Osmosis

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work.

Osmotic pressure is defined as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.

Osmosis is a vital process in biological systems, as biological membranes are semipermeable. In general, these membranes are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides, while being permeable to non-polar and/or hydrophobic molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, and nitric oxide. Permeability depends on solubility, charge, or chemistry, as well as solute size. Water molecules travel through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diffusing across the phospholipid bilayer via aquaporins (small transmembrane proteins similar to those responsible for facilitated diffusion and 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.

Osmosis (solitaire)

Osmosis (also known as Treasure Trove) is a solitaire game played with a deck of 52 playing cards where the object, like many solitaire games, is to put the cards into foundations, although not in numerical order.

Game play consists of four, vertically arranged reserve piles of four cards each (one face-up card on top of three face-down cards). A seventeenth card is put in the first (top) of four foundations, which are also arranged vertically to the right of the reserve piles. Cards with the same suit as this card must be moved to this foundation. The other three foundations are also built by suit, but must begin with cards of the same rank as the first card of the top foundation (the 17th card previously mentioned). Foundation piles are fanned from left to right. All undealt cards make up the stock.

To begin, the top cards in each reserve pile are the only cards in play and must be moved to the foundations if possible. A card can be moved to a foundation if a card of the same value has already been placed in the foundation above it. Once all possible cards have been placed in the foundations, the next face-down cards remaining in the reserve piles are turned face-up. When placing cards from the reserve piles is no longer possible, one can use the stock, deal three cards at a time, and use its top card to make possible moves. One can redeal the stock as long as there are possible moves from the stock or from the reserve piles to the foundations.

Osmosis (disambiguation)

Osmosis is the movement of molecules through a membrane.

Osmosis may also refer to:

Physical