问题 选择题

人的卷舌和不卷舌分别受A、a基因控制,则在人的精子中控制不卷舌的基因是(  )

A.基因a

B.基因aa

C.基因A或a

D.基因AA或Aa

答案

生物体的某些性状是由一对基因控制的,而成对的基因往往有显性和隐性之分,显性基因控制显性性状,隐性基因控制隐性性状,当控制某个性状的基因一个是显性,一个是隐性时,只表现出显性基因控制的性状.通常大写字母表示显性基因,小写字母表示隐性基因.由显性基因A控制的性状卷舌是显性性状,在体细胞中的基因型为AA或Aa,其形成的精子中的基因为A或a;由隐性基因a控制的性状不卷舌是隐性性状,在体细胞中的基因型是aa,其形成的精子中控制不卷舌的基因是a.

故选A

阅读理解

A

Steve Jobs, the CEO of Apple, was not a good student when he was in school. At that time, he always got into trouble with his schoolmates. When he went to college, he didn’t change a lot. Then he dropped out(退学). But he was full of new ideas.

After that, Steve Jobs worked as a video game designer in a company. He worked there only for a few months and then he went to India. He hoped that the trip would give him some new ideas and a new chance to change his life.

Steve Jobs lived on a farm in California for a year after he returned from India. In 1975, he began to make a new type of computer. He designed the first Apple Computer with his friend in his garage. He chose the name “Apple”just because it reminded him of a happy summer he once spent in an apple orchard.

His first Apple Computer was a great success. Because of this, Steve Jobs soon became famous all over the world.

小题1:Steven Jobs always got into trouble with _______ in school.

A.his schoolmates

B.his parents

C.his teachers

D.his brothers小题2:Steven Jobs designed the first Apple Computer with his friend _______.

A.in his school

B.in his company

C.in his garage

D.at home小题3:Which of the following is not true?

A.Steve Jobs didn’t finish his college.

B.Steve Jobs worked as a video game designer in a company for a few months.

C.Steve Jobs soon became famous all over the world because of his first Apple computer.

D.Steve Jobs chose the name “Apple” just because he liked eating apples.

单项选择题 B型题