Here's a breakdown:

* Glycoproteins: These molecules have carbohydrate chains (glycans) attached to their protein backbone. The glycans are typically short and branched. They play a role in cell recognition, cell signaling, and immune responses.

* Proteoglycans: These molecules have a protein core with long, unbranched carbohydrate chains called glycosaminoglycans (GAGs) attached. GAGs are negatively charged, attracting water and giving proteoglycans a gel-like consistency. They are important for structural support in tissues, lubrication, and filtration.

So, while both glycoproteins and proteoglycans are composed of proteins, their carbohydrate components differ in structure and function.