Endoplasmic Reticulum:

Rough E.R:
Appears like a stack of membranes close together. Has ribosomes on its surface. Newly made proteins leave the ribosomes and go into the Rough E.R, to be chemically modified.

Endoplasmic Reticulum:
The site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell. There is the rough E.R and smooth E.R.

Smooth E.R:
Smooth surface. Makes membrane lipids and detoxify chemicals including drugs and pesticides.