They're everywhere in cells throughout your body and they are responsible for lots of the biochemistry of cell/cell interaction and signaling.

它们在身体各处的细胞中都有,并负责很多细胞间的相互作用,及信号转导的生化过程

耶鲁公开课 - 生物医学工程探索课程节选

It does that through a complex set of sort of cellular interactions, and it turns out also gene rearrangements if you go further to study that.

而这此过程中,发生了一系列复杂的细胞间的相互作用,也会涉及到基因重排,如果你们深入学习的话就会学到

耶鲁公开课 - 生物医学工程探索课程节选

The reason that it's a sigma bond is sp3 because the s p 3 hybrid orbital is directly interacting with the 1 s orbital of the hydrogen atom, and that's going to happen on the internuclear axis, they're just coming together.

它是sigma键的原因,是因为,杂化轨道直接和氢原子1s轨道相互作用，它们作用发生在核间轴上，它们会到一起。

麻省理工公开课 - 化学原理课程节选