Question 1

Which of the following is NOT true of the equlibrium potential?

Accepted Answer

A)  It is the potential at which the flux of an ion is zero 
B)  It is the potential at which diffusive force balances electrical force 
C)  It is the potential for which $\Delta$$\mu$ for an ion is zero 
D)  It is the potential at which the conductance for an ion is zero 
E)  It is the potential at which the Nernst equation gives the membrane potential 
A)  It is the potential at which the flux of an ion is zero 
B)  It is the potential at which diffusive force balances electrical force 
C)  It is the potential for which $\Delta$$\mu$ for an ion is zero 
D)  It is the potential at which the conductance for an ion is zero 
E)  It is the potential at which the Nernst equation gives the membrane potential D

Question 2

The chord conductance for the ion x is defined as

Accepted Answer

A)  gx = Ix / Em 
B)  gx = dIx /dEm 
C)  gx = Px d [X]/dx 
D)  gx = Ix / (Em - Ex) 
E)  None of the above 
A)  gx = Ix / Em 
B)  gx = dIx /dEm 
C)  gx = Px d [X]/dx 
D)  gx = Ix / (Em - Ex) 
E)  None of the above D

Question 3

Incre asin g the extra cellular [K+] by itself should

Accepted Answer

A)  Increase EK (make it less negative) 
B)  Hyperpolarize the cell 
C)  Depolarize the cell 
D)  Have no effect on EK because gK would not change 
E)  Both A and C are correct 
A)  Increase EK (make it less negative) 
B)  Hyperpolarize the cell 
C)  Depolarize the cell 
D)  Have no effect on EK because gK would not change 
E)  Both A and C are correct E

Question 4

The equilibrium potential of an ion is the potential at which

Accepted Answer

A)  There is the same concentration of the ion on both sides of the membrane 
B)  The electrical force on the ion is zero 
C)  $\Delta$$\mu$ for passive ion transport across the membrane is zero 
D)  The conductance for an ion is zero 
E)  $\Delta$$\mu$ for ion transport is exactly matched by the$\Delta$$\mu$  for ATP hydrolysis 
A)  There is the same concentration of the ion on both sides of the membrane 
B)  The electrical force on the ion is zero 
C)  $\Delta$$\mu$ for passive ion transport across the membrane is zero 
D)  The conductance for an ion is zero 
E)  $\Delta$$\mu$ for ion transport is exactly matched by the$\Delta$$\mu$  for ATP hydrolysis

Question 5

The Goldm an-Ho dgkin-Katz current equation predicts the current for the ion is zero

Accepted Answer

A)  W hen Em = the resting mem brane potential 
B)  W hen [X]o = [X]i 
C)  When Em = 0 
D)  When Em = Ex , the equlibrium potential for the ion 
E)  The current is never zero 
A)  W hen Em = the resting mem brane potential 
B)  W hen [X]o = [X]i 
C)  When Em = 0 
D)  When Em = Ex , the equlibrium potential for the ion 
E)  The current is never zero

Question 6

The EK for a cell is -90 mV and ENA is + 55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na+ and K+,

Accepted Answer

A)  There is an inward K+ curr ent 
B)  There is an outward Na+ current 
C)  gNa > gK 
D)  The Na,K-ATPase pumps Na+ into and K+ ou t of the ce ll 
E)  The total current across the membrane is zero 
A)  There is an inward K+ curr ent 
B)  There is an outward Na+ current 
C)  gNa > gK 
D)  The Na,K-ATPase pumps Na+ into and K+ ou t of the ce ll 
E)  The total current across the membrane is zero

Question 7

The equilibrium potential for an ion is

Accepted Answer

A)  Given by the chord conductance equation 
B)  The potential at which the net passive flux of the ion is zero 
C)  Always negative inside 
D)  W hen the conductance balances the pump 
E)  When $\Delta$GATP—ADP + Pi = 0 
A)  Given by the chord conductance equation 
B)  The potential at which the net passive flux of the ion is zero 
C)  Always negative inside 
D)  W hen the conductance balances the pump 
E)  When $\Delta$GATP—ADP + Pi = 0

Question 8

Increasing gNa  with out affecting any of the other conductances , should

Accepted Answer

A)  Bring Em closer to ENa 
B)  Depolarize ENa only 
C)  Hyperpolarize ENa 
D)  Depolarize Em because of changes in ENa 
E)  Increase IK 
A)  Bring Em closer to ENa 
B)  Depolarize ENa only 
C)  Hyperpolarize ENa 
D)  Depolarize Em because of changes in ENa 
E)  Increase IK

Question 9

The EK for a cell is -90 mV and ENa is +55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na+ and K+,

Accepted Answer

A)  There is an outward K+ current 
B)  There is a net inward current 
C)  There is an net outward current 
D)  gNa > gK 
E)  None of the above 
A)  There is an outward K+ current 
B)  There is a net inward current 
C)  There is an net outward current 
D)  gNa > gK 
E)  None of the above

Question 10

The resting mem brane potential

Accepted Answer

A)  Is set by the Na,K -ATPase 
B)  Depends on the permeabilities and equilibrium potentials of all ions 
C)  Is closest to the equilibrium potential for Ca2+ 
D)  Is the same for all cells 
E)  Is the potential at which all ions are in equilibrium 
A)  Is set by the Na,K -ATPase 
B)  Depends on the permeabilities and equilibrium potentials of all ions 
C)  Is closest to the equilibrium potential for Ca2+ 
D)  Is the same for all cells 
E)  Is the potential at which all ions are in equilibrium

Question 11

The slope conductance for the ion x is defined as

Accepted Answer

A)  gx = Ix / Em 
B)  gx = dIx /dEm 
C)  gx = Px d [X]/dx 
D) gx = Ix / (Em - Ex) 
E)  None of the above 
A)  gx = Ix / Em 
B)  gx = dIx /dEm 
C)  gx = Px d [X]/dx 
D) gx = Ix / (Em - Ex) 
E)  None of the above

Question 12

The equilibrium potential for an ion across a membrane is the

Accepted Answer

A)  Potential at which the total current across a m em brane is zero 
B)  Electrochemical potential difference for the ion 
C)  Potential that stops diffusion of the ion across the membrane 
D)  Potential that opposes osmotic flow 
E)  Resting membrane potential 
A)  Potential at which the total current across a m em brane is zero 
B)  Electrochemical potential difference for the ion 
C)  Potential that stops diffusion of the ion across the membrane 
D)  Potential that opposes osmotic flow 
E)  Resting membrane potential

Question 13

The chord conductance equation for the m em brane potential is valid

Accepted Answer

A)  All the time 
B)  Only when dV/dt =0 
C)  Only at the resting membrane potential 
D)  Only at the equilibrium potential 
E)  Only at the peak of the action potential 
A)  All the time 
B)  Only when dV/dt =0 
C)  Only at the resting membrane potential 
D)  Only at the equilibrium potential 
E)  Only at the peak of the action potential

Question 14

The Na,K-ATPase

Accepted Answer

A)  Makes the resting membrane potential a little more negative 
B)  Makes no contribution to the resting membrane potential 
C)  Is electroneutral 
D)  Is inhibited by tetrodotoxin 
E)  Both A and C are correct 
A)  Makes the resting membrane potential a little more negative 
B)  Makes no contribution to the resting membrane potential 
C)  Is electroneutral 
D)  Is inhibited by tetrodotoxin 
E)  Both A and C are correct

Question 15

At the resting membrane potential

Accepted Answer

A)  Potassium is at its equilibrium potential 
B)  The total current across the membrane is zero 
C)  Sodium is at its equilibrium potential 
D)  There is an inward flow of K+ ions 
E)  Both A and C are correct 
A)  Potassium is at its equilibrium potential 
B)  The total current across the membrane is zero 
C)  Sodium is at its equilibrium potential 
D)  There is an inward flow of K+ ions 
E)  Both A and C are correct

Question 16

The equilibrium potential

Accepted Answer

A)  Is the potential at which total current of all ions across the membrane is zero 
B)  Depends on the permeability of the ion 
C)  Is the potential at which the electrical force for transport of the ion across the membrane is
zero 
D)  Occurs when the concentration of ions on both sides of the membrane is the same 
E)  Occurs when the current carried by the ion is zero 
A)  Is the potential at which total current of all ions across the membrane is zero 
B)  Depends on the permeability of the ion 
C)  Is the potential at which the electrical force for transport of the ion across the membrane is
zero 
D)  Occurs when the concentration of ions on both sides of the membrane is the same 
E)  Occurs when the current carried by the ion is zero

Question 17

If EK = -85 mV and E m = -70 mV , the potassium current is

Accepted Answer

A)  Positive,  meaning that IK is outward and K+ 
B)  Po sitive, mean ing that IK is inward and K+ flow is inward 
C)  Ne gative , meaning that IK is outward and K+ Flow is outward 
D)  Negative , meaning that IK is inward and K+ flow is inward 
E)  Cannot tell without knowing gK 
A)  Positive,  meaning that IK is outward and K+ 
B)  Po sitive, mean ing that IK is inward and K+ flow is inward 
C)  Ne gative , meaning that IK is outward and K+ Flow is outward 
D)  Negative , meaning that IK is inward and K+ flow is inward 
E)  Cannot tell without knowing gK

Exam 17: Origin of the Membrane Potential

Which of the following is NOT true of the equlibrium potential?

The chord conductance for the ion x is defined as

Incre asin g the extra cellular [K+] by itself should

The equilibrium potential of an ion is the potential at which

The Goldm an-Ho dgkin-Katz current equation predicts the current for the ion is zero

The EK for a cell is -90 mV and ENA is + 55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na+ and K+,

The equilibrium potential for an ion is

Increasing gNa with out affecting any of the other conductances , should

The EK for a cell is -90 mV and ENa is +55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na+ and K+,

The resting mem brane potential

The slope conductance for the ion x is defined as

The equilibrium potential for an ion across a membrane is the

The chord conductance equation for the m em brane potential is valid

The Na,K-ATPase

At the resting membrane potential

The equilibrium potential

If EK = -85 mV and E m = -70 mV , the potassium current is

Physical Foundations Ii: Electrical Force Potential Capacitance and Current

Chemical Foundations I: Chemical Energy and Intermolecular Forces

Chemical Foundations Ii: Concentration and Kinetics

Diffusion

Electrochemical Potential and Free Energy

Cell Structure

Dna and Protein Synthesis

Protein Structure

Biological Membranes

Passive Transport and Facilitated Diffusion

Active Transport: Pumps and Exchangers

Osmosis and Osmotic Pressure

Cell Signaling

ATP Production I: Glycolysis

Atp Production Ii: Tca Cycle and Oxidative Phosphorylation

Atp Production Iii: Fatty Acid Oxidation and Amino Acid Oxidation

The Action Potential

Propagation of the Action Potential

Skeletal Muscle Mechanics

Contractile Mechanisms in Skeletal Muscle

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Muscle Energetics Fatigue and Training

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the Chemical Senses

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Cellular Basis of Cardiac Contractility

the Cardiac Function Curve

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Mechanics of Breathing

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Acid Base Physiology I Bicarbonate Buffers and Respiratory Compensation

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Digestion and Absorption of the Macronutrients

Energy Balance and Regulation of Food Intake

General Principles of Endocrinology

Hypothalamus and Pituitary Gland

The Thyroid Gland

Incre asin g the extra cellular [K⁺] by itself should

The E_K for a cell is -90 mV and E_NA is + 55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na⁺ and K⁺,

Increasing g_Na with out affecting any of the other conductances , should

The E_K for a cell is -90 mV and E_Na is +55 mV. At a resting membrane potential of -70 mV and assuming conductances ONLY to Na⁺ and K⁺,