问题 单项选择题

下列叙述中,哪项不是核酸的生理功能()

A.作为遗传信息的载体,一般存在于每个细胞中

B.是生物的遗传物质

C.是生物体进行生命活动的主要承担者之一

D.对生物体的遗传变异和蛋白质的生物合成有极其重要的作用

答案

参考答案:C

解析:

核酸的功能有两个:遗传信息库;对生物的遗传、变异和蛋白质的生物合成有重要作用。故A、B、D正确,而蛋白质是生物体生命活动的主要承担者之一,故C不合题意。

考点:本题考查核酸的功能,意在考查考生理解所学知识的要点,把握知识间的内在联系的能力

阅读理解

阅读理解。

     Rebecca Stevens was the first British woman to climb Mount Chomulongma. Before she went up the

  highest mountain in the world, she was a journalist and lived in a small flat in South London.

     In 1993, Rebecca left her job and fer family and traveled to Asia with some other climbers. She found

  that life on Chumolongma is hard. "You must carry everything on your back," she said, "so you can only

 take things that you will need. You can't wash on the mountain, and in the end I didn't even take a

 toothbrush. I am usually a clean person but there is no water, only snow. Water is very heavy so you only

  take enough to drink!"

     When Rebecca reached the top of the Mount Chumolongma on May 17,1993, it was the best moment

  of her life. Suddenly she became famous.

     Now she has written a book about the trip and people often ask her to talk about it. She has a new job

 too, on science program on television.

     Rebecca is well known today and she has more money, but she still lives in the little flat in South

 London among her pictures and books about mountains.

1. Rebecca was a _____ before she climbed Chumolongma.

    A. climber        

    B. scientist        

    C. journalist        

    D. writer

2. Rebecca came to Asia to  _____ .

    A. leave her family                  

    B. to leave her job

    C. find a new job                  

    D. climb the mountain

3. According to the passage, life hard on Chumolongma because  _____ .

    A. the mountain is too high            

    B. all the living things hard to carry

    C. she is usually a clean person        

    D. water there is too little to wash

4. After her trip to Asia, Rebecca  _____ .

    A. lived in the same flat              

    B. did the same job

    C. learned to take pictures            

    D. began to write books

5. Rebecca became famous because  _____ .

    A. her hard woman                  

    B. her pictures and books

    C. having so much money            

    D. reaching the top of the world

填空题