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
2023-08-15
66
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/2927038.html
相关试题推荐
[originaltext]Whatkeepsushealthyandhappyaswegothroughlife?Ifyou
[originaltext]Moderator:Hello,ladiesandgentleman.Itgivesmegreatple
[originaltext]Moderator:Hello,ladiesandgentleman.Itgivesmegreatple
[originaltext]Today,ChineseAmericansmakeuplessthan1%oftheU.S.po
[originaltext]Today,ChineseAmericansmakeuplessthan1%oftheU.S.po
[originaltext]IfyouareinanymajorcityinAmerica,thechancesarehigh
[originaltext]IfyouareinanymajorcityinAmerica,thechancesarehigh
[originaltext]IfyouareinanymajorcityinAmerica,thechancesarehigh
[originaltext]M:Hi,Lynn.Isawyouatregistrationyesterday.Isailedright
[originaltext]M:Hi,Lynn.Isawyouatregistrationyesterday.Isailedright
随机试题
Everybodylovesafatpayrise.Yetpleasureatyourowncanvanishifyoul
RSI以交易日的天数作为参数,一般有()。A、5日B、9日C、10日D、14日A,B,DRSI以交易日的天数作为参数,一般有5日、9日、14日
PolitebehaviorisimportantintheAustraliansociety."Please"and"thank
《世界油船(基本)费率表》中费率计算依据的标准油船载重量是()吨。A.65000
患者,女性,25岁。因胃、十二指肠溃疡住院治疗。患者入病区因环境陌生有些紧张,护
某市中心区有一座市级医院,地处两条交通繁忙的城市干道交叉口的西北角,占地面积为0
人在每一瞬间,将心理活动选择了某些对象而忽略了另一些对象。这一特点指的是注意的(
当房地产开发企业受到外部市场环境的威胁而企业内部状况又不好时,应选择的发展战略是
企业未来经营净现金流量中,不能用于固定资产再投资的是()。A.折旧 B
医师在执业活动中应当享有的权利是() A.遵守法律、法规,遵守技术操作规范
最新回复
(
0
)