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Contractile vacuole

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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 ...

-- 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.

s are organelles in the cells of sponges and freshwater protozoans. In the freshwater Amoeba proteus, for example, the bubble-like swells with excess fluid from the cytoplasm .

Contractile vacuole an organelle found in some single-celled organisms which removes excess water from the cell.
Corolla a collective name for the petals of a flower.

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 ...

Some protists have specialized s for eliminating excess water.
The diagram below illustrates how energy from sunlight is used for the energy requirements of cells.

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.

Amoeba make use of s to collect excretory waste, such as ammonia, from the intracellular fluid by both diffusion and active transport.

The contractile vacuole is the Paramecium's response to this problem. The pumping of water out of the cell by this method requires energy since the water is moving against the concentration gradient.

Some cells, such as Paramecium have organelles called s which are basically little pumps which pump excess water out of cell
You can alter the rate of pumping by placing it in increasingly hypotonic solutions ...

Water accumulates within the contractile vacuole, a membrane-bounded structure, which inflates.
To expel the water, the vacuole connects with the plasma membrane and is squeezed by cytoskeletal systems within the cytoplasm.

s, found in freshwater protists, pump excess water out of the cell to maintain the appropriate concentration of salts.
A large central vacuole is found in many mature plant cells.

(f) Other examples are contractile vacuoles (see Figure, Evolutionary adaptations for osmoregulation in Paramecium) and food vacuoles (protozoa) ...

Sequences show the motility of this ciliated protozoan and the repetitious activity of both anterior and posterior s.
5.4 Spirostomum (ciliated protozoa) ...

See also: See also: Vacuole, Organ, Membrane, Cells, Plant

Biology  Contiguous gene syndrome  Convergence

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