[PhysioEX Chapter 1 exercise 1] PEX-01-01

Solved by ramonistry

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.

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 : c. glucose only
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 correctly answered: 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 Solute Concentration Average Diffusion Rate
Na+ Cl- 20 9.00 0.0000
Urea 20 9.00 0.0000
Na+ Cl- 50 9.00 0.0150
Na+ Cl- 50 18.00 0.0300
Na+ Cl- 100 9.00 0.0150
Urea 100 9.00 0.0094
Glucose 200 9.00 0.0040
Albumin 200 9.00 0.0000

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:
   size and concentration of solute.
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:
   As predicted, Urea was too big to pass through the 20 MWCO 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?
   Your answer:
   The glucose diffused through the 200MWCO membrane, while there was no diffusion of albumin as predicted. Albumin is
   too big to pass through 200 MWCO membrane.
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.