Friday, January 30, 2009

Golgi Apparatus

The Golgi apparatus is an organelle mainly devoted to processing the proteins synthesized in the endoplasmic reticulum. It is found in most eukaryotic cells and was discovered in 1898 by the Italian physcian Camillo Golgi.

The Golgi apparatus, also called Golgi complex, consists of a series of five to eight cup-shaped, membrane-covered sacs called cisternae that look something like a stack of deflated balloons. In some unicellular flagellates, however, as many as 60 cisternae may combine to make up the Golgi apparatus.

The number of Golgi complexes in a cell varies according to its function. Animal cells generally contain between ten and twenty Golgi stacks per cell, which are linked into a single complex by tubular connections between cisternae. This complex is usually located close to the cell nucleus.

The Golgi apparatus functions as the processing and distribution department for the cell's chemical products. It modifies proteins and lipids that have been built in the endoplasmic reticulum and prepares them for export outside of the cell or for transport to other locations in the cell. Proteins and lipids built in the smooth and rough endoplasmic reticulum bud off in tiny bubble-like vesicles that move through the cytoplasm until they reach the Golgi complex.