Final answer:
New sugars are added during glycosylation as proteins move from the cis to the trans face of the Golgi apparatus, with terminal glycosylation completing the synthesis of glycoproteins.
Step-by-step explanation:
New sugars are added during glycosylation in the Golgi apparatus. This process starts in the rough endoplasmic reticulum (RER) with the creation of a core glycoside. Once in the Golgi apparatus, terminal glycosylation occurs, where enzymes attach additional sugars to the core glycoside, completing the glycoprotein synthesis. The cis face of the Golgi receives proteins from ER transport vesicles, and as these proteins progress through the Golgi towards the trans face, they are modified, often by the addition of sugar chains. In plant cells, the Golgi also plays a role in synthesizing polysaccharides for the cell wall and other cell parts.