6.9 碳水合物
章节大纲
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The fluffy white fibers on this plant look like cotton balls because that’s what they are. The plant is a cotton plant, and the fibers are used to make cotton fabric. Cotton fibers consist of one of the most common compounds on Earth: cellulose. Cellulose is a found in all plants. It belongs to the class of biochemical compounds called .
::植物上的毛发白色纤维看起来像棉花球,因为正是如此。植物是棉花植物,纤维被用来制造棉花织物。 棉花纤维由地球上最常见的化合物之一组成:纤维素。 纤维素在所有植物中都是一种植物。 它属于被称为生化化合物的类别。What Are Carbohydrates?
::什么是碳水化合物?Carbohydrates are one of four classes of biochemical compounds. The other three classes are , , and . In addition to cellulose, carbohydrates include sugars and starches. Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for .
::碳水化合物是四类生化化合物之一,其他三类是,和。除了纤维素外,碳水化合物还包括糖和淀粉。碳水化合物分子含有碳原子、氢原子和氧原子。活物主要使用碳水化合物。Q: Which carbohydrates do you use for energy?
::问题:你用哪种碳水化合物作为能源?A: You may eat a wide variety of carbohydrates—from sugars in fruits to starches in potatoes. However, body cells use only sugars for energy.
::甲:你可以食用各种各样的碳水化合物——从水果中的糖到土豆中的淀粉,但人体细胞只用糖作为能量。Sugars
::糖糖Sugars are simple carbohydrates. Molecules of sugars have relatively few carbon atoms. Glucose (C 6 H 12 O 6 ) is one of the smallest sugar molecules. Plants and some other organisms make glucose in the process of . Living things that cannot make glucose obtain it by consuming plants or these other organisms.
::糖是简单的碳水化合物。 糖的分子中碳原子相对较少。 甘蔗(C6H12O6)是最小的糖分子之一。 植物和其他一些生物在食用植物或其他生物中制造葡萄糖。 无法通过食用植物或其他生物获得葡萄糖的生命物质。In the Figure , you can see structural formulas for glucose and two other sugars, named fructose and sucrose. Fructose is a sugar that is found in fruits. It is an of glucose. Isomers are compounds that have the same atoms but different arrangements of atoms. Do you see how the atoms are arranged differently in fructose than in glucose? You’re probably most familiar with the sugar sucrose, because sucrose is table sugar. It’s the sugar that you spoon onto your cereal or into your iced tea.
::在图中,您可以看到葡萄糖和其他两种糖的结构公式,称为fructose和sucrose。fructose是水果中发现的糖。它是葡萄糖的一种。异构体是具有相同原子的化合物,但原子的安排却不同。您看到在纤维糖中原子的排列方式与葡萄糖不同吗?您可能最熟悉糖sucrose,因为sucrose是餐桌糖。糖是您在麦片上或冰茶中的糖。Note : Each unlettered point where lines intersect represents a carbon atom.
::注:线条交叉代表碳原子的每个无字母点。Q: Compare the structure of sucrose with the structures of glucose and fructose. How is sucrose related to the other two sugars?
::问题:将苏格罗斯结构与葡萄糖和fructose结构进行比较。苏格罗斯与其他两种糖的关系如何?A: Sucrose consists of one molecule of glucose and one molecule of fructose bonded together.
::甲:苏克罗斯由葡萄糖的一个分子和软糖结合的一个分子组成。Starches
::Starches 星座Starches are complex carbohydrates. They are polymers of glucose. A polymer is a large molecule that consists of many smaller, repeating molecules, called monomers . The monomers are joined together by . Starches contain hundreds of glucose monomers. Plants make starches to store extra glucose. Consumers get starches by eating plants. Common sources of starches in the human diet are pictured in the Figure . Our digestive system breaks down starches to sugar, which our cells use for energy.
::恒星是复杂的碳水化合物,它们是葡萄糖的聚合物。聚合物是一个大型分子,由许多较小的、重复的分子组成,称为单体。单体结合由 .恒星包含数百个葡萄糖单体。植物制造淀粉以储存额外的葡萄糖。消费者通过食用植物获得淀粉。人类饮食中常见的淀粉来源如图所示。我们的消化系统将恒星分解成糖,而我们的细胞则用它作为能量。Foods that are good sources of starches.
::食物是很好的淀粉来源Cellulose
::纤维素Cellulose is another complex carbohydrate that is a polymer of glucose. However, glucose molecules are bonded together differently in cellulose than they are in starches. Cellulose molecules bundle together to form long, tough fibers, as you can see in the Figure . Have you ever eaten raw celery? If you have, then you probably noticed that the stalks contain long, stringy fibers. The fibers are mostly cellulose. Cellulose is the most abundant biochemical compound. It makes up the cell walls of plants and gives support to stems and tree trunks. Cellulose also provides needed fiber in the human diet. We can’t digest cellulose, but it helps keep food wastes moving through the digestive tract.
::细胞素是另一种复杂的碳水化合物,是葡萄糖聚合物。然而,葡萄糖分子在纤维素中相互结合的情况与在凝胶中不同。如图所示,细胞素分子聚集在一起形成长而硬的纤维,形成长而硬的纤维。你曾经吃过生菜吗?如果你吃过,那么你可能就会注意到,尾巴中含有长而细的纤维。纤维大部分是纤维。细胞素是最丰富的生化化合物。细胞素组成植物的细胞壁,为根茎和树干提供支持。细胞素也提供了人类饮食中所需的纤维。我们可以用消化纤维素,但它有助于食物废物在消化道中流动。Summary
::摘要-
Carbohydrates are biochemical compounds that include sugars, starches, and cellulose. They contain carbon, hydrogen, and oxygen, and they are used mainly for energy by living things.
::碳水化合物是生化化合物,包括糖、淀粉和纤维素。 它们含有碳、氢和氧,主要用于生物能源。 -
Sugars are simple carbohydrates such as glucose, which the cells of living things use for energy.
::糖是简单的碳水化合物,如葡萄糖,生物细胞用来制造能量。 -
Starches are complex carbohydrates that are polymers of glucose. Starches are used by plants to store energy. Consumers get starches by eating plants. They break down the starches to sugar for energy.
::恒星是复杂的碳水化合物,是葡萄糖的聚合物。 恒星是植物用来储存能源的。 消费者通过食用植物而获得恒星。 他们把恒星分解成糖以获取能量。 -
Cellulose is another complex carbohydrate that is a polymer of glucose. It is the most abundant biochemical compound. It makes up the cell walls of plants and provides fiber in the human diet.
::纤维素是另一种复杂的碳水化合物,是葡萄糖的聚合物,是最丰富的生化化合物,构成植物的细胞壁,为人类饮食提供纤维。
Review
::回顾-
What are carbohydrates?
::什么是碳水化合物? -
Compare and contrast sugars and starches.
::与糖和淀粉的对比和对比。 -
Describe the structure of cellulose. What is its function in plants?
::描述纤维素的结构。 它在植物中的功能是什么?
Explore More
::探索更多Watch the video about carbohydrates and then answer the questions below.
::观看关于碳水化合物的视频,然后回答下面的问题。-
A single, simple sugar is called a __________.
::一种简单的单一糖叫做"" -
What makes a molecule a carbohydrate?
::是什么使分子成为碳水化合物? -
When glucose and fructose combine chemically, they form __________ and __________.
::当葡萄糖和fructose以化学方式结合时,它们组成 和 。 -
Sucrose is a two-sugar carbohydrate, or __________.
::苏克罗斯是一种二苏格碳水化合物,或。 -
What is a polysaccharide? Give an example.
::什么是聚沙英?举个例子。
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Carbohydrates are biochemical compounds that include sugars, starches, and cellulose. They contain carbon, hydrogen, and oxygen, and they are used mainly for energy by living things.
