Final answer:
The statement that only the extracellular domains of membrane glycoproteins are glycosylated is true, as glycosylation occurs on the outer surface of the plasma membrane and contributes to the formation of the glycocalyx involved in cell recognition and signaling.
Step-by-step explanation:
Regarding the question, only the extracellular domains of membrane glycoproteins are glycosylated, the statement is true. Glycoproteins are proteins that have carbohydrates, or oligosaccharides, attached to them. The domains where this glycosylation occurs are present on the extracellular side of the cell's plasma membrane. These carbohydrate molecules do not extend into the cytosol but are involved in cell recognition, signaling, and forming the glycocalyx, which is a protective and interactive layer around the cell. In terms of glycosylation location, it's important to note that the carbohydrates associated with membrane glycoproteins are indeed found only on the outer surface, in contact with the extracellular space. Internal protein domains, those facing the cytoplasm, are not glycosylated.