Action Potential Quiz: Test Your Knowledge on Membrane Potential

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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?

Potassium ions (K+) Signup and view all the answers

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

-80 mV to -40 mV Signup and view all the answers

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

Intracellular fluid (cytosol) Signup and view all the answers

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

-90 millivolts Signup and view all the answers

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

Na+-K+ pump Signup and view all the answers

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

Voltage-gated calcium channel 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?

Calcium 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?

Voltage-gated sodium channel Signup and view all the answers

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

Increases by 500- to 5000-fold 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?

Voltage-dependent calcium channels (VDCCs) 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?

Na+-K+ pump 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?

Potassium Signup and view all the answers

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

Ligand-gated channels Signup and view all the answers

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

Voltage-dependent calcium channel Signup and view all the answers

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

Voltage-gated channels Signup and view all the answers

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

High concentration of protein inside the cell Signup and view all the answers

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

$-90$ to $-100$ millivolts Signup and view all the answers

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

Na+-K+ pump 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?

Voltage-dependent calcium channels (VDCC) Signup and view all the answers

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

It increases as much as 500- to 5000-fold Signup and view all the answers

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

-40 mV to -80 mV Signup and view all the answers

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

Variation in membrane permeability by ion Signup and view all the answers

Why is there a membrane potential in biological cells?

Difference in electrical potential between the intracellular and extracellular fluid Signup and view all the answers

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

Voltage-Dependent Calcium Channels Signup and view all the answers

What is membrane potential?

The difference in electrical potential between the intracellular and extracellular fluid 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.