Hw1_Extra_PractiseBkey

Hw1_Extra_PractiseBkey - Extra practice 1 solutions 1 Extra...

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Extra practice 1 solutions 1 Extra Practice Problems (for the extra practice problems, only abbreviated answers are given. Answeres are provided for quick check of your work and are not meant to be comprehensive) Extra Practice Problem #1 Given: how a dye stains depends on what property of the cell it exploits. Nissyl dye stains rough ER. Find a picture of a typical neuron in your textbook, copy it, and attempt to predict the portion of the neuron that will be stained by Nissyl dye. Explain why you shaded the picture the way you did. The soma should be shaded in because the rough ER is in the soma Extra Practice Problem #2 For this question use the chart below. permeability outside[] in [] Cl- 0.59 82 31 K+ 1 7 139 Na+ 0.2 82 94 Br - 0 0.2 0.5 other non-permeable ions for osmotic balance Which of the following statements is true (keep in mind you have just disabled the pumps)? (1) K+ will have a larger net flux across the cell membrane than Cl- (2) Cl- will have a larger net flux across the cell membrane than K+ (3) One cannot determine which leaks more readily with the information given (4) Both ions have the same net flux across the cell membrane. G. Explain your answer The two contributors to net flux are (1) the net force which pushes ions through the membrane and (2) the permeability which allows the net force to push the ions through. If the net force driving K + is larger than that driving Cl - , and the K + permeability is greater than the Cl - permeability, then K + has a larger net flux. If the cell is more permeable to K + than Cl - but there is a smaller net force on K + than Cl - , then you cannot determine the answer since we did not tell you how to compare permeabilities and forces. Calculate RMP using GHK Æ -39.92 mV Calculate F chemical for Cl- Æ 24.29 afus in Calculate F electrical for Cl - Æ 39.92 afus out Calculate F net for Cl - Æ 15.63 towards outside for Cl - . Calculate F chemical for K + Æ 74.6 afus out Calculate F electrical for K + Æ 39.92 afus in Calculate F net for K + Æ 35.4 towards outside for K + . K + Cl - Chemical Force 74.6 out 24.3 out in Electrical Force 39.9 in 39.9 out Net Force 35.4 out 15.63 out Permeability 1.00 0.59 Since there is a larger net force on K+ and there is greater permeability for K+, there will be a larger net flux of K+ across the membrane.
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Extra practice 1 solutions 2 Extra Practice Problem #3 Use the concentrations and permeabilities from module 2.11 on the DelComyn CD. Assume the temparature is 0 degrees Celsius (the cell will not freeze, in fact many experiments are performed at this temperature). We will disable all pumps and immediately measure the net flux of ions. Under these conditions which of the following statements is true? (1) Na + will have a larger net flux across the cell membrane than Cl (2) Cl- will have a larger net flux per across the cell membrane than K + (3) One cannot determine which leaks more readily with the information given (4) Both ions have the same net flux across the cell membrane.
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Hw1_Extra_PractiseBkey - Extra practice 1 solutions 1 Extra...

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