Further experiments were conducted to investigate the effect of compound A123 on relative activity of the current in cells expressing the mutant form of channel D. The results are presented below in Table 1.3. Relative activation Mutant Channel Vm (mV) Wild type Mutant Channel Channel D D D in the presence of Compound A123 -60 0.00 0.00 0.00 -50 0.00 0.00 0.00 -40 0.00 0.00 0.00 -30 0.01 0.01 0.02 -20 0.03 0.14 0.08 -10 0.20 0.48 0.29 0 0.48 0.85 0.67 10 0.74 0.99 0.96 20 0.91 1.00 1.00 30 0.98 1.00 1.00 Q 1d. Table 1.3. Relative activity values of currents at different membrane potentials (Vm) for wild type Channel D, the mutant form of the channel observed in Patient X and the mutant channel in the presence of Compound A123. The holding potential between voltage steps was -80mV. Plot the relative activation curves for each of the three conditions described. Explain briefly, giving reasons, what information these curves give about channel activity. Discuss possible reasons for the differences in activation curve for each condition. [20 marks] Q 1e. Given the effect that Compound A123 has on the activation properties of channels in Patient X, explain the effect that Compound A123 could have on the ventricular action potential. In your answer, draw a sketch of your predicted changes and explain your reasoning. [10 marks] Additional experiments using barium as the charge carrier, indicated a significant reduction in voltage dependent inactivation in the cells of Patient X. Q 1f. Explain, giving reasons, which channelopathy Patient X might be suffering from and which channel the mutated gene might be affecting. [10 marks]
Further experiments were conducted to investigate the effect of compound A123 on relative activity of the current in cells expressing the mutant form of channel D. The results are presented below in Table 1.3. Relative activation Mutant Channel Vm (mV) Wild type Mutant Channel Channel D D D in the presence of Compound A123 -60 0.00 0.00 0.00 -50 0.00 0.00 0.00 -40 0.00 0.00 0.00 -30 0.01 0.01 0.02 -20 0.03 0.14 0.08 -10 0.20 0.48 0.29 0 0.48 0.85 0.67 10 0.74 0.99 0.96 20 0.91 1.00 1.00 30 0.98 1.00 1.00 Q 1d. Table 1.3. Relative activity values of currents at different membrane potentials (Vm) for wild type Channel D, the mutant form of the channel observed in Patient X and the mutant channel in the presence of Compound A123. The holding potential between voltage steps was -80mV. Plot the relative activation curves for each of the three conditions described. Explain briefly, giving reasons, what information these curves give about channel activity. Discuss possible reasons for the differences in activation curve for each condition. [20 marks] Q 1e. Given the effect that Compound A123 has on the activation properties of channels in Patient X, explain the effect that Compound A123 could have on the ventricular action potential. In your answer, draw a sketch of your predicted changes and explain your reasoning. [10 marks] Additional experiments using barium as the charge carrier, indicated a significant reduction in voltage dependent inactivation in the cells of Patient X. Q 1f. Explain, giving reasons, which channelopathy Patient X might be suffering from and which channel the mutated gene might be affecting. [10 marks]
Human Physiology: From Cells to Systems (MindTap Course List)
9th Edition
ISBN:9781285866932
Author:Lauralee Sherwood
Publisher:Lauralee Sherwood
Chapter3: The Plasma Membrane And Membrane Potential
Section: Chapter Questions
Problem 2SQE: One of the important uses of the Nernst equation is in describing the flow of ions across plasma...
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i found this past paper but cant find the answers for my revision. please can you answer question 1f
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