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、Provide extra energy to start the reaction. B、Raise the temperature of the chemicals. C、Release a chemical needed to start the
A、Provide extra energy to start the reaction. B、Raise the temperature of the chemicals. C、Release a chemical needed to start the
admin
2019-10-03
95
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、Provide extra energy to start the reaction.
B、Raise the temperature of the chemicals.
C、Release a chemical needed to start the reaction.
D、Lower the amount of energy needed to start the reaction.
答案
D
解析
细节题。根据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可知,酶通过较少能量帮助开启生化反应。因此,正确答案为D。
转载请注明原文地址:https://kaotiyun.com/show/3MW7777K
0
大学英语六级
相关试题推荐
Peoplecannowavoidhavingtosortthroughalbumsfromseveraldifferentfriendswhentryingtoreliveparties,weddingsandot
Dependingonwhichplayeryouask,the"Fevernova"ballthatsportsequipmentmakerAdidassaysprovidestheultimatesoccerexp
Dependingonwhichplayeryouask,the"Fevernova"ballthatsportsequipmentmakerAdidassaysprovidestheultimatesoccerexp
RenewableEnergy[A]Inthepastcentury,ithasbeenseenthattheconsumptionofnon-renewablesourcesofenergyhascaused
RenewableEnergy[A]Inthepastcentury,ithasbeenseenthattheconsumptionofnon-renewablesourcesofenergyhascaused
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
患者青年男性,梦中遗精,夜寐不安,头晕心悸,精神不振,倦怠乏力,小便短赤,舌质红,脉细数。中医治法应为
南柴胡的原植物为()
根据监理(业主)确认的工程量计量结果,承包商向监理(业主)提出支付工程进度款申请,监理(业主)应在()天内向承包商支付工程进度款。
某承包商于某年承包某外资工程的施工,与业主签订的承包合同约定:工程合同价2000万元;若遇物价变动,工程价款采用调值公式动态结算。该工程的人工费占工程价款的35%,水泥占23%,钢材占12%,石料占8%,砂料占7%,不调值费用占15%;开工前业主向承包商支
对于饱和软黏土地基,通过强夯将级配良好的块石、碎石、矿渣及建筑垃圾等坚硬粗颗粒材料,夯入其中,从而形成块(碎)石墩,这种方法称强夯置换法,因其具有较高强度,由此()。
税务师对生产企业出口业务退(免)税申报进行审核时,认为正确的业务有()。
旧三民主义中的()被孙中山称为政治革命。
SDH信号最基本也是最重要的模块信号是______,其速率为155.520Mbps。
假定有以下循环结构DoUntil条件循环体Loop则正确的描述是()。
Ourorganizationhasdevelopedover15,000InternationalStandardsona(141)ofsubjects.Thefullrangeoftechnicalfieldsca
最新回复
(
0
)