The cell membranes of mammalian red blood cells are permeable tourea. If red blood cells are dropped into a solution of urea thatis identical in osmotic pressure (isosmotic) to the cytoplasm ofthe cells, although the cells do not swell and burst as quickly aswhen they are dropped simply into pure water, they eventually swelland burst. Explain. Also discuss how you would design a solutioninto which red cells could be placed without ever swelling. (Hint:Think about whether urea will stay on the outside of the cells andthe implications for osmotic pressures.)
