take place in an organism and dictate the composition of that organism.
protein sequencing The process of determining the amino acid sequence of a protein. Usually achieved following initially partial hydrolysis of the protein into smaller…
protein synthesis The creation of proteins from their constituent amino acid s, in accordance with the encoding gene DNA sequence.
proteinaceous infectious particle Believed to be the agent responsible for the class of diseases called spongiform encephalopathies, including scrapie in sheep, bovine spongiform…
Proteinaceous infectious particle (prion) A proposed pathogen composed only of protein with no detectable nucleic acid and which is responsible for Creutzfeldt-Jakob disease and kuru in humans and…
proteolysis Enzymatic degradation of a protein.
Proteolytic The ability to break down protein molecules.
Proteome The complete complement of proteins made by a given species in all its tissues and growth stages.
proteomics The study of the structure and function of proteins, including the way they work and interact with each other inside cells.
Proto-oncogene See oncogene.
protoclone Regenerated plant derived from protoplast culture or a single colony derived from protoplasts in culture.
protocol An action plan for a clinical trial. The plan states what the study will do, how, and why.
protocorm A tuberous structure, formed following the germination of orchid seeds, from which develops a complete plant.
protoderm A primary that gives rise to epidermis.
protogyny The condition in which the female reproductive organs (carpel s) of a flower mature before the male ones (stamen s), thereby ensuring that…
protomeristem See: pro-meristem.
protoplasm The essential, complex living substance of cells, upon which all vital functions of nutrition, secretion, growth and reproduction depend.
protoplast A bacterial or plant cell for which the cell wall has been removed either chemically or enzymatically, leaving its cytoplasm enveloped by a peripheral…
protoplast culture The culturing in vitro of plant protoplast s. Where protoplasts can be regenerated into whole plants, they represent an attractive target for genetic…
protoplast fusion The induced or spontaneous coalescence of two or more protoplast s of the same or different species origin.
prototroph A nutritionally independent cell. Opposite: auxotroph.
Protozoan Single-celled organism that can perform all necessary functions of metabolism and reproduction.
protruding end See: extension.
provenance The geographical and/or genetic origin of an individual.
Provirus See virus.
pseudo-affinity chromatography A chromatographic technique in which a ligand is immobilized selectively to retain enzymes or other protein s.
pseudo-autosomal region A section at one end of the X and Y chromosomes for which there is sufficient homology that there is synapsis between them during meiosis.
pseudocarp A fruit that incorporates, in addition to the ovary wall, other parts of the flower, such as the receptacle (e.g. strawberry). Synonym: false fruit.
pseudogene An incomplete or mutated copy of a gene which is not transcribed because it lacks a continuous open reading frame.
Pseudomonas spp. A widely distributed Gram-negative bacterial genus. Many of the soil forms produce a pigment that fluoresces under ultraviolet light, hence the…
psychrophile A micro-organism that can grow at temperatures below 30 °C and as low as 0 °C. See: mesophile, thermophile.
Public Health Service Act See Food and Drug Administration.
PUC A widely used expression plasmid containing a -galactosidase gene. (See Plasmid.)
pulsed-field gel electrophoresis (Abbreviation: PFGE). A procedure used to separate very large (50 kbp to several Mbp) DNA molecules by alteRNA ting the direction of electric current in a…
punctuated equilibrium The occurrence of speciation events in bursts, separated by long intervals of species stability.
pure line A strain in which all members are genetically nearly identical and are indistinguishable by phenotype.
purification tag See: affinity tag.
Purine A double-ring, nitrogen-containing base present in nucleic acids . Adenine (A) and guanine (G) are the two purines normally present in DNA and RNA…
PVA The Plant Variety Act. See U.S. Department of Agriculture.
PvP Player vs. Player. This means for one player to attack another player.
PVR Abbreviation for plant variety rights.
PWP Abbreviation for permanent wilting point.
pyrethrins Active constituents of pyrethrum (Tanacetum cinerariifolium) flowers, used as insecticides.
Pyrimidine A single-ring, nitrogen-containing base present in nucleic acid s. Cytosine (C) and thymine (T) are present in DNA, whereas uracil (U) replaces T in RNA.
pyrogen Bacterial substance that causes fever in mammals.
pyrophosphate A phosphate ion dimer; may be released on hydrolysis of ATP.