One of the reasons why you would want to segregate things into certain regions is that molecules have to move in order to accomplish these things; molecules have to move from one place to another.

将细胞功能定位于某个固定区域的,另一个原因是,生物大分子需要移动,以完成某些功能,分子从一个地方移动到另一个地方

耶鲁公开课 - 生物医学工程探索课程节选