Cell Permeability essays

Cell Permeability essays Most cells are freely permeable to water that diffuses through aquaporins (water channels) in the selectively permeable plasma membrane. This movement of water is termed osmosis and occurs in response to an osmotic pressure gradient across the cell membrane. The osmolality of a solution is the total concentration of particles of solute, measured by the number of osmotically active particles per kg-1 of water (Boron A solution with a higher osmolarity is hyperosmotic, and one with lower osmolarity is described as being hypoosmotic. The tonicity of a solution describes the effect of that solution on the volume of the cells suspended in it, and is sometimes referred to as the effective osmolality (Boron RBC's placed in a hypertonic solution will lose water, and shrink. This is termed crenation, where the shape of the RBC becomes shrivelled and spikey in appearance (Tortora and Derrickson, 2009). If the RBCs are placed in hypotonic solution, they swell until they are spherical in shape. Further swelling will cause rupture of th...