What is special about the membrane of the endoplasmic reticulum?

The endoplasmic reticulum has one continuous, unbroken phospholipid membrane that is made up of two layers. The membrane system forms a series of convoluted, flattened sacs called cisternae. It encloses a single continuous lumen. The membrane remains continuous with the membranes of the nuclear envelope, Golgi apparatus and plasma membrane.

The thickness of the ER membrane is about 50 to 60 Aº. It contains several important enzymes that are crucial for various cellular activities. Key enzymes found in the ER membrane include Mg++ activated ATPase, glucose-6-phosphatase, stearases, NADH diaphorase, and NADH-cytochrome C reductase.

The rough endoplasmic reticulum have ribosomes attached to the cytoplasmic surface of the membrane, which give them a rough appearance. The smooth endoplasmic reticulum has a smooth appearance because of the absence of ribosomes.