【考研类试卷】考博英语-532及答案解析.doc
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1、考博英语-532 及答案解析(总分:100.00,做题时间:90 分钟)一、Part Reading Compr(总题数:4,分数:30.00)The antigen-antibody immunological reaction used to be regarded as typical of immunological responses. Antibodies are proteins synthesized by specialized cells called plasma cells, which are funned by lymphocytes (cells from the
2、 lymph system when an antigen, a substance foreign to the organisms body, comes in contact with lymphocytes. Two important manifestations of antigen- antibody immunity are lysis, the rapid physical rupture of antigenic cells and the liberation of their contents into the surrounding medium, and phago
3、cytosis, a process in which antigenic particles are engulfed by and very often digested by macrophages and polymorphs. The process of lysis is executed by a complex and unstable blood constituent known as complement, which will not work unless it is activated by a specific antibody; the process of p
4、bagocytosis is greatly facilitated when the particles to be engulfed are coated by a specific antibody directed against them.The reluctance to abandon this hypothesis, however well it explains specific processes, impeded new research, and for many years antigens and antibodies dominated the thoughts
5、 of immunologists so completely that those immunologists overlooked certain difficulties. Perhaps the primary difficulty with the antigen-antibody explanation is the informational problem of how an antigen is recognized and how a structure exactly complementary to it is then synthesized. When molecu
6、lar biologists discovered, moreover, that such information cannot flow from protein to protein, hut only from nucleic acid to protein, the theory that an antigen itself provided the mold that directed the synthesis of an antibody had to be seriously qualified. The attempts at qualification and the i
7、nformation provided by research in molecular biology led scientists to realize that a second immunological reaction is mediated through the lymphocytes that are hostile to and bring about the destruction of the antigen. This type of immunological response is called cell- mediated immunity.Recent res
8、earch in cell-mediated immunity has been concerned not only with the development of new and better vaccines, but also with the problem of transplanting tissues and organs from one organism to another, for although circulating antibodies play a part in the rejection of transplanted tissues, the prima
9、ry role is played by cell-mediated reactions. During cell-mediated responses, receptor sites on specific lymphoeytes and surface antigens on the foreign tissue cells form a complex that binds the lymphocytes to the tissue. Such lymphocytes do not give rise to antibody- producing plasma cells but the
10、mselves bring about the death of the foreign-tissue cells, probably by secreting a variety of substances, some of which are toxic to the tissue cells and some of which stimulate increased phagocyte activity by white blood cells of the macrophage type. Cell-mediated immunity also accounts for the des
11、truction of intracellular parasites.(分数:7.50)(1).The passage suggests that scientists might not have developed the theory of cell-mediated immunological reactions if_.(分数:1.50)A.proteins existed in specific group typesB.proteins could have been shown to direct the synthesis of other proteinsC.antige
12、ns were always destroyed by proteinsD.antibodies were composed only of protein(2).The author argues that the antigen-antibody explanation of immunity “had to be seriously qualified“ because_.(分数:1.50)A.antibodies were found to activate unstable components in the bloodB.antigens are not exactly compl
13、ementary to antibodiesC.lymphocytes have the ability to bind to the surface of antigensD.antibodies are synthesized from protein whereas antigens are made from nucleic acid(3).The author most probably believes that the antigen-antibody theory of immunological reaction_.(分数:1.50)A.is wrongB.was accep
14、ted without evidenceC.is unverifiableD.is a partial explanation(4).The author mentions all of the following as being involved in antigen-antibody immunological reactions EXCEPT the_.(分数:1.50)A.synthesis of a proteinB.activation of complement in the bloodstreamC.destruction of antibodiesD.entrapment
15、of antigens by macrophages(5).The author supports the theory of cell-mediated reactions primarily by _.(分数:1.50)A.pointing out a contradiction in the assumption leading to the antigen-antibody theoryB.explaining how cell mediation accounts for phenomena that the antigen-antibody theory cannot accoun
16、t forC.revealing new data that scientists arguing for the antigen-antibody theory have continued to ignoreD.showing that the antigen-antibody theory fails to account for the breakup of antigensSince the dawn of human ingenuity, people have devised ever more cunning tools to cope with work that is da
17、ngerous, boring, burdensome, or just plain nasty. That compulsion has resulted in roboticsthe science of conferring various human capabilities on machines. And ff scientists have yet to create the mechanical version of science fiction, they have begun to come close.As a result, the modern world is i
18、ncreasingly populated by intelligent gizmos whose presence we barely notice but whose universal existence has removed much human labor. Our factories hum to the rhythm of robot assembly arms. Our banking is done at automated teller terminals that thank us with mechanical politeness for the transacti
19、on. Our subway trains are controlled by tireless robot-drivers. And thanks to the continual miniaturization of electronics and micro-mechanics, there are already robot systems that can perform some kinds of brain and bone surgery with submillimeter accuracyfar greater precision than highly skilled p
20、hysicians can achieve with their hands alone.But if robots are to reach the next stage of laborsaving utility, they will have to operate with less human supervision and be able to make at least a few decisions for themselvesgoals that pose a real challenge. “While we know how to tell a robot to hand
21、le a specific error,“ says Dave Lavery, manager of a robotics program at NASA, “we cant yet give a robot enough common sense to reliably interact with a dynamic world.“Indeed the quest for true artificial intelligence has produced very mixed results. Despite a spell of initial optimism in the 1960s
22、and 1970s when it appeared that transistor circuits and microprocessors might be able to copy the action of the human brain by the year 2010, researchers lately have begun to extend that forecast by decades if not centuries.What they found, in attempting to model thought, is that the human brains ro
23、ughly one hundred billion nerve cells are much more talentedand human perception far more complicatedthan previously imagined. They have built robots that can recognize the error of a machine panel by a fraction of a millimeter in a controlled factory environment. But the human mind can glimpse a ra
24、pidly changing scene and immediately disregard the 98 percent that is irrelevant, instantaneously focusing on the monkey at the side of a winding forest road or the single suspicious face in a big crowd. The most advanced computer systems on the earth cant approach that kind of ability, and neurosci
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