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Topic: Contractile vacuole


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  Contractile Vacuole
A vacuole is a large membrane-bound compartment in certain eukaryotic cells that serve a variety of different functions.
Contractile vacuoles are most often found in freshwater protozoa like paramecium and amoeba.
All vacuoles including contractile vacuoles are generally filled with cell sap, which is a liquid of varying composition.
www.iscid.org /encyclopedia/Contractile_Vacuole   (200 words)

  
  Infusoria - LoveToKnow 1911
One or more contractile vacuoles are present in some of the marine and all the freshwater species, and open to the surface by pores of permanent position: a system of canals in the deeper layers of the ectoplasm is sometimes connected with the vacucle.
The contractile vacuole may be single or multiple; it may receive the contents of a canal, or of a system of canals, which only become visible at the moment of the contraction of the vacuole (fig.
1, 2), the anus and the pore of the contractile vacuole.
www.1911encyclopedia.org /Infusoria   (5475 words)

  
 Vacuole   (Site not responding. Last check: 2007-10-31)
Vacuoles are fluid-filled sacs that are enclosed by a single membrane.
One type of vacuole is the food vacuole, which is a temporary vacuole containing food that is obtained through phagocytosis ("cell eating").
Contractile vacuoles, which are found in most freshwater protists, control the amount of water in the plant cell by a repeated process.
sun.menloschool.org /~birchler/cells/plants/vacuole   (270 words)

  
 [No title]
The contractile vacuole may be single or multiple, usually in the posterior region of the body and dorsal in position.
The contractile vacuole is central and dorsal; the macronucleus is in the anterior half of the body, with one attached micronucleus.
One contractile vacuole is situated in the dorsal swelling at the posterior end of the animal.
www2.cddc.vt.edu /gutenberg/1/8/3/2/18320/18320-8.txt   (19217 words)

  
 Vacuole
Vacuoles are large membrane-bound compartments within some eukaryotic cells and can serve different purposes, such as capturing food materials or unwanted structural debris surrounding the cell, sequestering materials that might be toxic to cells, maintaining fluid balance within the cell, exporting unwanted substances from the cell, and even determining relative cell size.
A contractile vacuole is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting apart.
Contractile vacuoles are used by some freshwater protozoa.
www.ebroadcast.com.au /lookup/encyclopedia/va/Vacuole.html   (195 words)

  
 Vacuole at AllExperts
Vacuoles and their contents are considered to be distinct from the cytoplasm, and are classified as ergastic according to some authors (Esau, 1965).
A contractile vacuole is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting, which is referred to as cytolysis or osmotic lysis.
Turgor pressure exerted by vacuoles is also helpful for cellular elongation: as the cell wall is partially degraded by the action of auxins, the less rigid wall is expanded by the pressure coming from within the vacuole.
en.allexperts.com /e/v/va/vacuole.htm   (767 words)

  
 Contractile vacuole - LoveToKnow 1911
CONTRACTILE VACUOLE, in biology, a spherical space filled with liquid, which at intervals discharges into the medium; it is found in all fresh-water groups of Protozoa, and some marine forms, also in the naked aquatic reproductive cells of Algae and Fungi.
It is absent in states with a distinct cell-wall to resist excessive turgescence, such as would lead to the rupture of a naked cell, and we conclude that its chief function is to prevent such turgescence in unprotected naked cells.
It fulfils also respiratory and renal functions, and is comparable, physiologically, to the contractile vesicle or bladder of Rotifers and Turbellarians.
www.1911encyclopedia.org /Contractile_vacuole   (138 words)

  
 Vacuole Summary
Vacuoles and their contents are considered to be distinct from the cytoplasm, and are classified as ergastic according to some authors (Esau, 1965).
A contractile vacuole is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting, which is referred to as cytolysis or osmotic lysis.
Turgor pressure exerted by vacuoles is also helpful for cellular elongation: as the cell wall is partially degraded by the action of auxins, the less rigid wall is expanded by the pressure coming from within the vacuole.
www.bookrags.com /Vacuole   (1625 words)

  
 Protozoa: Amoebae: Naked. An introduction to amoebae with photomicrographs.
The nucleus is visible as a dark spot surrounded by a clear zone at the centre of the body, and a number of food vacuoles and a contractile vacuole are seen in the rear portion.
The amoeba on the right (with large contractile vacuole) is in the act of ingesting the cells -- the one on the left has already ingested several algae of a similar kind which can be seen in its food vacuoles.
There are a large number of apparently empty vacuoles, and the nucleus, enclosed in a clear membrane, is seen near the centre of the body.
www.micrographia.com /specbiol/protis/homamoeb/amoe0100.htm   (1121 words)

  
 Cell Organelles: Vacuole
Vacuoles tend to be large in plant cells and play a role in turgor pressure.
When a plant is well-watered, water collects in cell vacuoles producing rigidity in the plant.
Without sufficient water, pressure in the vacuole is reduced and the plant wilts.
cellsalive.com /cells/vacuole.htm   (72 words)

  
 Cell Videos
Contractile vacuoles are vacuoles that function in osmoregulation.
The contractile vacuole is surrounded by radial canals which absorb water from the cytoplasm and move it into the contractile vacuole.
However, the radiating canals associated with the contractile vacuole of Paramecium are not seen.
www.linkpublishing.com /video-cell.htm   (1615 words)

  
 Vacuoles | World of Biology
Vacuoles are especially prominent in plant cells where they may occupy 95% or more of the cell volume.
It was found that during embryo formation and seed development, proteins accumulate in the vacuoles of some cells in the cotyledons, or seed leaves, of dicotyledons (flowering plants with two cotyledons per embryo).
The contractile vacuole functions in osmotic regulation by preventing excess water from entering the organism and swelling it beyond a viable size.
www.bookrags.com /research/vacuoles-wob   (317 words)

  
 Periodic tension development in the membrane of the in vitro contractile vacuole of Paramecium multimicronucleatum: ...
The contractile vacuole of the freshwater protozoan Paramecium
to the increased membrane tension of the in vivo contractile vacuole that
vitro contractile vacuole corresponded to the fluid-filling phase of the in
jeb.biologists.org /cgi/content/abstract/203/2/239   (558 words)

  
 contractile vacuole - Search Results - MSN Encarta
The body wall is composed of two sheets of cells—an inner layer (the endoderm) and an...
1972: Biology : A contractile rubber in protozoa.
It is of vital importance to many organisms that they should be able to determine the time of day.
encarta.msn.com /contractile_vacuole.html   (181 words)

  
 The contractile vacuole network   (Site not responding. Last check: 2007-10-31)
The contractile vacuole and endosomal compartments in a Dictyostelium cell.
The contractile vacuole complex consisting of ducts and bladders is labeled with GFP-tagged dajumin in green.
Activities in the dispersed contractile vacuole complex during mitosis, and the mode of its reorganization.
www.gel.ulaval.ca /~schwartz/mpi/projects/dajumin.htm   (480 words)

  
 Cell Organelles: Vacuole
Vacuoles tend to be large in plant cells and play a role in turgor pressure.
When a plant is well-watered, water collects in cell vacuoles producing rigidity in the plant.
Without sufficient water, pressure in the vacuole is reduced and the plant wilts.
www.cellsalive.com /cells/vacuole.htm   (72 words)

  
 New Page 0
Locate the contractile vacuole (a clear oval space in the cytoplasm) and make a note of its size and position.
As the vacuole fills it moves toward the "posterior" end of the Amoeba and eventually contracts to expel its fluid.
Contractile vacuoles help to regulate the internal osmotic environment and are therefore examples of osmoregulatory organelles.
cas.bellarmine.edu /tietjen/Laboratories/Protist2.htm   (1652 words)

  
 Osmoregulation and Contractile Vacuole Function
Even when cells are kept in a strongly hypertonic solution, which would appear to eliminate the necessity for further contractile vacuole (CV) activity, it was found that after a period of 12h the CV activity would commence again.
From the beginning of our studies in 1995 on the contractile vacuole it has always been our intention to determine how this organelle is able to sequester fluid from the cytosol and thereby regulate the cells cytosolic osmolarity.
Table I. Overview of the ionic activities in the contractile vacuole, the overrall cytosolic osmolarity, the estimated osmotic gradient across the contractile vacuole membrane, the rate of fluid segregation and the membrane potential of the contractile vacuole complex in P.
www.pbrc.hawaii.edu /mbl/membio/osmoregu.htm   (2961 words)

  
 Paramecium   (Site not responding. Last check: 2007-10-31)
The contractile vacuole and the radiating canals are also found on the outside of a paramecium.
Inside the paramecium is cytoplasm, trichocysts, the gullet, food vacuoles, the macronucleus, and the micronucleus.
When the vacuole reaches the anal pore the remaining undigested waste is removed.
www.geocities.com /garrah18/paramecium.html   (418 words)

  
 / Department of Biology / University of Northern Iowa   (Site not responding. Last check: 2007-10-31)
Although the function of the contractile vacuole complex as a means of removing fluids from the cell and maintaining cellular integrity is well documented, how the contractile vacuole complex performs this task is not completely understood.
Contractile vacuole size of single cells were measured and analyzed using computer imaging and analysis programs.
In cells treated with taxol, the contractile vacuole filled ot a lesser volume and the contractile event was shortened in comparison to control cells.
www.bio.uni.edu /students/wolf.html   (209 words)

  
 Paramecium Coloring
Contractile vacuoles are used in animal cells to remove the excess water.
The contractile vacuole is shaped like a star - color the contractile vacuole dark green.
Food vacuoles then remain in the cytoplasm until the food is digested.
www.biologycorner.com /worksheets/paramecium_color.html   (409 words)

  
 Essay: Cell Vacuole Essay - Coursework.Info
Plants, however, have much larger cell vacuoles which are usually the largest structure in a plant cell often dominating the inside of the cell, crowding other organelles to the cell wall.
Here are examples of some common types of cell vacuoles: · Plant sap vacuole - present only in plants · Contractile vacuole · Food vacuole · Lysosomes · Pinocytic vesicles As mentioned earlier, the plant cell vacuole is surrounded by a membrane, the tonoplast.
This membrane separates the cytoplasm from the vacuole and controls the exchange of substances between the vacuole and the cytoplasm.
www.coursework.info /GCSE/Biology/Cell_Vacuole_Essay_L20357.html   (248 words)

  
 Welcome to the website of Traffic the International Journal of Intracellular Transport
In this condition the contractile vacuole is very active swelling with water and expelling the water out of the cell.
Drainin is a peripheral membrane protein associated with the membranes of the contractile vacuole and is required for the expulsion phase of the vacuole.
Thus, contraction of the vacuole is necessary to disengage LvsA from the vacuole membrane.
www.traffic.dk /videos/5_4_bis.asp   (446 words)

  
 parts
There is something called a contractile vacuole, which drains the water that gets inside the amoeba.
Contractile vacuole means, 'a small space that can shrink.' The contractile vacuole is always in the back of an amoeba.
The contractile vacuole is in the bottom left and psuedopod.
www.oberlin.k12.oh.us /talent/isp/reports2002/amoebaproteus/parts.htm   (805 words)

  
 Contractile vacuole - Wikipedia, the free encyclopedia
A contractile vacuole is a type of vacuole involved in osmoregulation.
In a Paramecium, a common freshwater protist (this is the answer you idiots), the vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm.
When the vacuole is full, it expels the water through a pore in the cytoplasm which can be opened and closed.
en.wikipedia.org /wiki/Contractile_vacuole   (165 words)

  
 Association of calmodulin and an unconventional myosin with the contractile vacuole complex of Dictyostelium discoideum ...
Association of calmodulin and an unconventional myosin with the contractile vacuole complex of Dictyostelium discoideum -- Zhu and Clarke 118 (2): 347 -- The Journal of Cell Biology
Rohloff, P., Montalvetti, A., Docampo, R. Acidocalcisomes and the Contractile Vacuole Complex Are Involved in Osmoregulation in Trypanosoma cruzi.
The contractile vacuole network of Dictyostelium as a distinct organelle: its dynamics visualized by a GFP marker protein.
www.jcb.org /cgi/content/abstract/118/2/347   (993 words)

  
 The Cell Adhesion Molecule DdCAD-1 in Dictyostelium Is Targeted to the Cell Surface by a Nonclassical Transport Pathway ...
contractile vacuole membrane and the plasma membrane was observed
The fusion of contractile vacuoles with the plasma membrane and their subsequent contraction have been studied fairly extensively.
Proton pumps populate the contractile vacuoles of Dictyostelium amoebae.
www.jcb.org /cgi/content/full/138/4/939   (7061 words)

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