Xplain why the carbohydrate groups of membrane glycoproteins are always found on the outer surface of the plasma membrane. explain why the carbohydrate groups of membrane glycoproteins are always found on the outer surface of the plasma membrane. outer monolayer originally faced the interior of the rough er and golgi, where the enzymes involved in glycosylation are located. outer monolayer originally faced the exterior of the rough er and golgi, where the enzymes involved in protein hydrolysis are located. outer monolayer originally faced the exterior of the rough er and golgi, where the enzymes involved in glycosylation are located. outer monolayer originally faced the interior of the rough er and golgi, where the enzymes involved in protein hydrolysis are located.