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
医学
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
2013-12-06
108
问题
Let’s begin today by discussing enzymes. Enzymes are what make many of the body’s biochemical reactions possible. 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, just small padlocks. 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 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.
Questions 21 - 25 are based on the passage you have just heard.
21. What is the passage mainly about?
22. What point does the professor make about an enzyme when it is involved in a biochemical reaction?
23. What do enzymes do to help start a biochemical reaction?
24. Why does the professor talk about locks and keys?
25. What is enzymes?
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.
答案
B
解析
酶在化学反应过程中自身化学结构不发生变化。
转载请注明原文地址:https://kaotiyun.com/show/jwU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Justbeforedawnwereceivedacallthatanunresponsiveinfantwasbeingbroughtbyemergencymedicalservicestoourhospital.
Justbeforedawnwereceivedacallthatanunresponsiveinfantwasbeingbroughtbyemergencymedicalservicestoourhospital.
A、Thebuyingoflifeinsuranceisnotthebusinessofguessing.B、Theremustbeastandardamountoflifeinsuranceforpeople.
Ihadneverbeeninthepublicwardofahospitalbefore,anditwasmyfirstexperienceofdoctorswhohandleyouwithoutspeak
A、Sheconvincedthemantotakemedicineashismajor.B、Sheaskedthemantogiveatalkonmedicine.C、Shepersuadedthemann
Herstorywasacomplete______fromstarttofinish,sonobodybelievedinher.
A、Heartattack.B、Heartburn.C、Varicose.D、Cramp.A从“Look,Ijustdon’twantyouhavingaheartattackrunningupanddowntheco
A、Gotobedearlier.B、Gotothegymlessoften.C、Gotothegymlaterintheday.D、Gotothegymwithafriend.B由“butwhosay
A、Throwtheclothesaway.B、Makeadonationofhisoldclothes.C、Trytosellhisoldclothes.D、Savetheclothestogivetohis
A、Gotobedearlier.B、Gotothegymlessoften.C、Gotothegymlaterintheday.D、Gotothegymwithafriend.B由“butwhosay
随机试题
患者男性,24岁,近半年来腹部不适,多次剧烈腹痛,空腹12小时抽血分离血浆呈奶样乳白色,经15000转/分离心30分钟后,发现血浆下层较透明,而表面为奶油层。血脂测定结果:TC:9.01mmol/L,TG:1.36mmol/L如结合痘状;家族史与血脂测
如图所示,箭头所指的解剖组织是
用来判断暴露危险因素是否与疾病有关联其关联程度大小的—种观察性研究方法是()
张老汉现年70岁,家住某市A县农村,因早年丧妻,一人抚养三个儿子张大、张二和张三长大成人,三个儿子结婚后并分别居住在该市B区、C区、D区。2001年8月以来,张老汉患上某种老年慢性病,需要长期治疗,然而三个儿子唯恐花费过高,竞拒绝为其进行治疗,把张老汉一人
由于雇主不能按规定的时间向承包商提供进入和占用现场的权利,导致承包商受到损失,则承包商可以要求( )。
金融机构开展资产管理业务的公募产品主要投资于()。Ⅰ.标准化债权类资产Ⅱ.上市交易的股票Ⅲ.未上市企业股权Ⅳ.商品及金融衍生品
德育过程是对学生知、情、意、行的培养和提高过程,其实施顺序是()
动物骨头都含有钙的成分,很难溶解于水,有人曾做过实验,用5公斤猪骨头加上5公斤水,在高压锅里熬10个小时,结果一碗骨头汤中的钙含量不过10毫克,不及一袋牛奶钙含量的1/20。骨头汤里还溶解有大量骨内脂肪,经常食用会引发其他健康问题。因此,喝骨头汤未必是治疗
路由选择协议是IP网络实用化的关键,它决定了数据包从“源”传送到“目的地”的路径:IP网络中最广泛使用的路由协议之一是(11)。能够实现路由选择功能的设备(12)。
在当前表中,查找第2个男同学的记录,应使用命令
最新回复
(
0
)