Osmosis: Difference between revisions
No edit summary |
mNo edit summary |
||
| Line 1: | Line 1: | ||
Osmosis is the movement of [[Water|water]] molecules from a high water concentration ([[ | Osmosis is the movement of [[Water|water]] molecules from a high water concentration ([[Hypotonic solution|hypotonic solution]]) to a low water [[Concentration|concentration]] ([[Hypertonic solution|hypertonic solution]]) through a [[Semi-permeable membrane|semi-permeable membrane.]] It can also be described as the movement of water from a low [[Solute|solute]] concentration to a high solute concentration through a [[Semi-permeable membrane|semi-permeable membrane]]. | ||
*Concentration gradients affects osmosis, the higher the concentration gradient the higher the [[ | *Concentration gradients affects osmosis, the higher the concentration gradient the higher the [[Osmosis rate|osmosis rate]]. | ||
*Osmosis can be decreased by increasing the osmotic pressure of the hypertonic solution relative to the hypotonic solution <ref>Patlak, J., (2000) Osmosis, available at http://physioweb.uvm.edu/bodyfluids/osmosis.htm (last accessed 14/11/2011).</ref>. | *Osmosis can be decreased by increasing the osmotic pressure of the hypertonic solution relative to the hypotonic solution <ref>Patlak, J., (2000) Osmosis, available at http://physioweb.uvm.edu/bodyfluids/osmosis.htm (last accessed 14/11/2011).</ref>. | ||
Osmosis is very important in the biological systems, as water moves across cell | Osmosis is very important in the biological systems, as water moves across cell membranes by osmosis. Water movement is essential to maintain the osmolarity of the cell. | ||
Osmolarity is defined as the number of water particles per unit volume, it can be calculated using the formula:<br>Osm = M ([[Concentration|concentration]]) x n (number of particles) | Osmolarity is defined as the number of water particles per unit volume, it can be calculated using the formula:<br>Osm = M ([[Concentration|concentration]]) x n (number of particles) | ||
| Line 12: | Line 12: | ||
An example of osmosis:<br>Plants absorb water through their roots by osmosis | An example of osmosis:<br>Plants absorb water through their roots by osmosis | ||
[[Cell|Cells]] have a potential problem when maintaining their intracellular osmolarity due to metabolites e.g. sugars, amino-acids and nucleotides. These are large in size and highly charged, which attract many counterions. Thus significantly contribute to osmolarity. To control this problem cells actively pump out Na<sup>+</sup>, so their intracellular fluid contains a decreased number of inorganic [[ | [[Cell|Cells]] have a potential problem when maintaining their intracellular osmolarity due to [[Metabolites|metabolites]] e.g. sugars, amino-acids and nucleotides. These are large in size and highly charged, which attract many counterions. Thus significantly contribute to osmolarity. To control this problem cells actively pump out Na<sup>+</sup>, so their intracellular fluid contains a decreased number of inorganic [[Ion|ions]] than the extracellular fluid. This maintains osomotic equilibrium <ref>(Alberts B et al.,2008:664)</ref>. | ||
=== References''':''' === | === References''':''' === | ||
<references /> | <references /> | ||
Revision as of 16:14, 1 December 2015
Osmosis is the movement of water molecules from a high water concentration (hypotonic solution) to a low water concentration (hypertonic solution) through a semi-permeable membrane. It can also be described as the movement of water from a low solute concentration to a high solute concentration through a semi-permeable membrane.
- Concentration gradients affects osmosis, the higher the concentration gradient the higher the osmosis rate.
- Osmosis can be decreased by increasing the osmotic pressure of the hypertonic solution relative to the hypotonic solution [1].
Osmosis is very important in the biological systems, as water moves across cell membranes by osmosis. Water movement is essential to maintain the osmolarity of the cell.
Osmolarity is defined as the number of water particles per unit volume, it can be calculated using the formula:
Osm = M (concentration) x n (number of particles)
Water will always move from an area of low osmolarity to an area of high osmolarity.
An example of osmosis:
Plants absorb water through their roots by osmosis
Cells have a potential problem when maintaining their intracellular osmolarity due to metabolites e.g. sugars, amino-acids and nucleotides. These are large in size and highly charged, which attract many counterions. Thus significantly contribute to osmolarity. To control this problem cells actively pump out Na+, so their intracellular fluid contains a decreased number of inorganic ions than the extracellular fluid. This maintains osomotic equilibrium [2].
References:
- ↑ Patlak, J., (2000) Osmosis, available at http://physioweb.uvm.edu/bodyfluids/osmosis.htm (last accessed 14/11/2011).
- ↑ (Alberts B et al.,2008:664)