PhysioEx Exercise 1

Exercise 1: Cell Transport Mechanisms and Permeability: Activity 1: Simulating Dialysis (Simple Diffusion) Lab Report
Pre-lab Quiz Results
You scored 100% by answering 4 out of 4 questions correctly.
1. The driving force for diffusion is
You correctly answered: b. the kinetic energy of the molecules in motion.
2. In diffusion, molecules move
You correctly answered: a. from high concentration to low concentration.
3. Which of the following dialysis membranes has the largest pore size?
You correctly answered: d. 200 MWCO
4. Avogadro's number is a constant for the number of
You correctly answered: b. molecules.
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Post-lab Quiz Results
You scored 100% by answering 4 out of 4 questions correctly.
1. The effect of increasing the concentration of sodium chloride from 9 mM to 18 mM in the left beaker was to
You correctly answered: b. increase the rate of diffusion.
2. Describe the difference between the rate of diffusion seen for sodium and urea.
You correctly answered: c. Urea diffused more slowly because it is larger than sodium.
3. Which of the following solutes did not pass through any of the membranes?
You correctly answered: b. albumin
4. When diffusion stops, we say the solution has reached
You correctly answered: a. equilibrium.

Review Sheet Results
1. Describe two variables that affect the rate of diffusion.
Your answer:
The two variable that affect the rate of diffusion are as follows:
-the composition of the lipid layer which can vary from tissue to tissue
-the size of the molecule(the larger the size the slower the rate of diffusion)
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?
Your answer:
The urea was not able to diffuse through 20 MWCO membrane becuase the urea molecule is too large for the membrane pores that were to small. The moleculer weight of 60.07 is too large for 20 MWCO membrane. Therefore, yes I was able to predict the correct results.
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?
Your answer:
Glucose was able to diffuse through 200 MWCO membrane, but albumin was not able to diffuse through it. The reason that glucose was able to diffuse through it and not albumin was because of its molecular weight difference. Albumin is far too large for 200 MWCO membrane. The results I obtain did not quite match my predications because I had predicted that they both wouldnt be able diffuse through 200 MWCO membrane, because I didnt do the proper calculations.
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.
Your answer: sodium chloride, urea, glucose, albumin