Dictionary

G In genetics, guanine, one member of the G-C base pair (guanine-cytosine) in DNA. See also DNA; guanine; RNA.

G protein A guanine nucleotide binding protein in cells that interacts with cell surface receptors and affects biochemical actions within cells.

G6PD Glucose-6-phosphate dehydrogenase, an enzyme that red blood cells rely heavily on because it protects the cells against oxidative stresses. See also deficiency, G6PD.

GAG Glycosaminoglycan.

gait A manner of walking. Observation of gait can provide early diagnostic clues for a number of disorders, including cerebral palsy, Parkinson’s disease, and Rett syndrome.

galactose A sugar found in milk. Galactose is a disaccharide that is made up of two sugars, galactose and glucose, that are bound together.

galactosemia An inherited disorder of galactose metabolism that occurs in newborns and can result in damage to the liver, brain, kidneys, and other organs in infants due to the accumulation of galactose derivatives in the body. Individuals with galactosemia cannot tolerate any amount of human or animal milk intake. The symptoms of galactosemia resolve if…

galactosylceramidosis See Krabbe disease.

gallbladder A pear-shaped organ located below the liver that stores the bile secreted by the liver. During and after a fatty meal, the gallbladder contracts, delivering the bile through the bile ducts into the intestines to help with digestion.

gallbladder absence See agenesis of the gallbladder.

gallium A rare metal with the atomic weight 69. There are several isotopic forms of gallium that differ from it in atomic weight. One is gallium-68, which is produced by cyclotrons and emits gamma rays. The citrate form of gallium-68 is used as a radiotracer to locate sites of inflammation and tumor tissue within the…

gallium scan A test to detect sites in the body where cells are multiplying rapidly, such as tumors or areas of inflammation. A small amount of radioactive gallium is injected into a vein, and the element is taken up by cells that are rapidly dividing. A scanner is used to detect the areas of gallium…