问题 填空题

下表中列出了几种限制酶识别序列及其切割位点,图1、图2中箭头表示相关限制酶的酶切位点。请回答下列问题:

限制酶BamHⅠHindⅢEcoRⅠSmaⅠ
识别序列及切割位点

G GATC C

C CTAG G

A AGCT T

T TCGA A

G AATT C

C TTAA G

CCC GGG

GGG CCC

用图中的质粒和外源DNA构建重组质粒,不能使用SmaⅠ切割,原因是()。

答案

参考答案:SmaⅠ会破坏质粒的抗性基因、外源DNA中的目的基因

阅读理解

Have you been back to the place where your ancestors lived, worked, studied and played?  Robert Qian , a Chinese Canadian, already has.Now in China, he has found that his family is like a tall tree with long roots.

Robert is just one young overseas Chinese who has come to visit his ancestors’ homeland, as part of the In Search of Roots summer camp program. The program is organized by the local government of Guangdong Province. This program started in 1980, and so far has brought thousands of overseas Chinese students to China to look for their families’ roots. The young people are usually between 16 and 25 years old. (1) Most, like Robert, can hardly speak any Chinese and have never been to  China before.

The students mainly visit parts of Guangdong Province in southern China. During the two-week camp, they study Chinese culture, see changes that have happened in that area, and visit interesting sights. (2) Going to their ancestors’ village is often the most exciting part of the trip. The students feel that they are part of the village, and experience village life. They drink from the village well, go for walks through the countryside, and watch the villagers do their daily activities.

Cathy Qian, a young American student, had this to say, “ Thanks to In Search of Roots, I am beginning to understand my Chinese roots and who I am. It has been a great trip, and I have so many memories of China to take with me .”

The program leaders believe strongly in the program and say that the purpose of it is to give young overseas Chinese the chance to learn more about themselves. “I’ve really enjoyed the trip so far,” says Robert.“This has been a big step for me, and I’m looking forward to finding out more about my roots during my time here.   ”

小题1:将(1)处划线部分译成汉语。

                                                                  。

小题2:根据(2)处完成下面的句子。

            often the most exciting part of the trip                    their ancestors’village.

小题3:根据短文内容完成下面的句子。

The program In Search of Roots has helped Robert and many other overseas Chinese learn more about their             and             .

问答题 简答题