Physio Ex 9.0 Activity 1 Cell Transport Mechanisms and Permeability
ACTIVITY ONE- Cell Transport Mechanisms and Permeability: Simulating Dialysis (Simple Diffusion)
1. Describe two variables that affect the rate of diffusion.
Molecular weight affects the rate of diffusion because the bigger the size of the molecule the longer it will take to diffuse. Membrane size is another variable that affects the rate of diffusion because if the membrane’s pores are small it will take molecules longer to diffuse though it than if the pores were larger. Also, membrane thickness is a variable because the thinner the membrane the quicker the 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?
Our prediction was that urea was not going to be able to diffuse through the 20 Molecular Weight Cut Off (MWCO) membrane because urea is too big of a molecule to diffuse through the 20 MWCO membrane’s pores aren’t large enough for the urea to pass through. Our prediction was correct, the Urea was unable to diffuse though such a small 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?
We predicted that glucose and albumin would both diffuse very slowly through the 200 MWCO because they are large molecules. The results were; the glucose diffused through the 200 MWCO membrane at a rate of 0.0040 per minute. The albumin was not able to diffuse through the 200 MWCO because it is too large of a molecule to fit through the membrane pore.
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.
Sodium Chloride, Urea, Glucose, and Albumin.
ACTIVITY 2- Cell Transport Mechanisms and Permeability: Simulated Facilitated Diffusion
1. Describe two variables that affect the rate of diffusion.
Molecular weight affects the rate of diffusion because the bigger the size of the molecule the longer it will take to diffuse. Membrane size is another variable that affects the rate of diffusion because if the membrane’s pores are small it will take molecules longer to diffuse though it than if the pores were larger. Also, membrane thickness is a variable because the thinner the membrane the quicker the 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?
Our prediction was that urea was not going to be able to diffuse through the 20 Molecular Weight Cut Off (MWCO) membrane because urea is too big of a molecule to diffuse through the 20 MWCO membrane’s pores aren’t large enough for the urea to pass through. Our prediction was correct, the Urea was unable to diffuse though such a small 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?
We predicted that glucose and albumin would both diffuse very slowly through the 200 MWCO because they are large molecules. The results were; the glucose diffused through the 200 MWCO membrane at a rate of 0.0040 per minute. The albumin was not able to diffuse through the 200 MWCO because it is too large of a molecule to fit through the membrane pore.
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.
Sodium Chloride, Urea, Glucose, and Albumin.
ACTIVITY 2- Cell Transport Mechanisms and Permeability: Simulated Facilitated Diffusion