PEx9 ReviewSheet Ex01
Physioex 9.0
Review Sheet
Exercise 1
Cell Transport Mechanisms and Permeability
Name __Christopher Scott_
Lab Time/Date ___1/15/2014
Activity 1 Simulating Dialysis (Simple Diffusion)
1. Describe two variables that affect the rate of diffusion. ___
Two variables that affect rate of diffusion are molecule size and plasma membrane composition. A larger molecule will diffuse more slowly than a smaller molecule. The lipid content of the plasma membrane determines permeability of certain molecules. A plasma membrane with a higher lipid content is less permeable to water; however, it (more readily) allows transport of lipid soluble molecules. ___
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? Urea molecules are too large (molecular weight of Urea is 60.07 g/mol) to pass through the 20 MWCO membrane. The results of the experiment correlated with my prediction.
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? As expected, glucose, with a molecular weight of approximately 180 g/mol, readily diffused across the 200 MWCO membrane; whereas, albumin did not diffuse across the 200 MWCO. Albumin is a protein composed of 67 amino acids and its molecular weight is significantly greater than 200 g/mol, accordingly the molecules were too large to pass through the 200 MWCO membrane. The results of the experiment supported my predictions.___
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea. ___ Sodium chloride < urea < glucose < 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.___ Simple and facilitated diffusion both transport molecules down the concentration gradient of the solute. As well, they do not
Review Sheet
Exercise 1
Cell Transport Mechanisms and Permeability
Name __Christopher Scott_
Lab Time/Date ___1/15/2014
Activity 1 Simulating Dialysis (Simple Diffusion)
1. Describe two variables that affect the rate of diffusion. ___
Two variables that affect rate of diffusion are molecule size and plasma membrane composition. A larger molecule will diffuse more slowly than a smaller molecule. The lipid content of the plasma membrane determines permeability of certain molecules. A plasma membrane with a higher lipid content is less permeable to water; however, it (more readily) allows transport of lipid soluble molecules. ___
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? Urea molecules are too large (molecular weight of Urea is 60.07 g/mol) to pass through the 20 MWCO membrane. The results of the experiment correlated with my prediction.
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? As expected, glucose, with a molecular weight of approximately 180 g/mol, readily diffused across the 200 MWCO membrane; whereas, albumin did not diffuse across the 200 MWCO. Albumin is a protein composed of 67 amino acids and its molecular weight is significantly greater than 200 g/mol, accordingly the molecules were too large to pass through the 200 MWCO membrane. The results of the experiment supported my predictions.___
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea. ___ Sodium chloride < urea < glucose < 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.___ Simple and facilitated diffusion both transport molecules down the concentration gradient of the solute. As well, they do not