题干

关于人胰岛素基因表达载体的叙述,以下说法正确的是(    )

A:表达载体中的胰岛素基因可通过人肝细胞mRNA反转录获得

B:表达载体的复制和胰岛素基因的表达均启动于复制原(起)点

C:借助抗生素抗性基因可以将含胰岛素基因的受体细胞筛选出来

D:表达载体中的启动子和终止密码子均在胰岛素基因的转录中起作用

上一题 下一题 0.0难度 选择题 更新时间:2019-07-08 10:43:47

答案(点此获取答案解析)

C

同类题5

    Have you ever stayed in a hotel? Most Chinese hotels often provide guests(客人) with things like disposable (一次性的) toothbrushes, toothpaste, shampoo and slippers. Many guests like the idea because they don't have to bring their own. But, if you travel to Beijing, remember to bring your own things. Starting from June, some hotels in Beijing will no longer provide guests with these disposables. They want to ask people to use less disposable things.
    Many disposable things are made of plastic. People throw them away after only using them once. It is a waste of natural resources (资源) and is very bad for the environment. Do you know, one Chinese person makes as much as 400kg of waste a year! Most of that waste comes from disposable things. In Beijing, people throw away about 19,000 tons of plastic bags and 1,320 tons of plastic lunch bowls every year! Plastic can take between 100 and 400 years to break down. So the less plastic we throw out, the better. So, wherever you travel, bring your own things and use them again and again.
    Back at home and school, you can also do something to make our world a better place. Try to do these things in your daily life:  Use cloth shopping bags, not plastic ones. After using a plastic bag, wash it out and let it dry. Then you can use it over and over again. Do not use paper cups. At your school dining-room, use your own bowl and chopsticks instead of disposable ones.
    To protect our environment and our home, it is very necessary and important for us to save natural resources.