问题 选择题

下列有关细胞分裂分化生长叙述不正确的是(    )

A.细胞分裂产生的新细胞与原细胞的染色体数目一样多

B.癌细胞是一种高度分化的细胞,能不断进行分裂

C.细胞生长使得细胞的体积不断增大

D.造血干细胞经过诱导可以形成多种血细胞从而治疗相关疾病,依据的是细胞分化原理

答案

答案:B

题目分析:生物体从小长大,是与细胞的生长、分裂和分化分不开的.细胞的生长使细胞的体积增大,细胞分裂使细胞数目增多.新产生的细胞体积都很小,通过不断从周围环境吸收营养物质并且转变成组成自身的物质,体积会由小变大,这就是细胞的生长.但细胞不能无限制的长大长到一定大小会进行分裂.细胞的分裂就是一个细胞分裂成两个细胞.细胞分裂的过程是,细胞核先由一个分成两个,随后细胞质分成两份,每份各含有一个细胞核.最后,在原来的细胞中央,形成新的细胞膜,植物细胞还形成新的细胞壁.于是,一个细胞就分裂成为两个细胞.癌细胞是一种发生了基因突变的细胞,它的分裂导致病变的发生。

因此,癌细胞是一种高度分化的细胞,能不断进行分裂是错误的.故选:B

单项选择题 B型题
阅读理解

     Sometimes in the next century, the familiar early-newspaper on the front porch (门廊)  will disappear. And instead of reading your newspaper, it will read to you. You'll get up and turn on the computer

newspaper just like switching on the TV. An electronic voice will distribute stories about the latest

events, guided by a program that selects the type of news you want. You'll even get to choose the kind

of voice you want to hear. Want more information on the brief story? A simple touch makes the entire

text appear. Save it in your own personal computer if you like. These are among the predictions from

communication experts working on the newspaper of the future. Pictured as part of broader home based

on media and entertainment systems, computer newspapers would unite print and broadcast reporting,

offering news and analysis with video images of news events.

     Most of the technology is available now. but convincing more people that they don't need to read a

newspaper is the next step. Besides, resistance to computer newspaper may be stronger from within

journalism. Since it is such a cultural change, it may be that the present generation of joumalists and

publishers will have to die off before the next generation realize that the newspaper industry is no longer

a newspaper industry. Technology is making the end of traditional newspaper unavoidable.

     Despite technological advances, it could take decades to replace newsprint with computer screens.

It might take 30 t0 40 years to complete the change over because people need to buy computers and

because newspapers have established financial (财经的) interests in the paper industry.                   

1. The best title for this passage is          .   

A. Computer Newspapers Are Well Linked

B. Newspapers of the Future

C. Newspapers Are out of Fashion

D. New Communication Technology

2. It might take 30 to 40 years for computer newspapers to replace traditional newspapers because        .

A. it is technologically impossible now

B. computer newspapers are too expensive

C. there is strong resistance from both the general population and professional joumalists

D. traditional newspapers are more convenient

3. Joumalists are not eager to accept computer newspapers because       .

A. they don't know how to use computers

B.it will take time to leam the new technology

C. they doubt about the news technology

D. they have been trained to write for traditional newspapers

4. We can infer from the passage that            .

A. all technological changes are good

B. all technologies will eventually replace old ones

C. new technologies will eventually replace old ones

D. traditional newspapers will exist for another century