万物简史 第540期:令人惊叹的细胞(4)

 On average, however, a human cell is about twenty microns wide—that is about two hundredths of a millimeter, 不过，一个人体细胞的平均宽度不过20微米左右——也就是l毫米的大约2%，

which is too small to be seen but roomy enough to hold thousands of complicated structures like mitochondria, 小到几乎看不见，但大得足以容纳数以千计的像线粒体这样的复杂结构，

and millions upon millions of molecules¹. 以及几百万几百万个分子。

In the most literal way, cells also vary in liveliness. 从最基本的方面来说，细胞的活力也各不相同。

Your skin cells are all dead. 你的皮肤细胞都是死的。

It's a somewhat galling² notion to reflect that every inch of your surface is deceased. 想到自己身体表面的每一部分都是死的，你也许会感到有点屈辱。

If you are an average-sized adult you are lugging³ around about five pounds of dead skin, 如果你是个中等个儿的成年人，你身上裹着大约2千克的死亡皮肤，

of which several billion tiny fragments are sloughed⁴ off each day. 其中每天都有几十亿的微小组织从你身上脱落。

Run a finger along a dusty shelf and you are drawing a pattern very largely in old skin. 如果你将一个手指从布满灰尘的搁架上划过，那个痕迹在很大程度上是用你死去的皮肤划成的。

Most living cells seldom last more than a month or so, but there are some notable exceptions. 大多数细胞的存活时间很少超过l个月左右，但也有一些明显的例外。

Liver cells can survive for years, though the components⁵ within them may be renewed every few days. 肝脏细胞可以存活几年，虽然它们的内部成分每隔几天就更新一次。

Brain cells last as long as you do. 大脑细胞和你的寿命一样长。

You are issued a hundred billion or so at birth, and that is all you are ever going to get. 从你出生起，你拥有大约1000亿个细胞，这也就是你所能拥有的细胞数的最高值。

It has been estimated that you lose five hundred of them an hour, 据估计，你每小时大约丢失500个细胞。

so if you have any serious thinking to do there really isn't a moment to waste. 因此，要是你认真想一想的话，你真的是一刻光阴也不该浪费。

The good news is that the individual components of your brain cells are constantly renewed 令人欣慰的是，你脑细胞的组成部分总是在不断更新，

so that, as with the liver cells, no part of them is actually likely to be more than about a month old. 因此。与肝脏细胞相类似，你的大脑细胞实际上只存活1个月左右。

Indeed, it has been suggested that there isn't a single bit of any of us—not so much as a stray molecule—that was part of us nine years ago. 事实上，据认为，我们身上的任何一个部位——包括迷途分子在内——都与9年前不同。

It may not feel like it, but at the cellular⁶ level we are all youngsters. 这听起来似乎有些玄乎，但从细胞的层面上讲，我们都是年轻人。

 

1 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

2 galling   

adj.难堪的,使烦恼的,使焦躁的

参考例句：

• It was galling to have to apologize to a man she hated. 令人恼火的是得向她憎恶的男人道歉。
• The insolence in the fellow's eye was galling. 这家伙的傲慢目光令人恼怒。 来自英汉文学 - 嘉莉妹妹

3 lugging   

超载运转能力

参考例句：

• I would smile when I saw him lugging his golf bags into the office. 看到他把高尔夫球袋拖进办公室，我就笑一笑。 来自辞典例句
• As a general guide, S＄1 should be adequate for baggage-lugging service. 一般的准则是，如有人帮你搬运行李，给一新元就够了。 来自互联网

4 sloughed   

v.使蜕下或脱落( slough的过去式和过去分词 )；舍弃；除掉；摒弃

参考例句：

• Responsibilities are not sloughed off so easily. 责任不是那么容易推卸的。 来自《简明英汉词典》
• The scab has sloughed off. 痂脱落了。 来自辞典例句

5 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

6 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。