问题 问答题 简答题

试比较体外氧化和生物氧化的异同点?

答案

参考答案:

相同点:消耗的氧量,最终产物,释放的能量是相同的

不同点:生物氧化是:①生物体内的生物氧化过程是在37℃,近于中性的含水环境中,由酶催化进行

②CO2的产生方式为有机酸脱羧,H2O的产生是底物脱氢,再经电子传递过程最后与氧结合生成

③反应逐步释放出能量,相当一部分能量以化学能的方式储存在高能磷酸化合物中④生物氧化的速率受体内多种因素的调节。

选择题
阅读理解

阅读理解。

     Time spent in a bookshop can be most enjoyable, whether you are a book-lover or merely you are there

to buy a book as a present. You may even have entered the shop just to find shelter from a sudden shower.

Whatever the reason, you can soon become totally unaware of your surroundings. You soon become engrossed

in some book or other, and usually it is only much later that you realise you have spent far too much time there

and must dash off to keep some forgotten appointment-without buying a book, of course.

     This opportunity to escape the realities of everyday life is, I think, the main attraction of a bookshop. There

are not many places where it is possible to do this. You can wander round such places to your heart's content.

If it is a good shop, no assistant will disturb you with usual greetings,"Can I help you, sir?" Of course you may

want to find out where a particular section is. Then, and only then, are his services necessary. However, when

he has led you there, the assistant should retire carefully and look as if he is not interested in selling a single

book.

     You have to be careful not to be attracted by the variety of books in a bookshop. It is very easy to enter the

shop looking for a book on ancient coins and to come out carrying a copy of the latest best-selling novel. This

sort of thing can be very dangerous. Apart from running up a huge account, you can waste a great deal of time

wandering from section to section.

1. Which may not be included in the writer's experiences while he is in a bookshop?

A. Getting relaxed without buying a book.

B. Quarrelling with the shop assistant.

C. Buying other books instead of those he wanted.

D. Forgetting some important appointment.

2. What does the writer mean by saying "time spent in a bookshop can be most enjoyable"?

A. You may free yourself from the real life.

B. Reading is free of charge there.

C. There is nobody disturbing you there.

D. You can enter without any certain reason.

3. What does the underlined word engrossed most probably mean in the first paragraph?

A. Lost.

B. Forbidden.

C. Puzzled.

D. Impressed.

4. The writer wrote the passage in order to _____.

A. suggest a good way of running a bookshop

B. encourage people to do some reading in bookshops

C. share his experience in bookshops

D. give some advice on buying books in a bookshop