问题 单项选择题

萤火虫的荧光素基因转入烟草植物细胞,获得了高水平的表达。这一研究成果表明()

①萤火虫与烟草植物的DNA结构基本相同

②萤火虫与烟草植物共用一套遗传密码子

③烟草植物体内合成了荧光素

④萤火虫和烟草植物合成蛋白质的方式基本相同

A.①③

B.②③

C.①④

D.①②③④

答案

参考答案:D

解析:

萤火虫与烟草植物的DNA能够进行重组,说明不同生物的DNA结构基本相同;萤火虫的荧光素基因能在烟草植物细胞中表达,说明不同生物共用一套遗传密码子;由题干信息“获得了高水平的表达”可知烟草植物体内合成了荧光素;萤火虫和烟草植物合成蛋白质的方式基本相同,都是通过脱水缩合方式合成的。故选D 考点:本题考查基因工程的相关知识。 点评:本题意在考查考生的理解能力,属于容易题。

完形填空

Life in 30 years will be   31  because many changes will take place, but what will the changes be?

The population is growing fast. There will be    32   people in the world and most of them will live longer than before. Computers will be   33  smaller and more useful, and there will be at least one in every home. And computer studies will be one of the important  34  in school.

People will work fewer hours than they are doing now, and they will have more free time for sports, watching TV and traveling. Traveling will be much cheaper and  35 . And more people will go to other countries  36  holidays.

There will be changes in our food, too. More land will be used for  37   new towns and houses. Then there will be less  38  for cows and sheep, so meat will be more expensive. Maybe people won’t eat it every day, they will eat more vegetables and fruit instead. Maybe people will be healthier.

Work in the future will be different, too. Dangerous and hard work will  39  by robots. Because of this, many people will not have  40  to do. This will be a problem. 

小题1:A. same                    B. difference                C. different      

小题2:A. little and little     B. less and less              C. more and more

小题3:A. much                   B. many                   C. more          

小题4:A. subject                  B. subjects                 C. way                   

小题5:A. easily                   B. more easily              C. easier           

小题6:A. for                     B. with                    C. at           

小题7:A. build                   B. building                 C. to build        

小题8:A. rooms                  B. room                    C. spaces        

小题9:A. done                   B. do                      C. be done       

小题10:A. works enough             B. enough works             C. enough work

选择题