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-imp ...
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 mech ...
prevents the membrane from bursting, so cytolysis only occurs in
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
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 wate ...
.
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
A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole.
Overview
The contractile va ...
, which rapidly pumps out excessive water to prevent the build-up of water and the otherwise subsequent lysis.
See also
*
Cell disruption
Cell disruption is a method or process for releasing biological molecules from inside a cell.
Methods
The production of biologically interesting molecules using cloning and culturing methods allows the study and manufacture of relevant molecule ...
*
Crenation
Crenation (from modern Latin ''crenatus'' meaning "scalloped or notched", from popular Latin ''crena'' meaning "notch") in botany and zoology, describes an object's shape, especially a leaf or shell, as being round-toothed or having a scalloped ed ...
*
Lysis
Lysis ( ) is the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic (that is, "lytic" ) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a ''lysate''. In molecular bio ...
*
Osmotic pressure
Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane.
It is also defined as the measure of the tendency of a solution to take in a pure ...
*
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 wate ...
*
Water intoxication
Water intoxication, also known as water poisoning, hyperhydration, overhydration, or water toxemia, is a potentially fatal disturbance in brain functions that results when the normal balance of electrolytes in the body is pushed outside safe lim ...
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
240pages
Cell biology
Membrane biology
Articles containing video clips