I'm sorry this is sooo inappropriate, but funny. Every thing with Howard's face is funny

Smooth Endoplasmic Reticulum is a network of tubules and extension of nuclear membranes. They lack ribosomes. One of their functions consits of packaging proteins for transport within the cell. 

Rough Endoplasmic Reticulum have ribosomes attached to their surface that synthesize proteins for the cell. Rough ER transports these proteins to the regions in the cell where it is needed.