Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: Vemtira on Aug 15, 2011 Humany Anatomy & Physiology
Version 8.0 Physioex Exercise 1 CELL TRANSPORT MECHANISMS AND PERMEABILITY Solute Transport Through Nonliving Membranes Chart 1 - Dialysis Results (average diffusin rate in mM/min) Solute 20 50 100 200 NaCL - .0150 .0150 .0150 Urea - - .0094 .0094 Albumin - - - - Glucose - - - .0040 Which solute(s) were able to diffuse into the right beaker from the left? a. NaCl, Urea, and Glucose Which solute(s) did not difuse? a. Albumin If the solution in theleft beaker contained both urea and albumin, which membrane(s) could you choose to selectively remove the urea from the solution in the left beaker? How would you carry out this experiment? a. @16 min @ 200 = 4.5 in both beakers a. @16 min @ 100 = 4.5 in both beakers Assume that the solution in the left beaker contained NaCl in addition to the urea and albumin. How could you set up an experiment so that you removed the urea, but left the NaCL concentration unchanged? Hint: Assume that you also have control of the contents in the right beaker. a. put 9mm of NaCl in the right beker - equals out the urea @ 100 mwco Facilitated Diffusion Chart 2 - Facilitated Diffusion Results (glucose transport rate, mM/min) Glucose Concentration (mM) 500 700 900 2.00 .0008 .0010 .0012 8.0 .0023 .0031 .0038 What happened to the rate of facilitated diffusion as the number of protein carriers increased? Explain your answer. a. rate of diffusion increased as rate of protein carriers increased. What do you think would happen to the transport rate if you put the same concentration of glucose into both beakes instead of deionized wter in the right beaker? a. solutions are equal - no transfer occurs Should NaCL have an effect on glucose diffusion? Explain your answer. Use the simuation to see if it does. a. No - rate of diffusion is the same with NaCl added - NaCl has no transport proteins to aid in diffusing glucose. Simulating Osmotic Pressure Do you see any evidence of pressure changes in either beaker, using any of the four membranes? If so, which membrane(s). a. yes - the left beaker - increased pressure Does NaCl appear in the right beaker? If so, which membrane(s) allowed it to pass? a. yes - 50, 100, & 200 Chart 3 - Osmosis Results (pressuer in mm Hg) Solute 20 50 100 200 NaCl 272 - - - Albumin 153 153 153 153 Glucose 170 170 170 - Explain the relationship between solute concentration and osmotic pressure. a. if the solute concentration increases, the osmotic pressure increases. Will osmotic pressure be generated if solutes are able to diffuse? Explain your answer. a. No - if solutes diffuse, then the solutions will equalize Because the albumin molecule is much too large to pass through a 100 MWCO membrane, you should have noticed the development of osmotic pressure in the left beaker in the albumin run using the 100 MWCO membrane. What do you think would happen to the osmotic pressure if you replaced the deionized water in the right beaker with 9.00 mM albumin in that run? (Both beakers would contain 9.00 mM albumin.) a. Nothing - they are equalized. What would happen if you doubled the albumin concentration in the left beaker using any membrane? a. pressure remained the same - no diffusion occurs In the albumin run using the 200 MWCO membrane, what would happen to the osmotic pressure if you put 10 mM glucose in the right beaker instead of deionized water? Explain your answer. a. Albumin pressure remained @ 153 but 5.00 of the glucose diffused to the albumin beaker. What if you used the 100 MWCO membrane in the albumin/glucose run described in the previous question? a. No diffusion - but pressure in the right beaker increased to 17 mmHg. Simulating Filtration Chart 4 - Filtration Results Solute 20 50 100 200 Filtration Rate 1 2.5 5 10 NaCl in filtrate 0.00 4.80 4.81 4.81 NaCl membrane residue + + + + Urea in filtrate 0.00 0.00 4.74 4.74 Urea membrane residue + + + + Glucose in filtrate 0.00 0.00 0.00 4.39 Glucose in membrane + + + + residue Powdered Charcoal in filtrate 0.00 0.00 0.00 0.00 in membrane residue + + + + How did the membrane's MWCO affect the filtration rate? a. the filtration rate increased as the solute # increased Which solute did not appear in the filtrate using any of the membranes? a. powdered charcoal What would happen if you increased the driving pressure? Use the simulation to arrive at an answer. a. the concentration remained the same but the filtrate rate increased. Explain how you can increase the filtration rate t hrough living membranes. a. increasing pressure increases filtration rate. By examining the filtration results, we can predict that the molecular weight of glucose must be greater than 100 but less than 200. Simulating Active Transport Watch the solute concentration windows at the side of each beaker for any c hanges in Na and K concentrations. The Na transport rate stops before transport has completed. Why do you think that this happens? a. the Na/K concentrate have equalized. What would happen if you did not dispense anyt ATP? a. no transport occurs Has the amount of Na transported change? a. yes - ATP @ 1 = 5.613 ATP @ 3 = .001 What would happen if you decreased the number of sodium-potassium pumps? a. ATP @1 = 2.613 ATP @ 3 = no diffusion As ATP decreases, diffusion decreases Explain how you could show that phenomenon is not just simple diffusion. (Hint: Adjust the Na concentration in the right beaker.) a. as ATP decreases, diffusion decreases Click either Flush buttn to clean both beakers. Now repeat 1 through 6, dispensing 9.00 mM NaCl into the left beaker and 10.00 mM NaCl into the right beaker (instead of 6.00 mM KCl). Is Na transport affected by this change? Explain your answer. a. ATP @1 = no transport ATP @3 = no transport Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: bio_man on Aug 15, 2011 Are these answers to the questions? Hard to tell :P
Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: Vemtira on Aug 16, 2011 Yes sorry, my first time to use this program and had a really tough time with it. Every time I tried to put information in, the page would reboot. Don't know if I can edit it and put on the title that they are the answers. Can I? Hopefully it will get easier to post in here.
Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: cindy.a.shaw on Sep 5, 2011 I have to write a scientific lab report on these experiments. No idea how to tie them together? Can't even come up with my intro or hypothesis! Any ideas?
Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: duddy on Sep 5, 2011 Can't even come up with my intro or hypothesis! Well, what do you assume will happen? That's what a hypothesis is. Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: Vemtira on Sep 6, 2011 I agree with Duddy. You can find posts with answers here, and that helps you out, but if you don't understand the process, then the answers are not going to do you any good in the long run. You need to understand the processes of cell transport and membrane permeability, what can and cannot permeate the membrane. Even though the answers are posted here, you must do the experiments and utilize the answers to help you get an understanding of what is happening. Understanding this process is important for all the other chapters you will be studying throughout the semester. If you don't get a basic understanding of this process, then you will struggle the entire semester, and further studies down the line.
If you have access to Mastering A & P, there are some really good videos that help you to understand the process. Once you get an understanding of the processes, then you should be able to put this paper together. If you don't have access to Mastering A & P, there are videos posted on You Tube as well. Good luck! Title: Cell Transport Mechanisms and Permeability (Physioex 8.0) Post by: bio_man on Sep 6, 2011 If you don't have access to Mastering A & P, there are videos posted on You Tube as well. Or you can request animations and we'll post them here. |