Because these molecules can span across the membrane from outside to inside, they're in just the right position to take messages that they receive from outside the cell and transmit them through the membrane into the cells internal apparatus, and that's what they do.

因为这些分子能穿过细胞膜,连通细胞内外,它们所在的位置非常适于接受信息,它们能将外界获得的信息,通过细胞膜传递给细胞器,这正是它们的功能

耶鲁公开课 - 生物医学工程探索课程节选

If that protein is an enzyme then you've and you've switched it from an 'off' position where it's not catalyzing a reaction to an 'on' position where it is, you've changed the biochemical state of the cell, you've changed the chemical reactions that can occur within the cell, and you've changed its behavior.

如果这种蛋白是一种酶的话,你就能够将酶从无催化作用的静息态,激活至能催化反应的激活态,你改变了细胞的生化状态,也改变了细胞内发生的化学反应,改变了细胞的行为

耶鲁公开课 - 生物医学工程探索课程节选