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( Osmosis)
Osmosis is the diffusion of a solvent (frequently water) through a semi-permeable membrane, from a solution of low solute concentration (high water potential) to a solution with high solute concentration (low water potential), up a solute concentration gradient.[1] It is a physical process in which a solvent moves, without input of energy, across a semi-permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations.[2] Osmosis releases energy, and can be made to do work, as when a growing tree-root splits a stone. Net movement of solvent is from the less-concentrated (hypotonic) to the more-concentrated (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 osmotic pressure is defined to be the pressure required to maintain an equilibrium, with no net movement of solvent. Osmotic pressure is a colligative property, meaning that the property depends on the molar concentration of the solute but not on its identity. Osmosis is important in biological systems as many biological membranes are semipermeable. In general, these membranes are impermeable to organic solutes with large molecules, such as polysaccharides, while permeable to water and small, uncharged solutes. Permeability may depend on solubility properties, charge, or chemistry as well as solute size. Water molecules travel through the plasma cell wall, tonoplast (vacuole) or protoplast in two ways, either by diffusing across the phospholipid bilayer directly, or via 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 turgor pressure of a cell is largely maintained by osmosis, across the cell membrane, between the cell interior and its relatively hypotonic environment.[3] Osmosis may occur when there is a partially-permeable membrane, such as a cell membrane. When a cell is submerged in a glass of water, the water molecules pass through the cell membrane from an area of low solute concentration (outside the cell) to one of high solute concentration (inside the cell), this is called osmosis. The cell membrane is selectively permeable, so only necessary materials are let into the cell and waste left out.[4]
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Osmosis Subcategories
Osmosis Articles
Tips About GE Reverse Osmosis Water Filters by Andre Sylvester
GE reverse osmosis water filters use reverse osmosis technology to filter water for drinking. These filters require a semi-permeable membrane to catch any organisms that would otherwise come out of your tap. The filter can only catch substances that ...
Tips On What Is Reverse Osmosis and What Does It Do? by Andre Sylvester
What is reverse osmosis? Also called hyperfiltration, reverse osmosis is a commonly used water filtration system. While it was considered to be a fantastic invention in its time, it has now been superseded by more up to date and effective filter syst...
What You Need To Know About Water by Dr Edward Steiner
What makes up 70-80% of our planet? Water. What makes up 70-80% of our body? That's right, water.
Water is the single most important nutrient you will give your body apart from oxygen. Water rejuvenates us and carries vital nutrients al...
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