Phagocytose
In phagocytosis (literally, "cell eating"), large particles are enveloped by the cell membrane of a (usually larger) cell and
internalized to form a food vacuole.
In animals, phagocytosis is performed by specialized phagocytotic cells or phagocytes, which serve to remove foreign bodies and thus fight infection. In vertebrates these include larger macrophages and smaller granulocytes, types of blood cells. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytosed. Virulent bacteria may need to be coated in antibodies before it is possible
to consume them.
In many protists, phagocytosis is used as a means of feeding, providing part or all of their nourishment. This is called phagotrophic nutrition, as distinguished from osmotrophic nutrition which takes place by absorption. In some, such as amoebae, phagocytosis takes place by surrounding the target object with pseudopods, as in animal phagocytes. In other protozoa, for instance ciliates, there is a specialized groove or chamber in the cell where phagocytosis takes place. The resulting food vacuole may be merged with lysosomes containing digestive enzymes, and the resulting material is absorbed into the cytosol.
See also
