Final answer:
The carbohydrate chains of glycoproteins, proteoglycans, and glycolipids are found on the extracellular side of the plasma membrane, playing key roles in cell recognition and interaction with the environment.
Step-by-step explanation:
The carbohydrate chains of glycoproteins, proteoglycans, and glycolipids are located on the extracellular side of the plasma membrane. These carbohydrates, whether bound to proteins (forming glycoproteins) or to lipids (forming glycolipids), are always found on the exterior surface of cells and play a crucial role in cell recognition, signaling, and the formation of the glycocalyx. This glycocalyx acts as a 'sugar coating,' which is highly hydrophilic and aids in the interaction of the cell with its watery environment, as well as in the cell's ability to obtain substances dissolved in the water.