THE GOLGI COMPLEX
The overall purpose of this Learning Object is to learn the chemical makeup and the functions associated with the Golgi complex in eukaryotic cells.
LEARNING OBJECTIVES FOR THIS SECTION
The Golgi Complex (def) (see Fig. 31, Fig. 30, and Fig. 33)
The Golgi complex or Golgi apparatus consists of 3-20 flattened and stacked saclike structures called cisternae. A complex network of tubules and vesicles is located at the edges of the cisternae. The Golgi complex functions to:
1) sort proteins and lipids received from the ER;
2) modify certain proteins and glycoproteins; and
3) sort and package these molecules into vesicles for transport to other parts of the cell or secretion from the cell.
As mentioned above, proteins that have been produced in the rough ER are placed into transition vesicles by the smooth ER. The proteins and glycoproteins within the transition vesicle are then transported to the Golgi complex as the transition vesicles fuse with the Golgi complex membrane. Here the proteins and glycoproteins may be further modified and sorted. Finally the Golgi complex will package these molecules in membrane-bound vesicles for secretion from the cell or transport to lysosomes. The vesicles involved in secretion are called secretion vesicles. These form around the molecules to be secreted as they pinch off of the Golgi complex. The secretion vesicles then fuse with the cytoplasmic membrane to release the proteins and glycoproteins from the cell (see Fig. 33).
Copyright © Gary E. Kaiser
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Updated: March 12, 2007