Contractile vacuoleA contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole. The contractile vacuole is a specialized type of vacuole that regulates the quantity of water inside a cell. In freshwater environments, the concentration of solutes is hypotonic, lower outside than inside the cell. Under these conditions, osmosis causes water to accumulate in the cell from the external environment.
AmoebaAn amoeba (əˈmiːbə; less commonly spelled ameba or amœba; : am(o)ebas or am(o)ebae əˈmiːbi), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae 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.
