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限制性核酸内切酶，简称限制酶，是一类能识别双链DNA分子中特定的核苷酸序列，并在识别序列内或附近切割DNA双链结构的核酸酶。

限制性核酸内切酶切割DNA后不会产生（）

A.黏性末端

B.5′黏性末端

C.3′黏性末端

D.平末端

E.单链缺口

答案

参考答案：E

补全对话，情景问答

补全对话。

(Jack=J Susan=S)

S: It's Sara's birthday the day after tomorrow.  1. __________________?

J: Does she like reading? 2. __________________.

S: Well, she has had lots of books already.  Besides, her birthday present last year was also a book.

J: 3. __________________?

S: No, she doesn't like basketball, but she likes football.

J: Get her a football, then?

S:4. __________________?

J: I have no idea, about 20 dollars, maybe.

S: I have only 6 dollars.  5__________________?

J: I have eight.  Why not go and ask John if he would like to join us?

S: That's really a good idea.  Let's do that right away.

1. _________2. _________3. _________4. _________5. _________  ,
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填空题

能引起人类疾病的主要病原性支原体有（），（），（），（），（）5种.
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