There are - that's one class of proteins on the surface I'm sorry.

对不起这是细胞膜蛋白的一个种类
There are proteins that are responsible for receiving signals,

还有一些蛋白是负责接收信号的
chemical signals.

化学信号
There are proteins, for example,

比如说蛋白
on the surface of some cells

有些细胞表面上的蛋白
that bind insulin and respond to the presence of insulin.

捕获胰岛素并且对胰岛素进行应答
We're going to talk more about

我们下一周
these kinds of molecules on the surface next week.

会再讨论这些表面分子的内容
For now, just know that different kinds of cells,

现在你们只要知道有不同的细胞
one of the ways they're different is

它们之间的一种区别
that they express different proteins

就是它们表达不同的蛋白
and the population of proteins

而不同细胞表面的蛋白种类