The endoplasmic reticulum manufactures membranes and performs many other biosynthetic functions. The endoplasmic reticulum (ER) accounts for half the membranes in a eukaryotic cell. The ER includes membranous tubules and internal, fluid-filled spaces called cisternae. The ER membrane is continuous with the nuclear envelope, and the cisternal space of the ER is continuous with the space between the two membranes of the nuclear envelope. There are two connected regions of ER that differ in structure and function. Smooth ER looks smooth because it lacks ribosomes. Rough ER looks rough because ribosomes (bound ribosomes) are attached to the outside, including the outside of the nuclear envelope. The smooth ER is rich in enzymes and plays a role in a variety of metabolic processes. Enzymes of smooth ER synthesize lipids, including oils, phospholipids, and steroids. These include the sex hormones of vertebrates and adrenal steroids.
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.