湖北大冶市六中 陳亞梅

蛛絲柔軟、無毒、經(jīng)久耐用，能進(jìn)行生物降解，還可以在承受高張力的情況下不斷裂。幾十年來科學(xué)家們一直致力于研究蛛絲的生產(chǎn)原理，并嘗試復(fù)制這一過程?，F(xiàn)在科學(xué)家研究出一種方法，首次成功模仿蜘蛛紡制出人造絲。下面讓我們一起來了解這新型人造蜘蛛絲！

題材文章詞數(shù)生物科技2 7 1 難度 ★★★★體裁建議用時說明文5′

難詞掃障

1.nontoxicadj.無毒的

2.biodegradableadj.可生物降解的

3.proteinn.蛋白質(zhì)

4.moleculen.分子

5.amino acid氨基酸

6.repetitiveadj.重復(fù)的

7.DNA sequence DNA序列

8.modifyv.修改

9.solutionn.溶液

Being able to produceartificialspider silk has long been a dream of many scientists since spider silk is as strong as steel， stretchy，nontoxicandbiodegradable.But spiders are not easy to farm and they produce only a small amount of silk.For decades scientists have tried to mimic （模仿）the silvery thread but have fallen short.Now a team has developed a method that for the first time will allow researchers tospinartificial silk fibers as spiders do and to efficiently produce kilometers of silk.

Researchers have previously transplanted silk-making DNA from spiders into bacteria，silk worms，plants and even goatsin an effort tomass-produce the substance.However， the fibers have been only half as strong as the real thing.The secret of spider silk's strength lies in largeprotein moleculescomposed of hundreds of strings of repeatedamino acidsencoded by similarlyrepetitive DNA sequences.But“in general，nature does not like repetitive DNA and finds ways to get rid of it，” says Fuzhong Zhang， a professor of energy， environmental and chemical engineering at Washington University in St.Louis.

To avoid this problem，Zhang and his colleaguesmodifiedthe spider's DNAinvolved inproducing silk proteins.Then they made these proteins into a powder and mixed it into asolutionthat can be spun into fibers as strong as natural ones.

“These fibers could be asustainable alternativeto traditional fibers such as nylon，”Zhang says.But the challenge is producing it insufficientquantitiesat low cost.Besides，researchers are devoted to finding a water-based solution to replace the present one to produce the high-performance fibers.

Reading Check

1.How did researchers succeed in imitating spider silk？

A.They transplanted silk-making DNA into bacteria.

B.They found the repetitive spider DNA and found ways to remove it.

C.They modified the spider DNA related to making silk proteins.

D.They found a water-based solution to produce spider fibers.

2.From which is the text probably taken？

A.A biology textbook.

B.A health magazine.

C.A research magazine.

D.A chemistry brochure.

Language Study

Ⅰ.Important vocabulary in the text

1.artificialadj.人造的；人工的

2.spin （spun，spun）vt&vi紡紗；（使）旋轉(zhuǎn)

3.in an effort to do sth努力做某事

4.be involved in涉及；卷入；參與

5.sustainableadj.可持續(xù)的

6.alternativen.可供選擇的事物adj.替代的；備選的

7.sufficientadj.足夠的

8.at low cost以低價；以低成本

Ⅱ.Complete the following sentences in correct forms with the vocabulary given above.

1.Researchers made proteins into a powder and mixed it into a solution that can be_______into fibers as strong as natural ones.

2.Artificial silk could be a（n） ________to traditional fibers such as nylon.

3.Spiders produce only a small amount of silk，which is not_______for industrial use.

4.One of the challenges for scientists is to produce a large quantity of fibers _______.

5.Many scientists _______finding a waterbased solution to produce the high-performance fibers.

6.Researchers have tried many ways_______to find the secret of spider silk's strength and mass-produce the substance.