问题 填空题 案例分析题

下图是利用转基因技术生产干扰素的简化流程。请分析回答:

利用PCR扩增仪大量扩增目的基因的前提是目的基因的核苷酸序列要有一段是已知的,以便根据这一序列合成(),除了该物质和目的基因外,扩增仪中还需加入四种脱氧核苷酸和()酶,并适时调整温度,才能使目的基因数量成指数式增长。

答案

参考答案:引物;DNA聚合酶(Taq酶)

问答题
单项选择题

As a solo artist, Brightman has sold 26 million albums and two million DVDs in 34 countries. Her musical styles put opera, pop and jazz together. She is popular in the States but not here(Britain) - the image of her and her second husband, Andrew Lloyd Webber (he is much older, she is his muse) seems for ever frozen.

The 47-year-old singer talks about the new album Symphony that came out of a "very dark time", including her decision to give up trying to have children. "People have suggested I could adopt," Brightman says. "But work is central to my life now. And so I am going to put it to one side. After a while not having children becomes the norm and perhaps that might sound alarming, to parents especially, but I have never known anything different. I’m not hurt by not having children. My life and career are incredibly rich. "

Talking about growing up in a large family in Berkhamsted—her father is a property developer who later committed suicide, she says: "I was gifted as a child, and very musical. I seemed to be good at anything to do with the arts. At 5 I understood the music I was dancing to and had an eye for costume. " She first appeared in a West End musical at 11 and hated boarding school.

Brightman led the saucy dance troupe(辣妹三人舞) Hot Gossip and had her first hit with I Lost My Heart to a Starship Trooper in 1978. At 18 she married a music manager called Andrew Graham Stewart. "I was probably in love but I can’t remember. Girls change such a lot between 18 and 22. It didn’t really work out. " In 1981 she was spotted by Lloyd Webber. She became his leading lady in Song and Dance, Requiem and Phantom of the Opera. They married in 1984.

Brightman says she felt hostility "from the beginning. I haven’t tried to understand it. I’ve done very well everywhere else, especially the US, where I now live, I just accept it for what it is. The more you are away from Britain, the more you appreciate it. But I don’t miss it, although I miss my family. Our profession can be uncomfortable but I enjoy what I do. I get on with it. \

Brightman decided to give up having children because ().

A.she could adopt one

B.her life and career were unbelievably rich without children

C.she felt it normal not to have children

D.she was too busy