By Jeffrey Ho, Jesse Bogdan, and Maggie Klureza
Basics of Vacuoles
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Vacuoles are:
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relatively large, membrane-bound organelles
not a distinct shape but rather appear as expandable sacs that are often filled with
water, organic and inorganic material
primarily found in plant and fungi cells, occasionally in protist and bacterial cells,
but never in animal cells
generally used for structural support, waste removal and storage, but can have
distinctive functions for certain cells
both structure and function can vary between different vacuoles, even between two
in the same cell
General Structure – Plants and Fungi
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Plant and fungi cells have one
large, central vacuole, which
can take up as much as 80%
of the space in the cell. This
vacuole is made up of:
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Tonoplast, the membrane which
encloses the vacuole
Cell sap, the liquid that fills the
vacuole instead of protoplasm
Because it is enclosed by a
membrane, the vacuole is
part of the endomembrane
system. Essentially, this
means that it is part of a
group of organelles made
from membranes, connected
by the cytoplasmic network.
General Structure – Plants and Fungi
Vacuoles in Animals?
Vacuoles are only found in plant cells, fungi cells and some protist
and bacteria cells, NOT in animal cells.
 Animal cells DO have similar organelles, known as vesicles.
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Vesicles are generally much smaller than vacuoles but much more abundant.
Whereas plant and fungi cells often only have one, animal cells can have many.
Vesicles can have slightly different functions than vacuoles and are also used for
transporting material from one part of the cell to another.
In lower-level sources, the two terms, vesicle and vacuole, are
sometimes combined under the term “vacuole”. This is technically
incorrect but more a matter of terminology than concept.
General Functions in Cells
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Though specific function varies between different vacuoles, the
majority of vacuoles share the following functions:
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Containment – storing, decomposing or removing unwanted substances from the
cell’s interior
Protection – storing and isolating dangerous substances, toxic to the cell’s health
Defense – storing chemicals to be used against invading bacteria
Autophagy – breaking down and decomposing old cell parts at a rate that balances
out the production of cell organelles
Homeostasis – maintaining an acidic internal pH, turgor pressure and fluid balance
Specific Functions – Plants and Fungi
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In addition to the general functions, in plant and fungi cells, where
vacuoles play major roles, vacuoles may also have the following
functions:
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Growth and Development – storing salts, minerals, nutrients, and proteins that
assist in plant growth
Attraction – storing pigment that provides the plant and its flowers their color,
allowing them to attract insects for pollination
Defense – releasing poisonous or irritating molecules and chemicals that
discourage predators from consuming the plant
Structure – exerting pressure against the plant’s cell walls, enabling the cell to
maintain its form
Glossary
Cell Sap – the liquid enclosed in the vacuole (as opposed to
cytoplasm); is composed primarily of water, but exact composition
can vary from cell to cell.
 Tonoplast – literally meaning stretching, it is the cytoplasmic
membranes of vacuoles
 Turgor Pressure - the pressure the vacuole exerts on a plant or
fungi cell’s wall, which is determined by the volume of water in the
vacuole
 Vesicles – similar to vacuoles but are smaller and have some
different functions; they are found in animal cells
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Bibliography
Pictures
 http://www.tutorvista.com/biology/function-of-vacuole
 www.library.thinkquest.org
 www.micro.magnet.fsu.edu/cells/plants/vacuole.html
Information
 www.newton.dep.anl.gov/askasci/zoo00/zoo00296.htm
 www.dictionary.reference.com/browse/vacuoles
 www.iscid.org/encyclopedia/Vacuole
 http://www.buzzle.com/articles/vacuole-function.html