Bio 135 Anatomy and Physiology
Simple Diffusion 1. The following refer to Activity 1: Simulating Dialysis (Simple Diffusion). Which solute(s) were able to pass through the 20 MWCO membrane? None According to your results, which solute had the highest molecular weight? Albumin Which solute displayed the highest rate of diffusion through the 200 MWCO membrane? NACI_ Using the data from Chart 1, explain the relationship between the rate of diffusion and the size of the solute. The smaller the solute particle, the greater the rate of diffusion. Facilitated Diffusion 2. The following refer to Activity 2: Simulating Facilitated Diffusion.
Did any of the substances travel against their concentration gradient? Explain why or why not. No – In facilitated diffusion, substances can only move down their concentration gradient. Using your results from Chart 2, what was the fastest rate of facilitated diffusion recorded? 0. 0038 . Describe the conditions that were used to achieve this rate. 8mm glucose with 900 glucose carrier proteins. Name two ways to increase the rate of glucose transport. Increase amount of glucose solute and increase number of glucose carrier membrane. Did NaCl affect glucose transport? No Did NaCl require a transport protein for diffusion?
Why or why not? No because if its small size it can diffuse without a transport protein. Osmotic Pressure 3. The following refer to Activity 3: Simulating Osmotic Pressure. For NaCl, which MWCO membrane(s) provided for the net movement of water without movement of NaCl? 20 Explain how you determined this. (Hint: Correlate your results to the data in Chart 3. ) Osmotic pressure building up because of non-diffusable NACI in the solute causes water to diffuse its concentration gradient. For glucose, which MWCO membrane(s) provided for the net movement of glucose without net movement of water? 00 Explain how you determined this. No buildup of osmotic pressure shows glucose is able to diffuse down its concentration gradient. Is osmotic pressure generated if solutes diffuse freely? No Explain how the solute concentration affects osmotic pressure. The higher the solute concentration, the higher the osmotic pressure. Filtration 4. The following refer to Activity 4: Simulating Filtration. Using your results in Chart 4, which MWCO membrane had the greatest filtration rate? 200 Explain the relationship between pore size and filtration rate. The larger the pore size – the greater the filteration rate.
Which solute did not appear in the filtrate using any of the membranes? Powdered charcoal What is your prediction of the molecular weight of glucose compared to the other solutes in the solution? Greater weight. What happened when you increased the driving pressure? The filteration rate is increased. Explain why fluid flows from the capillaries of the kidneys into the kidney tubules. Because the pressure in the capillaries is higher than that of the kidney tubules. How do you think a decrease in blood pressure would affect filtration in the kidneys? Lower pressure would result in slower filtration rate. . The following refer to Activity 5: Simulating Active Transport. With 1 mMATP added to the cell interior (left beaker) and the extracellular space (right beaker), was all of the Na_ moved into the extracellular space? Why or why not? No, ATP was depleted in 3min. Describe the effect of decreasing the number of sodium-potassium pumps. Rate of active transport decreases. Describe how you were able to show that the movement of sodium was due to active transport. Sodium moved from left beaker to right beaker against its concentration gradient in active transport but not in diffusion.