Golgi apparatus An assembly of vesicles and folded membranes within the cytoplasm of eukaryotic cells that modifies proteins and packages them and other materials (e.g. polysaccharides) for delivery to the plasma membrane for secretion or to destinations within the cell. Proteins arrive in vesicles following their assembly in the endoplasmic reticulum; after processing in the Golgi apparatus, they are sorted into Golgi vesicles, for secretion, storage, or transport to lysosomes. Plant cells usually contain smaller arrays of Golgi-type vesicles, called dictyosomes. The apparatus is named after its discoverer, Camillo Golgi.

dictyosome A cup-shaped array of flattened membranous vesicles found in plant cells. Dictyosomes modify proteins from the endoplasmic reticulum, and may also polymerize sugars to polysaccharides. They then package these materials for delivery to destinations within the cell (e.g. the cell wall), for secretion, or for storage. In animal cells, and rarely in plant cells, numerous dictyosomes associate to form the Golgi apparatus.

Gol·gi ap·pa·rat·us (also Golgi body) • n. Biol. a complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport.

dictyosome A stack of flat, membranous cisternae which, with the vesicles, make up the Golgi apparatus.

Golgi apparatus (gol-ji) n. a collection of vesicles and folded membranes in a cell. It stores and later transports the proteins manufactured in the endoplasmic reticulum. [ C. Golgi (1844–1926), Italian histologist]