segregate things into certain regions

另一个原因是
is that molecules have to move

生物大分子需要移动
in order to accomplish these things;

以完成某些功能
molecules have to move from one place to another.

分子从一个地方移动到另一个地方
In general,

总的来说
inside of a cell molecules move by a process called diffusion.

细胞内的分子通过扩散作用来移动
They move from regions of high concentration

从高浓度区域
to regions of low concentration

向低浓度区域流动
by this natural flow down a concentration gradient.

顺浓度梯度流动
Movement down a concentration gradient occurs fairly rapidly

顺浓度梯度扩散在一微米左右的短距离内
over short distances like a micron or so,

相当迅速
like the size of a bacterium.

一微米相当于一个细菌的大小