Cell Transport Mechanisms and Permeability
Name: Jeffery Cook
Lab Time/Date: 12pm 2/09/2015
Activity 1 Simulating Dialysis (Simple Diffusion)
1. Describe two variables that affect the rate of diffusion. a. Two variables that affect the rate of diffusion are size and whether or not there is an electrical or concentration gradient. 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? a. My prediction was incorrect. I think the urea was not able to diffuse through the 20 MWCO membrane because the molecular weight of urea is about 60. This means it is above the molecular weight cut off and cannot diffuse. 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? a. The glucose was able to diffuse because its molecular weight was less than 200, while the albumin was much larger than 200 and could not diffuse. My prediction was wrong as I originally thought that the MW of glucose was higher than 200. 4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea. a. The molecular weight from smallest to greatest is 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. a. One way that facilitated diffusion and simple diffusion are the same is that the substance being moved will both move along or down with the concentration gradient. They are different in that Facilitated diffusion requires a membrane bound carrier protein while simple diffusion does not. 2. The larger value obtained when more glucose carriers were present corresponds to an increase in the rate of glucose transport. Explain why the rate increased. How well did the results compare...
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