Glycosylation is a biochemical process where sugar molecules, known as glycans, are attached to proteins or lipids. This modification occurs in cells and plays a crucial role in various biological functions, including cell signaling, immune response, and protein stability. Glycosylation can affect how proteins fold and function, influencing their interactions with other molecules. There are two main types of glycosylation: N-linked and O-linked. In N-linked glycosylation, glycans are attached to the nitrogen atom of asparagine residues in proteins, while in O-linked glycosylation, they are attached to the oxygen atom of serine or threonine residues. These modifications are essential for the proper functioning of many glycoproteins and glycolipids.