BIO 392 Exam 2 | 65 Latest Questions And Answers |
Verified Study Solutions
Sodium levels are ____ inside the cell than outside the cell ANS lower
The resting membrane potential (RMP) depends on two factors that influence the magnitude and direction of
Na+ and K+ diffusion across the plasma membrane. Identify these two factors. ANS The presence of
concentration gradients and leak channels
The membrane potential at rest is ANS negative
The membrane potential is a ANS local phenomenon right across the membrane differences in charge
between the inner and outer surface of the membrane.
The concentration gradients for sodium and potassium between the ICF and the ECF are maintained by the ___
ANS Na+/K+ ATPase pump
The concentration gradient of potassium across the plasma membrane favors the ___ movement of potassium
when more potassium channels open 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 ______ 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? ANS The inside surface of the plasma membrane is much more negatively charged than the outside
surface.
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 equilibrium potential of sodium is ANS positive
The electrical gradient is defined as ANS a difference in the net charge between two regions
The concentration gradient of sodium across the plasma membrane favors the ___ movement of sodium when
sodium channels open ANS inward (sodium is moving into the cell)
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
Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of
what type of channel? ANS Leak channels
What creates the membrane potential? ANS Ion concentration gradients between the ECF and the ICF; the
selective permeability of the membrane
The resting membrane potential results from ANS uneven distribution of ions across the cell membrane
and differences in membrane permeability to Na+ and K+.
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) ANS
Na+ would leak into the cell until the Na+ concentration inside the cell equaled the Na+ concentration outside
A neurotransmitter binds to a receptor, resulting in the opening of more sodium channels. How will this affect
the membrane potential? ANS it will become less negative (and thus more positive)
Ionic current (across the membrane of within the cell) is defined as ANS flow of an electrical charge across
the membrane
Verified Study Solutions
Sodium levels are ____ inside the cell than outside the cell ANS lower
The resting membrane potential (RMP) depends on two factors that influence the magnitude and direction of
Na+ and K+ diffusion across the plasma membrane. Identify these two factors. ANS The presence of
concentration gradients and leak channels
The membrane potential at rest is ANS negative
The membrane potential is a ANS local phenomenon right across the membrane differences in charge
between the inner and outer surface of the membrane.
The concentration gradients for sodium and potassium between the ICF and the ECF are maintained by the ___
ANS Na+/K+ ATPase pump
The concentration gradient of potassium across the plasma membrane favors the ___ movement of potassium
when more potassium channels open 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 ______ 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? ANS The inside surface of the plasma membrane is much more negatively charged than the outside
surface.
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 equilibrium potential of sodium is ANS positive
The electrical gradient is defined as ANS a difference in the net charge between two regions
The concentration gradient of sodium across the plasma membrane favors the ___ movement of sodium when
sodium channels open ANS inward (sodium is moving into the cell)
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
Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of
what type of channel? ANS Leak channels
What creates the membrane potential? ANS Ion concentration gradients between the ECF and the ICF; the
selective permeability of the membrane
The resting membrane potential results from ANS uneven distribution of ions across the cell membrane
and differences in membrane permeability to Na+ and K+.
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) ANS
Na+ would leak into the cell until the Na+ concentration inside the cell equaled the Na+ concentration outside
A neurotransmitter binds to a receptor, resulting in the opening of more sodium channels. How will this affect
the membrane potential? ANS it will become less negative (and thus more positive)
Ionic current (across the membrane of within the cell) is defined as ANS flow of an electrical charge across
the membrane
