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PSL 425 FINAL EXAM 2026/2027
ACTUAL QUESTIONS WITH
VERIFIED ANSWERS.
The resting membrane potential is mainly determined by:
a. The sodium gradient
b. The chloride gradient
c. The potassium gradient
d. The calcium gradient - ANSWER-The potassium gradient
The net outward flow of chloride would best be described as a:
a. Equilibrium Current
b. Inward current
c. Outward current
d. Positive Current - ANSWER-Inward current
What does the Nernst Equation predict for any concentration
gradient of a particular ion across a membrane?
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a. The resting membrane potential
b. The permeability of the ion
c. The equilibrium membrane potential
d. The charge of the ion - ANSWER-The equilibrium membrane
potential
When substance is uncharged, as in the case of glucose, when
can equilibrium occur?
a. Only when the concentration is equal on the two sides of the
membrane
b. Equilibrium can never occur in this instance
c. Only when the voltage different is zero
d. Only when the external concentration matches the internal
concentration of potassium - ANSWER-Only when the
concentration is equal on the two sides of the membrane
Which answer correctly orders the Nernst potentials of a cell at
37 C for potassium, sodium, calcium, and chloride from
depolarized to hyperpolarized?
a. Ca2+ > Na+ > Cl- > K+
b. K+ > Na+ > Ca2+ > Cl-
c. Na+ > Ca2+ > Cl- > K+
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d. K+ > Ca2+ > Cl- > Na+ - ANSWER-Ca2+ > Na+ > Cl- > K+
What is the name for the movement of a single ion species
through the membrane?
a. Charge
b. Resistance
c. Voltage
d. Current - ANSWER-Current
What directions are the chemical driving force (CDF) and the
electrical driving force (EDF) for a hypothetical positive ion (X+)
given values below:Extracellular concentration [X-] = 15
mMIntracellular concentration [X-] = 100 mMMembrane Voltage
Vm = -60 mV
a. CDF in & EDF out
b. CDF in & EDF in
c. CDF out & EDF in
d. CDF out & EDF out - ANSWER-CDF out & EDF in
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What would happen to the equilibrium potential of potassium if
the extracellular potassium concentration decreased?
a. Repolarize
b. Depolarize
c. Hyperpolarize
d. Nothing - ANSWER-Hyperpolarize
If neither the chemical nor the electrical term in the
electrochemical potential energy difference equation are zero,
when can equilibrium occur?
a. When the chemical term is positive and the electrical term is
negative
b. When the two terms are equal but of opposite sign
c. Equilibrium can never occur
d. When the chemical term is negative and the electrical term is
positive - ANSWER-When the two terms are equal but of
opposite sign
The net inward flow of potassium would best be described as a:
a. Equilibrium current
PSL 425 FINAL EXAM 2026/2027
ACTUAL QUESTIONS WITH
VERIFIED ANSWERS.
The resting membrane potential is mainly determined by:
a. The sodium gradient
b. The chloride gradient
c. The potassium gradient
d. The calcium gradient - ANSWER-The potassium gradient
The net outward flow of chloride would best be described as a:
a. Equilibrium Current
b. Inward current
c. Outward current
d. Positive Current - ANSWER-Inward current
What does the Nernst Equation predict for any concentration
gradient of a particular ion across a membrane?
,2 | Page
a. The resting membrane potential
b. The permeability of the ion
c. The equilibrium membrane potential
d. The charge of the ion - ANSWER-The equilibrium membrane
potential
When substance is uncharged, as in the case of glucose, when
can equilibrium occur?
a. Only when the concentration is equal on the two sides of the
membrane
b. Equilibrium can never occur in this instance
c. Only when the voltage different is zero
d. Only when the external concentration matches the internal
concentration of potassium - ANSWER-Only when the
concentration is equal on the two sides of the membrane
Which answer correctly orders the Nernst potentials of a cell at
37 C for potassium, sodium, calcium, and chloride from
depolarized to hyperpolarized?
a. Ca2+ > Na+ > Cl- > K+
b. K+ > Na+ > Ca2+ > Cl-
c. Na+ > Ca2+ > Cl- > K+
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d. K+ > Ca2+ > Cl- > Na+ - ANSWER-Ca2+ > Na+ > Cl- > K+
What is the name for the movement of a single ion species
through the membrane?
a. Charge
b. Resistance
c. Voltage
d. Current - ANSWER-Current
What directions are the chemical driving force (CDF) and the
electrical driving force (EDF) for a hypothetical positive ion (X+)
given values below:Extracellular concentration [X-] = 15
mMIntracellular concentration [X-] = 100 mMMembrane Voltage
Vm = -60 mV
a. CDF in & EDF out
b. CDF in & EDF in
c. CDF out & EDF in
d. CDF out & EDF out - ANSWER-CDF out & EDF in
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What would happen to the equilibrium potential of potassium if
the extracellular potassium concentration decreased?
a. Repolarize
b. Depolarize
c. Hyperpolarize
d. Nothing - ANSWER-Hyperpolarize
If neither the chemical nor the electrical term in the
electrochemical potential energy difference equation are zero,
when can equilibrium occur?
a. When the chemical term is positive and the electrical term is
negative
b. When the two terms are equal but of opposite sign
c. Equilibrium can never occur
d. When the chemical term is negative and the electrical term is
positive - ANSWER-When the two terms are equal but of
opposite sign
The net inward flow of potassium would best be described as a:
a. Equilibrium current
