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
43
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、It divides into two different parts.
B、It keeps the same chemical structure.
C、It becomes part of a new chemical compound.
D、It produces more of the enzyme(酶).
答案
B
解析
细节题。根据讲座内容及结尾的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.可知,教授指出酶在生化反应中保持不变的化学结构。因此,正确答案为B。
转载请注明原文地址:https://tihaiku.com/zcyy/3529648.html
相关试题推荐
[originaltext]Whenwethinkofgames,thereareallkindsofthings.Maybeyou’
[originaltext]MyfellowSingaporeans:Whatwereyourmostmemorablemoments
[originaltext]AbeetleinvasionintheUnitedStateshaskilledatleasttwenty
[originaltext]AbeetleinvasionintheUnitedStateshaskilledatleasttwenty
[originaltext][12]Intoday’spersonalitystakes,nothingismorehighlyvalued
[originaltext][12]Intoday’spersonalitystakes,nothingismorehighlyvalued
[originaltext][12]Intoday’spersonalitystakes,nothingismorehighlyvalued
[originaltext]Pianosarenormallyfoundinbuildingforobviousreasons.Howeve
[originaltext]Pianosarenormallyfoundinbuildingforobviousreasons.Howeve
[originaltext]W:Hello.M:Hello,isthatthereferencelibrary?W:Yes.CanI
随机试题
Whatproductarethespeakersdiscussing?[br][originaltext]W:Hi,Fred.Well,
ThehistoryofAfrican—Americansduringthepast400yearsistraditionally
[originaltext]Thefoodweeatseemstohaveproducedprofoundeffectsonou
A.右移10单位 B.左移10单位 C.右移40单位 D.左移40单位
资本市场划分为场内市场和场外市场,是按照()作出的划分。A.交易品种的不同
"乙癸同源"指的是A.心肺关系 B.肺肝关系 C.肝脾关系 D.肝肾关系
某研究小组汇集了140多种人类灵长类动物脑量数据,以研究灵长类动物大脑体积比其他
为了保障申请执行人的权利,在一定情形下,申请执行人可以向执行法院的上级法院申请执
1907年写了一本自传《一颗失而复得的心》对现代心理卫生运动做出贡献的是A.皮纳
某化工厂的原料、中间产品有火灾、爆炸、中毒的危险性,生产的最终产品有C12和化学
最新回复
(
0
)