Endoplasmic Reticulum


Common Function of Granular & Agranular Endoplasmic Reticulum:

1. The E.R. provide an ultrastructural skeletal framework to the cell and gives mechanical support to the colloidal cytoplasm matrix.

2. The exchange of the molecule by the process of osmosis, diffusion and active transport occurs thought the membrane of the E.R. like the plasma membrane, the E.R. membrane has permeases and carriers.

3. The E.R. contains an enzyme that performs various synthesis and metabolic activities.

4. The sarcoplasmic reticulum plays a role in releasing calcium when the muscle in stimulated and actively transporting calcium back into sarcoplasmic reticulum when muscle stimulation stops and muscle must be relaxed.

5. The E.R. acts as a transporting system.

Various product secretory of granular E.R. are transported to various organelles as follows GERL region, transport vesical or secretory granules.
Membrane flow may also be an important mechanism for carrying particles, molecules, and ions and out of the cells.

6. The E.R. form the new nuclear envelope after each nuclear division.


The function of smooth endoplasmic reticulum:
1.S.E.R. is found related to the glycogenosis or breakdown of glycogen.

2.Sterol metabolism: The S.E.R. contains serval key enzymes that catalyze the synthesis of cholesterol.

3.S.E.R. performs a synthesis of lipids (e.g., phospholipid, cholesterol etc,) and lipoproteins and degradation of lipid.

4.Detoxification: protectively, the E.R. chemically modifies xenobiotics in the body. So, degrade the liver by S.E.R. , Toxic materials such as drugs, insecticides, alcoholic products.


The function of rough endoplasmic reticulum:
1. The major function of R.E.R is the synthesis of protein.

2. The membrane-bound ribosomes attached with specific binding sites or receptors of R.E.R.

3.Protein glycosylation: The covalent addition of sugars of the secretory proteins (glycosylation) is one of the major biosynthetic function of R.E.R