Question 1

Which of the following best describes the primary function of cell-to-cell communication in multicellular organisms?

Accepted Answer

To coordinate the activities of cells in tissues, organs, organ systems, and the whole body.

Question 2

Which structure on a neuron is primarily responsible for receiving impulses and transmitting them inward toward the cell body?

Accepted Answer

Dendrite

Question 3

Squid axons have been historically important in neuroscience research because:

Accepted Answer

Their large diameter allows for direct observation and manipulation of electrical signals.

Question 4

Which of the following best describes the function of leak channels in the neuronal membrane?

Accepted Answer

They are usually open and allow ions to flow down their electrochemical gradient.

Question 5

The Na+/K+ ATPase pump moves ions across the membrane in which direction and ratio?

Accepted Answer

3 Na+ out, 2 K+ in

Question 6

Which equation is used to calculate the equilibrium potential for a single ion across a membrane?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 7

A neuron at rest has a membrane potential that is:

Accepted Answer

Negative inside relative to outside due to trapped anions and K+ leak.

Question 8

During an action potential, which event occurs first?

Accepted Answer

Opening of voltage-gated Na+ channels.

Question 9

Which of the following is TRUE about the refractory period in neurons?

Accepted Answer

It prevents the backward propagation of the action potential.

Question 10

What is the main role of the synaptic bouton in neuronal communication?

Accepted Answer

To store and release neurotransmitters for signal transmission across the synapse.

Question 11

Which of the following best explains why the inside of a cell is more negative than the outside?

Accepted Answer

Large negatively charged molecules are trapped inside the cell.

Question 12

If the extracellular concentration of K+ increases, what happens to the membrane potential according to the Nernst equation?

Accepted Answer

The membrane potential becomes less negative (depolarizes).

Question 13

Which of the following is a direct consequence of the opening of voltage-gated K+ channels during an action potential?

Accepted Answer

Repolarization of the membrane.

Question 14

Which type of ion channel is responsible for the rapid depolarization phase of the action potential?

Accepted Answer

Voltage-gated Na+ channel

Question 15

A mutation causes the Na+/K+ ATPase to pump only Na+ out but not K+ in. What is the most likely effect on the cell?

Accepted Answer

The cell will lose its negative resting membrane potential.

Question 16

Which of the following is NOT a function of the myelin sheath?

Accepted Answer

Releasing neurotransmitters at the synapse.

Question 17

Which equation would you use to calculate the membrane potential when multiple ions are permeable?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} \right)$$

Question 18

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing speed.

Question 19

A patient is exposed to a toxin that blocks voltage-gated Na+ channels. What is the most likely effect on their neurons?

Accepted Answer

Neurons will be unable to initiate action potentials.

Question 20

Which of the following is TRUE regarding ligand-gated ion channels?

Accepted Answer

They open when a specific chemical (ligand) binds to them.

Cell Communication and Signal Transduction Mechanisms: Electrical and Synaptic Signaling in Neurons

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