在基因工程操作中限制性核酸内切酶是不可缺少的工具。下列有关限_爱下问搜题

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问题选择题

在基因工程操作中限制性核酸内切酶是不可缺少的工具。下列有关限制性核酸内切酶的叙述错误的是[ ]

A．一种限制性核酸内切酶只能识别一种特定的脱氧核苷酸序列

B．限制性核酸内切酶的活性受温度和pH等因素的影响

C．限制性核酸内切酶可以从某些原核生物中提取

D．限制性核酸内切酶也可以识别和切割RNA

答案

答案：D

完形填空

完形填空。

     Some children want to be writers some day. They want to write  1 for people to read. That sounds  2 !
It's good to write something for people to read!  3 they don't know that they need to be good  4 first before
they become good writers because reading books  5 helpful for them to become good writers. They should
read  6 books instead of (代替) watching TV or spending a lot of time  7 games when they are free.
     There is much fun in reading If you are a good reader you will have fun  8 books.
     If you decide to be a good writer, you'd better say to  9 , "I'm going to do my best to read  10 books!"
Maybe this is a good way you can become a good writer.

( )1. A. newspapers
( )2. A. terrible
( )3. A. But
( )4. A. students
( )5. A. are
( )6. A. a lots of
( )7. A. playing
( )8. A. reading
( )9. A. him
( )10. A. few

B. paintings
B. out standing
B. Though
B. listeners
B. is
B. much
B. making
B. writing
B. them
B. much

C. books
C. happy
C. And
C. readers
C. was
C. many
C. listening
C. seeing
C. yourself
C. more

单项选择题

临床MRI检查的脑内血肿中一般少有（）

A、细胞内正铁血红蛋白。

B、含铁血黄素。

C、去氧血红蛋白。

D、氧合血红蛋白。

E、细胞外正铁血红蛋白。