Food Biotechnology — page 25 of 34

3,375 terms

Food Biotechnology terms

  1. plasma membrane (PLAZ-muh MEM-brayn) The outer membrane of a cell.
  2. plasmalemma The lipid bilayer and associated proteins and other molecules that surrounding the protoplast, within the cell wall.
  3. Plasmid An circular self-replicating non-chromosomal DNA molecule found in many bacteria, capable of transfer between bacterial cells of the same species, and…
  4. Plasmid (p) A circular DNA molecule, capable of autonomous replication, which typically carries one or more genes encoding antibiotic resistance proteins.
  5. plasmodesma (pl.: plasmodesmata) Fine protoplasmic thread that connects adjacent plant cells by passing through the plant cell wall.
  6. plasmolysis Shrinkage of protoplasm caused by removal of water from a cell through osmosis when surrounded by a hypertonic solution.
  7. plastid A general term for a number of plant s which carry non-nuclear DNA. Includes the pigment -carrying bodies: 1. chloroplasts in leaves, 2.
  8. plastoquinone One of a group of compounds involved in the transport of electrons as part of the process of photosynthesis.
  9. plate 1. Verb: to distribute a thin film of micro-organisms or plant cells onto a solid medium. 2. Noun: refers to the two segments of a Petri dish or similar.
  10. platform shaker See: shaker.
  11. plating efficiency The percentage of inoculated cells which give rise to cell colonies when seeded into culture vessels.
  12. Pleiotrophy The effect of a particular gene on several different traits.
  13. pleiotropic (adj.) See: pleiotropy.
  14. Pleiotropy The simultaneous effect of a given gene on more than one apparently unrelated trait.
  15. ploidy (PLOY-dee) The number of sets of chromosomes in a cell or an organism. For example, haploid means one set and diploid means two sets.
  16. plumule The first bud of an embryo, or that portion of the young shoot above the cotyledon s.
  17. Pluripotent (ploo-RIH-poh-tent) Able to mature or develop in any of several ways.
  18. plus tree See: elite tree.
  19. PNA Abbreviation for peptide nucleic acid.
  20. pneumatic reactor See: airlift fermenter.
  21. Point mutation A change in a single base pair of a DNA sequence in a gene. (See Mutation.)
  22. polar bodies In female animals, the products of a meiotic division that do not develop into a functional ovum.
  23. polar mutation A mutation that influences the functioning of genes that are downstream from the site of mutagenesis but are in the same transcription unit.
  24. polar nuclei Two centrally located nuclei in the embryo sac that unite with a second sperm cell in a triple fusion.
  25. polar transport A directed movement within plants of compounds (usually endogenous plant growth regulators) mostly in one direction; polar transport overcomes the…
  26. Polarity The observed differentiation of an organism, tissue or cell into parts having opposed or contrasted properties or form.
  27. pole cells A group of cells in the posterior of Drosophila embryos that are precursors to the adult germ line.
  28. pollen Mature microspores of seed plants.
  29. pollen culture The in vitro culture and germination of pollen grains to generate haploid plants. See: anther culture;.
  30. pollen grain The mature microspore, produced in the pollen sac of angiosperms or the microsporangium of gymnosperms.
  31. pollination Transfer of pollen from anther to stigma in the process of fertilization in angiosperms; transfer of pollen from male to female cone in the process of…
  32. Poly(A) polymerase Catalyzes the addition of adenine residues to the 3' end of pre-mRNAs to form the poly(A) tail. (See Polymerase.)
  33. poly-(A) tail See: polyadenylation.
  34. polyacrylamide gel Inert electrophoresis matrix, formed by the polymerization of acrylamide monomer in the presence of the cross-linker N,N'-methylene-bis-acrylamide.
  35. 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.
  36. polyadenylation Post-transcription al addition of multiple adenine residues to the 3' end of eukaryotic mRNA. Also called poly-(A) tailing.
  37. polycistronic A single mRNA that contains the information necessary for the production of more than one polypeptide. Particularly characteristic of prokaryotic mRNA s.
  38. Polyclonal antibodies A mixture of immunoglobulin molecules secreted against a specific antigen, each recognizing a different epitope.
  39. polyclonal antibody A serum sample that contains a mixture of distinct immunoglobulin molecules, each recognizing a different antigenic determinant of a given antigen.
  40. polycloning site See: polylinker.
  41. 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).
  42. polyethylene glycol (Abbreviation: PEG). A polymer having the general formula HOCH2(CH2OCH2)nCH2OH and available in a range of molecular weights.
  43. 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…
  44. polygene One of a number of genes, each of small effect, which together act to determine the phenotype of a quantitative trait.
  45. Polygenic Controlled by or associated with more than one gene.
  46. polyhydroxybutyrate (Abbreviation: PHB). A biopolymer, with physical properties similar to polystyrene, originally discovered in the bacterium Alcaligenes eutropus.
  47. Polylinker A short DNA sequence containing several re- striction enzyme recognition sites that is contained in cloning vectors.
  48. polymer (PAH-lih-mer) A molecule made up of small identical molecules called monomers. The monomers are joined together in a repeating pattern.
  49. polymerase An enzyme that catalyses the formation of polymers from monomers . A DNA polymerase synthesizes DNA from deoxynucleoside triphosphates using a…
  50. Polymerase (DNA) Synthesizes a double-stranded DNA molecule using a primer and DNA as a template.
  51. polymerase chain reaction (puh-LIM-eh-rayz ...) A laboratory method used to make many copies of a specific DNA sequence. Also called PCR.
  52. polymerase chain reaction (PCR) A procedure that en- zymatically amplifies a DNA polymerase. (See Polymerase.)
  53. polymerization The chemical fusion of a number of identical or similar monomers to form a polymer.
  54. polymery The phenomenon whereby a number of genes at different loci (which may be polygenes ) can act together to produce a single effect.
  55. polymorphism (PAH-lee-MOR-fih-zum) A common variation or mutation in DNA.
  56. Polymorphisms Variant forms of a particular gene that occur simultaneously in a population.
  57. Polynucleotide A DNA polymer composed of multiple nucleotides. (See Nucleotide.)
  58. Polypeptide A linear polymer composed of covalently linked amino acids. Each link is formed by a single peptide bond.
  59. Polypeptide (protein) A polymer composed of multiple amino acid units linked by peptide bonds.
  60. Polyploid A multiple of the haploid chromosome number that results from chromosome replication without nuclear division.
  61. polysaccharide (PAH-lee-SA-kuh-ride) A large carbohydrate molecule. It contains many small sugar molecules that are joined chemically. Also called glycan.
  62. polysaccharide capsule See: capsule.
  63. polysome A multi-ribosomal structure representing a linear array of ribosomes held together by mRNA.
  64. polyspermy The entry of several sperm nuclei into the egg during fertilization, although only one actually fuses with the egg nucleus.
  65. polytene chromosome Giant chromosomes produced by interphase replication without division, and consisting of many identical chromatid s arranged side by side.
  66. 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-.
  67. Polyvalent vaccine A recombinant organism into which has been cloned antigenic determinants from a number of different disease-causing organisms. (See Vaccine.)
  68. polyvinylpyrrolidone (Abbreviation: PVP). An occasional constituent of plant tissue culture isolation media.
  69. Population the totality of items or units of material under consideration.
  70. Population density Number of cells or individuals per unit. The unit could be an area, or a volume of medium.
  71. Population genetics The branch of genetics that deals with frequencies of alleles and genotypes in breeding populations.
  72. porcine endogenous retrovirus (Abbreviation: PERV). The provirus of a porcine retrovirus. The possibility that PERVs could be activated after xenotransplantation of pig organs into…
  73. position effect The influence of the location of a gene (particularly a transgene ) on its expression and hence its effect on phenotype.
  74. 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…
  75. 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…
  76. positive control system A mechanism in which a regulatory protein (s) is required to turn on gene expression.
  77. positive selectable marker See: dominant selectable marker.
  78. 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…
  79. post-replication repair A recombination-dependent mechanism for repairing damaged DNA.
  80. post-translational modification The addition of specific chemical residues to a protein after it has been translated.
  81. potentiometric See: enzyme electrode.
  82. PPA See U.S. Department of Agriculture.
  83. PPF Abbreviation for photosynthetic photon flux.
  84. PPM Abbreviation for parts per million.
  85. PR protein Abbreviation for pathogenesis related protein.
  86. 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.
  87. pre-mRNA See: primary transcript.
  88. pre-transplant A stage in micropropagation - the rooting and hardening process prior to transfer to soil.
  89. 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…
  90. precocious germination Early germination of a seed or embryo, prior to the full maturation of the embryo.
  91. 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.
  92. preventive immunization Infection with an antigen to elicit an antibody response that will protect the organism against future infections. Synonym: vaccination.
  93. Pribnow box Consensus sequence near the mRNA start-point of prokaryotic genes. See: TATA box.
  94. primary First in order of time or development.
  95. primary antibody In an ELISA or other immunological assay, the antibody that binds to the target molecule.
  96. Primary cell A cell or cell line taken directly from a living organism, which is not immortalized.
  97. primary cell wall The cell wall layer formed during cell expansion. Plant cells possessing only primary walls may divide or undergo differentiation.
  98. 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…
  99. Primary germ layers See: germ layer.
  100. primary growth 1. Apical meristem -derived growth; the tissues of a young plant. 2. Explant growth during the initial culture period.

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