Question 1

Which statement best describes the resting membrane potential of a typical cell?

Accepted Answer

It is a steady-state condition where the inside of the cell is more negative than the outside due to ion distribution.

Question 2

What is the primary ion responsible for establishing the resting membrane potential in most cells?

Accepted Answer

Potassium ($$\mathrm{K^+})$$

Question 3

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

Accepted Answer

Nernst equation: $$E_{ion} = \frac{61}{z} \log \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 4

A neuron’s membrane potential changes from $$-70\ \mathrm{mV} to$$ $$-50\ \mathrm{mV}. $$What term best describes this change?

Accepted Answer

Depolarization

Question 5

If the cell membrane becomes more permeable to $$\mathrm{K^+}$$, what will happen to the membrane potential?

Accepted Answer

It will become more negative (hyperpolarize).

Question 6

Which of the following best explains why the inside of the cell is negatively charged at rest?

Accepted Answer

Large anions cannot cross the membrane, and $$\mathrm{K^+}$$ diffuses out, leaving behind negative charge.

Question 7

Which process requires energy to separate electrical charges across the cell membrane?

Accepted Answer

Active transport via the sodium-potassium pump

Question 8

A cell is placed in a solution with a higher concentration of $$\mathrm{K^+}$$ outside than inside. According to the Nernst equation, what happens to the equilibrium potential for $$\mathrm{K^+}$$?

Accepted Answer

It becomes less negative (closer to zero).

Question 9

Which of the following is true regarding the electrochemical gradient?

Accepted Answer

It is the sum of the electrical and concentration gradients across the membrane.

Question 10

During insulin secretion in pancreatic beta cells, which event directly triggers exocytosis of insulin?

Accepted Answer

Depolarization leading to opening of voltage-gated $$\mathrm{Ca$$^{2+}$$}$$ channels

Question 11

Which of the following best describes the effect of closing ATP-dependent $$\mathrm{K^+}$$ channels in pancreatic beta cells?

Accepted Answer

The cell depolarizes, leading to insulin secretion.

Question 12

Which of the following is NOT a consequence of the law of conservation of electrical charges in cells?

Accepted Answer

Cells can have a net charge without any separation of ions.

Question 13

A cell’s membrane potential is measured using a micropipette and voltmeter. If the reading is $$-70\ \mathrm{mV}$$, what does this indicate?

Accepted Answer

The inside of the cell is $$70\ \mathrm{mV}$$ more negative than the outside.

Question 14

Which of the following would most likely cause hyperpolarization of a neuron?

Accepted Answer

Opening of $$\mathrm{Cl^-}$$ channels

Question 15

If a cell’s membrane potential becomes more negative than its resting value, what term describes this change?

Accepted Answer

Hyperpolarization

Question 16

Which of the following best describes the role of large intracellular anions in the resting membrane potential?

Accepted Answer

They are impermeable and contribute to the negative charge inside the cell.

Question 17

Which scenario would most likely result in depolarization of a cell membrane?

Accepted Answer

Increased permeability to $$\mathrm{Na^+}$$

Question 18

A patient’s beta cells fail to close ATP-dependent $$\mathrm{K^+}$$ channels in response to glucose. What is the most likely consequence?

Accepted Answer

Insulin secretion will be decreased due to lack of depolarization.

Question 19

Which of the following is a real-world example of membrane potential affecting cellular function?

Accepted Answer

Action potential initiation in neurons

Ch 5c Membrane Potential and Dynamics: Study Notes for Anatomy & Physiology

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