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GRE阅读题目解析:肽激素合成

2017-04-03 08:48:00来源:新东方在线整理

  P5

  1

  Until about five years ago, the very idea that peptide hormones might be made anywhere in the brain besides the hypothalamus was astounding.

  直到大概 5 年前,这样的理论还使人颇为震惊:不止下丘脑,肽激素可能在脑的任意部位合成。

  (peptide 肽

  hypothalamus 下丘脑)

  2

  But 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 that cross-react with the antiserums are present.

  但实验结果一再证明,当脑内被注射了抗肽激素血清,血清也固结在除下丘脑以外的其他部位,意味着要么是激素,要么有其他与血清交叉反应的物质存在。

  (antiserum 抗毒血清)

  3

  The immunological method of detecting peptide hormones by means of antiserums, however, is imprecise.

  然而,这种通过血清检测肽激素的免疫学方法并不准确。

  4

  Cross-reactions are possible and this method cannot determine whether the substances detected by the antiserums really are the hormones, or merely close relatives.

  交叉反应可能发生,而这方方法不能确定由血清检测出的物质到底是激素,还是单纯的近似相关物。

  5

  Furthermore, this method cannot be used to determine the location in the body where the detected substances are actually produced.

  此外,这种方法不能用来确定检出的物质是在身体的什么部位合成的。

  6

  New techniques of molecular biology, however, provide a way to answer these questions.

  比较而言,分子生物学的新技术为这些问题提供了一种解释。

  7

  It is possible to make specific complementary DNA‘s (cDNA‘s) that can serve as molecular probes to seek out the messenger RNA‘s (mRNA‘s) of the peptide hormones.

  有可能利用特定的,互补性的 DNA (cDNA's),让它作为一种分子探测器找出肽激素的信使 RNA's(mRNA‘s).

  8

  The brain cells containing these mRNA‘s can then be isolated and their mRNA‘s decoded to determine just what their protein products are and how closely the products resemble the true peptide hormones. (187 words)

  含有这些 mRNA’s 的脑细胞可以被分离出来,而它们的 mRNA's 也会被破解,并以此确定他们的蛋白质产物,以及它们和真正肽激素相似度几何。

  11. Which of the following titles best summarizes the passage?

  (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 Immunological Approach to Detecting Peptide Hormones

  (D) Peptide Hormones: How Scientists Are Attempting to Solve Problems of Their Detection

  (E) Peptide Hormones: The Role Played by Messenger RNA‘s in Their Detection

  选 D

  不好读的一篇文章,抛开一切专业方面的障眼法,第一句话告诉我们,直到五年前,一种观点还是 astounding,惊人的,不容易让人相信的,后面所有的内容都是说实验室做了什么样的事来证明这个理论 idea ,也就是解决一个问题的结构。

  所以,“ 肽激素:科学家们如何尝试解决它们的定位问题 ”,D 的标题是合适的。

  12. The passage suggests that a substance detected in the brain by use of antiserums to peptide hormones may

  (A) have been stored in the brain 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

  (E) play an important role in the functioning of the hypothalamus

  选 C

  根据句 5 :

  Furthermore, this method cannot be used to determine the location in the body where the detected substances are actually produced.

  不能确定位置,也就是说这种方法检出的物质,可能是其他身体部位产生的,最后运输到了脑部。

  13. Which of the following is mentioned in the passage 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 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.

  (E) It involves injecting foreign substances directly into the bloodstream.

  选 B

  问免疫学方法的缺点,考点跟上一题完全一样。

  以上就是新东方在线GER频道为你带来的GRE阅读题目解析:肽激素可能在脑的任意部位合成,更多精彩敬请关注新东方在线GRE频道。

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