Bulk movement

From Wikipedia, the free encyclopedia

Bulk movement is the movement of cell materials in and out of the cell. They are classified under active transport and they use the action of the energy currency ATP or adenosine triphosphate. There are two types of bulk movement, exocytosis and endocytosis.

Exocytosis is the expulsion of materials by cells. Here, waste products are first taken by the Golgi apparatus and then placed in a sac called the Golgi vesicle which is produced by the cell membrane. Then, the vesicle is released from the cell membrane and waste products are expelled.

Endocytosis is the reverse of exocytosis. Here, the desirable macromolecules are taken in by the cell through a sac. There are two types of endocytosis, pinocytosis and phagocytosis. Pinocytosis can be compared to "cellular drinking." One example is the pinocytosis of an amoeba. In phagocytosis, solids are taken in as food. One example is the act of a leukocyte taking in a bacterium.