Glucagon. A proteinaceous hormone antagonistic to insulin in action converting glycogen into glucose in the liver to raise blood-sugar level. Secreted by alpha cells of the islets of Langerhans in the pancreas.

Glucose. (Dextrose). A 6-carbon-atom sugar (a hexose) widely distributed in plants and animals, particularly in compounds as disaccharides, e.g. sucrose, and polysaccharides, e.g. starch, cellulose, glycogen. Splitting of glucose ultimately to CO₂ and water, involving intermediary combining with phosphate, is a major energy-source for metabolic processes. In green plants, glucose is product of photosynthesis, from CO₂ and water; it is stored as starch. In animals, glucose is obtained mainly from digestion of di-and polysaccharides and deamination of amino acids it is stored as glycogen. See Blood sugar.

Glume.
The Chaffy scale that encloses the spikelets of grass or the flowers of sedges.

Glycophorin. A glycopolypepide in human crythrocytes.

Glyosylation. The addition of a carbohydrate to an organic molecule such as a PROTEIN.

Gnathosiomata. The vertebrate that possesses jaws, all true fish, amphibian, reptiles, birds and mammals.

Goblet cell. A cell shaped something like a wineglass that is present in the columnar epithelium of the mammalian intestine and secretes Mucin.

Gonad. A reproductive organ (ovary, testis) in which gametes (ova or sperm) are produced.

Gonad Hormones.
Sex hormones produced by gonad. In vertebrates they are steroids.