题型：阅读选择 题类：模拟题 难易度：普通
广东省东莞市2019届英语中考二模试卷
For us humans, one of the greatest experiences is to taste all kinds of delicious food. But for penguins, they cannot get a taste of this happiness. That's because penguins can't actually taste the delicious flavors (味道) of their favorite food-fish!
Scientists from the University of Michigan examined the genome (基因组)of five species of penguins. They found that no one can taste umami (鲜味),the flavor of meat or fish, the BBC reported.
Many animals have five basic tastes: sweet, sour, salty, bitter and umami. But according to genetic data, penguins are believed to have only sour and salty tastes.
These findings are surprising and puzzling. And scientists don't have a good explanation for them. But they have a few ideas.
First, one of the umami genes doesn't work in cold temperatures. "It's about zero degrees when they eat cold fish," Zhang Jianzhi, the lead scientist, told the Daily Mail, so even if the penguins had a functional (功能的)gene, it might not work when they needed it.
Second, penguins' tongues (舌头) are very special which may have something to do with their lack of taste. Instead of being covered with taste buds which help to taste food, penguins' tongues are very spiky. This is better for them to hold slippery (滑的) fish than tasting them. One study even showed that some types of penguins don't even have taste buds.
However, penguins seem to be managing just fine.
"Their behavior of swallowing food whole, and their tongue structure and function, suggest that penguins need no taste perception," said Zhang.
试题篮
