宮東風(fēng)25個考研英語閱讀經(jīng)典試題及答案(13)

1、姓名：_ 班級：_ 學(xué)號：_-密-封 -線- 宮東風(fēng)25個考研英語閱讀經(jīng)典試題及答案(13)考試時間：120分鐘 考試總分：100分題號一二三四五總分分?jǐn)?shù)遵守考場紀(jì)律，維護知識尊嚴(yán)，杜絕違紀(jì)行為，確?？荚嚱Y(jié)果公正。sample 13醫(yī)學(xué)類until about five years ago, the very idea that peptide hormones might be made anywhere in the brain besides the hypothalamus was astounding. peptide hormones, scientists thought, we

2、re made by endocrine glands and the hypothalamus was thought to be the brains only endocrine gland. what is more, because peptide hormones cannot cross the blood-brain barrier, researchers believed that they never got to any part of the brain other than the hypothalamus, where they were simply produ

3、ced and then released into the bloodstream.but these beliefs about peptide hormones were questioned as laboratory after laboratory found that antiserums to peptide hormones, when injected into the brain, bind in places other than the hypothalamus, indicating that either the hormones or substances th

4、at cross-react with the antiserums are present. the immunological method of detecting peptide hormones by means of antiserums, however, is imprecise. cross-reactions are possible and this method cannot determine whether the substances detected by the antiserums really are the hormones, or merely clo

5、se relatives. furthermore, this method cannot be used to determine the location in the body where the detected substances are actually produced.new techniques of molecular biology, however, provide a way to answer these questions. it is possible to make specific complementary dnas (c dnas) that can

6、serve as molecular probes seek out the messenger rnas (mrnas) of the peptide hormones. if brain cells are making the hormones, the cells will contain these mrnas. if the products the brain cells make resemble the hormones but are not identical to them, then the c dnas should still bind to these mrna

7、s, but should not bind as tightly as they would to m rnas for the true hormones. the cells containing these mrnas can then be isolated and their mrnas decoded to determine just what their protein products are and how closely the products resemble the true peptide hormones.the molecular approach to d

8、etecting peptide hormones using cdna probes should also be much faster than the immunological method because it can take years of tedious purifications to isolate peptide hormones and then develop antiserums to them. roberts, expressing the sentiment of many researchers, states: “i was trained as an

9、 endocrinologist. but it became clear to me that the field of endocrinology needed molecular biology input. the process of grinding out protein purifications is just too slow.”if, as the initial tests with cdna probes suggest, peptide hormones really are made in brain in areas other than the hypotha

10、lamus, a theory must be developed that explains their function in the brain. some have suggested that the hormones are all growth regulators, but rosens work on rat brains indicates that this cannot be true. a number of other researchers propose that they might be used for intercellular communicatio

11、n in the brain.1. which of the following titles best summarizes the text?a is molecular biology the key to understanding intercellular communication in the brain?b molecular biology: can researchers exploit its techniques to synthesize peptide hormones?c the advantages and disadvantages of the immun

12、ological approach to detecting peptide hormones.d peptide hormones: how scientists are attempting to solve problems of their detection and to understand their function?2. the text suggests that a substance detected in the brain by use of antiserums to peptide hormones maya have been stored in the br

13、ain for a long period of time.b play no role in the functioning of the brain.c have been produced in some part of the body other than the brain.d have escaped detection by molecular methods.3. according to the text, confirmation of the belief that peptide hormones are created in the brain in areas o

14、ther than the hypothalamus would force scientists toa reject the theory that peptide hormones are made by endocrine glands.b revise their beliefs about the ability of antiserums to detect peptide hormones.c invent techniques that would allow them to locate accurately brain cells that produce peptide

15、 hormones.d develop a theory that account for the role played by peptide hormones in the brain.4. which of the following is mentioned in the text as a drawback of the immunological method of detecting peptide hormones?a it cannot be used to detect the presence of growth regulators in the brain.b it

16、cannot distinguish between the peptide hormones and substances that are very similar to them.c it uses antiserums that are unable to cross the blood-brain barrier.d it involves a purification process that requires extensive training in endocrinology.5. the idea that the field of endocrinology can ga

17、in from developments in molecular biology is regarded by roberts witha incredulity.b derision.c indifference.d enthusiasm. 答案與考點解析1. 【答案】d【考點解析】這是一道中心主旨題。全文從頭至尾討論的是“peptide hormones”在人體內(nèi)產(chǎn)生的部位，所以有關(guān)全文中心主旨內(nèi)容的答案應(yīng)該包含“peptide hormones”。從各段的主題句進行分析，第一至四段主要講如何“detect”(探測)肽激素(peptide hormones)所產(chǎn)生的位置，第五段主要講有關(guān)

18、肽激素的“function”?？梢姳绢}的正確選項應(yīng)該是d?？忌诮忸}時一定要搞清楚原文所涉及的對象并且抓住每段的主題句以及它們之間的相互關(guān)系。2. 【答案】c【考點解析】這是一道審題定位題。根據(jù)題干中的“a substance detected”可把本題的正確選項迅速確定在第二段的尾句。該句所涉及的核心問題是“where”，所以本題的正確選項應(yīng)該是c。考生在解題時一定要迅速而準(zhǔn)確地進行審題定位。3. 【答案】d【考點解析】本題是一道細(xì)節(jié)推導(dǎo)題。通過本題題干中的“peptide hormones are created in the brain in areas other than the h

19、ypothalamus”可將本題的答案信息迅速確定在尾段的第一句。尾段第一句主要就肽激素的“function”進行論述，可見本題的正確選項應(yīng)該是d，選項d中的“role”就等于原文中的“function”?？忌诮忸}時一定要善于抓住主句中的重要信息。4. 【答案】b【考點解析】這是一道句間關(guān)系題。根據(jù)本題題干中的”the immunological method”可將本題的答案信息迅速確定在第二段的第二句，而本題的確切答題點在第二段的第三句的后半部分。從第二段第三句的后半部分可以推導(dǎo)出本題的正確答案是b?？忌诮忸}時一定要注意一般概括句和具體陳述句之間的相互關(guān)系。5. 【答案】d【考點解析】本

20、題是一道細(xì)節(jié)推導(dǎo)題。根據(jù)本題題干中的人名“roberts”可將本題的答案迅速確定在倒數(shù)第二段引號部分的第二句話，即“but”一詞引導(dǎo)的句子。從該句中的“needed”一詞可以看出本題的正確選項應(yīng)該是d?？忌诮忸}時一定要學(xué)會深入理解原文的字面含義。參考譯文肽激素除了下丘腦能制造，在大腦中任何其它的地方都能夠制造。大約五年前僅這一想法本身就是令人驚詫的?？茖W(xué)家認(rèn)為，肽激素是由內(nèi)分泌腺制造的，而下丘腦被認(rèn)為是大腦中唯一的內(nèi)分泌腺。而且，由于肽激素?zé)o法穿過血腦障礙，研究人員認(rèn)為它們從不曾到過除下丘腦以外的大腦任何其它部位，肽激素僅在下丘腦制造出來，然后被釋放到血管中。但是關(guān)于肽激素的這種觀點已經(jīng)遭到質(zhì)疑。通過一次又一次的實驗發(fā)現(xiàn)，肽激素的抗血清一旦被注射到大腦中，它就會在下丘腦以外的地方粘接起來。這就說明這些地方或是有肽激素存在，或是有與抗血清發(fā)生交叉反應(yīng)的其他物質(zhì)存在。但是，通過抗血清來檢驗肽激