Microbiology terms - G
- G+C ratio
- In DNA (or RNA) from any organism, the percent of the total nucleic acid that consists of
guanine plus cytosine bases.
- gamete
- In eukaryotes, the haploid cell analogous to sperm and egg, which results from meiosis.
- gas chromatography
- A chromatographic technique in which the stationary phase is solid while the mobile phase is
gaseous samples. The gaseous samples are separated based on their different adsoprtion
ability to the solid phase.
- gas vacuole
- A subcellular organelle, found only in prokaryotes, which consists of clusters of hollow,
cylindrical, gas-filled vesicles (gas vesicles).
- gas vesicle
- The hollow, cylindrical, gas-filled structure in the gas vacuole. It confers ability for gas
vacuole to float.
- gel
- An inert polymer, usually made of agarose or polyacrylamide, used for separating
macromolecules such as nucleic acids or proteins by electrophoresis.
- gene
- A unit of heridity; a segment of DNA specifying a particular protein or polypeptide chain, a
tRNA or a rRNA.
- gene amplification
- see amplification.
- gene cloning
- The isolation of a desired gene from one organism and its incorporation into a suitable vector
for the production of large amounts of the gene.
- gene copy number
- see copy number.
- gene disruption
- Use of both in vitro and in vivo recombination to substitute an easily selected mutant gene
for a wild-type gene.
- gene library
- A collection of cloned DNA fragments that contains all the genetic information of a particular
organism.
- gene therapy
- Replacement or augmentation of a dysfunctional gene for medical purposes.
- genetic code
- The "code" in which information for the synthesis of proteins is contained in the nucleotide
seuqence of a DNA molecule (or in certain viruses, of an RNA molecule).
- generation time
- Time needed for a population to double. See also doubling time.
- genetic engineering
- The use of in vitro techniques in the isolation, manipulation, recombination, and expression
of DNA.
- genetic map
- The physical arrangement and order of genes on the chromosome.
- genetics
- The science of studying heredity and variation of organisms.
- genome
- The complete set of genes present in an organism.
- genotype
- The precise genetic constitution of an organism. Compare with phenotype.
- genus (plural genera)
- The first name of the scientific name (binomial); the taxon betwen family and species.
- germicide
- A substance that inhibits or kills microorganisms.
- glycocalyx
- General term for polysaccharide components outside the bacterial cell wall. See also capsule
and slime layer.
- glycolysis
- Reactions of the Embden-Meyerhof pathway in which glucose is oxidized to pyruvate.
- glycosidic bond
- A type of covalent bond that links sugar units together in a polysaccharide.
- Golgi complex
- An eukaryotic organelle involved in the secretion of certain proteins.
- gonococcus
- Neisseria gonorrhoeae, the gram-negative diplococcus that causes the disease gonorrhea.
- gonorrhea
- An acute infectious sexually transmitted disease of the mucous membranes of the
genitourinary tract, eye, rectum and throat. It is caused by Neisseria gonorrhoeae.
- gram-negative
- To describe a prokaryotic cell whose cell wall stains pink (negative) in Gram stain. The cell
wall of a gram-negative bacterium contains relatively little peptidoglycan but contains an outer
membrane composed of lipopolysaccharide (LPS), lipoprotein, and other complex
macromolecules.
- gram-positive
- To describe a prokaryotic cell whose cell wall stains purple (positive) in Gram stain. The cell
wall of a gram-positive bacterium consists chiefly of peptidoglycan and lacks the outer
membrane of gram-negative cells.
- Gram stain
- A differential stain that divides bacteria into two groups, gram-positive and gram-negative
based on the ability to retain crystal violet when decolorized with an organic solvent such as
ethanol.
- green (sulfur) bacteria
- Anoxygenic phototrophs containing chlorosomes and bacteriochlorophyll c, cs, d or e and
light harvesting chlorophyll.
- growth
- In microbiology, an increase in both cell number and cellular constituents.
- growth factor
- Organic compounds that must be supplied in the diet for growth because they are essential
cell components or precursors of such components and cannot be synthesized by the
organisms themselves.
- growth rate
- The rate at which growth occurs, usually expressed as the generation time.
Compiled by Tsute Chen, Converted by Ben Hoyt