首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、It divides into two different parts. B、It keeps the same chemical structure. C、It becomes part of a new chemical compound. D、I
A、It divides into two different parts. B、It keeps the same chemical structure. C、It becomes part of a new chemical compound. D、I
admin
2019-10-03
31
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://kaotiyun.com/show/tMW7777K
0
大学英语六级
相关试题推荐
Peoplecannowavoidhavingtosortthroughalbumsfromseveraldifferentfriendswhentryingtoreliveparties,weddingsandot
Peoplecannowavoidhavingtosortthroughalbumsfromseveraldifferentfriendswhentryingtoreliveparties,weddingsandot
Peoplecannowavoidhavingtosortthroughalbumsfromseveraldifferentfriendswhentryingtoreliveparties,weddingsandot
Peoplecannowavoidhavingtosortthroughalbumsfromseveraldifferentfriendswhentryingtoreliveparties,weddingsandot
A、Satisfied.B、Enthusiastic.C、Disappointed.D、Indifferent.C女士谈到,男士一定见证了公司很多的变化,男士回应说绝大部分的变化都是使事情变得更加糟糕。故选C。
Since2007,theAmericanPsychologicalAssociation(APA)hasconductedasurveyofdifferentaspectsofstressinAmerica,Thisye
Since2007,theAmericanPsychologicalAssociation(APA)hasconductedasurveyofdifferentaspectsofstressinAmerica,Thisye
Since2007,theAmericanPsychologicalAssociation(APA)hasconductedasurveyofdifferentaspectsofstressinAmerica,Thisye
随机试题
Whatistheaimoftheannouncement?
生产经营全面预算主要包括哪些内容?它们之间的相互关系怎样?
A.基础代谢率增高B.甲状腺摄133I率增高C.血压忽高忽低D.具备以上一种特征E.具备以上两种特征甲状腺功能亢进
患者,女,28岁。因右上肺结核,用异烟肼、利福平、链霉素三联抗痨治疗6个月,因自觉症状明显好转停药,1年后胸片提示左锁骨下浸润性病灶。此时治疗上应首选
致病性大肠杆菌食物中毒属于
在进行成本分析时,首先假定众多因素中的一个因素发生了变化,而其他因素则不变,然后逐个替换,分别计算结果,以确定各个因素的变化对成本的影响程度,这种成本分析的方法是()。
利用政府预算,通过调整税率和政府支出水平来影响总需求的一种政策是()。
岗位规范的具体内容不包括()
在进行初中数学七年级下册的“相交线”一课时,你将怎样开展教学,请完成以下任务:本课的“过程与方法”的教学目标是什么?
直接经验来源于实践,但是间接经验、书本知识则并不来源于实践。()
最新回复
(
0
)