英语短文：Cells and Temperature

 　　英语短文：Cells and Temperature

　　Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning. Enzyme¹ systems of mammals and birds are most efficient only within a narrow range around 37C;a departure of a few degrees from this value seriously impairs² their functioning. Even though cells can survive wider fluctuations³ the integrated actions of bodily systems are impaired⁴. Other animals have a wider tolerance⁵ for changes of bodily temperature.

　　For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology⁶ still reflects the old division into "warm-blooded" and "cold-blooded" species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded. As more species were studied, it became evident that this classification was inadequate⁷. A fence lizard⁸ or a desert iguana-each cold-blooded----usually has a body temperature only a degree or two below that of humans and so is not cold. Therefore the next distinction was made between animals that maintain a constant body temperature, called home0therms, and those whose body temperature varies with their environments, called poikilotherms. But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation⁹. Furthermore, many invertebrates¹⁰ that live in the depths of the ocean never experience change in the depths of the ocean never experience change in the chill of the deep water, and their body temperatures remain constant.

1 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

2 impairs   

v.损害，削弱( impair的第三人称单数 )

参考例句：

• Smoking impairs our health. 吸烟会损害我们的健康。 来自《简明英汉词典》
• Almost anything that impairs liver function can cause hepatitis. 任何有损于肝功能的因素，几乎都会引起肝炎。 来自辞典例句

3 fluctuations   

波动，涨落，起伏( fluctuation的名词复数 )

参考例句：

• He showed the price fluctuations in a statistical table. 他用统计表显示价格的波动。
• There were so many unpredictable fluctuations on the Stock Exchange. 股票市场瞬息万变。

4 impaired   

adj.受损的；出毛病的；有（身体或智力）缺陷的v.损害，削弱( impair的过去式和过去分词 )

参考例句：

• Much reading has impaired his vision. 大量读书损害了他的视力。 来自《现代汉英综合大词典》
• His hearing is somewhat impaired. 他的听觉已受到一定程度的损害。 来自《现代汉英综合大词典》

5 tolerance   

n.宽容；容忍，忍受；耐药力；公差

参考例句：

• Tolerance is one of his strengths.宽容是他的一个优点。
• Human beings have limited tolerance of noise.人类对噪音的忍耐力有限。

6 terminology   

n.术语；专有名词

参考例句：

• He particularly criticized the terminology in the document.他特别批评了文件中使用的术语。
• The article uses rather specialized musical terminology.这篇文章用了相当专业的音乐术语。

7 inadequate   

adj.(for,to)不充足的，不适当的

参考例句：

• The supply is inadequate to meet the demand.供不应求。
• She was inadequate to the demands that were made on her.她还无力满足对她提出的各项要求。

8 lizard   

n.蜥蜴，壁虎

参考例句：

• A chameleon is a kind of lizard.变色龙是一种蜥蜴。
• The lizard darted out its tongue at the insect.蜥蜴伸出舌头去吃小昆虫。

9 hibernation   

n.冬眠

参考例句：

• Bears wake up in the spring after a winter of hibernation.熊经过一个冬天的冬眠后在春季苏醒。
• The tortoise spends the winter months in hibernation.乌龟在冬眠中度过寒冬季节。

10 invertebrates   

n.无脊椎动物( invertebrate的名词复数 )

参考例句：

• Insects and worms are all invertebrates. 昆虫和蠕虫都是无脊椎动物。 来自辞典例句
• In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和许多其它无脊椎动物中，这些排泄结构称为肾管。 来自辞典例句