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It is a specific type of endoplasmic reticulum, which surrounds the nucleus.

SER is found in both animal cells and plant cells.

Unlike RER, it is tubular in form. Because it lacks ribosomes, it is known

as smooth ER. Large quantities of certain compounds

such as Phenobarbital cause an increase in the amount of SER.

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The smooth ER is the site of synthesis of lipids, including phospholipids, which are major components of the plasma and internal membranes.

SER contains enzymes that function in the synthesis of steroid hormones.

The membranes of SER contain enzymes that catalyze a series of reactions to detoxify both lipid-soluble drugs and harmful products of metabolism, especially in the liver cells.

It functions in the regulation of calcium concentration, which is important for muscle contraction.

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The SER represents only a small portion of ER in most cells, but it is a prominent constituent in the cells of the adrenal cortex, and the cells of the liver.

It serves as a transport of proteins synthesized in the RER to the Golgi apparatus.

It also contains the enzyme glucose-6-phosphatase which is converted to glucose (This is a step in gluconeogenesis).

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IN A PLANT CELL IN AN ANIMAL CELL

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