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A: Ion Channels and Resting Membrane Potential Table 1 below contains values for various intracellular concentrations, extracellular concentrations, and ion conductance information for a cardiac cell. Table 1: lon Extracellular (mM) Na* 284 K+ 4 CI Ca2+ 120 10 Intracellular (mM) Resting Conductance (mS/cm²) 15 0.001 300 0.1 20 0.01 0.0001 1 1. Calculate the Nernst potential (nearest mV) for each of the above four ions (Na*, K*, CI, Ca2+) assuming a temperature of 27 °C. Please show all work. (Possibly useful constants: R = 8.314 J K mol¹; F = 9.65 x 104 C mol¹; J=Joule; K=Kelvin; C=Coulomb) 2. What is the resting potential (nearest mV) across the membrane using the Nernst potentials calculated in part 1 and the given conductance? (Note, please use the Nernst potentials rounded to nearest mV calculated in part 1 and show all work). Which ion's conductance dominates resting membrane potential and state the reasoning you used. (one or sentences)? 3. We apply a voltage clamp at +30 mV. Give the expected current and direction (across the membrane) for each of the 4 ions. Show your work; include units in your answer. Again, please use the rounded values calculated in part 1. After a century of ion channel pharmacology, which general technique(s) would you use to test your expectation about the amplitude and direction of the 4 individual currents? 4. We have designed this part of the question, and this diagram, to help you think about the direction of current flow. A few minutes ago, the experimenter "clamped" the membrane by passing current from an external circuit (here denoted simply by a battery with thick lines) and two electrodes one intracellular and one extracellular. The "holding potential" or "clamped" voltage is +30 mV, so that the cytosol is positive. The equivalent circuit has five branches. Four branches have a pair of arrows showing the possible direction of current--the flow of positive charges. The upward and downward arrows denote inward and outward currents, respectively. For the top set of arrows, which way is current flowing? If there's an ambiguity, state the ambiguity. How much current is flowing? Use numbers and units. Why have we omitted the currents and arrows for the capacitance? One sentence or one equation. "Holding potential"= "Clamped Voltage" = +30 mV inward outward G outside Capacitance EK Бала Eca Ea Cytosol inside

A: Ion Channels and Resting Membrane Potential Table 1 below contains values for various intracellular concentrations, extracellular concentrations, and ion conductance information for a cardiac cell. Table 1: lon Extracellular (mM) Na* 284 K+ 4 CI Ca2+ 120 10 Intracellular (mM) Resting Conductance (mS/cm²) 15 0.001 300 0.1 20 0.01 0.0001 1 1. Calculate the Nernst potential (nearest mV) for each of the above four ions (Na*, K*, CI, Ca2+) assuming a temperature of 27 °C. Please show all work. (Possibly useful constants: R = 8.314 J K mol¹; F = 9.65 x 104 C mol¹; J=Joule; K=Kelvin; C=Coulomb) 2. What is the resting potential (nearest mV) across the membrane using the Nernst potentials calculated in part 1 and the given conductance? (Note, please use the Nernst potentials rounded to nearest mV calculated in part 1 and show all work). Which ion's conductance dominates resting membrane potential and state the reasoning you used. (one or sentences)? 3. We apply a voltage clamp at +30 mV. Give the expected current and direction (across the membrane) for each of the 4 ions. Show your work; include units in your answer. Again, please use the rounded values calculated in part 1. After a century of ion channel pharmacology, which general technique(s) would you use to test your expectation about the amplitude and direction of the 4 individual currents? 4. We have designed this part of the question, and this diagram, to help you think about the direction of current flow. A few minutes ago, the experimenter "clamped" the membrane by passing current from an external circuit (here denoted simply by a battery with thick lines) and two electrodes one intracellular and one extracellular. The "holding potential" or "clamped" voltage is +30 mV, so that the cytosol is positive. The equivalent circuit has five branches. Four branches have a pair of arrows showing the possible direction of current--the flow of positive charges. The upward and downward arrows denote inward and outward currents, respectively. For the top set of arrows, which way is current flowing? If there's an ambiguity, state the ambiguity. How much current is flowing? Use numbers and units. Why have we omitted the currents and arrows for the capacitance? One sentence or one equation. "Holding potential"= "Clamped Voltage" = +30 mV inward outward G outside Capacitance EK Бала Eca Ea Cytosol inside

Human Anatomy & Physiology (11th Edition)
Human Anatomy & Physiology (11th Edition)
11th Edition
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:Elaine N. Marieb, Katja N. Hoehn
Chapter1: The Human Body: An Orientation
Section: Chapter Questions
Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...
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help me with the three questions in part 4 please

 

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A: Ion Channels and Resting Membrane Potential Table 1 below contains values for various intracellular concentrations, extracellular concentrations, and ion conductance information for a cardiac cell. Table 1: lon Extracellular (mM) Na* 284 K+ 4 CI Ca2+ 120 10 Intracellular (mM) Resting Conductance (mS/cm²) 15 0.001 300 0.1 20 0.01 0.0001 1 1. Calculate the Nernst potential (nearest mV) for each of the above four ions (Na*, K*, CI, Ca2+) assuming a temperature of 27 °C. Please show all work. (Possibly useful constants: R = 8.314 J K mol¹; F = 9.65 x 104 C mol¹; J=Joule; K=Kelvin; C=Coulomb) 2. What is the resting potential (nearest mV) across the membrane using the Nernst potentials calculated in part 1 and the given conductance? (Note, please use the Nernst potentials rounded to nearest mV calculated in part 1 and show all work). Which ion's conductance dominates resting membrane potential and state the reasoning you used. (one or sentences)? 3. We apply a voltage clamp at +30 mV. Give the expected current and direction (across the membrane) for each of the 4 ions. Show your work; include units in your answer. Again, please use the rounded values calculated in part 1. After a century of ion channel pharmacology, which general technique(s) would you use to test your expectation about the amplitude and direction of the 4 individual currents? 4. We have designed this part of the question, and this diagram, to help you think about the direction of current flow. A few minutes ago, the experimenter "clamped" the membrane by passing current from an external circuit (here denoted simply by a battery with thick lines) and two electrodes one intracellular and one extracellular. The "holding potential" or "clamped" voltage is +30 mV, so that the cytosol is positive. The equivalent circuit has five branches. Four branches have a pair of arrows showing the possible direction of current--the flow of positive charges. The upward and downward arrows denote inward and outward currents, respectively. For the top set of arrows, which way is current flowing? If there's an ambiguity, state the ambiguity. How much current is flowing? Use numbers and units. Why have we omitted the currents and arrows for the capacitance? One sentence or one equation. "Holding potential"= "Clamped Voltage" = +30 mV inward outward G outside Capacitance EK Бала Eca Ea Cytosol inside
Transcribed Image Text:A: Ion Channels and Resting Membrane Potential Table 1 below contains values for various intracellular concentrations, extracellular concentrations, and ion conductance information for a cardiac cell. Table 1: lon Extracellular (mM) Na* 284 K+ 4 CI Ca2+ 120 10 Intracellular (mM) Resting Conductance (mS/cm²) 15 0.001 300 0.1 20 0.01 0.0001 1 1. Calculate the Nernst potential (nearest mV) for each of the above four ions (Na*, K*, CI, Ca2+) assuming a temperature of 27 °C. Please show all work. (Possibly useful constants: R = 8.314 J K mol¹; F = 9.65 x 104 C mol¹; J=Joule; K=Kelvin; C=Coulomb) 2. What is the resting potential (nearest mV) across the membrane using the Nernst potentials calculated in part 1 and the given conductance? (Note, please use the Nernst potentials rounded to nearest mV calculated in part 1 and show all work). Which ion's conductance dominates resting membrane potential and state the reasoning you used. (one or sentences)? 3. We apply a voltage clamp at +30 mV. Give the expected current and direction (across the membrane) for each of the 4 ions. Show your work; include units in your answer. Again, please use the rounded values calculated in part 1. After a century of ion channel pharmacology, which general technique(s) would you use to test your expectation about the amplitude and direction of the 4 individual currents? 4. We have designed this part of the question, and this diagram, to help you think about the direction of current flow. A few minutes ago, the experimenter "clamped" the membrane by passing current from an external circuit (here denoted simply by a battery with thick lines) and two electrodes one intracellular and one extracellular. The "holding potential" or "clamped" voltage is +30 mV, so that the cytosol is positive. The equivalent circuit has five branches. Four branches have a pair of arrows showing the possible direction of current--the flow of positive charges. The upward and downward arrows denote inward and outward currents, respectively. For the top set of arrows, which way is current flowing? If there's an ambiguity, state the ambiguity. How much current is flowing? Use numbers and units. Why have we omitted the currents and arrows for the capacitance? One sentence or one equation. "Holding potential"= "Clamped Voltage" = +30 mV inward outward G outside Capacitance EK Бала Eca Ea Cytosol inside
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