题型:阅读理解 题类:常考题 难易度:普通
四川省树德中学2019-2020学年高一上学期英语10月月考试卷
If you ask most people what water tastes like, they'll probably tell you that water has no taste and they may give you a funny look. But if you were a fruit fly, asking another fruit fly, that question might have a different answer.
To a fruit fly, water has a taste. Scientists want to know how the fruit fly knows water because this information may help in learning how other animals — or even individual cells — manage to use water in the right way. Water is vital to life, but too much or too little can be deadly to a living creature. So by understanding how the fruit fly tastes water, researchers may learn more about other living things.
According to the new study, a protein(蛋白质) called PPK28 makes it possible for a fly to taste water. Proteins build cells and tissues, fight disease and carry messages between cells. It's not surprising that a protein is responsible for the fruit fly's ability to taste water.
The PPK28 protein is part of a larger family of similar proteins. One of these related proteins is used by mammals (including humans) to taste salt. Scientists have not found a protein that enables humans to "taste" water.
In the experiment, Cameron and his team compared normal fruit flies with fruit flies whose taste cells had been disabled. The fruit flies were given a special chemical that would glow(发光) when the fly used the PPK28 protein. Then the scientists led the flies to water. When the normal flies tasted the water, the PPK28 protein lit up — showing that it was in use.
The fruit fly in particular is so interesting that some scientists are hard at work creating a complete map of the fruit fly brain. This map will show all of a fly's neurons and help scientists understand how the neurons work together.
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