问题 单项选择题

在细胞分化的过程中,一般不会发生改变的是()

A.细胞的形态

B.细胞的功能

C.染色体的数目

D.蛋白质的种类

答案

参考答案:C

解析:细胞分化是指在个体发育中,由一个或一种细胞增殖产生的后代,在形态、结构和生理功能上发生稳定性差异的过程。细胞分经过程中遗传物质DNA不会发生变化,染色体数目也不会发生变化。考点:考查细胞分化的知识。点评:难度较小,理解细胞分化过程中遗传物质不变。

阅读理解

阅读理解。

     What will people die of 100 years from now? If you think that is a simple question, you have not been

paying attention to the revolution that is taking place in bio-technology (生物技术). With the help of new

medicine, the human body will last a very long time. Death will come mainly from accidents, murder and

war. Today's leading killers, such as heart disease, cancer, and aging itself, will become distant memories.

     In discussion of technological changes, the Internet gets most of the attention these days. But the change

in medicine can be the real technological event of our times. How long can humans live, Human brains wer

e known to decide the final death. Cells (细胞) are the basic units of all living things, and until recently,

scientists were sure that the life of cells could not go much beyond 120 years because the basic materials

of cells, such as those of brain cells, would not last forever. But the upper limits will be broken by new

medicine. Sometime between 2050 and 2100, medicine will have advanced to the point at which every 10

years or so, people will be able to take medicine repair their organs (器官). The medicine, made up of the

basic building materials of life, will build new brain cells, heart cells, and so on-in much the same way our

bodies make new skin cells to take the place of old ones.

     It is exciting to imagine that the advance in technology may be changing the most basic condition of

human existence, but many technical problems still must be cleared up on the way to this wonderful future.

1. According to the passage, human death is now mainly caused by _____.

A. diseases and aging

B. accidents sad war

C. accidents and aging

D. heart disease and war

2. In the author's opinion, today's most important advance in technology lies in _____.

A. medicine

B. the Internet

C. brain cells

D. human organs

3. Humans may live longer in the future because _____.

A. heart disease will be far away from us

B. human brains can decide the final death

C. the basic materials of cells will last forever

D. human organs can be repaired by new medicine

4. We can learn from the passage that _____.

A. human life will not last more than 120 years in the future

B. humans have to take medicine to build new skin cells now

C. much needs to be done before humans can have a longer life

D. we have already solved the technical problems in building new cells

单项选择题 案例分析题