
Cytolysis, or osmotic lysis, occurs when a cell
bursts due to an
osmotic imbalance that has caused excess water to diffuse into the cell. Water can enter the cell by diffusion through the cell membrane or through selective membrane channels called aquaporins, which greatly facilitate the flow of water. It occurs in a
hypotonic environment, where water moves into the cell by
osmosis and causes its volume to increase to the point where the volume exceeds the membrane's capacity and the cell bursts. The presence of a
cell wall
A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...
prevents the membrane from bursting, so cytolysis only occurs in
animal
Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...
and
protozoa cells which do not have cell walls. The reverse process is
plasmolysis.
In bacteria
Osmotic lysis would be expected to occur when bacterial cells are treated with a hypotonic solution with added
lysozyme
Lysozyme (, muramidase, ''N''-acetylmuramide glycanhydrolase; systematic name peptidoglycan ''N''-acetylmuramoylhydrolase) is an antimicrobial enzyme produced by animals that forms part of the innate immune system. It is a glycoside hydrolase ...
, which destroys the bacteria's cell walls.
Prevention
Different cells and organisms have adapted different ways of preventing cytolysis from occurring. For example, the
paramecium uses a
contractile vacuole, which rapidly pumps out excessive water to prevent the build-up of water and the otherwise subsequent lysis.
See also
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Cell disruption
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Crenation
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Lysis
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Osmotic pressure
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Plasmolysis
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Water intoxication
References
General references
*
Inline citations
{{reflist
Cell biology
Membrane biology
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