Review Sheet
Exercise 1
Cell Transport Mechanisms and Permeability
Name: Gayane koshkakaryan
Lab Time/Date: Friday 8am
Activity 1 Simulating Dialysis (Simple Diffusion)
1. Describe two variables that affect the rate of diffusion. a. Molecular weight b. Solute concentration
2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? a. Urea was unable to diffuse through the 20MWCO membrane because urea is a big molecule and the 20MWCO membrane pore size was too small for Urea. My predication was accurate, as I predicted that Urea would not be able to diffuse through the 20MWCO membrane
3. Describe the results of the attempts to diffuse glucose and albumin through the 200 MWCO membrane. How well did the results compare with your prediction? a. Glucose was able to diffuse through the 200MWCO membrane at a 0.0040 rate. However, albumin was not able to diffuse through the membrane as predicted. Albumin is a large protein that was not able to diffuse through the pore size of a 200MWCO membrane.
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea. a. Sodium Chloride, urea, glucose and albumin
Activity 2 Simulated Facilitated Diffusion
1. Explain one way in which facilitated diffusion is the same as simple diffusion and one way in which it differs. a. Both facilitated diffusion and simple diffusion move down a concentration gradient. b. Facilitated diffusion requires membrane carriers, while simple diffusion does not require it. 2. The larger value obtained when more glucose carriers were present corresponds to an increase in the rate of glucose transport. Explain why the rate increased. How well did the results compare with your prediction? a. When the glucose concentration increased, this increased the concentration difference between the two