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
27
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/2927039.html
相关试题推荐
[originaltext]Ifyou’recarefulenough,you’llfindthatitiscommonnowad
[originaltext]Ifyou’recarefulenough,you’llfindthatitiscommonnowad
[originaltext]Ifyou’recarefulenough,you’llfindthatitiscommonnowad
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]OneofNewYork’smostbeautifulandvaluablebuildingsisin
[originaltext]OneofNewYork’smostbeautifulandvaluablebuildingsisin
[originaltext]OneofNewYork’smostbeautifulandvaluablebuildingsisin
[originaltext]Ababyspendsthefirstyearoflifelearningtolisten.(9)A
随机试题
Parentsoftenwonderwhattheirlittleonesareabsorbingfromthem.Forexa
Thisnewstyleofsportsshoesisverypopularanditis______inallsizes.A、i
A、Anareaoflowconservationvalueandlowfinancialvalue.B、Anareaoflowco
煤气中毒是指()中毒。A.一氧化氮 B.硫化氢 C.一氧化碳 D.二氧化
外表面灰白色或灰棕色、黑棕色,密布多数灰白色圆点状皮孔,内表面黄白色或黄棕色,味
健康者进入高原地区发生缺氧的主要原因是A.吸入气氧分压低 B.肺换气功能障碍
编制历史文化名城保护规划的依据有()。A.《中华人民共和国城乡规划法》
注册监理工程师从事执业活动时享有的权利有( )。(新教材删除该知识点,题目仅供参
医疗机构在处理医疗事故过程中发生涂改、伪造、隐匿、销毁病历资料的违法行为时,应当
定期考核不合格的医师暂停执业活动期满,再次考核仍不合格的A、再次接受培训 B、
最新回复
(
0
)