Question 1

Which of the following best describes the sequence of events in the knee-jerk (myotatic) reflex?

Accepted Answer

A sensory neuron synapses with a motor neuron, causing the extensor muscle to contract, while an interneuron inhibits the flexor muscle, resulting in leg extension.

Question 2

Given the ionic concentrations in mammalian neurons, which ion has the greatest driving force to enter the cell at resting membrane potential?

Accepted Answer

Na$$^+$$

Question 3

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 4

During the rising phase of the action potential, which of the following events occurs?

Accepted Answer

Voltage-gated Na$$^+$$ channels open, causing Na$$^+$$ influx.

Question 5

Which of the following is a key difference between electrical and chemical synapses?

Accepted Answer

Electrical synapses transmit signals via gap junctions, allowing ions to flow directly between cells.

Question 6

Which of the following is NOT a criterion that defines a neurotransmitter?

Accepted Answer

It must be able to cross the postsynaptic membrane without a receptor.

Question 7

Which of the following best explains why the resting membrane potential of a neuron is close to the equilibrium potential of K$$^+$$?

Accepted Answer

The membrane is much more permeable to K$$^+$$ than to Na$$^+ or Cl$^- at $$rest.

Question 8

Which of the following signaling mechanisms involves the release of signaling molecules that act on nearby cells?

Accepted Answer

Paracrine signaling

Question 9

Which of the following is a secondary messenger that is rapidly generated and activates effector proteins in the cell?

Accepted Answer

cAMP

Question 10

A mutation causes the Na$$^+/K$^+$$ ATPase to stop functioning in a neuron. What is the most likely immediate effect?

Accepted Answer

The neuron will lose its resting membrane potential.

Question 11

Which of the following best describes the role of calcium ions (Ca$$^{2+}) in $$synaptic transmission?

Accepted Answer

Ca$$^{2+}$$ influx into the presynaptic terminal triggers neurotransmitter release.

Question 12

Which of the following is a real-world application of the Nernst equation in neuroscience?

Accepted Answer

Calculating the equilibrium potential for K$$^+ in a $$neuron to predict the direction of ion flow during an action potential.

Question 13

Which of the following best explains why action potentials are unidirectional along an axon?

Accepted Answer

Voltage-gated Na$$^+$$ channels become inactivated after opening, creating a refractory period.

Question 14

Which of the following is a function of gap junctions at electrical synapses?

Accepted Answer

They allow the direct passage of ions and small molecules between adjacent neurons.

Question 15

Which of the following best describes the effect of opening K$$^+$$ channels in a neuron at rest?

Accepted Answer

The membrane potential becomes more negative (hyperpolarization).

Question 16

Which Nobel Prize-winning discovery allowed researchers to visualize multiple biological processes simultaneously in living cells?

Accepted Answer

The discovery of green fluorescent protein (GFP) and its color variants.

Question 17

Which of the following best describes the process of fluorescence resonance energy transfer (FRET) in cell biology?

Accepted Answer

It detects the proximity of two fluorescently labeled molecules based on energy transfer.

Question 18

Which of the following is a correct sequence of events for chemical synaptic transmission?

Accepted Answer

Action potential arrives, Ca$$^{2+}$$ influx, neurotransmitter release, neurotransmitter binds to postsynaptic receptors.

Signal Transduction Mechanisms: Electrical and Synaptic Signaling in Neurons

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