Phagocytosis

Phagocytosis is the engulfing of some foreign particle by a biological cell to form a food vacuole. It is found only among eukaryotes. Macrophages, a type of blood cell, consume pathogens by phagocytosis. Many protists obtain part or all of their nourishment by phagocytosis of smaller organisms, called phagotrophic nutrition to distinguish it from nourishment by absorption, which is called osmotrophic nutrition.

In many cells, phagocytosis takes place by surrounding the target object with pseudopods. In others, food particles are swept into a particular cavity within the cell, called a cytostome or mouth. In both cases, it ends up in an intracellular chamber, called a vacuole, which may be merged with lysosomes containing degistive enzymes. Once the object has been broken down, the resulting matter is absorbed into the cytosol.

See also the article on endocytosis for an overview of related cellular processes.