Enzymes, themselves a type of protein, dash everywhere, performing up to a thousand tasks a second. Like greatly speeded up worker ants, they busily build and rebuild molecules, hauling a piece off this one, adding a piece to that one. Some monitor passing proteins and mark with a chemical those that are irreparably damaged or flawed. Once so selected, the doomed proteins proceed to a structure called a proteasome, where they are stripped down and their components used to build new proteins. Some types of protein exist for less than half an hour; others survive for weeks. But all lead existences that are inconceivably frenzied. As de Duve notes, "The molecular world must necessarily remain entirely beyond the powers of our imagination owing to the incredible speed with which things happen in it."
酶本身也是一种蛋白质。它们到处横冲直撞，每秒钟要完成1000件任务，就像快镜头里的工蚁，它们不断地建立和重建分子。为这个减去一小块，为那个增加一小块。一些酶随时监控路过的蛋白质，为那些已损坏得无法修补的或有缺陷的蛋白质标上化学记号。接着，这些被标上记号的蛋白质形成了一种被称为蛋白酶的结构，在这个结构中进行分解，并形成新的蛋白质。有几种蛋白质的存活时间不超过半小时，另一些则达好几周。但是，它们都以令人难以置信的疯狂方式存在。正如德迪夫所指出的：“分子里面的一切都以不可思议的高速运转，我们简直无法想像。”

But slow things down, to a speed at which the interactions can be observed, and things don't seem quite so unnerving. You can see that a cell is just millions of objects—lysosomes, endosomes, ribosomes, ligands, peroxisomes, proteins of every size and shape—bumping into millions of other objects and performing mundane tasks: extracting energy from nutrients, assembling structures, getting rid of waste, warding off intruders, sending and receiving messages, making repairs. Typically a cell will contain some 20,000 different types of protein, and of these about 2,000 types will each be represented by at least 50,000 molecules.
但是，如果让分子世界事物运转的速度慢下来，慢到足以仔细观察其相互作用的程度，事情似乎就不会那么令人不知所措了。你会发现一个细胞不过是数百万个物体——不同大小、不同形状的溶酶体、内吞体、核糖体、配位体、过氧化物酶体、蛋白质，它们与数百万个别的物体相互撞击，从而完成了再普通不过的任务：从营养物里摄取能量、聚合成新的结构、排除废物、抵挡入侵者、接发信息、进行修补工作。一个细胞一般包含大约2万种不同的蛋白质，其中近2000种中的每一种至少有5万个分子。