Food molecules such as sugars, protein, or lipids enter the cells by simple diffusion, facilitated diffusion, or active transport. Food particles and other unicellular organisms are ingested by endocytosis. This involves the flexible plasma membrane forming extensions and engulfing the organism or food particles. The food becomes enclosed in a food vacuole. The way in which protozoans moves allows biologists to place protozoans into smaller groups.
Some protozoans move by means of one or more flagella.
These protozoans are called zooflagellates. Trypansosoma a human parasite and Trichonympha , a protozoan that lives in the gut of termites are examples of zooflagellates. These are called the sarcodines, and Amoeba is an example of this group. Ciliates move by means of cilia. Paramecium is an example of this group.