万物简史 第410期:生命的起源(4)(在线收听

 Yet we are talking about several hundred thousand types of protein, perhaps a million, 然而,我们在讨论的蛋白质有几十万种,也许是100万种,

each unique and each, as far as we know, vital to the maintenance of a sound and happy you. 就我们所知,每一种都别具一格,与众不同,对于维持你的健康和幸福必不可少。
And it goes on from there. 我们就从这里接着往下讨论。
A protein to be of use must not only assemble amino acids in the right sequence, 为了被派上用场,一个蛋白质分子不但要把氨基酸分子按照合适的顺序排列起来,
but then must engage in a kind of chemical origami and fold itself into a very specific shape. 还要从事一种化学打褶工作,把自己叠成特定的形状。
Even having achieved this structural complexity, a protein is no good to you if it can't reproduce itself, and proteins can't. 即使实现了这种复杂的结构,蛋白质分子对你依然没有用处,除非它能复制自己,而蛋白质分子不会。
For this you need DNA. 为了达到这个目的,你需要DNA(脱氧核糖核酸)。
DNA is a whiz at replicating—it can make a copy of itself in seconds—but can do virtually nothing else. DNA是复制专家——几秒钟就能复制一份自己,但除此之外没有别的本事中。
So we have a paradoxical situation. 于是,我们处于一种自相矛盾的境地。
Proteins can't exist without DNA, and DNA has no purpose without proteins. 蛋白质分子没有DNA就不能存在,DNA没有蛋白质就无所事事。
Are we to assume then that they arose simultaneously with the purpose of supporting each other? If so: wow. 那么,我们是不是该认为,它们为了互相支持而同时产生呢?如果是的,哇,太好了!
And there is more still. DNA, proteins, and the other components of life couldn't prosper without some sort of membrane to contain them. 还有,要是没有膜把DNA、蛋白质和别的生命要素包裹起来,它们也不可能兴旺发达。
No atom or molecule has ever achieved life independently. 原子或分子不会独立实现生命。
Pluck any atom from your body, and it is no more alive than is a grain of sand. 从你身上取上一个原子,它像一粒沙,那样没有生命。
It is only when they come together within the nurturing refuge of a cell that these diverse materials can take part in the amazing dance that we call life. 只有许多原子凑到一起,待在营养丰富的细胞里,这些不同的物质才能参加令人惊叹的舞会,我们称其为生命。
  原文地址:http://www.tingroom.com/lesson/syysdw/wwwjs/435023.html