Facilitated diffusion: Difference between revisions
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:''Not to be confused with [[diffusion]]. Facilitated diffusion is not a type of diffusion (thermal motion) but a type of transport process.'' |
:''Not to be confused with [[diffusion]]. Facilitated diffusion is not a type of diffusion (thermal motion) but a type of transport process.'' |
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'''Penis'' (also knownif u are a pot head like Erik you are stupid smell like penis and look funny as '''facilitated transport''' or '''passive-m or also known as penis sucker ediated transport''') is a process of [[passive transport]] (as opposed to [[active transport]]), with this passive transport aided by integral membrane proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins. The facilitated diffusion may occur either across [if u [biological membrane]]s or through aqueous compartments of an organism.<ref name="isbn0-471-41759-9">{{cite book |author=Pratt, Charlotte Amerley; Voet, Donald; Voet, Judith G. |title=Fundamentals of biochemistry upgrade |publisher=Wiley |location=New York |year=2002 |pages=264–266 |isbn=0-471-41759-9 |oclc= |doi= |accessdate=}}</ref> |
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Polar molecules and charged ions are dissolved in water but they cannot diffuse freely across the plasma membrane due to the [[hydrophobe|hydrophobic]] nature of the fatty acid tails of [[phospholipid]]s that make up the [[lipid bilayer]]s. Only small nonpolar molecules, such as [[oxygen]] can diffuse easily across the membrane. All polar molecules are transported across [[cell membrane|membranes]] by proteins that form transmembrane channels. These channels are gated so they can open and close, thus regulating the flow of ions or small polar molecules. Larger molecules are transported by transmembrane carrier proteins, such as [[permease]]s that change their conformation as the [[molecules]] are carried through, for example [[glucose]] or [[amino acids]]. |
Polar molecules and charged ions are dissolved in water but they cannot diffuse freely across the plasma membrane due to the [[hydrophobe|hydrophobic]] nature of the fatty acid tails of [[phospholipid]]s that make up the [[lipid bilayer]]s. Only small nonpolar molecules, such as [[oxygen]] can diffuse easily across the membrane. All polar molecules are transported across [[cell membrane|membranes]] by proteins that form transmembrane channels. These channels are gated so they can open and close, thus regulating the flow of ions or small polar molecules. Larger molecules are transported by transmembrane carrier proteins, such as [[permease]]s that change their conformation as the [[molecules]] are carried through, for example [[glucose]] or [[amino acids]]. |
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Non-Polar molecules, such as [[retinol]] or [[lipid]]s are poorly soluble in water. They are transported through aqueous compartments of cells or through extracellular space by water-soluble carriers as [[retinol binding protein]]. The metabolites are not changed because no energy is required for facilitated diffusion. Only permease changes its shape in order to transport the metabolites. The form of transport through cell membrane which modifies its metabolites is the [[PEP group translocation|group translocation]] transportation. |
Non-Polar molecules, such as [[retinol]] or [[lipid]]s are poorly soluble in water. They are transported through aqueous compartments of cells or through extracellular space by water-soluble carriers as [[retinol binding protein]]. The metabolites are not changed because no energy is required for facilitated diffusion. Only permease changes its shape in order to transport the metabolites. The form of transport through cell membrane which modifies its metabolites is the [[PEP group translocation|group translocation]] transportation. |
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Revision as of 13:09, 31 October 2013
 | This article needs additional citations for verification. (March 2010) |
- Not to be confused with diffusion. Facilitated diffusion is not a type of diffusion (thermal motion) but a type of transport process.
'Penis (also knownif u are a pot head like Erik you are stupid smell like penis and look funny as facilitated transport or passive-m or also known as penis sucker ediated transport) is a process of passive transport (as opposed to active transport), with this passive transport aided by integral membrane proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins. The facilitated diffusion may occur either across [if u [biological membrane]]s or through aqueous compartments of an organism.[1] Polar molecules and charged ions are dissolved in water but they cannot diffuse freely across the plasma membrane due to the hydrophobic nature of the fatty acid tails of phospholipids that make up the lipid bilayers. Only small nonpolar molecules, such as oxygen can diffuse easily across the membrane. All polar molecules are transported across membranes by proteins that form transmembrane channels. These channels are gated so they can open and close, thus regulating the flow of ions or small polar molecules. Larger molecules are transported by transmembrane carrier proteins, such as permeases that change their conformation as the molecules are carried through, for example glucose or amino acids. Non-Polar molecules, such as retinol or lipids are poorly soluble in water. They are transported through aqueous compartments of cells or through extracellular space by water-soluble carriers as retinol binding protein. The metabolites are not changed because no energy is required for facilitated diffusion. Only permease changes its shape in order to transport the metabolites. The form of transport through cell membrane which modifies its metabolites is the group translocation transportation.
Glucose, sodium ions and chloride ions are just a few examples of molecules and ions that must efficiently cross the plasma membrane but to which the lipid bilayer of the membrane is virtually impermeable. Their transport must therefore be "facilitated" by proteins that span the membrane and provide an alternative route or bypass.
Various attempts have been made by engineers to mimic the process of facilitated transport in synthetic (i.e., non-biological) membranes for use in industrial-scale gas and liquid separations, but these have met with limited success to date, most often for reasons related to poor carrier stability and/or loss of carrier from the membrane.
See also
References
- ^ Pratt, Charlotte Amerley; Voet, Donald; Voet, Judith G. (2002). Fundamentals of biochemistry upgrade. New York: Wiley. pp. 264–266. ISBN 0-471-41759-9.
{{cite book}}: CS1 maint: multiple names: authors list (link)
2. {http://www.biology-online.org/dictionary/Facilitated_transport Facilitated Diffusion- Definition and Supplement}