Cell Transport Mechanisms and Permeability: Computer Simulation

Simple Diffusion 1. The following refer to Activity 1: Simulating Dialysis (Simple Diffusion). Which solute(s) were able to pass through the 20 MWCO membrane? According to your results, which solute had the highest molecular weight? ______________________________________ Which solute displayed the highest rate of diffusion through the 200 MWCO membrane? __________________________ Using the data from Chart 1, explain the relationship between the rate of diffusion and the size of the solute. Facilitated Diffusion 2. The following refer to Activity 2: Simulating Facilitated Diffusion.

Did any of the substances travel against their concentration gradient? Explain why or why not. Using your results from Chart 2, what was the fastest rate of facilitated diffusion recorded? _______________. Describe the conditions that were used to achieve this rate. ___________________________________________________________ Name two ways to increase the rate of glucose transport. _____________________________________________________ Did NaCl affect glucose transport? ____________________________________________________________ __________ Did NaCl require a transport protein for diffusion? Why or why not? ___________________________________________ Cell Transport Mechanisms and Permeability: Computer Simulation E X E R C I S E NAME ____________________________________ LAB TIME/DATE ________________________ version 8 Osmotic Pressure 3. The following refer to Activity 3: Simulating Osmotic Pressure. For NaCl, which MWCO membrane(s) provided for the net movement of water without movement of NaCl? Explain how you determined this. (Hint: Correlate your results to the data in Chart 3. ) ______________________________ For glucose, which MWCO membrane(s) provided for the net movement of glucose without net ovement of water? Explain how you determined this. ____________________________________________________________ ___________ Is osmotic pressure generated if solutes diffuse freely? _______________________________________________________ Explain how the solute concentration affects osmotic pressure. ________________________________________________ Filtration 4. The following refer to Activity 4: Simulating Filtration. Using your results in Chart 4, which MWCO membrane had the greatest filtration rate? ____________________________ Explain the relationship between pore size and filtration rate. ________________________________________________ Which solute did not appear in the filtrate using any of the membranes? _________________________________________ What is your prediction of the molecular weight of glucose compared to the other solutes in the solution? _______________ What happened when you increased the driving pressure? ____________________________________________________ Explain why fluid flows from the capillaries of the kidneys into the kidney tubules. How do you think a decrease in blood pressure would affect filtration in the kidneys? _____________________________ PEx-18 Review Sheet 5B 5. The following refer to Activity 5: Simulating Active Transport. With 1 mMATP added to the cell interior (left beaker) and the extracellular space (right beaker), was all of the Na moved into the extracellular space? Why or why not? ____________________________________________________________ _ Describe the effect of decreasing the number of sodium-potassium pumps. _______________________________________ Describe how you were able to show that the movement of sodium was due to active transport. ______________________