Cell Sturcture Review.......

Endoplasmic Reticulum ( ER)

This cellular organelle was first described using phase microscopy by Porter, Claude and Fallam in 1945. It is an extensive network of interconnecting channels. The endoplasmic reticular membranes are unit membranes (triminar). When ribosomes line the outer surface it is designated as rough endoplasmic reticulum ( RER). The primary form of this organelle is the rough variety. The smooth is derived from the rough due to loss of ribosomes. The amount of each depends on the cell type and the cellular activity.

The RER is the synthetic machinery of the cell. It is mainly concerned with protein synthesis.

The Golgi Complex

This structure was discovered by Camillo Golgi in 1898. All eukaryotic cells, except for the red blood cell, possess a Golgi apparatus. Generally speaking the Golgi complex is prominent in glandular cells and is thought to function in the production, concentration packaging, and transportation of secretory material. IN summary one can link the Golgi complex to: secretion, membrane biogenesis, lysosome formation, membrane recycling, hormone modulation.

Lysosome

Lysosomes are described as containing proteolytic enzymes (hydrolases).Lysosomes contain acid phosphatase and other hydrolytic enzymes.. These enzymes are enclosed by a membrane and are released when needed into the cell or into phagocytic vesicles.

Lysosomal enzymes have the capacity to hydrolyze all classes of macromolecules.

A generalized list of substrates acted upon by respective enzymes is given below:

Lipids by lipases and phospholipases;

Proteins by proteases or peptidases;
Polysaccharides by glycosidases;

Nucleic acids by nucleases;

Phosphates ( organic-linked) by phosphatases;

Sulphates (organic-linked) by sulfatases.