Section outline

  • A depiction of a human brain, showcasing its complex surface and structure.

    What’s on your mind?
    ::你在想什么?

    The brain is a marvelous organ. And it’s a hungry one, too. The major fuel for the brain is the glucose. The average adult brain represents about 2% of our body’s weight , but uses 25% of the glucose in the body. Moreover, specific areas of the brain use glucose at different rates. If you are concentrating hard, (taking a test, for example) certain parts of the brain need a lot of extra glucose while other parts of the brain only use their normal amount. Something to think about.
    ::大脑是一个很棒的器官。它也是一个饥饿的器官。大脑的主要燃料是葡萄糖。平均成人大脑占我们身体重量的2%左右,但使用体内25%的葡萄糖。 此外,大脑的特定区域以不同的速度使用葡萄糖。 如果你在集中,(比如说测试 ) , 大脑的某些部分需要大量额外的葡萄糖,而其他部分则只使用正常数量。

    Monosaccharides
    ::单色度

    Some foods that are high in carbohydrates include bread, pasta, and potatoes. Because carbohydrates are easily digested, athletes often rely on carbohydrate rich foods to enable a high level of performance.
    ::一些碳水化合物含量高的食品包括面包、意大利面和土豆。 由于碳水化合物容易消化,运动员往往依赖碳水化合物丰富食品来取得高水平的性能。

    bananas, bread, honey, pasta, and potatoes as carbohydrate sources.

    Foods that serve as carbohydrate sources.
    ::用作碳水化合物来源的食物。

    The term carbohydrate comes from the fact that the majority contain carbon, hydrogen, and oxygen in a ratio of 1:2:1, making for an of CH 2 O. This is somewhat misleading because the molecules are not actually hydrates of carbon at all. Carbohydrates are monomers and polymers of aldehydes and ketones that have multiple hydroxyl groups attached.
    ::碳水化合物一词来自以下事实,即大多数碳、氢和氧含量的比例为1:2:1,使CH2O成为CH2O。这有点误导性,因为分子实际上根本不是碳的水合物。 碳水化合物是含有多种氢氧基组的甲状腺和甲酮的单体和聚合物。

    Carbohydrates are the most abundant source of energy found in most foods. The simplest carbohydrates, also called simple sugars, are plentiful in fruits. A monosaccharide is a carbohydrate consisting of one sugar unit. Common examples of simple sugars or monosaccharides are glucose and fructose. Both of these monosaccharides are referred to as hexoses since they have six carbons. Glucose is abundant in many plant sources and makes up sweetners such as corn sugar or grape sugar. Fructose occurs in a great many fruits and is also found in honey. These sugars are structural isomers of one another, with the difference being that glucose contains an aldehyde functional group whereas fructose contains a ketone functional group.
    ::碳水化合物是大多数食品中最丰富的能源来源。 简单的碳水化合物,也称为简单的糖,其水果丰富。 单沙酸是一种碳水化合物,由一个糖单位组成。 简单的糖或单沙酸盐的常见例子有葡萄糖和纤维糖。 这两个单沙酸盐被称为六种碳的赫克舍。 葡萄糖存在于许多植物来源中,构成甜料,如玉米糖或葡萄糖。 葡萄糖存在于许多水果中,也存在于蜂蜜中。 这些糖是另一个结构异构体,区别在于葡萄糖含有甲酰胺功能组,而纤维糖含有甲酮功能组。

    Structures of glucose and fructose, highlighting their cyclic forms and oxygen atoms.

    Glucose and fructose are monosaccharides, or simple sugars.
    ::葡萄糖和纤维糖是单沙糖,或简单的糖。

    Glucose and fructose are both very soluble in water. In aqueous solution , the predominant forms are not the straight-chain structure shown above. Rather, they adopt a cyclic structure (see Figure ). Glucose is a six-membered ring, while fructose is a five-membered ring. Both rings contain an oxygen .
    ::甘蔗和fructose在水中非常容易溶解。在水溶液中,主要形式不是上面显示的直链结构。相反,它们采用循环结构(见图 ) 。 甘蔗是一个六人环,而葡萄糖是一个五人环。 两种环都含有氧气 。

    Cyclic structures of glucose (six-membered) and fructose (five-membered) in aqueous solution.

    The cyclic form of sugars is the favored form in aqueous solution.
    ::糖的循环形式是水溶液的优美形式。

    Another important group of monosaccharides are the pentoses, containing five carbons in the chain. Ribose and deoxyribose are two pentoses that are components of the structures of .
    ::另一组重要的单核化合物是钢笔,其中含有链条中的5个碳。 脊椎和脱氧核糖核酸是作为结构组成部分的2个钢笔。

    Structures of ribose and deoxyribose, two important pentose monosaccharides in nucleic acids.

    Ribose and deoxyribose
    ::和脱氧核糖核酸

     

     

    Review
    ::回顾

    1. What functional groups are on glucose?
      ::在葡萄糖方面有哪些职能群体?
    2. What functional groups are on fructose?
      ::哪些职能群体处于僵化状态?
    3. Which monosaccharide form (straight chain or cyclic) is favored in aqueous solution?
      ::在水溶液中,哪一种单轨形式(直线链或环状)更受欢迎?