Food Biotechnology terms starting with S

300 terms

spheroplast (AlteRNA tive spelling: sphaeroplast). A microbial or plant cell from which most of the cell wall has been removed, usually by enzymatic treatment.
spike 1. An inflorescence in which the main axis is elongated and the flowers are sessile. 2.
spikelet The unit of inflorescence in grasses, made up of a small group of florets.
spindle An intracellular fibrous structure, involved in the control of chromosome movement in mitosis and meiosis.
spliceosome A complex of small nuclear ribonucleoproteins and other proteins that assemble on an immature mRNA and catalyse the excision of an intron. See: splicing.
Splicing 1. During the maturation of eukaryotic mRNA, the process that removes intron sequences and covalently joins exon sequences. Synonym: editing. 2.
splicing junction The DNA sequence immediately surrounding the boundary between an exon and an intron.
split gene In eukaryotes, the encoding DNA of many structural genes is made up of exons and introns .
spontaneous mutation A mutation occurring in the absence of any known mutagen.
sporangium (pl.: sporangia) A reproductive structure in plants that produces spores. A megasporangium produces megaspores, which give rise to the female gametophyte…
Spore A term used to describe a particle in plants, bacteria and fungi.
spore mother cell Synonym of sporocyte.
sporocyte A diploid germ line cell that is the parent of the four haploid spores generated by meiosis.
sporophyll A leaf that bears sporangia.
sporophyte The diploid generation in the life cycle of a plant, and that produces haploid spores by meiosis.
sport An individual plant, or portion thereof, showing a recognizably different phenotype from the parent, presumably as a result of spontaneous mutation.
ssDNA Abbreviation for single-stranded DNA.
SSR Abbreviation for simple sequence repeat. See: microsatellite.
stacked genes Refers to the insertion of two or more genes into the genome of an organism. An example would be a plant carrying a giving insect resistance, and a bar…
stages of culture (I-IV) See: micropropagation.
staggered cuts Symmetrically cleaved phosphodiester bonds that lie on both strands of double-stranded DNA, but are not opposite one another.
stamen Floral structure made up of an anther and a filament. The stamen is the male organ of a flower.
Standard deviation Standard deviation is a statistical measurement of how far a variable quantity, such as the price of a stock, moves above or below its average value.
standard error The standard error of an estimate is a measure of the sampling variability of the estimate.
starch A substance found in plants. It contains sugar molecules joined chemically. It is found in high levels in foods such as potatoes, rice, corn, and wheat.
StarLinkTM An insect-resistant variety of corn that was approved for animal feed only, not labeled for human consumption.
start codon The codon which specifies the first amino acid of a polypeptide chain and at which the ribosome starts the process of translation.
starter culture Micro-organisms that are deliberately added to foods to alter flavour, colour, texture, smell, or taste.
stationary culture A culture maintained without agitation.
Stationary phase The plateau of the growth curve after log growth, during which cell number remains constant. New cells are produced at the same rate as older cells die.
steady state In a continuous fermentation process, the condition under which the number of cells removed with the outflow is exactly balanced by the number of newly…
stele The central vascular cylinder, inside the cortex, of roots and stems of higher plants.
stem The main body of the above-ground portion of a tree, shrub, herb or other plant; the ascending axis, whether above or below ground, of a plant.
Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
sterile (STER-il) Unable to produce children. Also means free from germs.
sterile room Dedicated space for the carrying out of activities that require sterile conditions.
sterility Complete or partial failure of an individual to produce functional gametes or viable zygotes under a given set of environmental conditions.
sterilize 1. The elimination of micro-organisms, using heat, irradiation, filtration or chemicals. 2.
Steward bottle Flask developed for the growth of cells and tissues in a liquid medium, in which they can be periodically submerged during rotation.
Sticky end A protruding, single-stranded nucleotide se- quence produced when a restriction endonuclease cleaves off center in its recognition sequence.
stigma Receptive portion of the style, to which pollen adheres.
stirred-tank fermenter A growth vessel in which cells or micro-organisms are mixed by mechanically-driven impellers.
stock A share of stock that represents ownership in the company that issues it. The price of the stock goes up and down, depending on how the company performs…
stock plant The source plant from which cuttings or explants are obtained. Stock plants should be well maintained to optimize explant and cutting quality.
stock solution Pre-prepared solution of commonly used reagents.
Stolon A lateral stem that grows horizontally along the ground surface. Used by some plant species as a mechanism for dispersal, since stolon nodes can…
stoma (STOH-muh) A surgically created opening from an area inside the body to the outside.
stomatal complex Includes the stoma, together with its guard cells and, when present, any related subsidiary cells.
stomatal index A measurement of the surface density of stoma ta. This parameter has been found useful in comparing leaves of different sizes.
Stop codon See Termination codon.
STR Strength
Strain A genetic variant within a species.
Stratification Layering of a lake, by temperature, during warmer seasons.
streptavidin A small bacterial protein that binds with high affinity to the vitamin biotin. This streptavidin-biotin combination can be used to link molecules such as…
Stress The response of the body to physical, mental, or emotional pressure. This may make a person feel frustrated, angry, or anxious, and may cause unhealthy…
stress protein (... PROH-teen) One of a group of proteins that help protect cells from stresses such as heat, cold, and low amounts of oxygen or glucose (sugar).
Stringency Reaction conditions--notably temperature, salt, and pH--that dictate the annealing of single-stranded DNA/DNA, DNA/RNA, and RNA/RNA hybrids.
Stringent plasmid A plasmid that only replicates along with the main bacterial chromosome and is present as a single copy, or at most several copies, per cell. (See plasmid.
Stroma (stro' mah) the supporting tissue or matrix of an organ; as distinguished from the functional part of the organ.
structural gene A gene that encodes a polypeptide, with either enzymatic or structural functions, and that is required for the normal metabolism and growth of a cell or…
Structure-functionalism The scientific tradition that stresses the relationship between a physical structure and its function, for example, the related disciplines of anatomy and…
STS See Sequence\-tagged site.
style Slender column of tissue that arises from the top of the ovary and terminates in the stigma, and through which the pollen tube must grow to achieve…
sub-clone A procedure in which a large cloned DNA molecule is divided into smaller fragments, each one of which is then separately cloned.
sub-culture Division and transfer of a portion of a culture to fresh medium. Sometimes used to denote the adding of fresh liquid to a suspension culture.
sub-culture interval The time between consecutive sub-cultures of cells.
sub-culture number The number of times cells, etc., have been sub-cultured..
sub-strain Derived from a strain by the isolation of an individual or group of individuals having properties or markers not shared by the strain as a whole.
sub-unit vaccine One or more immunogenic protein s, either purified from the pathogen itself or produced from a cloned pathogen gene.
Subcloning The process of tranferring a cloned DNA fragment from one vector to another. (See Cloning.)
subgenomic promoter A promoter added to a virus for a specific heterologous gene, resulting in the formation of mRNA for that gene alone.
subspecies Population(s) of organisms sharing certain characteristics that are not present in other populations of the same species.
Substrate 1. A compound that is altered by an enzyme. 2. Food source for growing cells or micro-organisms. 3. Material on which a sedentary organism lives and grows.
Subunit vaccine A vaccine composed of a purified antigenic determinant that is separated from the virulent organism. (See Vaccine, Enzyme.)
sucker A shoot that arises from an underground root or stem. Of particular significance to grafted plants, since the sucker will be genotypically rootstock…
suckering Type of vegetative propagation where lateral buds grow out to produce an individual that is a clone of the parent.
sucrose density gradient centrifugation A procedure used to fractionate nucleic acids on the basis of their size.
superbug Jargon for a particular engineered strain of Pseudomonas, in which various hydrocarbon-degrading genes, derived from different plasmids, were combined…
supercoil The conformation of a double-stranded DNA molecule placed under torsional stress as a result of interactions with protein s.
Supercoiled plasmid The predominant in vivo form of plasmid, in which the plasmid is coiled around histone-like proteins.
Supergene A group of neighboring genes on a chromosome that tend to be inherited together and sometimes are functionally related.
Supernatant The soluble liquid &action of a sample after centrifugation or precipitation of insoluble solids.
suppressor mutation A mutation that reverses the effect of an earlier mutation, e.g. a mutation in a gene for a tRNA that permits it to read and override an amber mutation.
suppressor-sensitive mutant An organism that can grow in the presence, but not in the absence of a second genetic factor (the suppressor).
susceptible Inability to withstand injury due to biotic or. Opposite: resistance, tolerance.
suspension culture A type of culture in which cells and/or clumps of cells grow and multiply while suspended in a liquid medium.
symbiont An organism living in symbiosis with another, dissimilar organism.
Symbiosis The close association of two or more dissimilar organisms where both receive an advantage from the association. See Commensalism, Parasitism.
sympatric speciation The evolution of new species by population s that inhabit the same or overlapping geographic regions.
sympodial A type of plant development in which the terminal bud of the stem stops growing due either to its abortion, or to its differentiation into a floral…
Synapsis The pairing of homologous chromosome pairs during prophase of the first meiotic division, when crossing over occurs.
synaptonemal complex (Abbreviation: SC). A ribbon-like protein aceous structure formed between paired homologous chromosome s at the end of the first meiotic prophase.
synchronous culture A culture in which the cell cycle is synchronized for the majority of the cells present.
syncytium A large cell-like structure formed by the joining together of two or more cells. The plural is syncytia.
syndrome (SIN-drome) A set of symptoms or conditions that occur together and suggest the presence of a certain disease or an increased chance of developing the…
synergid One of the two haploid nuclei at the micropylar end of the embryo sac of higher plants. The third nucleus is the egg.
synergism An interaction between two organisms (e.g. Rhizobium and legumes) in which the growth of one is helped by the other. Opposite: antagonism.
Syngamy Synonym of fertilization.
synkaryon The initial of the zygote, formed by the fusion of the gametic nuclei upon fertilization.
Synteny The occurrence of two or more loci on the same chromosome, without regard to their genetic linkage.