You see a bleep going across the screen to indicate that they've got their finger on the pulse of what's happening, or you see it in TV shows like ER.

你们看到一个亮点在屏幕上来回跳动,来显示病人脉搏的,跳动情况,就像在急诊室的故事,这类电视中看到的那样

耶鲁公开课 - 生物医学工程探索课程节选

They're colored different here to indicate one new difference that you know about now, and that's that there is an orientation, there's an up and down on the chain.

这里被涂成不同的颜色,来表示另一个不同之处,它是有方向的,表示双链一条向上,一条向下

耶鲁公开课 - 生物医学工程探索课程节选