问题 单项选择题

下列不属于细胞因子的是()

A.趋化性细胞因子

B.过敏毒素

C.白细胞介素

D.集落刺激因子

E.干扰素

答案

参考答案:B

解析:细胞因子是机体免疫细胞和某些非免疫细胞合成和分泌的小分子的多肽因子,具有调节多种细胞生理功能的作用。细胞因子分为白细胞介素、干扰素、肿瘤坏死因子、生长因子、集落刺激因子、趋化性细胞因子。作用特点:通过与靶细胞表面受体结合产生作用;分泌过程的自限性;多以自分泌或旁分泌形式;多效性和重叠性;拮抗性和协同性。

阅读理解

If you want to stay young, sit down and have a good think. This is the research finding of a team of Japanese doctors, who say that most of out brains are not getting enough exercise, and as a result, we are growing old unnecessarily soon.

Professor Taiju Matsuzawa wanted to find out why quite healthy farmers in northern Japan appeared to be losing their ability to think and reason at a rather early age, and how the speed of getting old could be slowed down.

With a team of researchers at Tokyo National University, he set about measuring brain sizes of a thousand people of different ages with different jobs.

Computer technology helped the researchers to get most exact measurements of the sizes of the front and side parts of the brain, which have something to do with thinking and feeling, and decide the human character. As we all know, the back part of the brain, which controls task like eating and breathing, does not contract(萎缩) with age.

Contraction of front and side parts, as cells(细胞) die off, was seen in some people in their thirties, but it was still not found in some sixty and seventy-year-olds.

Matsuzawa concluded from his tests that there is a simple way to prevent the contraction---using the head.

The findings show that contraction of the brain begins sooner in people in the country than those in the towns. Those with least possibility, says Matsuzawa, are lawyers, followed by university professors and doctors. White-collar workers doing the same work day after day in government offices are, however, as possible to have contracting brains as the farm workers, bus drivers and shop assistants.

小题1: The team of doctors wanted to find out ____.

A.at what point people grow live longer.

B.how to make people live longer

C.the size of certain people’s brains.

D.which group of people are the busiest小题2:Their research findings are based on ______.c

A.an examination of farmers in northern Japan

B.using computer technology

C.examining the brain sizes of different people

D.tests given a thousand old people小题3:The doctor’s tests show that ______.

A.our brains contract as we grow older

B.one part of the brain does not contract

C.sixty-year-olds have better brains than thirty-year-olds

D.contraction of the brain begins sooner in people in the country小题4: According to the article, _____ are growing mentally old earlier.

A.engineers

B.office clerks

C.professors

D.researchers小题5:The most possible conclusion of the article is that ____.

A.most of us should take more exercise

B.it’s better to live in the towns

C.the brain contracts if it is not used

D.the more one uses his brain, the sooner he becomes old

单项选择题