Question

Research suggests that a newly-identified gene known as insomniacs(失眠症患者) may play a role in keeping us asleep. By cloning and testing this gene in about 21,000 fruit flies, Rockefeller University researchers say they have discovered an entirely new mechanism (机制) by which sleep is controlled.

By studying these flies, the researchers discovered that mutations(变异) in the insomniac gene were associated with a great reduction in sleep. While a typical fruit fly slept for an average of 927 minutes a day, the mutant flies slept for just 317. They also slept for shorter periods of time, and slept and woke more frequently.

“The results showed a great loss of both the time that the flies’ sleep lasted and their ability to remain asleep after they slept,” says researcher Nicholas Stavropoulos.

The researchers also examined the link between sleep and lifespan, finding that flies with mutations to the insomniac gene lived only about two-thirds as long as unchanged flies. But when the scientists removed insomniac only in neurons（神经细胞）---allowing it to remain in the rest of the flies’ bodies---this difference disappeared; the resulting animals slept poorly but lived just as long.

“This suggests that reduced sleep can be ‘uncoupled’(分开) from reduced lifespan, supporting the idea that some interruptions of sleep do not affect overall health, at least as far as lifespan is concerned,” Stavropoulos says.

Although flies and humans would appear to have little in common when it comes to lifestyle, scientists say that the mechanisms of sleep and wakefulness are likely to be quite similar.

“Sleep is a fundamental behavior in all animals, and it is poorly understood from a scientific standpoint, says Stavropoulos. This work could prove useful in understanding and treating sleep disorders”

1.The text is mainly about____.

A．the progress in cloning fruit flies

B．the methods of cloning fruit flies

C．the link between gene and lifespan

D．the influence of a gene on the ability to sleep

2.According to paragraph2, the mutant flies________.

A．slept about 5 hours a day

B．had problems waking up

C．didn’t seem sleepy at all

D．could not fall asleep

3.We can conclude from the text that________.

A．sleep and health go hand in hand

B．sleep can be controlled by humans

C．research into sleep is very fruitful

D．the findings are useful in medical treatment

 

Answer 1

【答案】

1.D

2.A

3.D

【解析】

试题分析：本文叙述了通过对果蝇的科学研究发现基因影响睡眠的能力，而一般情况下果蝇睡眠平均每天927分钟,变异果蝇睡了只有317分钟，他们睡眠的时间更短了,睡着了,醒来时却更频繁。苍蝇和人类在生活方式上似乎没有什么共同点,但是睡眠和清醒的情况也可能非常相似。这个研究发现可能对于治疗睡眠障碍有一定的帮助。

1.主旨大意题。根据By studying these flies, the researchers discovered that mutations(变异) in the insomniac gene were associated with a great reduction in sleep.可知基因影响睡眠的能力，故选D。

2.细节理解题。根据the mutant flies slept for just 317，变异果蝇一天睡眠的时间大约5个小时，故选A。

3.推理判断题。根据This work could prove useful in understanding and treating sleep disorders，故选D。

考点：科普类短文阅读。

点评：主旨大意题的难度较大，此类题目一般不易直接找到答案，最简单的方法是仔细研究文章开头的一二句，因为他们常是文章的主题句，然后，快速浏览文章首句和结尾句。如果第一句的主题不明，可注意结尾是否有概括总结，对选项要注意全面性和概括性。