GRE阅读题目解析:温血动物发病时体温升高

　　P5

　　Why during sickness should body temperature of warm-blooded animal rise? It has long been known that the level of serum iron in animals falls during infection. Garibaldi first suggested a relationship between fever and iron. He found that microbial synthesis of siderophores -- substances that bind iron -- in bacteria of the genus Salmonella declined at environmental temperatures above 37°C and stopped at 40.3°C. Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply. Cold-blooded animals were used to test this hypothesis. Kluger reported that of iguanas infected with the potentially lethal bacterium A. hydrophilia, more survived at temperatures of 42°C than at 37°C, even though healthy animals prefer the lower temperature. When animals at 42°C were injected with an iron solution, however, mortality rates increased significantly. (135 words)

　　9. According to the passage, Garibaldi determined which of the following?

　　(A) That serum iron is produced through microbial synthesis

　　(B) That microbial synthesis of siderophores in warm-blooded animals is more efficient at higher temperatures.

　　(C) That only iron bound to other substances can be used by bacteria.

　　(D) That there is a relationship between the synthesis of siderophores in bacteria of the genus Salmonella and environmental temperature.

　　(E) That bacteria of the genus Salmonella require iron as a nutrient.

　　10. If it were to be determined that similar phenomena occur in warm-blooded animals, which of the following, assuming each is possible, is likely to be the most effective treatment for warm-blooded animals with bacterial infections?

　　(A) Administering a medication that lowers the animals' body temperature

　　(B) Injecting the animals with an iron solution

　　(C) Administering a medication that makes serum iron unavailable to bacteria

　　(D) Providing the animals with reduced-iron diets

　　(E) Keeping the animals in an environment with temperatures higher than 37°C

1

　　Why during sickness should body temperature of warm-blooded animal rise?

　　为什么发病期间，温血动物的体温要升高?

　　(should 不是应该，是描述一种预期)

　　2

　　It has long been known that the level of serum iron in animals falls during infection.

　　人们很早就知道，感染中的动物，血浆中的铁元素会减少。

　　(serum 血浆，血清)

　　3

　　Garibaldi first suggested a relationship between fever and iron.

　　G 第一次提出了发烧与铁元素的关联性。

　　4

　　He found that microbial synthesis of siderophores -- substances that bind iron -- in bacteria of the genus Salmonella declined at environmental temperatures above 37°C and stopped at 40.3°C.

　　他发现，沙门氏菌中的铁载体的细菌合成，在超过37摄氏度时减少，达到40.3摄氏度时完全停止，铁载体是一种连结铁离子的物质。

　　5

　　Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply.

　　所以，发烧可以使入侵的细菌更难获得铁离子，因而更难繁殖。

　　6

　　Cold-blooded animals were used to test this hypothesis.

　　人们用冷血动物测试了这种假设。

　　7

　　Kluger reported that of iguanas infected with the potentially lethal bacterium A. hydrophilia, more survived at temperatures of 42°C than at 37°C, even though healthy animals prefer the lower temperature.

　　K 在鼠鳞蜥感染潜在致命细菌 A.h 的报告中称，体温42摄氏度的个体比处于37摄氏度的成活率更高，尽管健康的动物(鼠鳞蜥)更喜欢较低的温度。

　　(鼠鳞蜥)

　　(https://en.wikipedia.org/wiki/Iguana#/media/File:Iguana_delicatissima.jpg)

　　8

　　When animals at 42°C were injected with an iron solution, however, mortality rates increased significantly. (135 words)

　　然而，42摄氏度的蜥蜴如果被注射了铁离子溶液，死亡率会极大地上升。

　　(https://en.wikipedia.org/wiki/Iguana#/media/File:Iguana-001.jpg)

　　9. According to the passage, Garibaldi determined which of the following?

　　(A) That serum iron is produced through microbial synthesis

　　(B) That microbial synthesis of siderophores in warm-blooded animals is more efficient at higher temperatures.

　　(C) That only iron bound to other substances can be used by bacteria.

　　(D) That there is a relationship between the synthesis of siderophores in bacteria of the genus Salmonella and environmental temperature.

　　(E) That bacteria of the genus Salmonella require iron as a nutrient.

　　选 D

　　根据在句 3、4：

　　“Garibaldi first suggested a relationship between fever and iron.

　　He found that microbial synthesis of siderophores -- substances that bind iron -- in bacteria of the genus Salmonella declined at environmental temperatures above 37°C and stopped at 40.3°C. ”

　　10. If it were to be determined that similar phenomena occur in warm-blooded animals, which of the following, assuming each is possible, is likely to be the most effective treatment for warm-blooded animals with bacterial infections?

　　(A) Administering a medication that lowers the animals' body temperature

　　(B) Injecting the animals with an iron solution

　　(C) Administering a medication that makes serum iron unavailable to bacteria

　　(D) Providing the animals with reduced-iron diets

　　(E) Keeping the animals in an environment with temperatures higher than 37°C

　　选 C

　　A 搞反了，温度高于37才阻碍细菌结合铁离子，越降温细菌繁殖越 hign 。

　　B 想想句 8 的蜥蜴是怎么死的。

　　C 阻止细菌得到血浆中的铁离子。治本的办法。

　　D 提供低铁食谱。

　　最大的干扰项，它的问题在于：1，多低才合适，可能细菌只需要量不大的一点铁元素，没准还能重复利用;2，我们无法确定铁元素对患病个体只有坏处，也许铁元素还有很多不能忽略的好处，毕竟人是离不开铁元素的，不然怎么有一种贫血叫缺铁性贫血;……你也可以补充，我认为想到这两条中的任何一条，都足以排除此项，就不挖了。

　　E 保持环境温度在37摄氏度以上。

　　次干扰项，首先题目问的是温血动物，温血动物可以在一定范围内自主调节体温，不像蜥蜴如果想提高体温，几乎完全依赖外界环境;从常识想，人是会出汗的呀，环境 37 度，那基本是大夏天了，人肯定要大量出汗以降温，所以人的体温未必能维持在必要的 37 摄氏度以上;第三，我们不知道过高的温度对人体有没有坏处，这个最容易想到了，高烧不退的病人，经常需要在额头上敷个冰袋来降温。综上，这是一个未必有用，且基本肯定会添乱的办法，还请广大市民放心选 C 。

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