If Na+ diffuses into the cell, the interior becomes more

If Na+ diffuses into the cell, the interior becomes more

• A. Positive
• B. Negative
• C. No change
• D. More positive on outside

Answer: (A)

When a positively charged ion like Na+ moves into the cell, it adds positive charge to the interior. This influx makes the inside less negative and more positive, depolarizing the membrane. In other words, the intracellular space becomes more positive relative to the outside. The other options don’t fit because Na+ entry does not make the interior more negative, nor leave it unchanged, and it doesn’t make the outside more positive—the key effect is the interior becoming more positive.

When a positively charged ion like Na+ moves into the cell, it adds positive charge to the interior. This influx makes the inside less negative and more positive, depolarizing the membrane. In other words, the intracellular space becomes more positive relative to the outside. The other options don’t fit because Na+ entry does not make the interior more negative, nor leave it unchanged, and it doesn’t make the outside more positive—the key effect is the interior becoming more positive.