Membrane Potentials and Action Potential Quiz
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Questions and Answers

What is membrane potential?

  • The flow of ions within the cell
  • The production of ATP within the cell
  • The difference in electrical potential between the intracellular fluid and the extracellular fluid (correct)
  • The synthesis of proteins within the cell

    • Why is there a membrane potential in biological cells?

  • To maintain a balance between intracellular and extracellular fluid (correct)
  • To synthesize neurotransmitters for cell communication
  • To produce energy for cellular activities
  • To allow the flow of ions freely across the cell membrane

    • What contributes to the unequal distribution of charges across the cell membrane?

  • Easy diffusion of sodium ions out of the cell
  • High concentration of chloride ions in the cytosol
  • Presence of positively charged proteins inside the cell (correct)
  • Equal permeability of all ions through the cell membrane

    • Which ion has higher permeability through the cell membrane?

    <p>Potassium ions (K+)</p> Signup and view all the answers

    What is the typical range of membrane potential in biological cells?

    <p>-80 mV to -40 mV</p> Signup and view all the answers

    In which fluid do potassium ions (K+) have high concentrations?

    <p>Intracellular fluid (cytosol)</p> Signup and view all the answers

    What is the typical resting membrane potential of large nerve fibers?

    <p>-90 millivolts</p> Signup and view all the answers

    What is the primary mechanism for preventing the influx of ions and cell swelling in nerve cells?

    <p>Na+-K+ pump</p> Signup and view all the answers

    What type of channel is normally closed at the physiologic or resting membrane potential?

    <p>Voltage-gated calcium channel</p> Signup and view all the answers

    Which ion is about 1000-fold more permeable than sodium ions through voltage-dependent calcium channels under normal physiological conditions?

    <p>Calcium</p> Signup and view all the answers

    What is the necessary actor in causing both depolarization and repolarization of the nerve membrane during the action potential?

    <p>Voltage-gated sodium channel</p> Signup and view all the answers

    During the action potential, what happens to the sodium permeability of the nerve membrane?

    <p>Increases by 500- to 5000-fold</p> Signup and view all the answers

    What type of channels are found in excitable cells like muscle and neurons with a permeability to calcium ions?

    <p>Voltage-dependent calcium channels (VDCCs)</p> Signup and view all the answers

    What is the primary mechanism for preventing cell swelling due to large numbers of negatively charged proteins inside the cell?

    <p>Na+-K+ pump</p> Signup and view all the answers

    Which ion has high cell permeability due to leakage through the nerve cell membrane, contributing to the resting membrane potential?

    <p>Potassium</p> Signup and view all the answers

    Which type of stimulus channels are named according to the ligand to which they respond?

    <p>Ligand-gated channels</p> Signup and view all the answers

    What does the abbreviation 'VDCC' stand for in the context of nerve cells?

    <p>Voltage-dependent calcium channel</p> Signup and view all the answers

    Which type of ion channel responds based on the stimulus to which they are exposed?

    <p>Voltage-gated channels</p> Signup and view all the answers

    What contributes to the unequal distribution of charges across the cell membrane?

    <p>High concentration of protein inside the cell</p> Signup and view all the answers

    What is the typical range of membrane potential in biological cells?

    <p>$-90$ to $-100$ millivolts</p> Signup and view all the answers

    What is the primary mechanism for preventing the influx of ions and cell swelling in nerve cells?

    <p>Na+-K+ pump</p> Signup and view all the answers

    What type of channels are found in excitable cells like muscle and neurons with a permeability to calcium ions?

    <p>Voltage-dependent calcium channels (VDCC)</p> Signup and view all the answers

    During the action potential, what happens to the sodium permeability of the nerve membrane?

    <p>It increases as much as 500- to 5000-fold</p> Signup and view all the answers

    What is the typical range of membrane potential in biological cells?

    <p>-40 mV to -80 mV</p> Signup and view all the answers

    What contributes to the unequal distribution of charges across the cell membrane?

    <p>Variation in membrane permeability by ion</p> Signup and view all the answers

    Why is there a membrane potential in biological cells?

    <p>Difference in electrical potential between the intracellular and extracellular fluid</p> Signup and view all the answers

    What does the abbreviation 'VDCC' stand for in the context of nerve cells?

    <p>Voltage-Dependent Calcium Channels</p> Signup and view all the answers

    What is membrane potential?

    <p>The difference in electrical potential between the intracellular and extracellular fluid</p> Signup and view all the answers

    Study Notes

    Membrane Potential

    • Membrane potential is the separation of electric charge across the cell membrane.
    • There is a membrane potential in biological cells because of the unequal distribution of charges across the cell membrane.

    Unequal Distribution of Charges

    • The unequal distribution of charges is contributed by the concentration of potassium ions (K+) being higher inside the cell and sodium ions (Na+) being higher outside the cell.
    • The permeability of the cell membrane to potassium ions is higher than to sodium ions.

    Resting Membrane Potential

    • The typical range of membrane potential in biological cells is -60 to -80 millivolts (mV).
    • The typical resting membrane potential of large nerve fibers is -70 mV.

    Ion Channels

    • Voltage-dependent calcium channels are normally closed at the physiologic or resting membrane potential.
    • Calcium ions (Ca²⁺) are about 1000-fold more permeable than sodium ions through voltage-dependent calcium channels under normal physiological conditions.

    Action Potential

    • The necessary actor in causing both depolarization and repolarization of the nerve membrane during the action potential is voltage-gated ion channels.
    • During the action potential, the sodium permeability of the nerve membrane increases.

    Channel Types

    • Ligand-gated channels are named according to the ligand to which they respond.
    • Voltage-gated channels respond based on the stimulus to which they are exposed.
    • Voltage-dependent calcium channels (VDCC) are found in excitable cells like muscle and neurons with a permeability to calcium ions.

    Cell Swelling Prevention

    • The primary mechanism for preventing cell swelling due to large numbers of negatively charged proteins inside the cell is the efflux of potassium ions.
    • The primary mechanism for preventing the influx of ions and cell swelling in nerve cells is the efflux of potassium ions through leakage channels.

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    Description

    Test your knowledge of membrane potentials and action potentials with this quiz. Learn about the difference in electrical potential between the intracellular fluid and the extracellular fluid of a biological cell, and the reasons behind membrane potential.

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