Simulating Osmotic Pressure Lab Report

Cell Transport Mechanisms and Permeability: Simulating Osmotic Pressure Lab Report 1. Which of the following is true of osmosis? You correctly answered: c. It is a type of diffusion. 2. Which of the following occurs when a hypertonic solution is added to cells? You correctly answered: d. The cells shrink. 3. The variable that affects osmotic pressure is You correctly answered: a. the concentration of nondiffusing solutes. 4. The net movement of water would be into the cell in a You correctly answered: b. hypotonic solution. Experiment Results Predict Question: Predict Question 1: What effect do you think increasing the Na+ Cl- concentration will have? Your answer : a. increased osmotic pressure Predict Question 2: What do you think will be the pressure result of the current experimental conditions? Your answer : c. pressure above the left beaker Stop & Think Questions: Why do you think there is no pressure change? You correctly answered: b. Sodium is able to diffuse through the pores. Why do you think there was no pressure change? You correctly answered: c. There is no net movement of water because the solute concentrations are the same. Experiment Data: Run Number 1 1 1 2 2 2 3 3 Solute Na+ ClAlbumin Glucose Na+ ClAlbumin Glucose Na+ ClAlbumin MWCO 20 20 20 20 20 20 50 50 Start Conc. L 5.00 0.00 0.00 10.00 0.00 0.00 10.00 0.00 Pres. L 170 170 170 340 340 340 0 0 Start Conc. R 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Pres. R 0 0 0 0 0 0 0 0 Rate 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0167 0.0000 3 4 4 4 5 5 5 6 6 6 7 7 7 Glucose Na+ ClAlbumin Glucose Na+ ClAlbumin Glucose Na+ ClAlbumin Glucose Na+ ClAlbumin Glucose 50 100 100 100 100 100 100 200 200 200 200 200 200 0.00 0.00 0.00 8.00 0.00 0.00 8.00 0.00 0.00 8.00 0.00 9.00 0.00 0 136 136 136 0 0 0 0 0 0 153 153 153 0.00 0.00 0.00 0.00 0.00 0.00 8.00 0.00 0.00 0.00 0.00 0.00 10.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0036 0.0000 0.0000 0.0044 Post-lab Quiz Results 1. If you double the concentration of a nondiffusible solute that is on one side of a membrane, the osmotic pressure will You correctly answered: c. double. 2. Which membrane did not allow Na+ Cl- to pass through? You correctly answered: a. 20 MWCO 3. When a solute is able to diffuse through a membrane You correctly answered: b. equilibrium is reached. 4. Water diffuses You correctly answered: c. toward solutes. Review Sheet Results 1. Explain the effect that increasing the Na+ Cl- concentration had on osmotic pressure and why it has this effect. How well did the results compare with your prediction? Your answer: Increasing the sodium chloride ion concentration increased the osmotic pressure because it could not diffuse across the membrane. My prediction was confirmed by my results. 2. Describe one way in which osmosis is similar to simple diffusion and one way in which it is different. Your answer: Osmosis is the movement of water and diffusion is the movement of molecules. Both of them move from high concentration to low concentration. 3. Solutes are sometimes measured in milliosmoles. Explain the statement, “Water chases milliosmoles.” Your answer: Water goes where the milliosmoles are the highest because water moves toward regions of higher solute concentrations. 4. The conditions were 9 mM albumin in the left beaker and 10 mM glucose in the right beaker with the 200 MWCO membrane in place. Explain the results. How well did the results compare with your prediction? Your answer: Glucose can diffuse through the 200 MWCO membrane because of it is smaller than the membrane size. The albumin is too large therefore there is an increase in pressure. My results confirmed my prediction.