Question

Ion channels are classified as membrane transport proteins. They discriminate between ions based on size and charge. In addition to Na⁺, which one of the following ions would you expect to be able to freely diffuse through a Na⁺ channel? Explain your answer.

1) K⁺
2) Ca₂⁺
3) Cl⁻
4) Mg₂⁺

Answer 1

K⁺ can freely diffuse through a Na⁺ channel because of their similar sizes and charges.

Step-by-step explanation:

Ion channels are membrane transport proteins that allow specific ions to cross the cell membrane. They are selective based on the size and charge of ions. In addition to Na⁺, you would expect K⁺ to be able to freely diffuse through a Na⁺ channel. This is because Na⁺ and K⁺ have similar sizes and charges, so they can fit through the channel.