Q: Which equation best represents the Nernst equation for calculating the equilibrium potential of potassium ions ($$K^+) $$across a cell membrane?

$$E_{K^+} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{\text{outside}}}{[K^+]_{\text{inside}}} \right)$$

Q: Which of the following equations correctly represents the Goldman-Hodgkin-Katz equation for membrane potential?

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

Question 1

Which of the following best describes the primary contributors to the resting membrane potential in a neuron?

Accepted Answer

The sodium-potassium pump, ion channels, and selective permeability of the cell membrane

Question 2

A patient is experiencing muscle weakness due to prolonged opening of chloride channels in their muscle cell membranes. Which phenomenon does this scenario best illustrate?

Accepted Answer

Hyperpolarization and action potentials

Question 3

Which statement correctly applies the all-or-none principle to neuronal action potentials?

Accepted Answer

An action potential either occurs fully or not at all, regardless of stimulus strength once threshold is reached.

Question 4

Which equation best represents the Nernst equation for calculating the equilibrium potential of potassium ions ($$K^+) $$across a cell membrane?

Accepted Answer

$$E_{K^+} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{	ext{outside}}}{[K^+]_{	ext{inside}}} ight)$$

Question 5

During the relative refractory period, which of the following is true regarding the generation of a new action potential?

Accepted Answer

A stronger than normal stimulus is required to generate an action potential.

Question 6

Which of the following best explains why graded potentials differ from action potentials?

Accepted Answer

Graded potentials vary in magnitude and can be summed, while action potentials are all-or-none.

Question 7

A patient is exposed to a continuous, low-level stimulus in a dark room and gradually becomes more sensitive to light. Which type of receptor adaptation does this scenario illustrate?

Accepted Answer

Tonic receptor adaptation

Question 8

Which of the following cranial nerves is classified as purely sensory and is responsible for transmitting visual information?

Accepted Answer

Optic nerve

Question 9

Which process is primarily responsible for the movement of ions across the neuronal membrane during the generation of an action potential?

Accepted Answer

Opening and closing of voltage-gated ion channels

Question 10

Which of the following best describes the role of pacemaker cells in cardiac muscle?

Accepted Answer

They spontaneously generate action potentials without external input.

Question 11

A person touches a hot surface and immediately withdraws their hand. Which type of receptor is primarily responsible for detecting this painful stimulus?

Accepted Answer

Free nerve endings

Question 12

Which of the following best explains the concept of sensory cortex representation in the brain?

Accepted Answer

The brain allocates more space to body regions with higher sensory input.

Question 13

Which of the following equations correctly represents the Goldman-Hodgkin-Katz equation for membrane potential?

Accepted Answer

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

Question 14

Which of the following best describes the function of erythrocytes in the circulatory system?

Accepted Answer

Transport oxygen and carbon dioxide between the lungs and tissues

Question 15

A patient with myocardial infarction reports pain in their left arm. What is the best explanation for this phenomenon?

Accepted Answer

Referred pain, where pain from the heart is perceived in the arm due to shared neural pathways

Question 16

Which of the following is true regarding the absolute refractory period of a neuron?

Accepted Answer

No new action potential can be generated, regardless of stimulus strength

Question 17

Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It actively transports $$3$$ $$Na^+$$ ions out and $$2$$ $$K^+$$ ions into the cell, maintaining a negative internal environment.

Question 18

Which of the following best explains why action potentials do not decrease in amplitude as they travel along an axon?

Accepted Answer

Action potentials are regenerated at each segment of the axon by voltage-gated ion channels.

Membrane Potentials and Sensory Receptors: Key Concepts for General Chemistry

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