What are long, linear, unbranched polysaccharides that are attached to proteins called?

The correct answer refers to proteoglycans, which are molecules composed of a core protein and long, linear, unbranched polysaccharide chains known as glycosaminoglycans (GAGs). These polysaccharides are integral to the structure and function of proteoglycans, contributing to the gel-like consistency of the extracellular matrix and playing vital roles in cellular signaling, hydration, and structural integrity within tissues.

In contrast, glycoproteins, while they also contain carbohydrates, typically consist of shorter, branched polysaccharides that are attached to proteins, differing significantly from the long, unbranched nature of GAGs in proteoglycans. Phospholipids and cholesterol are lipid-based molecules that do not fit the description of polysaccharides attached to proteins and are primarily involved in membrane structure and function.