Human Erythrocytes OsmoticPressure PhaseContrast Plain

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 In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane-i ...

environment, where water moves into the cell by

osmosis Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of ...

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 surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering me ...

prevents the membrane from bursting, so cytolysis only occurs in

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in ...

and

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

cells which do not have cell walls. The reverse process is

plasmolysis Plasmolysis is the process in which cells lose water in a hypertonic solution. The reverse process, deplasmolysis or cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external osmotic pressure and a net flow of wat ...

In bacteria

Osmotic lysis would be expected to occur when bacterial cells are treated with a hypotonic solution with added

lysozyme Lysozyme (EC 3.2.1.17, 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 ...

, 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 '' ''Paramecium'' ( , ; also spelled ''Paramoecium'') is a genus of eukaryotic, unicellular ciliates, commonly studied as a representative of the ciliate group. ''Paramecia'' are widespread in freshwater, brackish, and marine environments and a ...

uses a contractile vacuole, which rapidly pumps out excessive water to prevent the build-up of water and the otherwise subsequent lysis.

References

*{{cite book , last =McClendon , first =Jesse Francis , title =Physical Chemistry of Vital Phenomena: , publisher =Princeton University Press , year =1917 , location =Original from the University of California , url =https://archive.org/details/bub_gb_BZUaAAAAIAAJ, quote =Cytolysis -wikipedia. , doi = , page
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In bacteria

Prevention

See also

References