And actually, a question that might come up, I just explained, the sodium channel, you might say, well, how do potassium channels work then, because I can understand how you can filter something big out, but how do you filter out something small.

实际上，可能大家会问一个问题，我刚解释过，钠离子通道，你可以说，好吧，那么钾离子通道该如何起作用呢，因为我可以理解你是如何把大东西过滤掉的，但是你如何把小东西过滤掉呢？

麻省理工公开课 - 化学原理课程节选

We'll talk about some chemistry today, what DNA molecules are like, why they have the behavior that they do, and you need to understand this in order to understand how you manipulate DNA.

今天我们会谈到一些化学结构,比如DNA分子的形态,它们为什么会以这种形态存在,你必须先掌握这些,才能理解如何操控DNA

耶鲁公开课 - 生物医学工程探索课程节选