If sodium ions diffuse into the cell freely, how will the resting membrane potential change?
Group of answer choices
not change
increase, then decrease
decrease
increase
The correct answer is increase.
If sodium ions diffuse into the cell freely, the resting membrane potential will increase.
To determine how the resting membrane potential would change if sodium ions diffuse into the cell freely, we need to understand the role of sodium ions in generating the resting membrane potential.
The resting membrane potential is the electrical potential difference across the cell membrane when the cell is at rest. It is primarily generated by the movement of ions, specifically sodium (Na+), potassium (K+), and chloride (Cl-) ions.
Under normal resting conditions, there is a higher concentration of sodium ions outside the cell compared to inside, while potassium ions have a higher concentration inside the cell. This concentration gradient, along with the selective permeability of the cell membrane, establishes the resting membrane potential.
If sodium ions were to freely diffuse into the cell, it would disrupt the concentration gradient, leading to an increase in the concentration of sodium ions inside the cell. This increase in sodium ions inside the cell would result in a depolarization, meaning the inside of the cell becomes less negative compared to the outside. As a consequence, the resting membrane potential would increase, moving towards a less negative or positive value.
Therefore, the correct answer is: increase.