| Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile(1.6 kilometer) tall. Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy-looking "hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some little-understood mechanism. From the bacteria point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the watery molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacteria have all been replaced by new ones; even bacteria without flagella are thus constantly exposed to a changing environment. | |
| 细菌是极其微小的生物体。我们用英寸或厘米来测量自己的大小，而测量细菌却要用微米。一微米等于千分之一毫米。针头直径大约一毫米。 棒状细菌通常有2～4微米长，而圆形细菌的直径一般只有1微米。因此，即使你把一个圆形细菌放大1000倍，它也不过一个针头那么大。 可是如果把一个成年人放大1000倍，就会变成1英里(或1.6公里)多高。 用一般的显微镜观察细菌时，你必须仔细观察才能看见它们。使用100倍的显微镜时，你会发现细菌不过是隐约可见的小细棒或小点点，而它们的结构你却根本看不出来。使 用特殊的着色剂后，你会发现有的细菌上长着不少波状的"毛发"即鞭毛，而有的细菌只有一根鞭毛。鞭毛的旋转可以推动细菌在水中行进。不少细菌没有鞭毛，因而不能自己行进。还有些细菌却能通过某些鲜为人知的机制沿物体表面滑动。 我们所熟知的世界在细菌眼中完全是另一个样子。对于细菌来说，水就同糖浆之于人类一样稠密。细菌是如此的微小，周围化学分子的一举一动都会对它们产生影 响。在显微镜下，细菌，甚至包括那些没有鞭毛的细菌，经常在水中跳来跳去。这是因为它们与水分子相撞后，被弹向各个方向。分子移动很迅速，仅0.1秒之 隔，一个细菌周围的分子就会完全更新。因此，即使是没有鞭毛的细菌也暴露在一个不断变化的环境中。 |
| Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rodshaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile 1. 6 kilometer tall. Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavylooking " hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some littleunderstood mechanism. From the bacteria point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the watery molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacteria have all been replaced by new ones even bacteria without flagella are thus constantly exposed to a changing environment. | |
| xi jun shi ji qi wei xiao de sheng wu ti. wo men yong ying cun huo li mi lai ce liang zi ji de da xiao, er ce liang xi jun que yao yong wei mi. yi wei mi deng yu qian fen zhi yi hao mi. zhen tou zhi jing da yue yi hao mi. bang zhuang xi jun tong chang you 2 4 wei mi zhang, er yuan xing xi jun de zhi jing yi ban zhi you 1 wei mi. yin ci, ji shi ni ba yi ge yuan xing xi jun fang da 1000 bei, ta ye bu guo yi ge zhen tou na me da. ke shi ru guo ba yi ge cheng nian ren fang da 1000 bei, jiu hui bian cheng 1 ying li huo 1. 6 gong li duo gao. yong yi ban de xian wei jing guan cha xi jun shi, ni bi xu zi xi guan cha cai neng kan jian ta men. shi yong 100 bei de xian wei jing shi, ni hui fa xian xi jun bu guo shi yin yue ke jian de xiao xi bang huo xiao dian dian, er ta men de jie gou ni que gen ben kan bu chu lai. shi yong te shu de zhuo se ji hou, ni hui fa xian you de xi jun shang zhang zhe bu shao bo zhuang de" mao fa" ji bian mao, er you de xi jun zhi you yi gen bian mao. bian mao de xuan zhuan ke yi tui dong xi jun zai shui zhong xing jin. bu shao xi jun mei you bian mao, yin er bu neng zi ji xing jin. hai you xie xi jun que neng tong guo mou xie xian wei ren zhi de ji zhi yan wu ti biao mian hua dong. wo men suo shu zhi de shi jie zai xi jun yan zhong wan quan shi ling yi ge yang zi. dui yu xi jun lai shuo, shui jiu tong tang jiang zhi yu ren lei yi yang chou mi. xi jun shi ru ci de wei xiao, zhou wei hua xue fen zi de yi ju yi dong dou hui dui ta men chan sheng ying xiang. zai xian wei jing xia, xi jun, shen zhi bao kuo nei xie mei you bian mao de xi jun, jing chang zai shui zhong tiao lai tiao qu. zhe shi yin wei ta men yu shui fen zi xiang zhuang hou, bei dan xiang ge ge fang xiang. fen zi yi dong hen xun su, jin 0. 1 miao zhi ge, yi ge xi jun zhou wei de fen zi jiu hui wan quan geng xin. yin ci, ji shi shi mei you bian mao de xi jun ye bao lu zai yi ge bu duan bian hua de huan jing zhong. |
| Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rodshaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile 1. 6 kilometer tall. Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavylooking " hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some littleunderstood mechanism. From the bacteria point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the watery molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacteria have all been replaced by new ones even bacteria without flagella are thus constantly exposed to a changing environment. | |
| xì jūn shì jí qí wēi xiǎo de shēng wù tǐ. wǒ men yòng yīng cùn huò lí mǐ lái cè liáng zì jǐ de dà xiǎo, ér cè liáng xì jūn què yào yòng wēi mǐ. yī wēi mǐ děng yú qiān fēn zhī yī háo mǐ. zhēn tóu zhí jìng dà yuē yī háo mǐ. bàng zhuàng xì jūn tōng cháng yǒu 2 4 wēi mǐ zhǎng, ér yuán xíng xì jūn de zhí jìng yì bān zhǐ yǒu 1 wēi mǐ. yīn cǐ, jí shǐ nǐ bǎ yí gè yuán xíng xì jūn fàng dà 1000 bèi, tā yě bù guò yí gè zhēn tóu nà me dà. kě shì rú guǒ bǎ yí gè chéng nián rén fàng dà 1000 bèi, jiù huì biàn chéng 1 yīng lǐ huò 1. 6 gōng lǐ duō gāo. yòng yì bān de xiǎn wēi jìng guān chá xì jūn shí, nǐ bì xū zǐ xì guān chá cái néng kàn jiàn tā men. shǐ yòng 100 bèi de xiǎn wēi jìng shí, nǐ huì fā xiàn xì jūn bù guò shì yǐn yuē kě jiàn de xiǎo xì bàng huò xiǎo diǎn diǎn, ér tā men de jié gòu nǐ què gēn běn kàn bu chū lái. shǐ yòng tè shū de zhuó sè jì hòu, nǐ huì fā xiàn yǒu de xì jūn shàng zhǎng zhe bù shǎo bō zhuàng de" máo fà" jí biān máo, ér yǒu de xì jūn zhǐ yǒu yī gēn biān máo. biān máo de xuán zhuǎn kě yǐ tuī dòng xì jūn zài shuǐ zhōng xíng jìn. bù shǎo xì jūn méi yǒu biān máo, yīn ér bù néng zì jǐ xíng jìn. hái yǒu xiē xì jūn què néng tōng guò mǒu xiē xiǎn wéi rén zhī de jī zhì yán wù tǐ biǎo miàn huá dòng. wǒ men suǒ shú zhī de shì jiè zài xì jūn yǎn zhōng wán quán shì lìng yī ge yàng zi. duì yú xì jūn lái shuō, shuǐ jiù tóng táng jiāng zhī yú rén lèi yí yàng chóu mì. xì jūn shì rú cǐ de wēi xiǎo, zhōu wéi huà xué fèn zǐ de yī jǔ yī dòng dōu huì duì tā men chǎn shēng yǐng xiǎng. zài xiǎn wēi jìng xià, xì jūn, shèn zhì bāo kuò nèi xiē méi yǒu biān máo de xì jūn, jīng cháng zài shuǐ zhōng tiào lái tiào qù. zhè shì yīn wèi tā men yǔ shuǐ fèn zi xiāng zhuàng hòu, bèi dàn xiàng gè gè fāng xiàng. fèn zǐ yí dòng hěn xùn sù, jǐn 0. 1 miǎo zhī gé, yí gè xì jūn zhōu wéi de fèn zǐ jiù huì wán quán gēng xīn. yīn cǐ, jí shǐ shì méi yǒu biān máo de xì jūn yě bào lù zài yí gè bù duàn biàn huà de huán jìng zhōng. |
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