题干

下列有关基因工程技术的叙述,正确的是(    )

A:重组DNA技术所用的工具酶是限制酶、连接酶和DNA聚合酶

B:所有的限制酶都只能识别同一种特定的核苷酸序列

C:选用细菌为受体细胞是因为质粒易进入细菌细胞且繁殖快

D:只要目的基因进入受体细胞就能成功实现表达

上一题 下一题 0.0难度 选择题 更新时间:2018-08-17 01:31:19

答案(点此获取答案解析)

C

同类题4

通读下面短文,掌握其大意,然后在各题所给的四个选项中选出一个最佳答案。

    Three soldiers were on their way home from the war. They arrived at a small village, they were very tired and 1 but they had no food or money. The only thing they did have was a cooking pot(锅).

    The soldiers built a small cooking fire, 2 their pot on it, and poured in some water. When a few villagers asked what they were doing, one of the soldiers answered that he was making stone soup. A few more villagers walking by stopped to 3 what was going on when they heard about it.

    "Any soup needs salt and pepper," the first soldier said, 4 some children ran to fetch salt and pepper. "Stones can be used to prepare good soup, but tomatoes would 5 it so much better," the second soldier added. One woman said, "Why, I think I have a tomato or two! "She ran to get the tomatoes.

    "Some cabbage would be a proper choice for a good stone soup! "said the third soldier. Another woman said, "I think I can probably find some cabbage," and she ran 6.

    "If only we had a bit of beef and some potatoes, this soup would be fit for a rich man's 7." The villagers thought it over, then ran to fetch what they had in their homes. A rich man's soup, and all from a few stones! It seemed like 8!

    The soldiers said, "If only we had a little milk, this soup would be fit for a king!" And so other villagers 9 to get some milk.

    "The soup is ready," said the cooks, "and all will 10 it, but first we need to set the tables." Some of the villagers said, "Such a great soup would be better 11 some bread and cakes," so they brought the 12 two things and the meal was 13 by all. Never had there been such a 14 meal. Never had the villagers had such delicious soup, and all made from stones! They ate and drank and danced well into the night.

    In the morning, the villagers gathered to say goodbye. "Many thanks to you," they said, "for we shall 15 go hungry now that we have learned how to make soup from stones."