Section outline

  • General

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  • 酶

    What you will learn
    ::你会学到什么

    • How enzymes catalyze
      ::酶如何催化
    • Importance of enzymes
      ::酶的重要性

    A sleek, modern train speeding along a track with a clear sky backdrop.

    What is a biological catalyst?
    ::什么是生物催化剂?

    This super fast train can obviously reach great speeds. And there's a lot of technology that helps this train go fast. Speaking of helping things go fast brings us to enzymes. Life could not exist without enzymes. Essentially, enzymes are biological catalysts that speed up biochemical reactions.
    ::这辆超快列车显然可以达到高速。而且有很多技术可以帮助这列列车快速行进。说到帮助事情快速行进,我们就会发现酶。没有酶,生命就不可能存在。基本上,酶是加速生化反应的生物催化剂。

    Enzymes
    ::酶

    Enzymes and Biochemical Reactions
    ::酶和生化反应

    Most chemical reactions within organisms would be impossible under the conditions in . For example, the body temperature of most organisms is too low for reactions to occur quickly enough to carry out life processes. Reactants may also be present in such low concentrations that it is unlikely they will meet and collide. Therefore, the rate of most biochemical reactions must be increased by a catalyst. A catalyst is a chemical that speeds up chemical reactions. In organisms, catalysts are called enzymes . Essentially, enzymes are biological catalysts.
    ::例如,大多数生物体的体温太低,无法迅速发生反应,无法进行生命过程。再活性剂也可能存在于极低的浓度中,因此它们不可能满足并碰撞。因此,大多数生化反应的速度必须由催化剂来提高。催化剂是一种加速化学反应的化学物质。在生物体中,催化剂被称为酶。基本上,酶是生物催化剂。

    Like other catalysts, enzymes are not reactants in the reactions they control. They help the reactants interact but are not used up in the reactions. Instead, they may be used over and over again. Unlike other catalysts, enzymes are usually highly specific for particular chemical reactions. They generally catalyze only one or a few types of reactions.
    ::与其他催化剂一样,酶在它们控制的反应中不是反应反应器,它们帮助反应器相互作用,但没有在反应中加以利用。相反,它们可能被反复使用。与其他催化剂不同,酶通常对特定化学反应非常特殊,它们通常只催化一种或几种反应。

    Enzymes are extremely efficient in speeding up reactions. They can catalyze up to several million reactions per second. As a result, the difference in rates of biochemical reactions with and without enzymes may be enormous. A typical biochemical reaction might take hours or even days to occur under normal cellular conditions without an , but less than a second with an enzyme.
    ::酶在加速反应方面极为有效,它们每秒可以催化几百万次反应。 因此,生化反应率与无酶的差别可能非常大。 典型的生化反应可能需要数小时甚至数天才能在正常的细胞条件下发生,没有细胞反应,但只有不到一秒的酶。

    How does an enzyme affect the rate of a biochemical reaction?
    ::酶如何影响生化反应的速率?

     

     

     

     

     

     

    DID YOU KNOW?
    The first enzyme, diastase, was discovered by French chemist Anselme Payen in 1833. This enzyme, now known as amylase , belongs to the group of enzymes that catalyze the breakdown of starch to maltose.
     

    Importance of Enzymes
    ::酶的重要性

    Enzymes are involved in most of the biochemical reactions that take place in organisms. About 4,000 such reactions are known to be catalyzed by enzymes, but the number may be even higher. Enzymes allow reactions to occur at the rate necessary for life.
    ::酶涉及在生物体中发生的大多数生化反应,已知约有4,000种这种反应被酶催化,但数量可能更高。 酶允许以生命所需的速度发生反应。

    In , an important function of enzymes is to help digest food . Digestive enzymes speed up reactions that break down large molecules of , , and fats into smaller molecules the body can use. Without digestive enzymes, animals would not be able to break down food molecules quickly enough to provide the energy and nutrients they need to survive.
    ::酶的一个重要功能是帮助消化食物。 消化酶加速反应,将体内的大分子、脂肪和脂肪分解成小分子。 没有消化酶,动物将无法快速地分解食物分子以提供生存所需的能量和营养。

    Science Friday: Stained Glass
    ::科学星期五:染色玻璃

    Stained glass from the Middle Ages is often hundreds of years old. Unfortunately, many of these relics are in need of cleaning and maintenance. In this video by Science Friday , conservator Mary Higgins discusses the methods used to protect the stained glass.
    ::中世纪的染色玻璃往往有数百年的历史。 不幸的是,许多这些遗迹需要清理和维护。 在科学星期五的录像中,玛丽·希金斯(Mary Higgins)讨论了保护染色玻璃的方法。

     

     

     

     

     

     

    DID YOU KNOW?
    Carbonic anhydrase is one of the fastest known enzymes present in the . It can produce up to 600,000 molecules of product per second. It catalyzes the conversion between carbon dioxide and bicarbonate ions and maintains the pH, acid-base in , and regulates fluid balance .
     

    Summary
    ::摘要

    • Enzymes are biological catalysts. They speed up biochemical reactions.
      ::酶是生物催化剂 它们加速生化反应
    • Enzymes are involved in most of the chemical reactions that take place in organisms.
      ::酶参与了在生物体内发生的大多数化学反应。

    Review
    ::回顾

    1. What are enzymes?
      ::什么是酶?
    2. Are enzymes reactants? Explain your answer.
      ::是酶反应剂吗?
    3. What happens to an enzyme after a biochemical reaction?
      ::生化反应后的酶会怎样?
    4. Explain why organisms need enzymes to survive.
      ::解释为什么生物需要酶生存。