NEUR 2035 Midterm - Lab 3 Flashcards
When an ion inside and outside reaches a balanced state (with no net movement), the chemical (diffusional) force is exactly offset by its electrical force.
True or False:
This balance point is known as the reversal potential (or equilibrium potential) for that ion.
True
Cell membrane potential becomes ____ during hyperpolarization.
More negative
Which ion has the highest concentration inside a neuron?
A. Calcium
B. sodium
C. potassium
D. chloride
C
True or false:
A sodium ion can pass through a potassium ion channel freely because it is much smaller than a potassium ion.
False
Which ion has the lowest concentration inside a neuron?
A. chloride
B. sodium
C. potassium
D. calcium
D
1 mM sodium means…
A. 0.01 moles sodium per liter
B. 0.001 moles sodium per liter
C. 0.1 moles sodium per liter
D. 1 mole sodium per liter
B
Cell membrane potential becomes ____ during depolarization.
Less negative
Which ions have a higher concentration in the extracellular fluid than in the intracellular fluid?
A. calcium
B. potassium
C. sodium
D. chloride
A, C, D
Cell membrane potential becomes ____ during repolarization.
More negative
True or false:
The opening or closing of leaky potassium channels is controlled by changes in the membrane potential (voltage).
False
What does membrane potential refer to?
A. the amount of current that can flow out of a cell
B. the potential of the cell membrane
C. the amount of ions that can cross the cell membrane
D. the voltage difference across the cell membrane
D
True or false:
A cell can have different membrane potentials at different spots on its cell membrane.
True
How will positive ions move if the membrane potential is more negative than the ion’s reverse potential?
A. They will move out of the neuron
B. They will move into the neuron
C. There will be no ion movement
B
True or false:
EPSP can always cause an action potential, while IPSP always inhibits an action potential.
False
If a positively charged ion has an extracellular concentration of 10mM, an intracellular concentration of 100nM, and its equilibrium potential is -65mV:
A. the ion will flow in
B. we cannot determine the behavior
C. the ion will flow out
B
Which variables are needed to calculate the equilibrium potential of an ion?
A. extracellular concentration
B. charge
C. intracellular concentration
D. permeability
E. temperature
A, B, C, E
True or false:
When calculating using the Nernst equation, we use the constants that we get for the current temperature times ([X]outside/[X]inside).
False
An ion with zero permeability but ten times higher concentration extracellular compared to intracellular, based on the Goldman equation, this ion ____ affect the membrane potential.
Will not
True or false:
In hot weather, compared to cooler weather (without air conditioning), our body temperature will increase slightly. This increase also raises the cell membrane potential, even with the same concentration and permeability of ions. This increase makes neurons more likely to reach action potential. Therefore, in hot weather, people tend to be more reactive to stimuli.
True
What is the ratio for every sodium and potassium ion to leave and enter the neuron while the sodium-potassium pump is working?
A. 2 sodium enter / 3 potassium leave
B. 3 sodium enter / 2 potassium leave
C. 3 sodium leave / 2 potassium enter
D. 2 sodium leave / 3 potassium enter
C
How would an elevated extracellular potassium concentration impact potassium’s reversal potential?
It would become less negative
How would an elevated extracellular potassium concentration affect the propagation of action potentials?
Membrane potential would become more positive, increasing excitability
How would a low extracellular sodium concentration affect sodium’s equilibrium potential?
It would become more negative
How would a low extracellular sodium concentration affect the propagation of action potentials?
Lower magnitude EPSPs would lead to fewer action potentials
