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Hope this helps,
Simple Diffusion
Activity 1: Simulating Simple diffusion
1. What is the molecular weight of Na+? 22.99
2. What is the molecular weight of Cl-? 35.45
3. Which MWCO dialysis membranes allowed both of these ions through? 50, 100 and 200
4. Which materials diffused from the left beaker to the right beaker? NaCl, Urea, Glucose
5. Which did not? Why? Albumin, it was too large to diffuse. The weight exceeds the MWCO causing it to be too big to pass through.
Activity 2: Simulating Dialysis
1. What happens to the urea concentration in the left beaker (the patient)? It is balanced out by mixing with water.
2. Why does this occur? Molecules are making room but moving around.
Facilitated Diffusion
Activity 3: Facilitated Diffusion
1. At a given glucose concentration, how does the amount of time it takes to reach equilibrium change with the number of carriers used to “build” the membranes? The molecules have to rely on proteins that are carriers. The amount of these carriers varies due to available membrane transport. The bigger the number of carriers the quicker it reaches the equilibrium.
2. Does the diffusion rate of Na+/Cl- change with the number of receptors? Yes
3. What is the mechanism of the Na+/Cl- transport? Plasma Vesticles
4. If you put the same amount of glucose in the right beaker as in the left, would you be able to observe any diffusion? No
5. Does being unable to observe diffusion necessarily mean that diffusion is not taking place? No
Osmosis
Activity 4: Osmosis
1. Did you observe any pressure changes during the experiment? If so, in which beaker(s), and with which membranes? The left beaker, 20MWCO Membrane the pressure increased.
2. Why? No occurrence of diffusion took place.
3. Did the Na+/Cl- diffuse from the left beaker to the right beaker? If so, with which membrane(s)? yes, 50 MWCO, 100 MWCO, 200 MWCO
4. Why? Because diffusion took place
5. Explain the relationship between solute concentration and osmotic pressure? yes, 50 MWCO, 100 MWCO, 200 MWCO
6. Does diffusion allow osmotic pressure to be generated? If solutes are able to diffuse then equilibrium will be established and osmotic pressure will bot be generated.
7. Would pressure be generated if solute concentrations were equal on both sides of the membrane? Osmotic pressure would be zero if albumin concentration was the same on both sides of the membrane.
8. Why or why not? If an increase in the concentration of albumin happens so will the increase of osmotic pressure.
9. Would pressure be generated if you had 9 mM glucose on one side of a 200 MWCO membrane and 9 mM NaCl on the other side? If so, which solution was generating the pressure? no, glucose and NaCl are diffusible with a 200 MWCO membrane.
10. Would pressure be generated if you had 9 mM albumin on one side of a 200 MWCO membrane and 9 mM NaCl on the other side? If so, which solution was generating the pressure? The albumin does not diffuse therefore it would generate pressure.
Filtration
Activity 5: Filtration
1. What were the results of your initial membrane analysis? Solute residue for all solutes were present.
2. Does the membrane MWCO affect filtration rate? Yes
3. Does the amount of pressure applied affect the filtration rate? Yes
4. Did all solutes pass through all the membranes? No
5. If not, which one(s) did not? Powdered Charcoal
6. Why? It was too large
7. How can the body selectively increase the filtration rate of a given organ or organ system? Increasing the pressure or a large porous membrane
Active Transport
Activity 6: Active Transport
1. At the end of this experimental run, did the Na+/Cl- move from the left vessel to the right vessel? No
2. Why? It was used up during the first three minutes.
3. As the run progresses, the concentrations of the solutes will change in the windows next to the two beakers. The rate will slow down markedly, then stop before completed. Why? The rate of active transport decreases.
4. Does the amount of NaCl/KCl transported change? Yes
5. Does the amount of solute transported across the membrane change with an increase in carriers or pumps? Yes
6. Is one solute more affected than the other? No they are both the same.
7. Does the membrane you “built” allow simple diffusion? No
8. If you placed 9 mM NaCl on one side of the membrane and 15 mM on the other side, would there be movement of the NaCl? Why? No because it is the same chemical so they are already balanced and have reached equilibrium.
9. Does the amount of ATP added make any difference? Yes
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