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, and Glucose at MWCO 200
5. Which did not? Why? Albumin, too large to diffuse
Activity 2: Simulating Dialysis
1. What happens to the urea concentration in the left beaker (the patient)? It mixes with the water to balance out the structure.
2. Why does this occur? Molecules are moving around to make space.
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 carrier porteins which varies in number due to the available membrane transport.
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?
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? It can still take place due to molecules moving all the time due to the mixture of concentration.
Activity 4: Osmosis
1. Did you observe any pressure changes during the experiment? If so, in which beaker(s), and with which membranes? Pressure changed in the left beaker with 20 MWCO
2. Why? Lower number in molecules moving around
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? Balance out the molecular structure
5. Explain the relationship between solute concentration and osmotic pressure? The solute cocentration will increase along with the