endoplasmic reticulum (ER)

endoplasmic reticulum (ER) /-plaz″mik/ [Gk, endon + plassein, to mold] , an extensive network of membrane-enclosed tubules in the cytoplasm of cells. The structure functions in the synthesis of proteins and lipids and in the transport of these metabolites within the cell. It is the site where some proteins get glycosylated.