what is facilitated diffusion?
the movement of molecules from an area of high to low concentrations via protein channels or carriers not involving ATP
when not using the cells metabolic energy what forms of energy do substances passing though the membrane use?
kinetic energy
what molecules can diffuse through the bilayer
fat soluble molecules such as steroid hormones
because they dissolve in the lipid bilayer
why does water diffuse through a protein channel?
because it is polar and insoluble in lipid
factors that affect rage of diffusion
temperature diffusion distance surface area size of diffusing molecule concentration gradient
comment on the specificity of carrier proteins
there are specific carrier proteins for different types of molecules