SSC MTS EXAM

Detailed explanation-1: -Proteins are assembled at organelles called ribosomes. When proteins are destined to be part of the cell membrane or exported from the cell, the ribosomes assembling them attach to the endoplasmic reticulum, giving it a rough appearance.

Detailed explanation-2: -The rough endoplasmic reticulum is made up of membranes which have ribosomes attached to it. This gives it the rough appearance. This is contrary to the smooth endoplasmic reticulum which does not have these membrane bound ribosomes.