Amoeba Cell Description

Amoebae are single-celled, crawling organisms often found in ponds. They have no definite shape and consist of flowing cytoplasm encased in a very flexible cell membrane. Amoebae have organelles (including one or more nuclei) and a contractile vacuole.

Movement

Amoebae move when cytoplasm flows out into a long extension of the cell; this crawling, flowing motion is called psuedopodia.

Habitat

Most amoebae live in pond water, moist soil or the ocean; some species are parasitic, living inside the body of another organism.

Diet

Amoebae are heterotrophic and ingest food through phagocytosis (the process whereby a cell engulfs a piece of food and ingests it). Basically tiny predators, they feed mainly on other microorganisms.

Osmoregulation

Amoebae that live in freshwater ponds must deal with water constantly rushing into the cell. Organelles called contractile vacuoles constantly fill with excess water, and pump it out of the cell. Without a contractile vacuole, the amoeba would explode in a freshwater environment.

Size

Although they are fairly large cells, most amoebas are too small to see with the naked eye; however, some species grow to grape size.

Respiration

Gas exchange in the amoeba occurs solely due to passive diffusion.

References

• Cosmos Magazine
• Biology (8th Edition); Campbell and Reece; 2008
• Internet Encyclopedia of Science