Question

In the resting state of the neural membrane, diffusion due to concentration gradients, if allowed, would drive

• A. $K^{+}$ and $N{a}^{+}$ out of the cell
• B. $N{a}^{+}$ into the cell
• C. $N{a}^{+}$ out of the cell
• D. $K^{+}$ into the cell

Answer 1

The correct option is B $N{a}^{+}$ into the cell

In the resting nerve fibre, the cytoplasm inside the axon has a high concentration of K ions and a low concentration of Na ions, in contrast to the fluid outside the axon. Thus if diffusion occurs, then through concentration gradient, Na ions would enter the nerve cells.