# Cell Transport

Topics: Molecular diffusion, Diffusion, Transport phenomena Pages: 2 (579 words) Published: December 6, 2011
Exercise 1: Cell Transport Mechanisms and Permeability: Activity 1: Simulating Dialysis (Simple Diffusion) Lab Report Pre-lab Quiz Results You have not completed the Pre-lab Quiz.

09/20/11

page 1

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 : a. neither glucose nor 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 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 Na+ ClUrea Na+ ClNa+ ClNa+ ClUrea Glucose Albumin MWCO 20 20 50 50 100 100 200 200 Solute Concentration 9.00 9.00 9.00 18.00 9.00 9.00 9.00 9.00 Average Diffusion Rate 0.0000 0.0000 0.0150 0.0300 0.0150 0.0094 0.0040 0.0000

09/20/11

page 2

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: c. no change to 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. Your answer: b. Urea diffused faster because it is smaller than sodium. Correct answer: c. Urea...