问题 单项选择题 A1/A2型题

DNA变性时其结构变化正确的是()。

A.磷酸二酯键断裂

B.N-C糖苷键断裂

C.戊糖内C-C键断裂

D.碱基内C-C键断裂

E.对应碱基间氢键断裂

答案

参考答案:E

解析:DNA变性指DNA分子双螺旋解开成单链的过程,其本质是互补碱基之间的氢键断裂。

阅读理解

Michael Jackson is one of the world’s best singers. Michael Jackson was born in the middle west of Gary, Indiana, in 1958. He began singing with his four brothers. They called the group “Jackson Five”. The group became very popular after appearing on a television progam. They started singing in 1965, became popular soon. In 1970 the group made their first record the name of “I Want You Back”. It was very popular. One of their hit records was “Never Say Goodbye”.

Michael was good at dancing as well as singing, for example, his dance moves and moon walking. He was asked to act in a film in 1978 for the first time, in the same year he made a record on his own, which sold eight million copies all over the world.

Michael nearly didn’t go out because he was too famous. Once his fans went off in a faint(晕倒) when they saw him at the concert. No one can do it by now. He lived in a large house and kept lots of animals. He never ate meat. He often raises money for charity. This made him win the Guinness World Records(吉尼斯世界纪录)in 2006. He died on June 25th, 2009, but he would live in our heart forever.

小题1:What’s the name of their first record?

A.“Never Say Goodbye”

B.“See You, See Me”

C.“I Want You Back”

D.“On the World”小题2:Michael was good at __________ according to the passage.

A.rock music

B.street dance

C.playing the piano

D.moon walking小题3:Why did Mochael have to stay at home most of the time?

A.Because he was too famous

B.Because he often felt lonely.

C.Because he had no friends

D.Because his company asked him to do so

多项选择题