It's also a place where we form polysaccharides. We modify our proteins in many different ways. Now, the rough endoplasmic reticulum primarily functions to create our proteins that end up being placed either into the cell membrane or leave the cell entirely. And our smooth Er has several important functions. It basically acts to deepen detoxify drugs and toxin. It acts to create or synthesize lipids, such as fatty acids, phospholipids, and cholesterol, as well as create different types of steroids.