首页
登录
职称英语
During the Second World War, doctors tried to save severely burned pilots wit
During the Second World War, doctors tried to save severely burned pilots wit
游客
2023-06-29
21
管理
问题
During the Second World War, doctors tried to save severely burned pilots with grafts of donated skin. The grafted skin looked good for a few days, but then withered and died. Studies led by Peter Medawar—who won a 1960 Nobel Prize for his work—found that grafts of an individuals own skin did work, while those of a donor did not. We now know that the donor skin grafts failed because the recipient’s immune system recognized the grafted skin as foreign and killed it. The same process leads to the rejection of donated organs. But how does our immune system learn what is self and what is foreign?
As immunologist Daniel Davis explains in The Compatibility Gene, it is all down to specific genes—formally known as the major histocompatibility complex genes. Although our appearance, lifestyle and career path may make us feel unique, we are actually always one of a group: it is only our compatibility genes that define us as true individuals. Davis provides a well-written and easy-to-read account of the sometimes complicated biology behind the crucial genes that affect our lives so profoundly.
From early on in the evolution of life, individual cells—and later multicellular organisms— developed the ability to recognize that which was the same as them, and that which was different. Davis recounts how, when we are growing as fetuses, our compatibility genes train the immune system to recognize our own cells and tissues as "self" and so, in healthy people, they know what not to attack. Our cells are identified by the presence of unique surface molecules, coded for by the compatibility genes.
Meanwhile, our immune systems make antibodies. These are randomly generated in a kind of lottery, which means they will be able to attack a great diversity of molecules, especially those of pathogens. By chance, though, a few of these antibodies will also match the compatibility-gene molecules on our own cells. Leaving such antibodies around would be suicide—literally. To stop this, Darwinian-style selection comes into play within the immune system, eliminating any cells that produce antibodies matching "self". [br] Why did the grafted skin withere and die after a few days?
选项
A、Because a person’s immune system identifies the grafted skin which comes from other people.
B、Because people have different immune systems, and these immune systems can not be blended together.
C、Because the special features of grafted skin can not be adapted by the recipients.
D、Because the recipients do not have powerful immune system for fighting diseases.
答案
A
解析
根据题干可以将该题定位至文章第一段,第一段指出We now know that the donor skin grafts failed because the recipient’s immune system recognized the grafted skin as foreign and killed it,因此可以很快选出A选项,A中的identifies是recognized的同义替换。B、C和D选项都是对文章相关信息的曲解。
转载请注明原文地址:https://tihaiku.com/zcyy/2792412.html
相关试题推荐
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
Duringthe1992presidentialcampaign,HillaryRodhamClintonobserved,"Our
[originaltext]Duringa1995roofcollapse,afirefighternamedDonaldHerbe
[originaltext]Doctorshavefullyseparatedthefusedlegsofababygirlwh
RichSecondGeneration1.现在富裕家庭越来越多,富二代成为社会关注的焦点2.富二代可以从富裕中受益,也可能由于娇生惯养而养成许多陋习
随机试题
PASSAGETHREEToshownoteveryartifacthaspotentialscientificvalue.题目关键词Cypr
Whenwewantto【C1】______otherpeoplewhatwethink,wecandoitnotonlyw
Wedon’thavebedsinthespacecraft,butwedohavesleepingbags.Duringt
某省HND大桥由中标的CHD公司大桥项目经理部施工,KNS咨询监理公司进行施工监
下列介质访问控制方法中,不可能发生冲突的是()。A.CDMA.B.CSMA.C.
决定导游讲解语音音量大小的因素有( )。A.游客情绪的好坏 B.游客数量的多少
【教学过程】 (一)新课导入 (谈话导入)我们学过很多李白的诗歌,你对李白诗歌印象最深的一点是什么?请几位同学来谈。1.李白属于浪漫主义诗人,他的诗中夸
在教育法规体系中具有最高的法律效力,仅次于宪法的基本法律是()A.《中华人
(2020年真题)(增值税+消费税)甲卷烟厂为增值税一般纳税人,主要生产销售A牌
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
最新回复
(
0
)