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
2023-08-10
9
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、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://tihaiku.com/zcyy/2913389.html
相关试题推荐
[originaltext]Areportonsleepandnutritionreleasedthismonthfoundthat
[originaltext]ResearchershavefoundnotjustadiversityprobleminHollywo
[originaltext]ResearchershavefoundnotjustadiversityprobleminHollywo
[originaltext]Areportonsleepandnutritionreleasedthismonthfoundthat
[originaltext]M:(5)Yousayyourshophasbeendoingwell.Couldyougivemesom
[originaltext]M:(5)Yousayyourshophasbeendoingwell.Couldyougivemesom
[originaltext]M:(5)Yousayyourshophasbeendoingwell.Couldyougivemesom
[originaltext]M:Guesswhat?TheworstfoodI’veeverhadwasinFrance.W:Rea
[originaltext]M:Guesswhat?TheworstfoodI’veeverhadwasinFrance.W:Rea
[originaltext]M:(5)Yousayyourshophasbeendoingwell.Couldyougivemesom
随机试题
[originaltext]Nowadaysmoreandmorepeoplehavetospendlengthyhoursbef
Theofficergaveanorderthatevervone______backbeforedark.A、getB、wouldget
We______overestimatetheimportanceofthedevelopmentofrelationshipbetween
关于新媒体运营的特点,下列说法错误的有( )。A.形式多元 B.即时互动
D
土建工程直接费中,人工费约占()。A.l%~5% B.5%~9% C.1
61.选择超高压电流互感器时除了考虑变比误差,角误差外,还必须考虑互感器铁芯和影
下列说法中,正确的是( )。A.大赦既赦其刑,又赦其罪B.特赦只赦其刑
某方案初期投资额为500万元,此后每年年末的作业费用为40万元,方案的寿命期为1
流感嗜血杆菌不能引起A、支气管炎 B、化脓性脑膜炎 C、咽喉会厌炎 D、化
最新回复
(
0
)