题干

回答下列有关基因工程的问题.

(1)用限制酶HindⅢ、BamH I同时切割目的基因,可得到____ 个DNA片段.

(2)用限制酶HindⅢ和BamH I切割Ti质粒,可得到____ 个DNA片段.

(3)过程①需要用到____ 酶.

(4)切割目的基因和质粒的酶与①过程的酶作用的化学键都是____

(5)如果把目的基因直接注入植株细胞,一般会被植株细胞____ .

(6)构建重组质粒时,常用Ti质粒作为载体,是因为Ti质粒上具有____ ,它能把目的基因整合到受体细胞(植株细胞)的____  上.

(7)将目的基因导人植物细胞,除采用图中的方法外,还可采用____法和花粉管通道法.

上一题 下一题 0.0难度 选择题 更新时间:2018-09-05 09:16:43

答案(点此获取答案解析)

4,2,DNA连接酶,磷酸二酯键,核酸酶分解,T﹣DNA,染色体DNA,基因枪

同类题5

阅读理解

    In today's Internet age, the demand for online games continues to grow. Online computer game centers exist in many cities and towns throughout Asia. Facing the pressures of school and life, people turn to the virtual world, expecting a diversion from these problems. Too often, however, they can lead to problems and unhealthy addictions.

    This is most clearly seen in the example of South Korea. The country has the world's highest percentage of high-speed Internet services. It also has a high number of online game players and related problems. In 2013, a young man collapsed and died while playing online games. He had been playing almost nonstop for 86 hours at an Internet cafe. Another young man killed his sister after becoming confused between the online world and real life. A 12-year-old boy stole US $ 16,000 from his father and ran away from home. He did this to continue his obsession with an online game. Such problems, however, don't just happen in South Korea. They are spreading to other parts of Asia, as well.

    What kinds of people develop online game addiction? What does the problem look like? Dr. SueHuei Chen, a clinical psychologist, researches Internet addiction. She discovered some signs of at-risk individuals such as lack friendships and good social skills. Those problem individuals feel it so compulsive to play online games that they could sacrifice things such as school or family. They feel the need to spend more and more time online. And they become upset if anyone tries to limit their online game playing.

    How many problem game players are there? In mainland China, the potential number of problem online gamers is alarming. In 2014, the China Daily reported that China had 13.8 million online game players. Furthermore, it stated that 80 percent of these were under 25 and had signs of addiction. Such numbers point toward a growing problem among Chinese youth.

Make sure to keep control over your online game playing. If you don't control it, it can get control of you.