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  • General

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  • 碳水合物

    What you will learn
    ::你会学到什么

    • The chemical structure and function of carbohydrates
      ::碳水合物的化学结构和功能
    • Examples of carbohydrates and where they are used
      ::碳水合碳水合物实例及其使用地点
    • Sugars used as biofuels
      ::用作生物燃料的糖糖

    A spoon adding sugar to a glass of iced tea with lemon and ice cubes.

    Sugar. Is it good for you?
    ::糖,对你好么?

    You may have heard that sugar is bad for you. Well, that's not exactly true. When people say sugar is bad for you, they usually refer to sugars added to foods and drinks, like table sugar (sucrose). While it is true that consuming high levels of sugars too often can lead to negative health effects, sugars are essential to the survival of living organisms .
    ::你可能听说过糖对你不好。嗯,这不是真的。当人们说糖对你不好时,他们通常是指食物和饮料中添加的糖,比如餐桌糖(sucrosse ) 。 尽管消费高水平的糖经常会导致负面的健康影响,但糖对活生物体的生存至关重要。

    Carbohydrates
    ::碳水合物

    Carbohydrates are the most common type of . A carbohydrate is an organic compound such as sugar or starch and is used to store energy . Like most organic compounds, carbohydrates are built of small, repeating units that form bonds with each other to make a larger molecule. In the case of carbohydrates, the small repeating units are called monosaccharides . Carbohydrates contain only carbon, hydrogen, and oxygen.
    ::碳水化合物是最常见的碳水化合物类型。碳水化合物是一种有机化合物,如糖或淀粉,用于储存能源。与大多数有机化合物一样,碳水化合物由小的、重复的单位组成,形成一个更大的分子。在碳水化合物方面,小的重复单位称为单沙酸。碳水化合物只含有碳、氢和氧。

    Monosaccharides and Disaccharides
    ::单数和分数

    A monosaccharide , the monomer of carbohydrates, is a simple sugar such as fructose or glucose . Fructose is mostly found in fruits , whereas glucose generally results from the digestion of other carbohydrates. Glucose (C 6 H 12 O 6 ) is used for energy by the of most organisms and is a product of .
    ::碳水化合物的单体单体碳水化合物是一种简单的糖,如浮糖或葡萄糖。 葡萄糖大多存在于水果中,而葡萄糖通常来自其他碳水化合物的消化。 甘糖(C6H12O6)是大多数生物的能源,是...的产物。

    DID YOU KNOW?
    The adult brain depends mainly on glucose for the energy it needs to function.
     

    Another monosaccharide, fructose, has the same chemical formula as glucose, but the atoms are arranged differently. Molecules with the same chemical formula but with atoms in a different arrangement are called isomers . Compare the glucose and fructose molecules in the Figure . Can you identify their differences? The only differences are the positions of some of the atoms. These differences affect the properties of the two monosaccharides.
    ::另一种单沙落物(fructose)的化学公式与葡萄糖相同,但原子的排列却不同。使用相同化学公式但有原子的分子被称作异构体。比较图中的葡萄糖和浮糖分子。你能辨别它们的区别吗?只有部分原子的方位不同。这些差异影响两个单沙落的特性。

    Comparison of glucose and fructose molecular structures, highlighting their isomer differences.
    Sucrose Molecule. This sucrose molecule is a disaccharide. It is made up of two monosaccharides: glucose on the left and fructose on the right.

    If two monosaccharides bond together, they form a carbohydrate called a disaccharide . An example of a disaccharide is sucrose (table sugar), which consists of the monosaccharides glucose and fructose ( Figure ). Monosaccharides and disaccharides are also called simple sugars. They provide the major source of energy to living cells.
    ::如果将两种单生碳酸盐结合在一起,它们就形成一种碳水化合物,称为非碳酸盐。一种非碳酸盐的例子就是sucrose(可食糖),它由单生碳酸酯甘蔗和浮糖组成(图)。单生碳酸盐和不可食酸盐也被称为简单的糖。它们为活细胞提供了主要的能量来源。

     

    Polysaccharides
    ::复数

    A polysaccharide is a complex carbohydrate that forms when simple sugars bind together in a chain. Polysaccharides may contain just a few simple sugars or thousands of them. Complex carbohydrates have two main functions: storing energy and forming structures of living things. Some examples of complex carbohydrates and their functions are shown in the Table . Which type of complex carbohydrate does your own body use to store energy?
    ::聚碳酸盐是一种复杂的碳水化合物,当简单的糖结合在一个链条中时,它就会形成一种复杂的碳水化合物。 多碳水化合物可能只含有几个简单的糖或数千个糖。复杂的碳水化合物有两个主要功能:储存能量和形成生物体结构。一些复杂的碳水化合物及其功能的例子在表格中显示。哪种复杂的碳水化合物是您自己的身体用来储存能量的?

    Name Function Example
    Starch Used by plants to store energy.

    Potatoes in a burlap sack, illustrating starch storage in underground tubers.

    A potato stores starch in underground tubers.
    ::土豆仓库在地下管子堆淀粉。

    Glycogen Used by to store energy.

    Microscopic view of liver cells showing glycogen storage in pink-stained tissue.

    A human stores glycogen in liver cells.
    ::肝细胞中的甘油是人类储存的

    Cellulose Used by plants to form rigid walls around cells.

    Cellulose structure illustrating plant cell walls, highlighting rigidity and cellular organization.

    Plants use cellulose for their cell walls .
    ::植物在细胞壁上使用纤维素。

    Chitin Used by some animals to form an external skeleton.

    A grasshopper on wood, showcasing its colorful exoskeleton made of chitin.

    A grasshopper uses chitin for its exoskeleton .
    ::一只用来做它的外骨骼。

     

    DID YOU KNOW?
    Your group (A, B, AB, or O) is determined by the type of small carbohydrates attached to certain in the membranes of your red blood cells .
     

     

     

    Biofuels: From Sugar to Energy
    ::生物燃料:从糖到能源

    For years there's been a buzz, both positive and negative, about generating ethanol fuel from corn. Is this a good idea? Is it necessary? These questions need to be discussed. However, the Bay Area of California is rapidly becoming a world center for the next generation of green fuel alternatives. The Joint BioEnergy Institute is developing methods to isolate biofuels from the sugars in cellulose.
    ::多年来,人们一直对从玉米中产生乙醇燃料有积极和消极的呼声。这是否是一个好主意?是否有必要?这些问题需要讨论?然而,加利福尼亚湾地区正在迅速成为下一代绿色燃料替代品的世界中心。 联合生物能源研究所正在开发将生物燃料从纤维素糖中分离出来的方法。

     

     

     

    Summary
    ::摘要

    • Carbohydrates are organic compounds used to store energy.
      ::碳水化合物是用于储存能源的有机化合物。
    • A monosaccharide, the monomer of carbohydrates, is a simple sugar, such as fructose or glucose.
      ::一种单沙律,碳水化合物的单体, 是一种简单的糖,如浮糖或葡萄糖。
    • Complex carbohydrates have two main functions: storing energy and forming structures of living things.
      ::复合碳水化合物有两个主要功能:储存能源和形成生物结构。

    Review
    ::回顾

    1. What is a carbohydrate?
      ::什么是碳水化合物?
    2. List three facts about glucose.
      ::列举三个有关葡萄糖的事实。
    3. Assume that you are trying to identify an unknown organic molecule. It contains only carbon, hydrogen, and oxygen and is found in the cell walls of a newly discovered plant species. What type of organic compound is it? Why?
      ::假设您正在试图识别未知的有机分子。 它只包含碳、氢和氧, 在新发现的植物物种的细胞壁中被发现。 它是什么类型的有机化合物? 为什么?
    4. Compare and contrast the structures and functions of simple sugars and complex carbohydrates.
      ::比较和比较简单的糖和复杂的碳水化合物的结构和功能。