章节大纲

  • 常规

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  • 生物化学反应

    What you will learn
    ::你会学到什么

    • Chemical reactions and biochemical reactions
      ::化学反应和生化反应
    • Reactants and products in a chemical reaction
      ::化学反应中的活性剂和产品
    • How to write a chemical equation
      ::如何写入化学方程式
    • of matter in chemical reactions
      ::化学反应中的物质

    Chemical structures related to biochemistry, including phosphates and nucleotides.

    Understanding chemistry is essential to fully understand biology. Why?
    ::理解化学是完全理解生物学的关键。为什么?

    A general understanding of chemistry is necessary to understand biology . Essentially, our are just thousands of chemicals — made of elements like carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur — in just the right combinations. And these chemicals combine through chemical reactions.
    ::对化学的普遍理解对于理解生物学是必要的。 从根本上说,我们只有数千种化学物质 — — 由碳、氢、氧、氮、磷和硫等元素组成 — — 以正确的组合组成。 这些化学物质通过化学反应结合在一起。

    Chemical Reactions
    ::化学反应

    The element chlorine (Cl) is a greenish poison. Would you eat chlorine? Of course not, but you often eat a compound containing chlorine. In fact, you probably eat this chlorine compound just about every day. Do you know what it is? It’s table salt. Table salt is sodium chloride (NaCl), which forms when chlorine and sodium (Na) combine in certain proportions. How does chlorine, a toxic green chemical, change into harmless white table salt? It happens in a chemical reaction.
    ::元素氯( Cl) 是一种绿色的毒药。 您会吃氯吗? 当然不会, 但经常吃含有氯的化合物。 事实上, 您可能每天都要吃氯化合物。 您知道它是什么吗? 这是桌盐。 表格盐是氯化钠( NaCl), 当氯和钠( Na) 混合成一定比例时, 表格盐是氯化钠( NaCl ) 。 氯是一种有毒的绿色化学物质, 如何变成无害的白盐? 它会发生在化学反应中 。

    A chemical reaction is a process that changes some chemical substances into others. A substance that starts a chemical reaction is called a reactant , and a substance that forms as a result of a chemical reaction is called a product . During a chemical reaction, the reactants are used up to create the products. Chemical reactions that take place inside living things are called biochemical reactions .
    ::化学反应是一种将某些化学物质改变为其他化学物质的过程。 开始化学反应的物质被称为反应剂,因化学反应而形成的物质被称为产品。 在化学反应中,反应剂被用来制造产品。 在生物物质中发生的化学反应被称为生化反应。

    An example of a chemical reaction is the burning of methane. In this chemical reaction, the reactants are methane (CH 4 ) and oxygen (O 2 ), and the products are carbon dioxide (CO 2 ) and (H 2 O). A chemical reaction involves the breaking and forming of chemical bonds . When methane burns, bonds break in the methane and oxygen molecules, and new bonds form in the molecules of carbon dioxide and water.
    ::一种化学反应的例子就是甲烷的燃烧,在这种化学反应中,反应物是甲烷(CH4)和氧(O2),产品是二氧化碳(CO2)和(H2O),化学反应是化学联结的破碎和形成。当甲烷燃烧、甲烷和氧分子的联结破裂以及二氧化碳和水分子的新联结形式出现时,化学反应是化学联结的破裂和形成。

    Chemical Equations
    ::化学等量

    A chemical reaction can be represented by a chemical equation . For example, the burning of methane can be represented by the chemical equation
    ::化学反应可以用化学方程式表示,例如,甲烷的燃烧可以用化学方程式表示。

    CH 4 + 2O 2 → CO 2 + 2H 2 O
    ::CH4 + 2O2 + 2O2 + CO2 + 2H2O

    The arrow in a chemical equation separates the reactants from the products and shows the direction in which the reaction proceeds. If the reaction could occur in the opposite direction as well, two arrows pointing in opposite directions would be used. The number 2 in front of O 2 and H 2 O shows that two oxygen molecules and two water molecules are involved in the reaction. (With no number in front of a chemical symbol, just one molecule is involved.)
    ::化学方程式中的箭头将反应器与产品分离,并显示反应过程的方向。如果反应也可能在相反的方向发生,则将使用两个方向相反的箭头。O2和H2O前面的数字2显示,反应涉及两个氧分子和两个水分子。 (化学符号前面没有数字,只涉及一个分子。 )

    Conservation of Matter
    ::物料的养护

    In a chemical reaction, the quantity of each element does not change; there is the same amount of each element in the products as there was in the reactants. This is because matter is always conserved. The conservation of matter is reflected in a reaction’s chemical equation. The same number of atoms of each element appears on each side of the arrow. For example, in the chemical equation for the burning of methane, there are four hydrogen atoms on each side of the arrow. Can you find all four of them on each side of the equation?   
    ::在化学反应中,每个元素的数量没有变化;产品中每个元素的数量与反应器中每个元素的数量相同。这是因为物质总是被保存的。物质的保存反映在反应的化学方程式中。每个元素的原子数量相同,箭头两侧都出现。例如,在甲烷燃烧的化学方程式中,箭头两侧都有四个氢原子。你能在方程式的两侧找到所有四个原子吗?

     

     

     

     

    Summary
    ::摘要

    • A chemical reaction is a process that changes some chemical substances into others. During a chemical reaction, the reactants are used up to create the products.
      ::化学反应是一种将某些化学物质改变为其他化学物质的过程,在化学反应中,反应剂被用来制造产品。
    • In a chemical reaction, matter is always conserved.
      ::在化学反应中,物质总是得到保护的。

    Review
    ::回顾

    1. Define a chemical reaction.
      ::定义化学反应。
    2. Describe the roles of reactants and products in chemical reactions.
      ::描述反应物和产品在化学反应中的作用。
    3. How does a chemical equation show that matter is always conserved in a chemical reaction?
      ::化学方程式如何显示物质总是在化学反应中保存?
    4. Knowing that water (H 2 O) forms from hydrogen (H 2 ) and oxygen (O 2 ), write a chemical equation for the formation of water from these two elements.
      ::了解氢(H2)和氧(O2)产生的水(H2O),从这两个元素中为水的形成写出化学方程。