Protozoa Nutrition

Protists receive nutrients by breaking down organic matter (heterotrophic) and can grow in both aerobic and anaerobic environments, such as protists that live in the intestine of animals. Some protists, such as Euglena, receive nutrients from organic matter and through photosynthesis because they contain chlorophyll. These protists are considered both algae and protozoa.

Protists obtain food in one of three ways:

• Absorption: Food is absorbed across the protist's plasma membrane.

• Ingestion: Cilia outside the protist create a wave-like motion to move food into a mouth-like opening in the protist called a cytosome. An example is the paramecium.

• Engulf: Pseudopods (meaning "false feet") on the protist engulf food, then pull it into the cell using a process called phagocytosis. An example of this type of protist is the amoeba.

Food is digested in the vacuole after the food enters the cell. The vacuole is a membrane-bound organelle. Waste products are excreted using a process called exocytosis.

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