However, when that gate is opened, the sodium channel is now going to be incredibly selective and only let through sodium ions and no other type of ion.

但是，当闸门打开的时候，钠离子通道,将会有极高的选择性,不允许除钠离子以外的任何其它离子通过。

麻省理工公开课 - 化学原理课程节选

For these purposes think about a channel, it only allows sodium to go through for example.

基于此目的,我们来讲离子通道,拿仅允许钠离子通过的通道作为例子

耶鲁公开课 - 生物医学工程探索课程节选

And that's all that's big enough to pass through or small enough to pass through. And if we go up even just one row on the periodic table to potassium, what we actually see is now that it's going to be too large, and, in fact, a potassium solvated with one water molecule won't go through our channel.

就是这样刚好大到它通过,或者说刚好小到它通过,即使我们再沿着周期表往下走仅仅一行到钾离子，我们看到的就将是它的个头太大了，实际上，溶解于一个水分子的单个钾离子,不能穿过我们的通道。

麻省理工公开课 - 化学原理课程节选

A state where it's closed, so imagine a channel with a lid on top of it; when it's closed nothing can go through the channel, when it's open then things can go through.

一种是闭合状态,想想一个有盖子的通道吧,当盖子合上的时候任何东西都不能通过,而打开时就畅通无阻

耶鲁公开课 - 生物医学工程探索课程节选