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　　Sugar power for cell phones

　　Using enzymes commonly in living cells, a new type of fuel cell produces small amounts of electricity from sugar. If the technology is able to succeed in mass production, you may some day share your sweet drinks with your cell phone.

　　In fuel cells, chemical reactions generate electrical currents. The process usually relies on precious metals, such as platinum. In living cells, enzymes perform a similar job, breaking down sugars to obtain electrons and produce energy.

　　When researchers previously used enzymes in fuel cells, they had trouble keeping them active, says Shelley D.Minteer of St Louis University. Whereas biological cells continually produce fresh enzymes, there’s no mechanism in fuel cells to replace enzymens as they quickly degrade.

　　Minter and Tamara Klotzbach, also of St Louis University, have now developed polymers that wrap around an enzyme and preserve it in a microscopic pocket. “ We tailor these pockets to provide the ideal microenvironment” for the enzyme, Minteer says. The polymers keep the enzyme active for months instead of days.

　　In the new fuel cell, tiny polymer bags of enzyme are embedded in a membrane that coats one of the electrodes. When glucose from a sugary liquid gets into a pocket, the enzyme oxidizes it , releasing electrons and protons. The electrons cross the membrane and enter a wire through which they travel to the other electrode, where they react with oxygen in the atmosphere to produce water. The flow of electrons through the wire constitutes an electrical current that can generate power.

　　So far, the new fuel cells don’t produce much power, but the fact that they work at all is exciting, syas Paul Kenis, a chemical engineer at the University of Illinois at Urbana-Champaign. “Just getting it to work,” Kenis says, “is a major accomplishment.”

　　Sugar-eating fuel cells could be an efficient way to make electricity. Sugar is easy to find. And the new fuel cells that run on it are biodegradable, so the technology wouldn’t hurt the environment. The scientists are now trying to use different enzymes that will get more power from sugar. They predict that popular products may be using the new technology in as little as 3 years.

　　練習：

　　1. According to the first paragraph, when can we share our sweet drinks with our cell phones?

　　A when enzymes can be commonly found in living cells.

　　B when the technology of producing a new type of fuel cell appears.

　　C when the technology of a new type of fuel cell is suitable for mass production.

　　D when the technology of mass producing cell phones appears.

　　2. What trouble did Minteer and Klotzbach have in their research?

　　A they had trouble keeping emzymes in fuel cells active.

　　B they had trouble keeping biological cells active.

　　C they had trouble producing cells active.

　　D they had trouble finding mechanism for producing enzymes.

　　3. According to paragraph 5, electrons are released

　　A when bags of enzyme are embedded in the new fuel cell.

　　B when glucose from a sugary liquid goes through the enzymes.

　　C when the enzyme oxidizes the glucose from a sugary liquid that goes through a pocket.

　　D when the enzyme oxidizes the sugary liquid that goes through a pocket.

　　4. What is exciting about the new fuel cells?

　　A their limitless power generation capacity is amazing.

　　B their limited power generation capacity is a good beginning.

　　C their limited power generation capacity is the result of great efforts.

　　D their limited power generation capacity is a major accomplishment.

　　5. According to the last paragraph, what is NOT true of the new fuel cells?

　　A the new fuel cells run on sugar that is easy to find.

　　B the new fuel cells are environment friendly.

　　C the new fuel cells are biologically degradable.

　　D it will take some time before the new fuel cells can be used in popular products.

　　參考答案：C A C B D