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
2019-01-06
26
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/QMH7777K
0
大学英语六级
相关试题推荐
A、Lecturenotes.B、Exams.C、Contactwithteachers.D、Videosofdemonstrations.C细节题。根据短文中Somematerialsfromacoursemaynotbe
A、Sometimeshehastoworkoutdoorsinbadweather.B、Itistoohard.C、Hecannotgetagoodpay.D、Itisextremelyboring.A细节题
A)Reduce,reuse,andrecycle.RecyclinghasbecomeapartofAmericanlife.Italsoisanimportantpartofthewaste-processing
A、TheynoticedanapparentchangeinthepositionoftheNorthStar.B、Theyobservedeclipsesatdifferenttimesoftheyear.C、
A、Afive-dayweek.B、1,899hours.C、2,100hours.D、1,992hours.C细节题。根据原文,Thecountryshouldcutdownfromits2,100hoursavera
A、TheynoticedanapparentchangeinthepositionoftheNorthStar.B、Theyobservedeclipsesatdifferenttimesoftheyear.C、
ItwasmusictomyearstohearthattheGovernment’schiefadviseron【C1】______,SusanJebb,wantsparentsto【C2】______fruitj
A、Shocked.B、Acceptable.C、Incredible.D、Indifferent.B女士提醒男士,每周的工作时间要超过50小时,压力大。男士欣然接受,并表示自己愿意接受挑战。故B是男士的态度。
A、Bytravellingwithawoman.B、Bywaitinginaqueue.C、Bymeetingdifferentpeople.D、Bygivingothersahand.A女士问男士如果他跟一个女的旅
A、Totrysomethingdifferent.B、Totravelandmeetpeople.C、Tolearndifferentculture.D、Tosavemoney.B女士问男士搭便车是为了省钱还是出于别的原因
随机试题
反映流动资产周转情况的指标有()
编码因子Ⅷ的基因位点在
初孕妇,29岁,妊娠37+3周,破水4小时来急诊室。检奎血压14/10kPa(110/75mmHg),头高浮,胎心100次/分。对该患者最佳的处理是
小儿急性喉炎的表现不包括
肛漏的局部症状为()肛门旁皮下脓肿的症状多表现为()
检验检测机构要验证自身诚信的状况,需要开展()等活动。
单位犯前款罪的,对单位判处罚金,并对直接负责的主管人员和其他直接责任人员,处( )有期徒刑或者拘役。
4,13,61,202,124,()
下列关于各情形所属法律解释类型的说法,正确的是:
滚筒式扫描仪大多数采用CIS技术,光学分辨率为300 dpi,有彩色和灰度两种,彩色类型一般为( )位彩色。
最新回复
(
0
)