Name: carbohydrate structure and bonding
Uploaded: 2023-04-30T18:28:47.000Z
Duration: 3 min 25 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.18

SC.912.L.18.1

Chemistry of Carbohydrates

碳水化合物是由 碳、氢和氧组成的化合物。这些分子的名字 来自许多单糖的经验公式，单糖中的每个碳原子 对应两个氢原子和一个氧原子。简单碳水化合物是称为单糖的单体 和称为二糖的二聚体。复合碳水化合物是 称为多糖的聚合物。单糖按照它的官能团 可分类为醛糖或酮糖。带有醛基的单糖称为醛糖，带有酮基的单糖 称为酮糖。单糖链中通常含有 3 到 7 个 碳原子。每个碳都可以编号，从离羰基碳最近的端以数字 1 开始。糖可以形成非平面环状结构，自然界中的糖大多数以这种环状形式存在。当羰基通过缩合反应 与分子另一端的羟基反应时，就形成了环状结构。连接到反应性醛或酮上的碳 也称为异头碳。这些碳-氧环结构可以 作为两种异头体形式存在：阿尔法和贝塔。异头体是羰基碳上 构型不同的结构异构体。在阿尔法形式中，异头碳上的羟基 和环内最后一个碳上的 CH2OH 基团 位于环的相对侧，在贝塔形式中，它们位于同一侧。单糖和其他分子 连接的键也有 类似的命名惯例。在环结构下方形成的键 称为阿尔法键，在环上方形成的键称为贝塔键。糖苷键名称中的数字 表示参与键合的 单糖的碳原子数。当两个单糖通过糖苷键连接在一起时，它们就形成了二糖。糖苷键是一种共价键，当一个单糖的羟基 与另一个单糖的异头碳反应，消除一个水分子时，形成共价键。多糖或复合碳水化合物是 通过共价键结合在一起的 单糖链。这些分子中存在的糖苷键的变化 可导致同一单糖产生 不同类型的多糖。葡萄糖分子通过β-1, 4-糖苷键连接形成纤维素，纤维素是一种不溶于水的多糖。葡萄糖分子通过α-1, 4-糖苷键连接形成直链淀粉，直链淀粉是一种水溶性聚合物，是淀粉的一种成分。淀粉和纤维素是 存在于植物中的多糖。糖原是一种不溶于水的分子，由葡萄糖通过α-1, 4-糖苷键连接形成，并带有通过α-1, 6-糖苷键连接的不连续支链。糖原是动物体内的一种贮藏多糖。

碳水化合物化学

碳水化合物是人类和动物饮食的重要组成部分。 谷物，水果和蔬菜是碳水化合物的自然来源，可为身体提供能量，特别是通过葡萄糖，葡萄糖是淀粉的一个组成部分，也是许多主食的一个组成部分。 化学化学式 (CH2O)n，其中 n 是分子中的碳数量，表示碳水化合物。 换言之，碳水化合物分子中的碳与氢与氧气的比率为 1:2:1。 该公式还解释了“碳水化合物”一词的起源：成分是碳 (“碳水化合物”) 和水 (“碳水化合物”)。 碳水化合物可分为简单和化合物两类。 单糖和二糖是简单的碳水化合物。 多糖是化合物碳水化合物。 
 单糖 
 单糖是简单的糖，其中最常见的是葡萄糖。 在单糖中，碳的数量通常在三到七之间。 如果糖有醛组 (结构为 R-CHO 的官能团) ，则为醛，如果糖组有酮组 (结构为 RC(=O)R' 的官能团) ，则为酮。 根据糖中的碳数量，它们可以是trioses (三碳) ，pentoses (五碳) 和 / 或hexoses (六碳)。 
 半乳糖和果糖是其他常见的单糖。 葡萄糖，半乳糖和果糖是异构体单糖 (六体) ，这意味着它们具有相同的化学配方，但结构略有不同。 葡萄糖和半乳糖是剂量，果糖是氯化物。 
 单糖可作为线性链或环状分子存在。 在水溶液中，它们通常采用环状形式。 环状葡萄糖在异常碳周围可能有两种不同的羟基组排列 (OH) (环状形成过程中的碳 1 不对称)。 如果羟基组在糖中低于 1 号碳，则它处于 α (α) 位置，如果它在基准面上方，则它处于 β (β) 位置。 
 <h4>二糖 </h4>
 当两种单糖发生脱水反应 (或凝结反应或脱水合成) 时，二糖形成。 在此过程期间，一种单核苷酸的羟基组与另一种单核苷酸氢相结合，释放一种水分子并形成一种共价键。 这称为糖苷类键。 糖苷类键 (或糖苷类链接) 可以是 α 或 β 类型。 当第一种葡萄糖的碳 -1 上的 OH 组低于环形平面时，将形成一个 α 键，当碳 -1 上的 OH 组高于环形平面时，将形成一个 β 键。 最常见的脱衣剂是用葡萄糖和果糖单体组成的葡萄糖或表格糖。 
 <h4>多糖 </h4>
 由糖苷类键连接的一条长长的单糖链是多糖苷类。 链条可以分支或分离，并且可能包含不同类型的单糖。 分子重量可能是 100,000 吨或以上，具体取决于联合单体的数量。 淀粉，糖原，纤维素和香草是多糖的示例。 
 植物以糖的形式储存淀粉。 在植物中，淀粉和淀粉素混合物 (均为葡萄糖聚合物) 构成了这些糖。 淀粉由葡萄糖单体组成，由 α 1-4 或 α 1-6 糖苷类键连接。 1 至 4 和 1 至 6 是指已连接形成键的两种残留物的碳数量。 
 糖原是人类和其他脊椎动物的葡萄糖储存形式，由葡萄糖单体组成。 糖原是与淀粉等效的动物，是一种通常储存在肝脏和肌肉细胞中的高分支分子。 每当血糖水平下降时，糖原会分解以释放葡萄糖。 
 纤维素是最丰富的天然生物聚合物。 纤维素主要由植物的细胞壁组成。 这提供了细胞结构支撑。 木材和纸张在自然中大多是纤维素。 葡萄糖单体由 β 1-4 糖苷类键链路的纤维素组成 
 本文改编自 <a href="https://openstax.org/books/biology-2e/pages/3-2-carbohydrates"> Openstax, 生物学 2e, 第 3.4 章：碳水化合物。 </a>

碳水化合物是人类和动物饮食中的重要组成部分。谷物、水果和蔬菜是天然的碳水化合物来源，可提供……

Education

教育

JoVE Core

Cell Biology

细胞生物学

Unit 1

第一单元

Biochemistry of the Cell

细胞生物化学

KEY TERMS AND CONCEPTS

关键术语与概念

碳水化合物的化学

carbohydrate structure and bonding

Carbohydrates are built from sugar units and the bonds that link them. Their chemistry explains how simple sugars join to form larger molecules. It also helps show why carbohydrates have different structures and functions.

The video focuses on the main sugar types found in carbohydrates. These include monosaccharides, disaccharides, and polysaccharides. Monosaccharides are single sugar units. Disaccharides contain two sugar units, while polysaccharides are long chains of many sugar units.

The transcript also highlights how these sugar units connect through chemical bonds. These links change the size and structure of the carbohydrate molecule. That structural change is important because it affects how the molecule behaves in living systems.

Carbohydrate Structure and Bonding

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Elements in the Human Body and Periodic Table

Elements are the smallest units of matter that cannot be broken down further by chemical processes. Scientists know 118 elements, but not all of them occur naturally. Only a small number are essential for life, and living matter depends mostly on carbon, nitrogen, hydrogen, and oxygen. The periodic table organizes elements by their physical and chemical properties. Each square shows the element name, chemical symbol, atomic number, and atomic weight. The atomic number is the number of protons...

functional groups

Functional Groups in Organic Molecules

Functional groups are the part of an organic molecule that gives it specific chemical behavior. They help explain why compounds with similar carbon skeletons can react in different ways. In organic chemistry, these groups are often used to classify compounds. A functional group can change the properties of a molecule and affect how it behaves in a reaction. Knowing functional groups helps students recognize patterns in organic compounds. It also makes it easier to compare molecules that share...

types of chemical bonds

Chemical Bonds and How Atoms Join

Chemical bonds hold atoms together and help explain how different substances form. In chemistry, the main bond types are ionic bonds, covalent bonds, and metallic bonds. Ionic bonds form when electrons move from one atom to another. Covalent bonds form when atoms share electrons. Metallic bonds occur in metals, where electrons are held in a shared arrangement that gives metals their characteristic behavior. Understanding these bond types helps students compare how atoms connect in different...

noncovalent attractions in biomolecules

Biomolecule Interactions Without Covalent Bonds

Biomolecules often stay together through noncovalent attractions instead of covalent bonds. These weaker interactions help molecules recognize each other and form structures needed for life. The main noncovalent attractions are hydrogen bonds, electrostatic interactions, van der Waals forces, and hydrophobic interactions. Each one works in a different way, but all of them can influence how biomolecules fold, bind, and behave in cells. Hydrogen bonds form when a hydrogen atom is attracted to...

polymers

Polymer Chains and Their Properties

Polymers are large molecules made from repeating units called monomers. These long chains can form many common materials. Their structure helps explain why different polymers can behave in different ways. Polymers can be built in more than one way. Some form by addition polymerization, where monomers join together directly. Others form by condensation polymerization, which releases a small molecule as the chain grows. The type of polymer affects its properties and uses. Some polymers are...

what are lipids?

Lipids in Cells: Membranes, Energy, and Signals

Lipids are important cell molecules that act as membrane parts, energy stores, and signaling molecules. They are a diverse group of hydrocarbons, which are compounds made of carbon and hydrogen atoms. The carbon-carbon and carbon-hydrogen bonds are nonpolar, so lipids have an overall nonpolar character. Lipids are also hydrophobic, or “water-hating.” They do not form hydrogen bonds with water, so they are nearly insoluble in water. They are, however, soluble in organic solvents such as...

structure of lipids

How Lipid Molecules Are Built

Lipid molecules are built from hydrocarbon chains and a few key structural parts. Their shape helps explain why they behave differently from many other biological molecules. In high school biology, this structure is often linked to how lipids store energy and help form cell membranes. Some lipids are made from fatty acids joined to other small molecules. Triglycerides contain glycerol and three fatty acids, while phospholipids contain glycerol, two fatty acids, and a phosphate group. These...

chemistry of carbohydrates

Carbohydrates are built from sugar units and the bonds that link them. Their chemistry explains how simple sugars join to form larger molecules. It also helps show why carbohydrates have different structures and functions. The video focuses on the main sugar types found in carbohydrates. These include monosaccharides, disaccharides, and polysaccharides. Monosaccharides are single sugar units. Disaccharides contain two sugar units, while polysaccharides are long chains of many sugar units. The...

nucleic acids

DNA and RNA in Cells

DNA and RNA are nucleic acids that help store and use genetic information in cells. They are key molecules in biology and are often studied together because they work as a pair in living systems. Nucleic acids are built from repeating units called nucleotides. Each nucleotide has a sugar, a phosphate group, and a nitrogenous base. The order of these bases carries the genetic code. There are two main nucleic acids: DNA, or deoxyribonucleic acid, and RNA, or ribonucleic acid. DNA usually stores...

protein and protein structures

How Protein Shape Determines Function

Proteins are essential molecules in living things, and their shape affects how they work. Protein structure is described at several levels, including primary, secondary, tertiary, and quaternary structure. These levels help explain how a protein is built and how its final form supports its job. Primary structure is the sequence of amino acids in a protein. Secondary structure forms when parts of the chain fold into regular patterns. Tertiary structure is the overall three-dimensional shape of...

ph regulation in cells

Cell pH and Organelle Balance

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Cell Chemistry: Water, Ions, and Molecules

Cell chemistry explains the substances that make cells work. Water is the main component of cells, and it supports the chemical reactions that keep life going. Cells also contain organic molecules, which are carbon-based compounds, and inorganic ions, which are charged particles needed for cell function. Organic molecules in cells include carbohydrates, lipids, proteins, and nucleic acids. These molecules have different roles, but together they build cell structures, store energy, and carry...

key terms and concepts

Explore carbohydrate structure, from monosaccharides to polysaccharides, and see how chemical bonds link sugar units into larger molecules.

Carbohydrate Structure and Bonding | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

SC.912.L.18.2

Macromolecules

Biomolecules
Organisms contain a wide variety of organic molecules with numerous functions which depend on the chemical structures and properties of these ...

Polymers

What are Lipids?

Lipids function as structural components of cellular membranes, in addition to acting as energy reservoirs and signaling molecules. They are thus crucial ...

Structure of Lipids

lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

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Fats as Energy Storage Molecules

Amino acids

Amino acids are the monomers that comprise proteins. Each amino acid has the same fundamental structure, which consists of a central carbon atom, or the ...

Peptide Bonds

A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid&#39;s carboxyl group and another amino acid&#39;s amino ...

What are Proteins?

Protein and Protein Structures

Protein Organization

Globular Proteins

In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins ...

Fibrous Proteins

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Protein Denaturation

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Role of Proteins in the Human Body

Proteins are the building block of life. They are also&#160; the most abundant macromolecules with as many diverse roles in the body. They are part of ...

Mechanical Protein Function

Structural Protein Function

Introduction to Carbohydrates

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Sugars as Energy Storage Molecules

Nucleic Acids and Nucleotides

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Nucleic Acid Structure

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The DNA Helix

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RNA Structure

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Types of RNA

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Noncovalent Attractions in Biomolecules

Describe the basic molecular structures and primary functions of the four major categories of biological macromolecules.

Cellulose and Pectic Polysaccharides

&#160;Every plant cell has a cell wall that protects the cell, provides structural support, and gives the cell shape. Cellulose, the main structural ...

Membrane Carbohydrates

The plasma membrane is a dynamic barrier composed of lipids, proteins, and carbohydrates. It is the epicenter of many cellular processes required for cell ...

Describe the important structural characteristics of monosaccharides, disaccharides, and polysaccharides and explain the functions of carbohydrates in living things.

Overview of Fatty Acid Metabolism

Lipids also are sources of energy that power cellular processes. Like carbohydrates, lipids are composed of carbon, hydrogen, and oxygen, but these atoms ...

What are Membranes?

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Membrane Fluidity

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Fluid Mosaic Model

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Membrane Lipids

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Asymmetric Lipid Bilayer

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Lipids as Anchors

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The Significance of Membrane Transport

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Describe the structures of fatty acids, triglycerides, phospholipids, and steroids. Explain the functions of lipids in living organisms. Identify some reactions that fatty acids undergo. Relate the structure and function of cell membranes.

SC.912.L.18.3

Ligand Binding Sites

Cofactors and Coenzymes

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Introduction to Enzymes

The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an ...

Enzymes and Activation Energy

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Introduction to Enzyme Kinetics

Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate ...

Turnover Number and Catalytic Efficiency

The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from ...

Catalytically Perfect Enzymes

The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at ...

introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

For many years, scientists thought that enzyme-substrate binding took place in a simple &#34;lock-and-key&#34; fashion. This model stated that the enzyme ...

Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

Enzyme Activity

Biological Catalysts

All living organisms continuously perform numerous biochemical reactions to sustain their presence. Most of these reactions require ...

Describe the structures of proteins and amino acids. Explain the functions of proteins in living organisms. Identify some reactions that amino acids undergo. Relate the structure and function of enzymes.

SC.912.L.18.4

Chemiosmosis

Oxidative phosphorylation is a highly efficient process that generates large amounts of adenosine triphosphate (ATP), the basic unit of energy that drives ...

electron-transport-chain-complex-i-and-ii

Electron Transport Chain: Complex I and II

The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce ...

electron-transport-chain-complex-iii-and-iv

Electron Transport Chain: Complex III and IV

During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then ...

The Electron Transport Chain

The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is ...

the-supercomplexes-in-the-crista-membrane

The Supercomplexes in the Crista Membrane

The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through ...

ATP Synthase: Structure

ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in ...

ATP Synthase: Mechanism

In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear ...

The ADP/ATP Carrier Protein

ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, ...

ATP Yield

Cellular respiration produces 30 - 32 ATP per glucose molecule. Although most of the ATP results from oxidative phosphorylation and the electron transport ...

Discuss the use of chemiosmotic gradients for ATP production in chloroplasts and mitochondria.

SC.912.L.18.5

Fermentation

Most eukaryotic organisms require oxygen to survive and function adequately. Such organisms produce large amounts of energy during aerobic respiration by ...

biofuels-producing-ethanol-from-cellulosic-material

Biofuels: Producing Ethanol from Cellulosic Material

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
In this experiment, cellulosic material (such as corn stalks, leaves, ...

Discuss the role of anaerobic respiration in living things and in human society.

SC.912.L.18.6

Photosynthesis

Autotrophs

Almost all living organisms on Earth depend on photosynthesis, which is the process that converts sunlight energy into a simple sugar called ...

What is Photosynthesis?

All living organisms on Earth are directly or indirectly dependent on photosynthesis. It is the only biological process that can capture energy from ...

The Anatomy of Chloroplasts

Green algae and plants, including green stems and unripe fruit, harbor specialized organelles called chloroplasts to carry out photosynthesis. They ...

Photosystems

Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in ...

The Photochemical Reaction Center

Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center ...

The Antenna Complex

Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - ...

the-z-scheme-of-electron-transport-in-photosynthesis

The Z-Scheme of Electron Transport in Photosynthesis

The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of ...

Identify the reactants, products, and basic functions of photosynthesis.

SC.912.L.18.7

A. All living things are composed of four basic categories of macromolecules and share the same basic needs for life.

B. Living organisms acquire the energy they need for life processes through various metabolic pathways (primarily photosynthesis and cellular respiration).

C. Chemical reactions in living things follow basic rules of chemistry and are usually regulated by enzymes.

D. The unique chemical properties of carbon and water make life on Earth possible.

Carbohydrate Structure and Bonding

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