Name: Amber Pitcher
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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Experiment Results
Predict Question:
Predict Question 1: The molecular weight of urea is 60.07. Do you think urea will diffuse through the 20 MWCO membrane?
Your answer : c. No, not at all.
Predict Question 2: Recall that glucose is a monosaccharide, albumin is a protein with 607 amino acids, and the average molecular weight of a single amino acid is 135 g/mole.
Which of the following will be able to diffuse through the 200 MWCO membrane?
Your answer : b. both glucose and albumin
Stop & Think Questions:
The reason sodium chloride didn't diffuse left to right is that
You correctly answered: c. the membrane pore size was too small.
Glucose is a six-carbon sugar. Albumin is a protein with 607 amino acids. The average molecular weight of a single amino acid is 135 g/mole. There is no reason to run these solutes at the 20 MWCO because
You did not answer this question.
Correct answer: d. glucose and albumin are both too large to pass.
The rate of diffusion for urea
You correctly answered: b. is slower than that for sodium because urea is a larger molecule.
Experiment Data:
Solute

MWCO

Left Solute Concentration

Right Solute Concentration

Na+ ClUrea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose
Na+ Cl-

20
20
20
20
20
20
20
20
50
50
50
50
50
50
50
50
100
100
100
100
100

9.00
0.00
0.00
0.00
0.00
9.00
0.00
0.00
9.00
0.00
0.00
0.00
18.00
0.00
0.00
0.00
9.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

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Average Diffusion
Rate
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0150
0.0000
0.0000
0.0000
0.0273
0.0000
0.0000
0.0000
0.0150
0.0000
0.0000
0.0000
0.0000

Solute

MWCO

Left Solute Concentration

Right Solute Concentration

Urea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose
Na+ ClUrea
Albumin
Glucose

100
100
100
200
200
200
200
200
200
200
200

9.00
0.00
0.00
0.00
0.00
0.00
9.00
0.00
0.00
9.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

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Average Diffusion
Rate
0.0094
0.0000
0.0000
0.0000
0.0000
0.0000
0.0042
0.0000
0.0000
0.0000
0.0000

Post-lab Quiz Results
You scored 50% by answering 2 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
Your answer: a. decrease the rate of diffusion.
Correct answer: 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?
Your answer: a. glucose
Correct answer: b. albumin
4. When diffusion stops, we say the solution has reached
You correctly answered: a. equilibrium.

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Review Sheet Results
1. Describe two variables that affect the rate of diffusion.
Your answer:
A larger molecular size slows the rate of diffusion, and a smaller concentration increases 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 molecule was too large.
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 diffues, while Albumin was not, because it was too large.
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.
Your answer:
Sodium Chloride, Urea, Glucose, and Albumin

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