| 释义 |
osmosis
os·mo·sis O0138500 (ŏz-mō′sĭs, ŏs-)n. pl. os·mo·ses (-sēz) 1. a. Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal solute concentration on both sides of the membrane.b. The tendency of fluids to diffuse in such a manner.2. A gradual, often unconscious process of assimilation or absorption: learned French by osmosis while residing in Paris for 15 years.
[From obsolete osmose, from earlier endosmose, from French : Greek endo-, endo- + Greek ōsmos, thrust, push (from ōthein, to push).]
os·mot′ic (-mŏt′ĭk) adj.os·mot′i·cal·ly adv.osmosis (ɒzˈməʊsɪs; ɒs-) n1. (Biology) the passage of a solvent through a semipermeable membrane from a less concentrated to a more concentrated solution until both solutions are of the same concentration2. (Chemistry) the passage of a solvent through a semipermeable membrane from a less concentrated to a more concentrated solution until both solutions are of the same concentration3. (General Physics) diffusion through any membrane or porous barrier, as in dialysis4. gradual or unconscious assimilation or adoption, as of ideas[C19: Latinized form from osmose (n), from Greek ōsmos push, thrust] osmotic adj osˈmotically advos•mo•sis (ɒzˈmoʊ sɪs, ɒs-)
n. 1. a. the tendency of a fluid, usu. water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane. b. the diffusion of fluids through membranes or porous partitions. 2. a subtle or gradual absorption: to learn by osmosis. [1865–70; Latinized form of now obsolete osmose osmosis, extracted from endosmose endosmosis < French, =end- end- + Greek ōsm(ós) push, thrust + French -ose -osis] os•mot′ic (-ˈmɒt ɪk) adj. os•mot′i•cal•ly, adv. ![]() osmosisleft: The concentration of sugar molecules is greater on the right side of the membrane than on the left. The water molecules are small enough to move across the membrane, but the larger sugar molecules cannot pass through.right: The water molecules move across the membrane until the water and sugar molecules are of equal concentration on both sides. This lowers the water level on the left side and raises it on the right side.os·mo·sis (ŏz-mō′sĭs) The movement of a solvent through a membrane separating two solutions of different concentrations. The solvent from the side of weaker concentration usually moves to the side of the stronger concentration, diluting it, until the concentrations of the solutions are equal on both sides of the membrane. ♦ The pressure exerted by the molecules of the solvent on the membrane they pass through is called osmotic pressure. Osmotic pressure is the energy driving osmosis and is important for living organisms because it allows water and nutrients dissolved in water to pass through cell membranes.osmosisthe process by which fluids pass through a semipermeable membrane into a solution of lower concentration to equalize the concentration on both sides of the membrane. — osmotic, adj.See also: Processes
the process by which fluids pass through a semipermeable membrane into a solution of lower concentration to equalize the concentration on both sides of the membrane. — osmotic, adj.See also: Cellsosmosis
1. Movement of water through a selectively permeable membrane, e.g. a cell membrane.2. The movement of solvent molecules through a semipermeable membrane from a dilute solution to a more concentrated solution.3. Diffusion of a fluid (e.g., water) through a semipermeable membrane.Thesaurus| Noun | 1. |  osmosis - (biology, chemistry) diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equaldialysis - separation of substances in solution by means of their unequal diffusion through semipermeable membranesbiological science, biology - the science that studies living organismschemical science, chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactionsdiffusion - (physics) the process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentrationreverse osmosis - (chemistry) a method of producing pure water; a solvent passes through a semipermeable membrane in a direction opposite to that for natural osmosis when it is subjected to a hydrostatic pressure greater than the osmotic pressure |
TranslationsOsmoseώσμωσηosmosiosmoseосмосosmosis
osmosis (ŏzmō`sĭs), transfer of a liquid solvent through a semipermeable membrane that does not allow dissolved solids (solutes) to pass. Osmosis refers only to transfer of solvent; transfer of solute is called dialysisdialysis
, in chemistry, transfer of solute (dissolved solids) across a semipermeable membrane. Strictly speaking, dialysis refers only to the transfer of the solute; transfer of the solvent is called osmosis.
..... Click the link for more information. . In either case the direction of transfer is from the area of higher concentration of the material transferred to the area of lower concentration. This spontaneous migration of a material from a region of higher concentration to a region of lower concentration is called diffusiondiffusion,
in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life processes.
..... Click the link for more information. . Principles of Osmosis Osmosis will occur if a vessel is separated into two compartments by a semipermeable membrane, both compartments are filled to the same level with a solvent, and solute is added to one side. The level of the liquid on the side containing the solute will rise as the solvent flows from the side of its higher concentration to the side of lower concentration. If an external pressure is exerted on the side containing the solute, the transfer of solvent can be stopped and even reversed (reverse osmosis). Two solutions separated by a semipermeable membrane are said to be isotonic if no osmosis occurs. If osmosis occurs, transfer of solvent is from the hypotonic solution to the hypertonic solution, which has the higher osmotic pressure. The minimum pressure necessary to stop solvent transfer is called the osmotic pressure. Since the osmotic pressure is related to the concentration of solute particles, there is a mathematical relationship between osmotic pressure, freezing-point depression, and boiling-point elevation. Properties such as osmotic pressure, freezing point, and boiling point, which depend on the number of particles present rather than on their size or chemical nature, are called colligative properties. For dilute solutions the mathematical relationship between the osmotic pressure, temperature, and concentration of solute is much like the relation between pressure, temperature, and volume in an ideal gas (see gas lawsgas laws,
physical laws describing the behavior of a gas under various conditions of pressure, volume, and temperature. Experimental results indicate that all real gases behave in approximately the same manner, having their volume reduced by about the same proportion of the
..... Click the link for more information. ). A number of theories explaining osmotic pressure by analogy to gases have been devised, but most have been discarded in favor of thermodynamic interpretations using such concepts as the entropy of dilution. Biological Importance of Osmosis Osmosis and dialysis are of prime importance in living organisms, where they influence the distribution of nutrients and the release of metabolic waste products. Living cells of both plants and animals are enclosed by a semipermeable membrane called the cell membrane, which regulates the flow of liquids and of dissolved solids and gases into and out of the cell. The membrane forms a selective barrier between the cell and its environment; not all substances can pass through the membrane with equal facility. Without this selectivity, the substances necessary to the life of the cell would diffuse uniformly into the cell's surroundings, and toxic materials from the surroundings would enter the cell. If blood cells (or other cells) are placed in contact with an isotonic solution, they will neither shrink nor swell. If the solution is hypertonic, the cells will lose water and shrink (plasmolyze). If the solution is hypotonic (or if pure solvent is used) the cells will swell; the osmotic pressure that is developed may even be great enough to rupture the cell membrane. Saltwater from the ocean is hypertonic to the cells of the human body; the drinking of ocean water dehydrates body tissues instead of quenching thirst. In plants osmosis is at least partially responsible for the absorption of soil water by root hairs and for the elevation of the liquid to the leaves of the plant. However, plants wilt when watered with saltwater or treated with too much fertilizer, since the soil around their roots then becomes hypertonic. Osmosis the passage of a substance, usually a solvent, through a semipermeable membrane that separates a solution from a pure solvent or two solutions of different concentrations from each other. A semipermeable membrane allows small molecules of a solvent to pass through but is impermeable to larger molecules. The concentrations on both sides of such a membrane can be equalized only by unilateral diffusion of the solvent. Hence, osmosis always proceeds from a pure solvent to a solution or from a dilute solution to a more concentrated one. Osmosis within an enclosed volume of liquid is called endosmosis, and osmosis to the outside is called exosmosis. A solvent is transported through a membrane by osmotic pressure, which is equal to the excess external pressure that has to be exerted by the solution in order to stop osmosis, that is, to create the condition of osmotic equilibrium. Excess pressure above the osmotic pressure may lead to reversal of osmosis, or reverse diffusion, of the solvent. In cases where a membrane is permeable not only to a solvent but also to some dissolved substances, diffusion of the solutes from the solution into the solvent is called dialysis, which is used to separate polymers and colloidal systems from low-molecular admixtures. Osmosis was first observed by J. A. Nollet in 1748 but was not thoroughly studied until a century later. A major factor in biological processes, it is widely used in laboratory work to study various biological structures and to determine the molecular characteristics of polymers and the concentration of solutions. Osmotic phenomena are sometimes utilized in industry, for example, to produce certain polymeric materials or to purify highly mineralized water by reverse osmosis. L. A. SHITS osmosis[ä′smō·səs] (physical chemistry) The transport of a solvent through a semipermeable membrane separating two solutions of different solute concentration, from the solution that is dilute in solute to the solution that is concentrated. osmosis1. the passage of a solvent through a semipermeable membrane from a less concentrated to a more concentrated solution until both solutions are of the same concentration 2. diffusion through any membrane or porous barrier, as in dialysis osmosis
osmosis [oz-mo´sis, os-mo´sis] the diffusion of pure solvent across a membrane in response to a concentration gradient, usually from a solution of lesser to one of greater solute concentration. adj., adj osmot´ic.
The process of osmosis and the factors that influence it are important clinically in the maintenance of adequate body fluids and in the proper balance between volumes of extracellular and intracellular fluids.
The term osmotic pressure refers to the amount of pressure necessary to stop the flow of water across the membrane. The hydrostatic pressure of the water exerts an opposite effect; that is, it exerts pressure in favor of the flow of water across the membrane. The osmotic pressure of the particles in a solute depends on the relative concentrations of the solutions on either side of the membrane, and on the area of the membrane. The osmotic pressure exerted by the nondiffusible particles in a solution is determined by the numbers of particles in a unit of fluid and not by the mass of the particles. If the solution surrounding a cell has the same solute concentration as the internal environment of the cell (isotonic), the flow rates in and out of the cell are the same, and the cell remains the same size. If the solute concentration outside the cell is lower (hypotonic), more water will flow into the cell than out, and the cell will swell and perhaps burst. If the solute concentration outside the cell is greater (hypertonic), more water will flow out of the cell than into it, and the cell will shrivel. Demonstration of osmotic pressure on the two sides of a semipermeable membrane.os·mo·sis (os-mō'sis), The process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of the solutes to which the membrane is relatively impermeable. [G. ōsmos, a thrusting, an impulsion] osmosis (ŏz-mō′sĭs, ŏs-)n. pl. osmo·ses (-sēz) 1. a. Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal solute concentration on both sides of the membrane.b. The tendency of fluids to diffuse in such a manner.2. A gradual, often unconscious process of assimilation or absorption: learned French by osmosis while residing in Paris for 15 years.
os·mot′ic (-mŏt′ĭk) adj.os·mot′i·cal·ly adv.os·mo·sis (oz-mō'sis) The process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of the solutes to which the membrane is relatively impermeable. [G. ōsmos, a thrusting, an impulsion]osmosis (oz-mō′sĭs) [Gr. osmos, impulse, + osis, condition]  OSMOSISThe passage of solvent through a semipermeable membrane that separates solutions of different concentrations. The solvent, usually water, passes through the membrane from the region of lower concentration of solute to that of a higher concentration of solute, thus tending to equalize the concentrations of the two solutions. The rate of osmosis is dependent primarily upon the difference in osmotic pressures of the solutions on the two sides of a membrane, the permeability of the membrane, and the electric potential across the membrane and the charge upon the walls of the pores in it. See: illustrationreverse osmosisA form of water treatment that removes infectious particles and dissolved ions more effectively than other water purification techniques. Water so purified can be used in hemodialysis. osmotic (oz-mot′ik), adjectiveillustrationosmosis The automatic movement of the fluid part of a solution through a membrane, separating two quantities of the solution, in such a direction as to dilute the solution of higher concentration. The membrane is permeable to the liquid but not to the dissolved substance. Such a membrane is said to be semipermeable and membranes of this kind occur widely in the body. Osmosis is an important principle on which much of physiology is based.osmosis the movement of a solvent (water in biological systems) through a differentially permeable membrane from a solution with high water concentration and low solute concentration, to one with a low water concentration and high solute concentration.osmosis A passive process of movement of water through a semipermeable membrane in response to a concentration gradient, from an area of low solute (e.g. glucose molecules) concentration (i.e. high water concentration) to one of high solute concentration (i.e. low water concentration). The membrane is permeable to water but relatively impermeable to solutes. See osmotic pressure; hypertonic solution.os·mo·sis (os-mō'sis) Process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of solutes to which membrane is relatively impermeable. [G. ōsmos, a thrusting, an impulsion]OSMOSIS
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osmosis
Related to osmosis: reverse osmosis, diffusionWords related to osmosisnoun (biology, chemistry) diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equalRelated Words- dialysis
- biological science
- biology
- chemical science
- chemistry
- diffusion
- reverse osmosis
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