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阅读理解(46)研制DNA计算机  

2011-11-11 19:28:37|  分类: 阅读理解 |  标签: |举报 |字号 订阅

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阅读理解(46)研制DNA计算机 - 佳中 - 嘉华相恋

   阅读理解(46)     

                              研制DNA计算机

                                                                          佳中命题

                                                 

 

 

                                                                               Text 2

        Scientists have made a small but vital step forward in the quest to harness the vast computing potential

of DNA. The U.S. research team says that DNA computing can be simplified by attracting molecules to a

surface and then using them to tackle real and complex problems.

        DNA computing is still very much a dream for scientists. They hope to harness the enormous data —

storing capacity of DNA, biological molecules that are also able to perform operations similar to a computer’s. 

The new research, published in the journal Nature, reports the development of novel surface chemistry that

greatly simplifies the complex and repetitive steps previously used in rudimentary DNA computers. It takes

DNA out of the test tube and puts it on a solid surface, making the technology simpler, more accessible and

more amendable to the development of DNA computers with greater storing capacity.

      In the experiments, DNA molecules were applied to a small glass plate that is overlaid with folds. The DNA

was modified so that all the possible answers to a computationally difficult problem were included. By exposing

the molecules to certain enzymes, the molecules with the wrong answers were weeded out, leaving only the

 DNA molecules with the rights answers.

      The appeal of DNA computing lies in the fact that DNA molecules can store far more information than any

existing computer memory chip. It has been estimated that a gram of dried DNA can hold as much information

as a trillion CDs. What is more, in a biochemical reaction taking place in a tiny surface area, hundreds of

trillions of DNA molecules can operate in concert, creating a parallel processing system that resembles the

processing architecture of the most powerful supercomputer.

      Conventional computing, with ever more and smaller features packed onto the silicon chips that power it,

is approaching the limits of miniaturization. Many scientists believe that DNA computing is a way around the

barrier. Current DNA computing technology, Professor Smith emphasizes, is still far from overtaking the silicon

chip at the present time. He says his new method is simply an idea for working out an improved and simpler

chemistry for DNA computing. It takes time to prove its validity. Nevertheless, he adds, the new surface

chemistry provides an opportunity for harnessing DNA to make the biggest non-conventional computer yet:

“We are interested in scaling up. We believe that based on the principles we have worked out here, we can

see scalping by a factor of a trillion or more sometime in the future. By then computer science will have been

elevated to an entirely new horizon.”                      

                                                                                                                                       (432 words)

 

26. Some scientists are interested in DNA computing because they believe it can

      [A] perform more complex operations.

      [B] store an enormous amount of information.

      [C] simplify the process of calculation.

      [D] make computers still smaller.

27. The main problem with the present conventional computer lies in its

      [A] inability to accommodate ever increasing amount of information.

      [B] failure to tackle real and complex problems.

      [C] limitation to operate in concert.

      [D] lack of attraction to active biochemical materials.

28. By “DNA computing is a way around the barrier”, the author means that DNA computing

      [A] is approaching the limits of miniaturization.

      [B] promises to overcome the flaw of the conventional computer.

      [C] overcome the barrier to packing more power into the silicon chips.

      [D] will take the place of the silicon chips someday in the future.

29. What Professor Smith said in the last paragraph implies that

      [A] scaling up is the biggest barrier in the development of DNA computers.

      [B] there are too many factors affecting the development of DNA computers.

      [C] DNA computing technology may be a big leap in computer science.

      [D] the principles he worked out require testing on the biggest non-conventional computer.

30. It can be deduced from the passage that the idea of DNA computers

      [A] is subjected to much skepticism of its validity.

      [B] will come true in not too long a time.

      [C] remains to be a theoretical speculation.

      [D] has provided an opportunity to scale up the computer’s capacity.

 

 

 

答案: B   A   B   C    C

 

 

 

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