The membrane is not, as most of us imagine it, a durable, rubbery casing, something that you would need a sharp pin to prick. Rather, it is made up of a type of fatty material known as a lipid, which has the approximate consistency "of a light grade of machine oil," to quote Sherwin B. Nuland. If that seems surprisingly insubstantial, bear in mind that at the microscopic level things behave differently. To anything on a molecular scale water becomes a kind of heavy-duty gel, and a lipid is like iron.
细胞膜并不是我们大多数人想象的那样是一层你用别针能刺穿的耐久胶状物，相反，它是由一种叫做脂质的脂肪物质所构成，用舍温·B·纽兰的话说，它和“轻度机油”大体相像。如果你觉得这些东西似乎很不坚实，请记住：在显微镜下，事物的表现形式是不同的。在分子的层面上，对于任何东西而言，水成了重型凝胶，而脂质简直就像钢铁一样。

If you could visit a cell, you wouldn't like it. Blown up to a scale at which atoms were about the size of peas, a cell itself would be a sphere roughly half a mile across, and supported by a complex framework of girders called the cytoskeleton. Within it, millions upon millions of objects—some the size of basketballs, others the size of cars—would whiz about like bullets. There wouldn't be a place you could stand without being pummeled and ripped thousands of times every second from every direction. Even for its full-time occupants the inside of a cell is a hazardous place. Each strand of DNA is on average attacked or damaged once every 8.4 seconds—ten thousand times in a day—by chemicals and other agents that whack into or carelessly slice through it, and each of these wounds must be swiftly stitched up if the cell is not to perish.
如果你有机会去访问一个细胞，你一定不会喜欢它的。若是将原子放大到豌豆一样大小，那么一个细胞就会变成直径达800米的一个球体，由一个名叫细胞骨架的大梁似的复杂架子支撑着。在它的里面，几百万几百万个物体——有的大如篮球，有的大如汽车——像子弹一样呼啸而过。在这里你简直难以找到立足的地方，每一秒钟都会遭到数千次来自四面八方的物体的撞击和撕扯。即使对长期待在细胞里面的成员来说，这里也是一个险象环生的地方。每一段DNA链平均每8.4秒就要遭到一次袭击或损害——每天要遭到1万次——被化学物质或是其他物质撞击或撕成碎片，所有这些伤口必须很快被缝合，除非细胞不想再活下去。
The proteins are especially lively, spinning, pulsating, and flying into each other up to a billion times a second.
蛋白质极为活跃，它们总是处于不停旋转、颤动和飞舞的状态之中，每秒钟它们都要彼此撞击10亿次。