问题 单项选择题 A型题

关于胰岛素的描述哪一项是错误的 ()

A.这是由胰岛β细胞分泌的酸性蛋白

B.多由猪、牛胰腺提得

C.口服给药吸收快而完全

D.t1/2时间短,但作用维持时间长

E.主要在肝、肾灭活

答案

参考答案:C

解析:胰岛素是胰腺β细胞受内源或外源性物质如葡萄糖、乳糖、核糖、精氨酸和高血糖素等的激动而分泌的一种蛋白激素,是治疗糖尿病的有效药物。传统胰岛素是从猪胰腺、牛胰腺或猪牛胰腺混合物中提取的,只经过一步重结晶的纯化过程。但目前胰岛素的制备工艺有很大改进,随着单一组分猪胰岛素的出现,普通结晶的胰岛素已逐渐被淘汰。胰岛素口服无效,因易被消化酶破坏,因此所有制剂都必须注射,皮下注射吸收快;代谢快,t1/2为9~10分钟,但作用可维持数小时。因其分布于组织后,与组织结合而在其中发挥作用。主要在肝、肾灭活,经谷胱甘肽转氨酶还原二硫键,再由蛋白水解酶水解成短肽或氨基酸,也可被肾胰岛素酶直接水解。

阅读理解

Twenty-five years ago if you made a trip to the local library and searched for articles on globing warming, you’d probably come up with a few from the leading magazines in the world. As an Internet search on global warming now shows, the subject has become as rooted in people’s mind as Madonna or microwave cooking.

With the possible exception of another world war, a giant planet, or an incurable disease, global warming may be the largest danger to our planet. For decades human factories and cars have sent billions of tons of greenhouse gases into the atmosphere, and the climate has begun to show some signs of warming. If steps are not taken soon to reduce the amount of carbon dioxide sent into the atmosphere, the result could terribly affect human life. We have already seen growing destruction, such as drought and death in Sudan, flooding in Asia, bush fires in Indonesia, and fierce winter storms in central Europe.

The Republic of Maldives is barely above sea level. Its 250, 000 citizens are scattered across 1,200 islands in the Indian Ocean. A strong typhoon could spell the end for the entire country, as sea levels could continue rising. The entire population would have to be moved away as the country disappears under the sea.

The greenhouse effect is a naturally occurring phenomenon that keeps our planet at a comfortable temperature averaging 60°F. Since the mid-nineteenth century, however, carbon dioxide in the atmosphere has increased nearly 30% because of the increased use of fossil fuels to run cars, heat homes and power factories. Without controlling, the amount of carbon-dioxide by 2100 may increase by 30%-150% and could lift the average global temperature by up to 2.5° F the next 50 years.

小题1:.

With the first paragraph, the author intends to       .

A.scold people for not paying enough attention to global warming

B.draw people’s attention to global warming

C.how to search for the articles on global warming

D.point out the serious effect of global warming小题2:.

Global warming could affect human life in the following ways EXCEPT       .

A.producing more greenhouse gases

B.causing more floods

C.making winter storms fiercer

D.starting more bush fires小题3:.

The Republic of Maldives       .

A.has moved away their citizens

B.will be more likely to be destroyed by a strong typhoon than by the rising sea level

C.is mostly likely to be destroyed by the rising sea level

D.will have to move away most of their population小题4:.

. Why is the Republic of Maldives especially mentioned in the passage?

A.Because smaller countries are easier to be affected by global warming.

B.Because seaside countries are in danger of disappearing.

C.Because it’s necessary to rescue a country before the sea level rises.

D.Because the serious result of global warming could end a whole country.小题5:.

. From the last paragraph, we can infer that greenhouse effect       .

A.can only affect the earth in an unfavorable way

B.is something easy to control

C.is caused by human act

D.will be good to us if it remains at a proper level

单项选择题