Biology 241 - Accelerated General Human Physiology » Summer 2021 » Lab Q7

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Question #1
If the response to a stimulus is a change from a negative potential to a less negative potential, the change is called:
A.   stimulus recovery
B.   depolarization
C.   stimulus response
D.   repolarization
Question #2
At rest, what are the concentration gradients of the ions sodium and potassium in a neuron?
A.   sodium high inside cell, potassium high inside cell
B.   sodium low inside cell, potassium low inside cell
C.   sodium low inside cell, potassium high inside cell
D.   sodium high inside cell, potassium low inside cell
Question #3
What is the resting membrane potential of the neuron when the electrode is placed inside the axon (intracelluar)?
A.   -40 mV
B.   -70 mV
C.   + 70 mV
D.   -7 V
Question #4
According to the Nerst equation, if sodium were permeable to the membrane, its membrane potential would be:
A.   -90mV, depolarizing effect
B.   -90mV, repolarizing effect
C.   +66mV, repolarizing effect
D.   +66mV, depolarizing effect
Question #5
Which of the following solutions has the greatest concentration of potassium?
A.   1 mEq K+/L.
B.   50 mEq K+/L.
C.   10 mEq K+/L.
D.   100 mEq K+/L.
Question #6
In a resting cell, the permeability of the membrane to sodium is:
A.   less than that to potassium.
B.   There is no such thing as a sodium channel; sodium and potassium ions go through the same channel.
C.   greater than that to potassium.
D.   the same as that to potassium.
Question #7
What characteristics do the forces pushing sodium across the membrane of a resting cell have?
A.   The electrical gradient and the chemical gradient both draw sodium into the cell.
B.   The electrical gradient draws sodium into the cell while the chemical gradient pushes it out.
C.   The electrical gradient and the chemical gradient both push sodium out of the cell.
D.   The chemical gradient draws sodium into the cell while the electrical gradient pushes it out.
Question #8
What was the relationship between the membrane potential and the concentration of sodium outside the cell?
A.   The membrane potential became more negative (hyperpolarized) when the concentration of sodium was decreased.
B.   The membrane potential became less negative (depolarized) when the concentration of sodium was decreased.
C.   The membrane potential did not change when the concentration of sodium was decreased.
Question #9
In the experiment when the level of sodium changed by a factor of 10 (say from 5 to 50) the membrane potential changed by about 8mV. While, in the potassium experiment, increasing the level of potassium in the Ringer’s solution by a factor of 10 caused the membrane potential to increase by about 30 mV. This means that, when compared with sodium:
A.   potassium has the same effect on the membrane potential.
B.   potassium has a greater effect on the membrane potential.
C.   potassium has less of an effect on the membrane potential.

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