BILD 2 Week 2 Section Practice

BILD 2 Week 2 - 36 250 K ⁺ 165 50 Ca² ⁺ 8 200 Clˉ.01 8 a Multiple synthesized chloride leak channels are inserted into the cell Taking only

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TA: Lauren Herzog Email : [email protected] Office Hours: Mondays, 11-11:50am, Geisel HSS Library (tables to the left of the computer area) or by appointment After this week, multiple practice problems will be posted on WebCT on the Friday night before Monday’s section. Please print them out beforehand. I strongly encourage you to attempt these problems before coming to section. Practice Problem: Cystic Fibrosis is a serious disease caused by the mutation of a gene needed for proper transmembrane transport. A researcher is interested in studying ion transport in cells of patients with this disease. The researcher isolates the cells and then measures the intracellular and extracellular concentrations of various common ions in the cell and the extracellular fluid. The following chart shows the results of the initial measurements: Ion Intracellular Conc (mM) Extracellular Conc (mM) Na
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Unformatted text preview: 36 250 K ⁺ 165 50 Ca² ⁺ 8 200 Clˉ .01 8 a) Multiple synthesized chloride leak channels are inserted into the cell. Taking only concentration gradients into account, in which direction will the chloride ions diffuse? Explain. b) Extra potassium was added to the intracellular fluid, and the cell was given time to reach electrochemical equilibrium. What would occur if potassium leak channels were then inserted into the plasma membrane? c) The sodium-calcium exchanger (NCX) is an important transmembrane protein used by cells to move Ca² ions against their gradient by utilizing the energy released when Na diffuses down its ⁺ ⁺ gradient. What type of transporter is NCX? Describe the movement of sodium and calcium in this pump under normal physiological conditions and what would happen to the NCX mechanism if Na /K -ATPase in this cell failed to function. ⁺ ⁺...
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This note was uploaded on 02/05/2011 for the course BILD 2 taught by Professor Schroeder during the Spring '08 term at UCSD.

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