BIO 392 Exam 2 | 243 Latest Questions And Answers |
Complete Study Quizzes
What prevents the Na+ and K+ gradients from dissipating?
H+-K+ ATPase
Na+-K+ ATPase pump
Na+ cotransporter
Na+ and K+ leak channels ANS Na+-K+ ATPase pump
True or false? The equilibrium potential of Na+ is the membrane potential of a hypothetical cell that is very
permeable to Na+ at a given concentration gradient. For Na+, the equilibrium potential is positive ANS
True
he concentration gradient of potassium across the plasma membrane favors the ____________ movement of
potassium when more potassium channels open
-potassium does not move because the potassium channels are closed
-outward (potassium is moving into the ECF)
-potassium doesn't move because there is no concentration gradient for potassium across the plasma membrane
-inward (potassium is moving into the cell) ANS Outward (potassium is moving into the ECF)
At rest (in a resting neuron, so we're talking about the resting membrane potential), there is a little bit more
_____ than ________
K+ influx; Na+ efflux
Na+ efflux; K+ influx
Na+ influx; K+ efflux
K+ efflux; Na+ influx ANS K+ efflux; Na+ influx
,On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell
you?
-The outside surface of the plasma membrane is much more negatively charged than the inside surface.
-The inside surface of the plasma membrane is much more positively charged than the outside surface.
-There is no electrical potential difference between the inside and the outside surfaces of the plasma
membrane.
-The inside surface of the plasma membrane is much more negatively charged than the outside surface. ANS
The inside surface of the plasma membrane is much more negatively charged than the outside surface.
Maintaining a polarized membrane potential at rest requires energy
No
Yes
No, but it requires some ATP
Yes, but it requires some ATP ANS Yes
Potassium levels are ____ inside the cell than outside the cell
higher
lower
there is no difference ANS higher
The following is important for maintaining a negative resting membrane potential: Leak channels specific to
_______ in a membrane causes this ion to leave the cell, while ______ cannot follow this ion.
(A-: negatively charged ions)
A-;Na+
,Na+; A-
A-; K+
K+; A ANS K+; A-
The resting membrane potential depends on each item below, EXCEPT:
the concentration gradient for potassium ions.
the greater permeability of the plasma membrane to potassium ions.
the greater permeability of the membrane to anions rather than cations.
the concentration gradient for sodium ions.
the greater number of potassium leak channels ANS the greater permeability of the membrane to anions
rather than cations.
The major determinant (because there are more leak channels for this ion) of the resting potential of all cells is
K+ electrochemical gradient
Na+ electrochemical gradient
Cl- electrochemical gradient
Ca2+ electrochemical gradient ANS K+ electrochemical gradient
Potassium levels are increased in a patient in the ECF. Assuming that all else remains unchanged (this means
that intracellular potassium levels are the same as in a normal person), how will this affect the membrane
potential?
t will become more negative than -70 mV (e.g. -80 mV) because the concentration gradient of potassium is
steeper, so there will be more movement of potassium down its electrochemical gradient.
it will become less negative than -70 mV (e.g. -60 mV) because the concentration gradient of potassium is less
steep, so there will be more movement of potassium down its electrochemical gradient. ANS it will
become less negative than -70 mV (e.g. -60 mV) because the concentration gradient of potassium is less steep,
so there will be more movement of potassium down its electrochemical gradient.
If a small amount of anions is leaked into the cell, the cell would
, repolarize
hyperpolarize
depolarize ANS hyperpolorize
Overall, the body is _______
electrically negative; there are more cations than anions
electrically positive; there are more cations than anions
electrically negative; there are more anions than cations
electrically neutral; for every cation there is a matching anion ANS electrically neutral; for every cation
there is a matching anion
Consider the following movement of ions across the membrane due to an increase in membrane permeability
to these ions (e.g. movement of chloride results from opening of chloride channels).
Which of the following would NOT cause the membrane potential to change from -70 mV to +30 mV? (there
are actually two correct answers, just pick one)
potassium ions leaving the cell
calcium ions entering the cell
sodium ions entering the cell
chloride entering the cell ANS potassium ions leaving the cell
When calcium channels open, calcium rushes into the cell. This will cause
depolarization (inner side of the membrane becomes more positively charged)
hyperpolarization ANS depolarization (inner side of the membrane becomes more positively charged)
Image a world without electrical gradients (this is a hypothetical situation that does not exist). What would
happen to the Na+ concentration gradient? (assume there are leak channels to Na+ so Na+ can move)
Complete Study Quizzes
What prevents the Na+ and K+ gradients from dissipating?
H+-K+ ATPase
Na+-K+ ATPase pump
Na+ cotransporter
Na+ and K+ leak channels ANS Na+-K+ ATPase pump
True or false? The equilibrium potential of Na+ is the membrane potential of a hypothetical cell that is very
permeable to Na+ at a given concentration gradient. For Na+, the equilibrium potential is positive ANS
True
he concentration gradient of potassium across the plasma membrane favors the ____________ movement of
potassium when more potassium channels open
-potassium does not move because the potassium channels are closed
-outward (potassium is moving into the ECF)
-potassium doesn't move because there is no concentration gradient for potassium across the plasma membrane
-inward (potassium is moving into the cell) ANS Outward (potassium is moving into the ECF)
At rest (in a resting neuron, so we're talking about the resting membrane potential), there is a little bit more
_____ than ________
K+ influx; Na+ efflux
Na+ efflux; K+ influx
Na+ influx; K+ efflux
K+ efflux; Na+ influx ANS K+ efflux; Na+ influx
,On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell
you?
-The outside surface of the plasma membrane is much more negatively charged than the inside surface.
-The inside surface of the plasma membrane is much more positively charged than the outside surface.
-There is no electrical potential difference between the inside and the outside surfaces of the plasma
membrane.
-The inside surface of the plasma membrane is much more negatively charged than the outside surface. ANS
The inside surface of the plasma membrane is much more negatively charged than the outside surface.
Maintaining a polarized membrane potential at rest requires energy
No
Yes
No, but it requires some ATP
Yes, but it requires some ATP ANS Yes
Potassium levels are ____ inside the cell than outside the cell
higher
lower
there is no difference ANS higher
The following is important for maintaining a negative resting membrane potential: Leak channels specific to
_______ in a membrane causes this ion to leave the cell, while ______ cannot follow this ion.
(A-: negatively charged ions)
A-;Na+
,Na+; A-
A-; K+
K+; A ANS K+; A-
The resting membrane potential depends on each item below, EXCEPT:
the concentration gradient for potassium ions.
the greater permeability of the plasma membrane to potassium ions.
the greater permeability of the membrane to anions rather than cations.
the concentration gradient for sodium ions.
the greater number of potassium leak channels ANS the greater permeability of the membrane to anions
rather than cations.
The major determinant (because there are more leak channels for this ion) of the resting potential of all cells is
K+ electrochemical gradient
Na+ electrochemical gradient
Cl- electrochemical gradient
Ca2+ electrochemical gradient ANS K+ electrochemical gradient
Potassium levels are increased in a patient in the ECF. Assuming that all else remains unchanged (this means
that intracellular potassium levels are the same as in a normal person), how will this affect the membrane
potential?
t will become more negative than -70 mV (e.g. -80 mV) because the concentration gradient of potassium is
steeper, so there will be more movement of potassium down its electrochemical gradient.
it will become less negative than -70 mV (e.g. -60 mV) because the concentration gradient of potassium is less
steep, so there will be more movement of potassium down its electrochemical gradient. ANS it will
become less negative than -70 mV (e.g. -60 mV) because the concentration gradient of potassium is less steep,
so there will be more movement of potassium down its electrochemical gradient.
If a small amount of anions is leaked into the cell, the cell would
, repolarize
hyperpolarize
depolarize ANS hyperpolorize
Overall, the body is _______
electrically negative; there are more cations than anions
electrically positive; there are more cations than anions
electrically negative; there are more anions than cations
electrically neutral; for every cation there is a matching anion ANS electrically neutral; for every cation
there is a matching anion
Consider the following movement of ions across the membrane due to an increase in membrane permeability
to these ions (e.g. movement of chloride results from opening of chloride channels).
Which of the following would NOT cause the membrane potential to change from -70 mV to +30 mV? (there
are actually two correct answers, just pick one)
potassium ions leaving the cell
calcium ions entering the cell
sodium ions entering the cell
chloride entering the cell ANS potassium ions leaving the cell
When calcium channels open, calcium rushes into the cell. This will cause
depolarization (inner side of the membrane becomes more positively charged)
hyperpolarization ANS depolarization (inner side of the membrane becomes more positively charged)
Image a world without electrical gradients (this is a hypothetical situation that does not exist). What would
happen to the Na+ concentration gradient? (assume there are leak channels to Na+ so Na+ can move)
