Therefore, the membranes of the ER divide the cytoplasm up into interconnected compartments in which different types of reactions take place.
The ER plays an important role in the synthesis of proteins and some lipids. Expanded regions of the ER may serve as storage areas. The ER also functions as a system for transporting materials from one part of the cell to another.
The smooth ER is more tubular and its outer membrane surfaces have a smooth appearance. It is the primary site of phospholipids, steroid, and fatty acid metabolism
The smooth ER also contains enzymes that detoxify harmful chemicals, breaking them down into water-soluble substances that can be excreted.
The Rough ER has a more granular appearance under EM due to the presence of Ribosomes
Ribosomes of course serve as the sites of protein synthesis and can be found assoc. with the ER or free in the cytoplasm. RER is especially abundant in cells that synthesize proteins destined for exocytosis.
Factory for packaging proteins
Consists of stacks of flattened membranous sacs that may be distended in certain regions because they are filled with cell products.
Proteins that pass through the golgi are:
• secreted from the cell
• plasma membrane proteins
• and proteins routed to other intracellular