high permeability Figure 11-2 Permeability coefficients (cm/sec)for the passage of various H2O molecules through synthetic lipid bilayers. The rate of flow of a solute across the bilayer is directly proportional to the difference in its concentration on the urea glycerol two sides of the membrane. Multiplying this concentration difference(in mol/cm) tryptophan glucose by the permeability coefficient(cm/sec) gives the flow of solute in moles per second per square centimeter of membrane. a concentration difference of tryptophan of 10-4 mol/cms(10-4/10-L 0.1 M), for example would cause a flow of 10 10-4 mol/cm3x 10-7 cm/sec=10-11 mol/sec through 1 cm2 of membrane or6x 104 10 molecules/sec through 1 microns 2 of low permeability membraneFigure 11-2 Permeability coefficients (cm/sec) for the passage of various molecules through synthetic lipid bilayers. The rate of flow of a solute across the bilayer is directly proportional to the difference in its concentration on the two sides of the membrane. Multiplying this concentration difference (in mol/cm3 ) by the permeability coefficient (cm/sec) gives the flow of solute in moles per second per square centimeter of membrane. A concentration difference of tryptophan of 10-4 mol/cm3 (10-4 /10-3 L = 0.1 M), for example, would cause a flow of 10-4 mol/cm3 x 10-7 cm/sec = 10-11 mol/sec through 1 cm2 of membrane, or 6 x 104 molecules/sec through 1 microns2 of membrane