Depolarization of a cell membrane occurs becauseMultiple ChoiceThe concentration of sodium and potassium ions in the cell is at equilibriumSodium ions are blocked from entering the cellMore sodium ions diffuse into the cell than potassium ions diffuse out of itThe concentration of sodium and potassium ions in the extracellular fluid is at equilibrium
Question
Depolarization of a cell membrane occurs becauseMultiple ChoiceThe concentration of sodium and potassium ions in the cell is at equilibriumSodium ions are blocked from entering the cellMore sodium ions diffuse into the cell than potassium ions diffuse out of itThe concentration of sodium and potassium ions in the extracellular fluid is at equilibrium
Solution
Depolarization of a cell membrane occurs because more sodium ions diffuse into the cell than potassium ions diffuse out of it.
Here's a step-by-step explanation:
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In a resting state, the inside of the neuron is negatively charged compared to the outside. This is due to a higher concentration of sodium ions outside the cell and a higher concentration of potassium ions inside the cell.
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When a stimulus reaches a resting neuron, the gated ion channels on the resting neuron's membrane open suddenly and allow the sodium ions present outside the neuron to diffuse into the neuron.
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As more and more sodium ions enter the neuron, the inside of the neuron becomes more positive compared to the outside. This change from a negative to a positive charge is called depolarization.
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After the influx of sodium ions, the sodium channels close and potassium channels open. Potassium ions begin to move out of the neuron, initiating the process of repolarization to restore the negative charge inside the neuron.
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Therefore, depolarization of a cell membrane occurs because more sodium ions diffuse into the cell than potassium ions diffuse out of it.
Similar Questions
Depolarization of a cell membrane occurs because
Depolarization occurs becauseMultiple Choicethe extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value.more sodium ions diffuse into the cell than potassium ions diffuse out of it.the inactivation gates of the voltage-gated sodium ion channels begin to open, and the diffusion of sodium ions decreases.potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close.the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.
A recently depolarized area of a cell membrane cannot generate an action potential because of theMultiple Choiceabsolute refractory period.high concentration of sodium ions in the extracellular fluid.the high concentration of potassium ions in the cytoplasm.presence of receptor sites on the membrane.
What is produced when depolarization of a cell membrane reaches threshold?Multiple ChoiceA new action potential is produced.An existing action potential is stopped.Voltage-gated ion channels close.The absolute refractory period ends.
During the depolarisation stage of an action potentialThe membrane potential returns to resting conditionsSodium (Na+) enters the cell down it's concentration gradientVoltage gated K+ channels are openPotassium (K+) enters the cell against its concentration gradient
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