Smooth ER Definiton: Type of organelle in the cells of eukaryotic organisms that forms flattened, membrane-enclosed sacs or tubes known as cisternae. The membranes are continuous with the outer membrane of the nuclear envelope.

Structure of the SER

What's your functions? The endoplasmic reticulum is composed of a network of smooth tubules and sac- like structures. Smooth endoplasmic reticulum does not have ribosomes attached to its surface. Extensive system of interconnected tubules and cisternae (flattened sac-like structures). Can be found in almost all eukaryotic cells, excepting red blood cells of mammals.

Functions of the Parts Carbohydrate and Lipid Synthesis produces cholesterol and membrane phospholipids, which are used for membrane formation. metabolism Transportation of Proteins It regulates the transportation of proteins by acting as a transitional area for vesicles that transfer proteins to various locations. transports the products of RER to Golgi apparatus and other parts of the cell. Detoxification Drug detoxification, as well as detoxification of wastes generated in metabolic processes takes place in SER present in the liver cells. contains enzymes that catalyze a number of reactions that can make lipid-soluble drugs and metabolic wastes water- soluble, so that they can be easily expelled from the body. Other Important Functions provides surface area for the action and storage of enzymes and their products attaches receptors to cell membrane proteins stores calcium in the muscle cells

Structure of the SER

Alzheimer's disease caused by Smooth ER ? Previous evidence suggests that the increase in platelet membrane fluidity associated with a subgroup of patients with Alzheimer's disease rA statistically significant change in enzyme activity was observed only for antimycin A-insensitive NADH-cytochrome reductase, a selective marker for smooth endoplasmic reticulum (SER) in platelets. Reduction was limited to the subgroup of demented patients who had increased platelet membrane fluidity, and therefore is not a nonspecific concomitant of neurodegeneration, medication exposure, or chronic illness in general. Since the platelet membrane alteration associated with Alzheimer's disease results from the inheritance of a single major locus, these results suggest that a defect in SER function may exist in brain cells as well as peripheral cells that express this genotypeesults from the accumulation of internal membrane.

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