Activity 2: Facilitated Diffusion



No. of glucose carrier proteins

Glucose Concentration (mM)





















At a given glucose concentration, how does the amount of time it takes to reach equilibrium change with the number of carriers used to “build” the membrane?






Does the diffusion rate of Na+/Cl- change with the number of receptors?






What is the mechanism of the Na+/Cl- transport?






If you put the same amount of glucose in the right beaker as in the left, would you be able to observe any diffusion?






Does being unable to observe diffusion necessarily mean that diffusion is not taking place?


Activity 4: Filtration


What were the results of your initial membrane analysis?




Does the membrane MWCO affect filtration rate?




Does the amount of pressure applied affect the filtration rate?




Did all solutes pass through all the membranes?





If not, which one(s) did not?











How can the body selectively increase the filtration rate of a given organ or organ system?














Activity 6: Active Transport


At the end of this experimental run, did the Na+/Cl- move from the left vessel to the right vessel?







As the run progresses, the concentrations of the solutes will change in the windows next to the two beakers.  The rate will slow down markedly, then stop before completed.  Why?





Now that you have performed the basic experiment, let’s conduct two variations.

12. Repeat the experiment, except increase the amount of ATP added to the system.


Does the amount of NaCl/KCl transported change?




13. Repeat the experiment, except change the number of carriers and pumps when you build the membrane.


Does the amount of solute transported across the membrane change with an increase in carriers or pumps?



Is one solute more affected than the other?




Does the membrane you “built” allow simple diffusion?



If you place 9 mM NaCl on one side of the membrane and 15 mM on the other side, would there be movement of the NaCl?






Does the amount of ATP added make any difference?