首页
登录
职称英语
[originaltext] Let’s begin today by discussing enzymes. Enzymes are what make
[originaltext] Let’s begin today by discussing enzymes. Enzymes are what make
游客
2024-03-13
22
管理
问题
Let’s begin today by discussing enzymes. Enzymes are what make many of the body’ s biochemical reactions pos sible. Actually biochemical reactions can take place without them, but at much lower rates. In fact an enzyme may cause a reaction to proceed billions of times faster than it would otherwise. Before I go on to the biochemical specifics of how this works, let me provide a figurative example. I think it will help illustrate the power of enzymes more clearly. Now, suppose you got a bag and you put a bunch of locks in it. Then you put in all the keys that go with the locks. And you closed the bag and shook it hard. No matter how long you shook, chances are very small that any key would get inserted in any of the locks. But if you took them all out of the bag and this time used your hands to insert the keys in the locks, you could combine them much quicker.Enzymes act like your hands, quickly allowing chemical reactions that would otherwise take much longer. Now, there are two reasons that enzymes are so effective at enabling biochemical reactions. First enzymes greatly reduce the amount of energy required to start the reactions, and with less energy needed the reactions can proceed a lot faster than they could without the enzyme. The second reason is that on a small amount of an enzyme is needed to enable the biochemical reaction. That’s because the chemical structure of the enzyme itself does not become altered as if enables the reaction. So a single enzyme can be used to start the same biochemical reaction over and over again.
Now listen to the following recording and answer questions 19 to 21.
19. What point does the professor make about an enzyme when it is involved in a biochemical reaction?
20. What do enzymes do to help start a biochemical reaction?
21. Why does the professor talk about locks and keys?
选项
A、To show that enzymes are very effective.
B、To point out that enzymes can sometimes fail to work.
C、To explain what enzymes are made of.
D、To describe different types of enzymes.
答案
A
解析
细节题。根据Enzymes act like your hands,quickly allowing chemical reactions that would otherwise take much longer.Now,there are two reasons that enzymes are so effective at enabling biochemical reactions.可知,教授提及锁和钥匙主要是为了表明酶很有效。因此,正确答案为A。
转载请注明原文地址:https://tihaiku.com/zcyy/3529650.html
相关试题推荐
[originaltext](13)Agrowingnumberofwomenaredevelopingsomethingcalled
[originaltext]Arefrigeratorofthefuturethattellsyouwhattocookwith
[originaltext]Arefrigeratorofthefuturethattellsyouwhattocookwith
[originaltext]W:OK,I’vegotallthepaperworkhereforyourapplication.Ever
[originaltext]W:OK,I’vegotallthepaperworkhereforyourapplication.Ever
[originaltext]M:ItsaysherethatyougraduatedfromUniversityofPennsylvani
[originaltext]M:ItsaysherethatyougraduatedfromUniversityofPennsylvani
[originaltext]Allpartsofourbodyage.Andourbraindoestoo.Now,howeve
[originaltext]Hello,ladiesandgentlemen.Welcometotoday’slecture.First
[originaltext]Everyonefacesdifficultiesfromtimetotime.Sometimesthed
随机试题
Thefamilytodayisnolongertheunitofeconomicproductionthatitoncew
[originaltext]M:Whatareyougoingtohave?W:IhavenoideaCouldyouhelpm
Necessarymeditationsontheactual,includingthemeanbread-and-cheeseque
Lastweek,speakersataprograminWashingtondiscussedusingnanotechnolog
重大火灾是指造成30人以上死亡,或者100人以上重伤,或者一亿元以上直接财产损失
汪力是一民营企业的职员,他工作中经常接到来自上边的两个有时甚至相互冲突的命令。以
患儿.6岁。右髋关节疼痛跛行2个月,髋关节屈曲,托马斯(Thomas)征阳性,X
某饭店某会计年度年末资产总额为2000万元,权益总额为940万元,负债总额为10
下列店堂告示,哪一项没有违反《中华人民共和国消费者权益保护法》的规定A.“本店商
原位癌是指 A.早期癌 B.原发癌 C.黏膜内癌 D.未发生转移的
最新回复
(
0
)