contractile vacuole
a hollow structure that alternately contracts and expands, as found in amebae, paramecia, and so forth
Source: Noland, George B. 1983. General Biology, 11th Edition. St. Louis, MO. C. V. Mosby ...
contractile vacuole -- In many protists, a specialized vacuole with associated channels designed to collect excess water in the cell.
contractile vacuole Organelle in many eukaryotes that acts as a bilge pump in the active transport of excess water from the cell.
contrast In relation to microscopes, the ability to distinguish different densities of structures.
contractile vacuole
An organelle that pumps excess water out of many freshwater protist cells.
cork cambium
A cylinder of meristematic tissue in plants that produces cork cells to replace the epidermis during secondary growth.
contractile vacuole A clear fluid-filled cell vacuole in protozoa and a few lower metazoa; takes up water and releases it to the outside in a cyclical manner, for osmoregulation and some excretion.
A contractile vacuole is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting. Contractile vacuoles are found in some freshwater protozoa.
Vacuoles in plant cells: the central vacuole ...
Amoeba make use of contractile vacuoles to collect excretory waste, such as ammonia, from the intracellular fluid by both diffusion and active transport.
Organisms in the Euglenophyta have two flagella, a contractile vacuole, a photoreceptive eyespot, several chloroplasts, lack a cell wall, and can live as either autotrophs or heterotrophs.
Fresh water ciliates cope with the continuous influx of water from their hypotonic surroundings by pumping it out with one or more contractile vacuoles. Parasitic ciliates, which live in isotonic surroundings, have no contractile vacuole.
Some protists have specialized contractile vacuoles for eliminating excess water and food vacuoles that contain food within the cell.
Chloroplasts ...
Sequences show the motility of this ciliated protozoan and the repetitious activity of both anterior and posterior contractile vacuoles.
5.4 Spirostomum (ciliated protozoa) ...
 See also: Vacuole, Organ, Protein, Membrane, Plant
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