Can sodium ions move through the potassium ion channel Choos

Can sodium ions move through the potassium ion channel? Choose the best answer.

Yes, they are small enough to fit through the pore.

No, they cannot form favorable interactions with the selectivity filter or the pore.

No, they are too big to fit through the pore.

Yes, they form favorable interactions with the selectivity filter of the pore.

Solution

Answer: (b) No, they cannot form favorable interactions with the selectivity filter or the pore.

Sodium ions cannot move through the potassium ion channel. This is due to the fact that sodium ions are smaller and cannot interact favorably with the residues of the selectivity filter and the pore. Moreover, binding of sodium ions in this case is thermodynamically unfavorable.