Biotechnology and Genetics terms starting with S

345 terms

S phase The phase in the cell cycle during which DNA synthesis occurs.
S&E See U.S. Department of Agriculture.
S1 mapping A method to characterise post-transcriptional modifications in RNA (removal of introns etc.
S1 nuclease An enzyme obtained from the filamentous fungus Aspergillus oryzae which specifically degrades RNA or single-stranded DNA into its constituent…
saccharifaction Following liquefaction, the hydrolysis of polysaccharides by glucoamylase to maltose and glucose.
saline resistance Synonym for salt tolerance.
Salivary gland (SA-lih-VAYR-ee gland) A gland in the mouth that produces saliva.
Salmonella A genus of rod-shaped, gram-negative bacteria that are a common cause of food poisoning.
salt tolerance The ability of a plant in soil or in culture to withstand a concentration of common salt (sodium chloride) which is damaging or lethal to most other…
Sanger sequencing A widely used method of determining the order of bases in DNA. See also: sequencing, shotgun sequencing
SAP Fluid content of the xylem and phloem cells of plants. Fluid content of the vacuole generally referred to as cell sap.
saprophyte An organism (generally a fungus) that depends on dead plant or animal tissue for its source of nutrition and metabolic energy.
satellite A chromosomal segment that branches off from the rest of the chromosome but is still connected by a thin filament or stalk.
satellite DNA Highly repetitive DNA in plant and animal genomes, consisting of millions of copies of sequences typically in the range 5-500 bp long.
satellite RNA A small, self-splicing RNA molecule that accompanies several plant viruses, including tobacco ringspot virus. Synonym: viroid.
Satellite RNA (viroids) A small, self-splicing RNA molecule that accompanies several plant viruses, including tobacco ringspot virus.
SC Abbreviation for synaptonemal complex.
SCA Abbreviation for specific combining ability.
Scaffold The central protein aceous core structure of condensed eukaryotic chromosomes. The scaffold is composed of non-histone chromosomal protein s.
Scale Up Conversion of a process, such as fermentation of a micro-organism, from a small laboratory scale to a larger industrial scale.
scanning electron microscope (Abbreviation: SEM). An electron-beam-based microscope used to examine, in a three dimensional screen image, the surface structure of prepared specimens.
SCAR Abbreviation for sequence characterized amplified region.
scarification The chemical or physical treatment given to certain seed s having hard, impermeable seed coats in order to puncture or weaken the seed coat sufficiently…
SCE Abbreviation for sister chromatid exchange.
Schwann cell A type of glial cell of the peripheral nervous system that helps separate and insulate nerve cells.
scion A twig or bud used for grafting onto another plant or rootstock.
scion-stock interaction The effect of a rootstock on a scion (and vice versa) in which a particular scion grafted onto a specific s performs differently than it would either on…
sclerenchyma A strengthening tissue in plants, composed of cells with heavily lignified cell walls.
SCP Standing Committee on the Law of Patents
Scrapie A spongiform encephalopathy disease of sheep. See: proteinaceous infectious particle.
screen A screen is a set of criteria against which you measure stocks or other investments to find those that meet your criteria.
SDS Abbreviation for sodium dodecyl sulphate.
SDS-PAGE Abbreviation for sodium dodecyl sulphate polyacrylamide gel electrophoresis.
secondary antibody In an ELISA or other immunological assay system, the antibody designed to bind to the primary antibody, and to which a label is generally attached.
secondary cell wall The innermost layer of cell wall, giving rigidity to the cells. Characterized by its highly organized microfibrillar structure, and only formed in certain…
secondary growth Type of growth characterized by an increase in the thickness of stem and root, and resulting from the formation of secondary s by the vascular cambium.
secondary immune response The rapid immune response that occurs during the second (and subsequent) encounters of the immune system of a mammal with a specific antigen.
secondary messenger A chemical compound within a cell that is responsible for initiating the response to a signal from a chemical messenger (such as a hormone) that cannot…
secondary metabolism The production by living organisms of substances not essential for primary metabolic functions or physiology.
secondary metabolite Product of secondary metabolism.
secondary oocyte See: oocyte.
secondary phloem Phloem tissue formed by the vascular cambium during secondary growth in a vascular plant.
secondary plant product See: secondary metabolite.
secondary root A branch or lateral root.
secondary spermatocyte See: spermatocyte.
secondary structure Localized three dimensional conformations adopted by macromolecules, in particular nucleic acids and polypeptides.
secondary thickening Deposition of secondary cell wall materials which result in an increase in thickness in stems and roots.
secondary vascular tissue Vascular tissue (xylem and phloem ) formed by the vascular cambium during secondary growth in a vascular plant.
secondary xylem See: secondary vascular tissue.
secretion The transport of a molecule from the inside of a cell through the cell membrane.
SEED Botanically, the matured ovule without accessory parts. Colloquially, anything which may be sown; i.e.
seed storage proteins Proteins accumulated in large amounts in protein bodies within seed s. They act as a source of amino acids during germination.
segment-polarity gene A gene that functions to define the anterior and posterior components of body segments in Drosophila.
segregant An individual derived from a cross between two unlike parents.
segregation For genes, the separation of allele pairs from one another and their resulting assortment into different cells at meiosis.
selectable Having a gene product that, when present, enables the identification and preferential propagation of a particular genotype. See: reporter gene.
Selectable marker A gene whose expression allows one to identify cells that have been transforrned or transfected with a vector containing the marker gene.
selection 1. Differential survival and reproduction of phenotypes . 2. A system for either isolating or identifying specific genotypes in a mixed population.
selection coefficient A measure of the intensity of selection at a locus, commonly abbreviated as s. It represents the proportionate reduction in the gametic contribution of a…
selection culture A selection based on difference(s) in environmental conditions or in culture medium composition, such that preferred variant cells or cell lines…
selection differential The difference between the mean of the individuals selected to be parents and the mean of the overall population; it represents the average superiority of…
selection pressure The intensity of selection acting on a population of organisms or on cells in culture.
selection response The difference between the mean of the individuals selected to be parents and the mean of their offspring.
Selective breeding Making deliberate crosses or matings of organisms so the offspring will have a desired characteristic derived from one of the parents.
self-incompatibility In plants, the inability of the pollen to fertilize ovules (female gametes) of the same plant.
Self-pollination Pollen of one plant is transferred to the female part of the same plant or another plant with the same genetic makeup.
self-replicating elements Extrachromosomal DNA elements that have origins of replication for the initiation of their own DNA synthesis.
self-sterility Synonym of self-incompatibility.
SEM Abbreviation for scanning electron microscope.
semen sexing Synonym of sperm sexing.
semi-conservative replication During DNA duplication, each strand of a parent DNA molecule acts as a template for the synthesis of a new complementary strand.
semi-continuous culture Cells in an actively dividing state which are maintained in culture by periodically draining off the medium and replenishing it with fresh medium.
semi-permeable membrane A natural or synthetic material which selectively allows the passage of certain ions or molecules.
semi-sterility The condition of partial fertility. Often associated with chromosomal aberrations or the result of mutagenesis.
Semiconservative replication During DNA duplication, each strand of a parent DNA molecule is a template for the synthesis of its new complementary strand.
senescence A late stage in the development of multicellular organisms, during which irreversible loss of function and degradation of biological components occur.
sense RNA The RNA transcript of the coding strand DNA (often represented as the (+)-strand). Opposite: antisense RNA.
Sensitivity When referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have…
sepsis (SEP-sis) The presence of bacteria or their toxins in the blood or tissues.
septate (SEP-tate) An organ or structure that is divided into compartments.
septum A dividing wall or partition, which splits a structure into separate cells or compartments.
sequence The linear order of nucleotides along a DNA or RNA molecule, and the process of obtaining this.
Sequence assembly A process whereby the order of multiple sequenced DNA fragments is determined.
sequence characterized amplified region (Abbreviation: SCAR). A molecular marker obtained by the conversion to a sequence-tagged site of a single random amplified polymorphic DNA product.
sequence divergence The percent difference in the nucleotide sequence between related nucleic acid sequences, or in the amino acid sequence in a comparison between related…
Sequence hypothesis Francis Crick's seminal concept that genetic information exists as a linear DNA code; DNA and protein sequence are colinear.
Sequence tagged site (STS) A unique (single-copy) DNA sequence used as a mapping landmark on a chromosome.
sequence tandem repeat (Abbreviation: STR). See: tandem repeat.
sequence-tagged site (Abbreviation: STS). Short unique DNA sequence (200-500 bp long) that can be amplified by PCR and is thus tagged to the site on the chromosome from which…
Sequencing Determination of the order of nucleotides (base sequences) in a DNA or RNA molecule or the order of amino acids in a protein.
Sequencing technology The instrumentation and procedures used to determine the order of nucleotides in DNA.
serial division Splitting of excised shoot-tip material growing in vitro, in order to induce the development of greater numbers of plantlets.
serial float culture A technique whereby immature anthers are floated on a liquid medium, and continue their development through to the release of pollen.
Serology The branch of science dealing with the measurement and characterization of antibodies and other immunological substances in body fluids, particularly…
serum The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.
serum albumin The main protein in blood plasma. Low levels of serum albumin occur in people with malnutrition, inflammation, and serious liver and kidney disease.
severe combined immunodeficiency (SCID) A disease affecting the immune system. SCID is fatal if affected individuals do not receive bone marrow transplants. See also antibody
sewage treatment A widespread biotechnological processes in developed economies. Methods vary widely, but all are designed for the biological break-down of human and…
sex chromosome Differentiated chromosome which is responsible for the determination of sex of the individual.
sex determination Any method by which the distinction between males and females is established in a species, particularly at an early stage of foetal development.