Changes

==Origin==

==Origin==

New Latin, short for ''endosmosis''. From the [[Greek]] words ένδον (''endon'' : within), έξο (''exo'' : outside), and ωσμος (''osmos'' : push, impulsion).

New Latin, short for ''endosmosis''. From the [[Greek]] words ένδον (''endon'' : within), έξο (''exo'' : outside), and ωσμος (''osmos'' : push, impulsion).

*[http://en.wikipedia.org/wiki/19th_century 1867]

*[https://en.wikipedia.org/wiki/19th_century 1867]

==Definitions==

==Definitions==

*1: movement of a solvent (as [[water]]) through a semipermeable membrane (as of a living [[cell]]) into a solution of higher solute [[concentration]] that tends to equalize the concentrations of solute on the two sides of the membrane

*1: movement of a solvent (as [[water]]) through a semipermeable membrane (as of a living [[cell]]) into a solution of higher solute [[concentration]] that tends to equalize the concentrations of solute on the two sides of the membrane

*2: a [[process]] of [[absorption]] or [[diffusion]] suggestive of the [[flow]] of osmotic action; especially : a usually effortless often [[unconscious]] [[assimilation]] <learned a number of languages by osmosis — Roger Kimball>  

*2: a [[process]] of [[absorption]] or [[diffusion]] suggestive of the [[flow]] of osmotic action; especially : a usually effortless often [[unconscious]] [[assimilation]] <learned a number of languages by osmosis — Roger Kimball>  

==Description==

==Description==

'''Osmosis''' is the net movement of solvent [[molecules]] through a partially [http://en.wikipedia.org/wiki/Semipermeable_membrane permeable] membrane into a region of higher solute [[concentration]], in order to [[equalize]] the solute concentrations on the two sides. It may also be used to [[describe]] a [[physical]] [[process]] in which any solvent moves, without input of [[energy]], across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Although osmosis does not require input of [[energy]], it does use [[kinetic energy]] and can be made to do work.

'''Osmosis''' is the net movement of solvent [[molecules]] through a partially [https://en.wikipedia.org/wiki/Semipermeable_membrane permeable] membrane into a region of higher solute [[concentration]], in order to [[equalize]] the solute concentrations on the two sides. It may also be used to [[describe]] a [[physical]] [[process]] in which any solvent moves, without input of [[energy]], across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Although osmosis does not require input of [[energy]], it does use [[kinetic energy]] and can be made to do work.

Net movement of solvent is from the less [[concentrated]] ([http://en.wikipedia.org/wiki/Tonicity#Hypotonicity hypotonic]) to the more concentrated ([http://en.wikipedia.org/wiki/Tonicity#Hypertonicity hypertonic]) solution, which tends to reduce the [[difference]] in [[concentrations]]. This [[effect]] can be countered by increasing the [[pressure]] of the hypertonic solution, with respect to the hypotonic. The [http://en.wikipedia.org/wiki/Osmotic_pressure osmotic pressure] is defined to be the [[pressure]] required to maintain an [[equilibrium]], with no net movement of solvent. Osmotic pressure is a [http://en.wikipedia.org/wiki/Colligative_properties colligative property], meaning that the osmotic pressure depends on the [http://en.wikipedia.org/wiki/Concentration#Molarity molar concentration] of the solute but not on its [[identity]].

Net movement of solvent is from the less [[concentrated]] ([https://en.wikipedia.org/wiki/Tonicity#Hypotonicity hypotonic]) to the more concentrated ([https://en.wikipedia.org/wiki/Tonicity#Hypertonicity hypertonic]) solution, which tends to reduce the [[difference]] in [[concentrations]]. This [[effect]] can be countered by increasing the [[pressure]] of the hypertonic solution, with respect to the hypotonic. The [https://en.wikipedia.org/wiki/Osmotic_pressure osmotic pressure] is defined to be the [[pressure]] required to maintain an [[equilibrium]], with no net movement of solvent. Osmotic pressure is a [https://en.wikipedia.org/wiki/Colligative_properties colligative property], meaning that the osmotic pressure depends on the [https://en.wikipedia.org/wiki/Concentration#Molarity molar concentration] of the solute but not on its [[identity]].

Osmosis is essential in [[biological]] systems, as [http://en.wikipedia.org/wiki/Biological_membrane biological membranes] are semipermeable. In general, these membranes are impermeable to large and polar [[molecules]], such as ions, proteins, and polysaccharides, while being permeable to non-polar and/or [http://en.wikipedia.org/wiki/Hydrophobic hydrophobic] molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, nitric oxide, etc. Permeability depends on solubility, charge, or [[chemistry]], as well as solute size. [[Water]] molecules travel through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diffusing across the phospholipid bilayer via [http://en.wikipedia.org/wiki/Aquaporin aquaporins] (small transmembrane proteins similar to those in facilitated [[diffusion]] and in creating ion channels). Osmosis provides the primary means by which water is [[transported]] into and out of [[cells]]. The [http://en.wikipedia.org/wiki/Turgor turgor] pressure of a cell is largely maintained by osmosis, across the cell membrane, between the [[cell]] interior and its relatively hypotonic environment.

Osmosis is essential in [[biological]] systems, as [https://en.wikipedia.org/wiki/Biological_membrane biological membranes] are semipermeable. In general, these membranes are impermeable to large and polar [[molecules]], such as ions, proteins, and polysaccharides, while being permeable to non-polar and/or [https://en.wikipedia.org/wiki/Hydrophobic hydrophobic] molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, nitric oxide, etc. Permeability depends on solubility, charge, or [[chemistry]], as well as solute size. [[Water]] molecules travel through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diffusing across the phospholipid bilayer via [https://en.wikipedia.org/wiki/Aquaporin aquaporins] (small transmembrane proteins similar to those in facilitated [[diffusion]] and in creating ion channels). Osmosis provides the primary means by which water is [[transported]] into and out of [[cells]]. The [https://en.wikipedia.org/wiki/Turgor turgor] pressure of a cell is largely maintained by osmosis, across the cell membrane, between the [[cell]] interior and its relatively hypotonic environment.

[http://en.wikipedia.org/wiki/Jean-Antoine_Nollet Jean-Antoine Nollet] first documented observation of osmosis in 1748. The word "osmosis" descends from the words "endosmose" and "exosmose", which were coined by French physician [http://en.wikipedia.org/wiki/Henri_Dutrochet René Joachim Henri Dutrochet] (1776–1847) from the [[Greek]] words ένδον (endon : within), έξο (exo : outside), and ωσμος (osmos : push, impulsion).

[https://en.wikipedia.org/wiki/Jean-Antoine_Nollet Jean-Antoine Nollet] first documented observation of osmosis in 1748. The word "osmosis" descends from the words "endosmose" and "exosmose", which were coined by French physician [https://en.wikipedia.org/wiki/Henri_Dutrochet René Joachim Henri Dutrochet] (1776–1847) from the [[Greek]] words ένδον (endon : within), έξο (exo : outside), and ωσμος (osmos : push, impulsion).

[[Category: Biology]]

[[Category: Biology]]