The rough ER is an internal membrane system found in cells with a nucleus. It is sort of a transport system, with proteins that are synthesized on the rough ER, processed, packaged and sent to the Golgi Apparatus for further sorting within the cell or export out of the cell. Other soluble proteins are synthesized directly within the cytoplasm however. This system of membranes provides a large surface area where chemical activities take place. The rough ER appears rough because it has ribosomes attached to its surface.
Ribosomes are non-membranous organelles that are associated with the synthesis of proteins.