An amoeba, often called amoeboid, is a type of cell or unicellular organism which has the ability to alter its shape, primarily by extending and retracting pseudopods. The shells of amoebas are often composed of calcium. The proteins or materials are synthesized in the cell and exported just outside the cell membrane.
Amoebas do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.
Other well known species include the so-called "brain-eating amoeba" Naegleria fowleri, the intestinal parasite Entamoeba histolytica, which causes amoebic dysentery, and the multicellular "social amoeba" or slime mould Dictyostelium discoideum.
The best known amoeboid protists are the "giant amoebae" Chaos carolinense and Amoeba proteus, both of which have been widely cultivated and studied in classrooms and laboratories.
Images for kids
Amoeba Facts for Kids. Kiddle Encyclopedia.