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[高考复习指南] 2016届高考英语一轮复习课时作业:语言朋友(26)(北师大版)

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  语言朋友(26)(香水) come in tiny bottles,

  perfect a particular smell, perfume­makers often use an ingredient that comes from sperm whales, called ambergris.But using ambergris, which helps a perfume last longer, is strongly opposed by many people who think it is wrong to kill whales just so we can smell sweet.Joerg Bohlmann is neither a perfumer nor a whale expert.He's a plant biologist at the University of British Columbia in Canada.But his discovery of a new plant gene (基因) might push whales out of the perfume business.

  The gene comes from fir trees, found throughout North America and commonly used as Christmas trees.The trees produce a chemical that can be used in perfume in place of ambergrisbut with_a_catchmical is mixed with many others.That makes separation a challenge,” Bohlmann says.“It's like trying to isolate sugar from a biscuit.”

  This is where science becomes useful.When Bohlmann learned that fir trees produce the ambergrisike chemical, he decidted to use his gene know­how to find the instructions for how to make the ambergris­substitute.

  Bohlmann found that gene and took it out of the tree cells.Then he did something that might sound strange to someone who doesn't work in genetics: Bohlmann put the gene from the tree into yeast (酵母) cells.t the fir tree gene into the yeast, the yeast started making the same chemical that had been produced by the tree.

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