Phagocytosis - in Protists

In Protists

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 amoeba, phagocytosis takes place by surrounding the target object with pseudopods, as in animal phagocytes. In humans, Entamoeba histolytica can phagocytose red blood cells. This process is known as "erythrophagocystosis", and is considered the only reliable way to distinguish Entamoeba histolytica from noninvasive species such as Entamoeba dispar.

• Ciliates also engage in phagocytosis. In ciliates there is a specialized groove or chamber in the cell where phagocytosis takes place, called the cytostome or mouth.

The resulting phagosome may be merged with lysosomes containing digestive enzymes, forming a phagolysosome. The food particles will then be digested, and the released nutrients are diffused or transported into the cytosol for use in other metabolic processes.

Mixotrophy can involve phagotrophic nutrition and phototrophic nutrition.