like the one shown here,

就像这里展示的一样
that's coupled to a special molecule called a G-protein.

是与一种叫做G蛋白的特殊分子偶联的
When the ligand is present it binds to the receptor outside the cell

当配体存在并与细胞表面的受体结合时
and it activates this G-protein.

就会激活G蛋白
The G-protein then goes on

然后G蛋白在细胞内
to create some other biochemical changes inside the cell.

诱发其它的一些生化反应
We're not going to talk about this in any detail,

我们不会讲细节方面的内容
there's a little bit more detail described in your book.

在你们的课本上会有更详细的讲解
These are fascinating molecules that turn out to be ubiquitous.

这类奇妙的分子是普遍存在的
They're everywhere in cells throughout your body and they are

它们在身体各处的细胞中都有
responsible for lots of the biochemistry of

并负责很多细胞间的相互作用
cell/cell interaction and signaling.

及信号转导的生化过程