GRE阅读题目解析:卡路里摄入与动物寿命

　　Animals live longer when their calorie intake is restricted to two-thirds of what is considered normal for their species. Animals so restricted are also generally healthier: most disease, including cancer, diabetes, and neurodegenerative illness, are forestalled. This phenomenon was long attributed to a simple slowing of metabolism (cells’ production of energy from fuel molecules) and consequent reproduction of its toxic by-products in response to less food. In fact, however, calorie restriction does not slow mammalian metabolism, and in yeast and worms, metabolism is both sped up and altered. Some scientists now theorize that calorie restriction is a biological stressor that, like natural food scarcity, induces a more complex defensive response, which in mammals includes changes in cellular defenses and repair.

　　1. In the passage, the function of the highlighted portion is to

　　A. Provide specific examples of organisms whose longevity does not increase in response to calorie restriction.

　　B. Illustrate the probable means by which organisms placed on a calorie-restriction diet compensate for the reduction in available food-based level.

　　C. Suggest the mechanism that is responsible for prolonging the life of organism whose calorie intake is significantly reduced.

　　D. Give an example that explain why scientists’ thinking about the physiological effects of calorie restriction changed.

　　E. Distinguish the different ways that mammalian and non-mammalian metabolisms respond to significant reductions in calorie intake

　　Consider each of the choices separately and select all that apply.

　　2. The passage implies which of the following about the explanation mentioned in the highlighted text?

　　A. There are empirical findings that conflict with a presumption of the explanation.

　　B. The explanation predicts that the effect of calorie restriction on longevity will be the greatest for the species with the highest rate of metabolism.

　　C. The explanation predicts that the effects of calorie restriction will be uniformly positive.

　　1

　　Animals live longer when their calorie intake is restricted to two-thirds of what is considered normal for their species.

　　当卡路里摄入量被限制在该物种正常水平的三分之二时，动物的寿命变长。

　　2

　　Animals so restricted are also generally healthier: most disease, including cancer, diabetes, and neurodegenerative illness, are forestalled.

　　这样食量受限的动物往往更健康：多数疾病，包括癌症，糖尿病，以及神经组织退化疾病，都会被预防。

　　3

　　This phenomenon was long attributed to a simple slowing of metabolism (cells’ production of energy from fuel molecules) and consequent reproduction of its toxic by-products in response to less food.

　　这种现象长久以来被简单地归于新陈代谢(细胞利用食物分子生产能量)变慢，以及因食物变少而随之(减少)的有毒副产物的增殖。

　　4

　　In fact, however, calorie restriction does not slow mammalian metabolism, and in yeast and worms, metabolism is both sped up and altered.

　　然而实际上，摄入能量受限并不减缓哺乳动物的新陈代谢，而酵母菌和虫类(实验显示)，新陈代谢都加速且发生改变。

　　【mə-'mā-lē-ən, ma-】

　　5

　　Some scientists now theorize that calorie restriction is a biological stressor that, like natural food scarcity, induces a more complex defensive response, which in mammals includes changes in cellular defenses and repair.

　　一些科学家现在提出理论认为，卡路里限制是一种生物学意义上的压力刺激，类似自然状态下的食物短缺，引发了一种更复杂的防卫反应，在哺乳动物表现为改善了细胞的防护和修复。

　　1. In the passage, the function of the highlighted portion is to

　　A. Provide specific examples of organisms whose longevity does not increase in response to calorie restriction.

　　B. Illustrate the probable means by which organisms placed on a calorie-restriction diet compensate for the reduction in available food-based level.

　　C. Suggest the mechanism that is responsible for prolonging the life of organism whose calorie intake is significantly reduced.

　　D. Give an example that explain why scientists’ thinking about the physiological effects of calorie restriction changed.

　　E. Distinguish the different ways that mammalian and non-mammalian metabolisms respond to significant reductions in calorie intake

　　选 D

　　一个长期被观察到的事实是，吃正常食量三分之二的动物更健康长寿。科学家以前觉得是因为新陈代谢变慢，产生的有毒产物增殖也变慢。后来发现，少吃并不减慢动物的新陈代谢，科学家对限制食量使动物更健康的机制的看法改变了。标记部分正是举例解释了科学家看法的这种改变，因为观察到没有变慢(反而变快了)，所以因少吃而变慢而健康的看法改变了。

　　Consider each of the choices separately and select all that apply.

　　2. The passage implies which of the following about the explanation mentioned in the highlighted text?

　　A. There are empirical findings that conflict with a presumption of the explanation.

　　B. The explanation predicts that the effect of calorie restriction on longevity will be the greatest for the species with the highest rate of metabolism.

　　C. The explanation predicts that the effects of calorie restriction will be uniformly positive.

　　选 A

　　基于观察的发现与一种解释的假设矛盾。

　　empirical 经验的，可通过观察和经验证明的

　　本文中的 empirical findings 指句 4 提到的，实验观察到，新陈代谢不因进食减少而改变;presumption of the explanation 指句 3 提到的，进食受限新陈代谢变慢有毒物质累积变慢，变慢是一种假设，没有被证实过。标记部分暗示二者矛盾。

       以上就是本文的全部内容，更多精彩请随时关注新东方长春学校官网。

相关推荐

长春新东方留学直通车