Charlie Melançon and Osmotic pressure: Difference between pages
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{{Infobox_Congressman |
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| name =Charles J. "Charlie" Melancon |
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| image name =Charlie_Melancon.jpg |
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| date of birth=[[October 3]] [[1947]] |
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| place of birth =[[Napoleonville, Louisiana]] |
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| state = [[Louisiana]] |
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| district = [[Louisiana's 3rd congressional district|3rd]] |
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| term = [[2005]]-present |
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| preceded = [[Billy Tauzin]] |
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| succeeded = Incumbent |
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| party =[[Democratic Party (United States)|Democrat]] |
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| spouse = |
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}} |
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'''Osmotic pressure''' is the [[Fluid statics|hydrostatic]] [[pressure]] produced by a solution in a space divided by a [[semipermeable membrane|differentially permeable membrane]] due to a differential in the concentrations of solute. |
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'''Charles J. (Charlie) Melancon''' (pronounced Meh-law-soɴ) (born [[October 3]] [[1947]], in [[Napoleonville, Louisiana]]) is a [[United States Democratic Party|Democrat]] who was elected in to represent [[Louisiana's 3rd congressional district]].([http://nationalatlas.gov/printable/images/preview/congdist/la03_109.gif map]) in a [[December 4]], [[2004]], [[general election]]. |
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'''Osmotic potential''' is the opposite of [[water potential]] with the former meaning the degree to which a solvent (usually water) would want to stay in a liquid. |
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The grandson and great-grandson of [[sugarcane]] farmers, Melancon owned and operated several [[small business]]es (including two [[Baskin Robbins]]) before winning a [[1987]] [[special election]] for the Louisiana House of Representatives. After serving 2 more terms, he headed the [[American Sugar Cane League]] from [[1993]] to [[2004]]. Melancon lives in [[Napoleonville, Louisiana|Napoleonville]], a village an hour and a half south of [[Baton Rouge]]. He has been married to Peachy Melancon (nee Clark) for over 30 years and they have two children, Charles Joseph (Seph) and Claire. |
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When a [[biological]] [[cell (biology)|cell]] is in a [[hypotonic]] environment (the cell interior contains a lower concentration of [[water]] than its exterior), water flows across the [[cell membrane]] into the cell, causing it to expand due to osmotic pressure. In [[plant cell]]s, the [[cell wall]] restricts the expansion, resulting in pressure on the cell wall from within called [[turgor pressure]]. The osmotic pressure π of a dilute solution can be calculated using the formula |
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Melancon threw his hat into the 3rd CD ring after longtime incumbent [[Billy Tauzin]] announced his retirement. Considered an underdog for much of the race, he managed to squeak into a runoff due to an especially ugly intraparty battle between [[United States Republican Party|Republican]] candidates [[Billy Tauzin III]] (the incumbent's son) and state senator [[Craig Romero]]. In the runoff campaign, Melancon repeatedly hammered away at Tauzin, III,'s youth, inexperience, criminal record, and family ties (many members of both major parties resented Tauzin's status as [[frontrunner]] for the seat solely because his father was the [[incumbent]]). Because of the attacks on Tauzin, the makeup of the district, and Romero's refusal to endorse Tauzin, Melancon eked out a victory by 569 votes. [http://www.washtimes.com/upi-breaking/20041208-052455-8962r.htm] |
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:<math>\pi = MRT \,</math> |
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where |
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Very soon after being sworn in January of [[2005]], Melancon joined the [[Blue Dog Democrats]]. He is a fairly conservative Democrat by national standards--in fact, a section of his campaign site, "Louisiana Values," detailed his opposition to [[gun control]], [[abortion]] and [[same-sex marriage]]. He later said that the 2004 election campaign was the first time in his life that he was called a [[liberal]]. |
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:''M'' is the [[molarity]] |
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:''R'' is the [[gas constant]], where ''R'' = 8.314472 J · K<sup>-1</sup> · mol<sup>-1</sup> |
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:''T'' is the [[absolute temperature|thermodynamic temperature]] (formerly called absolute temperature) |
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Note the similarity of the above formula to the [[ideal gas law]], and also that osmotic pressure is not dependent on particle charge. |
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Melancon has been a harsh critic of the federal government's response to [[Hurricane Katrina]], which devastated much of his district. However, it remains to be seen how this disaster and his criticisms will impact his [[2006]] re-election chances. Melancon will face [[Republican Party (United States)|Republican]] [[Craig Romero]] in the [[Louisiana House elections, 2006|mid-term election of 2006]]. |
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== Applications == |
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A recent poll released on September 5, 2006 puts Melancon with a 32-point lead over Romero. [http://www.melanconforcongress.com/2006pollingmemo.pdf] |
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Osmotic pressure is the basis of [[reverse osmosis]], a process commonly used to purify water. The water to be purified is placed in a chamber and put under an amount of pressure greater than the osmotic pressure exerted by the water and the solutes dissolved in it. Part of the chamber opens to a differentially permeable membrane that lets water molecules through, but not the solute particles. The osmotic pressure of ocean water is about 27 [[Atmosphere (unit)|atm]]. Reverse osmosis [[desalination|desalinator]]s use pressures around 50 atm to produce fresh water from [[seawater|ocean salt water]]. |
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Osmotic pressure is necessary for most plants. It is the resulting turgor pressure on the cell wall that allows herbaceous plants to stand upright, and how plants regulate the aperture of their [[stomata]]. In animal cells which lack a cell wall however, excessive osmotic pressure can result in [[cytolysis]]. |
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*[http://www.melancon.house.gov/ Charlie Melancon's Official House Website] |
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*[http://www.melanconforcongress.org/ Charlie Melancon's Official Campaign Site] |
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*[http://projects.washingtonpost.com/congress/members/m001161/ Voting record maintained by the Washington Post] |
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== See also == |
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{{start box}} |
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* [[Cell wall]] |
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{{succession box | before=[[Billy Tauzin]] | title=United States Representative for [[Louisiana's 3rd congressional district]] | years=[[2005]]– | after=Incumbent}} |
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* [[Cytolysis]] |
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{{end box}} |
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* [[Osmosis]] |
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* [[Pfeffer cell]] |
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* [[Plasmolysis]] |
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* [[Turgor pressure]] |
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{{LA-FedRep}} |
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* [http://www.bbc.co.uk/dna/h2g2/A686766 Osmotic pressure and potential] |
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* [http://www.biologie.uni-hamburg.de/b-online/e22/22c.htm Osmotic pressure] |
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* [http://www.nyu.edu/classes/tuckerman/honors.chem/lectures/lecture_13/node10.html Equations for osmotic pressure] |
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[[Category: |
[[Category:Cell biology]] |
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[[Category: |
[[Category:Membrane biology]] |
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[[Category:University of Louisiana at Lafayette alumni|Melancon, Charlie]] |
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[[cs:Osmotický tlak]] |
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[[Category:Kappa Sigma brothers|Melancon, Charlie]] |
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[[de:Turgor]] |
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[[Category:Living people|Melancon, Charlie]] |
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[[he:לחץ טורגור]] |
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[[Category:Members of the Louisiana House of Representatives|Melancon, Charlie]] |
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[[is:Osmótískur þrýstingur]] |
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[[Category:Members of the United States House of Representatives from Louisiana|Melancon, Charlie]] |
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[[it:Pressione osmotica]] |
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[[Category:Roman Catholic politicians|Melancon, Charlie]] |
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[[ja:浸透圧]] |
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[[Category:United States Army officers|Melancon, Charlie]] |
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[[mk:Осмотски притисок]] |
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[[Category:Current members of the United States House of Representatives|Melancon, Charlie]] |
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[[nl:Osmotische druk]] |
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[[pl:Turgor]] |
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[[pt:Pressão osmótica]] |
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[[ru:Осмотическое давление]] |
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[[sk:Osmotický tlak]] |
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[[fi:Osmoottinen paine]] |
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[[uk:Осмотичний тиск]] |
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[[zh:滲透壓]] |
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Revision as of 03:12, 16 October 2006
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Osmotic pressure is the hydrostatic pressure produced by a solution in a space divided by a differentially permeable membrane due to a differential in the concentrations of solute.
Osmotic potential is the opposite of water potential with the former meaning the degree to which a solvent (usually water) would want to stay in a liquid.
When a biological cell is in a hypotonic environment (the cell interior contains a lower concentration of water than its exterior), water flows across the cell membrane into the cell, causing it to expand due to osmotic pressure. In plant cells, the cell wall restricts the expansion, resulting in pressure on the cell wall from within called turgor pressure. The osmotic pressure π of a dilute solution can be calculated using the formula
where
- M is the molarity
- R is the gas constant, where R = 8.314472 J · K-1 · mol-1
- T is the thermodynamic temperature (formerly called absolute temperature)
Note the similarity of the above formula to the ideal gas law, and also that osmotic pressure is not dependent on particle charge.
Applications
Osmotic pressure is the basis of reverse osmosis, a process commonly used to purify water. The water to be purified is placed in a chamber and put under an amount of pressure greater than the osmotic pressure exerted by the water and the solutes dissolved in it. Part of the chamber opens to a differentially permeable membrane that lets water molecules through, but not the solute particles. The osmotic pressure of ocean water is about 27 atm. Reverse osmosis desalinators use pressures around 50 atm to produce fresh water from ocean salt water.
Osmotic pressure is necessary for most plants. It is the resulting turgor pressure on the cell wall that allows herbaceous plants to stand upright, and how plants regulate the aperture of their stomata. In animal cells which lack a cell wall however, excessive osmotic pressure can result in cytolysis.