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Unformatted text preview: CMSC 131 Partial Solution for Lab #2, Ionic Channels and the Action Potential I.2 and I.4. When you plot EK vs log[K]out, you should get a plot like that shown below. If you calculate the slope of the line using two points that are on it, you get slope = (y2-y1)/(x2-x2) = 24.1. This is very close to the calculated value of (RT/zF) obtained using the values for the Nernst Equation on the handout that I provided. This equation is applicable because we are examining the equilibrium between electrostatic and thermal forces for a single, isolated ion species, K+. Similar slope values are obtained for Na+ (not shown). IV.4. In this experiment you are varying the external concentration of Na, which is similar to what Hodgkin and Katz did in their 1949 paper. H&K manipulated Na by varying the salinity of the external sea water. They also argue that the internal concentration of sodium remains constant, though I'm not sure what level they assumed for it. Their methods state that they used 0.560 molar NaCl diluted to 80%, sure what level they assumed for it....
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- Fall '09