Final answer:
There are two kinds of protein glycosylation: N-glycosylation and O-glycosylation. N-glycosylation attaches sugars to asparagine residues, while O-glycosylation attaches sugars to serine or threonine residues.
Step-by-step explanation:
In biology, there are two kinds of protein glycosylation: N-glycosylation and O-glycosylation. N-glycosylation involves the attachment of sugars to the amide nitrogen of asparagine residues, while O-glycosylation involves the attachment of sugars to the hydroxyl group of serine or threonine residues. Both types of glycosylation play important roles in protein function and cell-cell recognition.