chapter 6 carbohydrate
生化中英对照单词
Chapter 14 Protein Biosynthesis
第十四章 蛋白质的生物合成
Antibiotics 抗生素 Cap-site binding protein 帽子结合蛋白 Chloromycetin 氯霉素 Diphtheria toxin 白喉毒素 Eukaryote 真核生物 Genetic code 遗传密码 Insulin 胰岛素 Interferon 干扰素 Molecular chaperone 分子伴侣 Parathyroid hormone 甲状旁腺激素 Streptomycin 链霉素 Translational initiation complex 翻译起始复合物 Transpeptidase 转肽酶
丝氨酸／苏氨酸蛋白磷酸酶
Chapter 12 DNA Biosynthesis 第十二章 DNA生物合成
Bidirectional replication 双向复制 Endonuclease 内切核酸酶 Exonuclease 外切核酸酶 Gene expression 基因表达 Polymerases 聚合酶类 Primase 引发酶 Primosome 引发体 Proliferating cell nuclear antigen 增殖细胞核抗原 Recombination repairing 重组修复 Replicon 复制子 Reverse transcriptase 逆转录酶 Semiconservative replication 半保留复制 Single stranded DNA binding protein 单链DNA结合蛋白 Telomerase 端粒酶 Telomere 端粒 DNA topoisomerase DNA拓扑异构酶
Chapter 1 Nucleic Acid 第一章 核酸
digestion1
Sacral spinal cord
Enteric nervous system
Myenteric plexus Submucosal plexus
Postganglionic fibres
Smooth muscle
Secretory cells
Endocrine cells
Blood vessels
SPINAL CORD
Spinal afferent
17
2. The autonomic nervous system
Symቤተ መጻሕፍቲ ባይዱathetic system: Noradrenaline EFFECTS
ACTION
Mid brain
Parasympathetic system: Acetylcholine (Ach)
19
Innervation of the GI tract
3. Intrinsic (enteric) nerve plexuses
Located in the submucosa (submucosal or Meissner’s plexus) and between circular and longitudinal muscle layers (myenteric or Auerbach’s plexus) Control Motility - Myenteric plexus Secretion - Submucosal plexus
Processing of food by the DS
4. Chemical digestion • catabolic steps in which food is broken down to basic building blocks • accomplished by enzymes in digestive juices 5. Absorption : passage of food particles into the bloodlymph 6. Defecation: elimination of indigestible food substances
绪论2005
五、生物化学发展历程
Roots of Biochemistry
❖Wohler's synthesis of urea ❖Buchners' fermentation of sugar
from yeast extracts ❖Sumner's crystallization of urease
❖Watson and Crick's structure of DNA
Return
六、生物化学的应用 Revolution in biological
sciences
1.作为其它生命科学的理论基础
对各种生命现象和生物生产过程进行 机理和本质解释
2.作为方法与工具直接应用于生产 过程
生物产品生产制备提取加工等
❖ 2.1 构成生物体的基本物质化学组成、结构、 性质、功能
❖ Biochemistry as a Biological Science Distinguishing Characteristics of Living Matter --- Describe structure, organization, function of cells in molecular terms --- Structural Chemistry
Seawater (%)
Human body (%) Earth's crust (%)
H
66
H
63
O
47
O
33
O
25.5
Si
28
Cl
0.33
C
9.5
Al
7.9
Na
0.28
N
1.4
Carbohydrates
Outline of the section
1. Digestion and absorption of carbohydrates (糖的消化吸收) 2. Anaerobic oxidation (糖的无氧氧化—糖酵解) 3. Tricarboxylate cycle (TCA 循环) 4. Pentose phosphate pathway (PPP, 磷酸戊糖途径) 5. Gluconeogenesis (糖异生) 6. Glycogenesis and glycogenolysis (糖原合成与分解) 7. Blood glucose regulation (血糖的调节)
Glucose(葡萄糖) Galactose(半乳糖)
Monosaccharides （单糖）
O
H
OH
H
OH
H
OH
Glucose（葡萄糖, 己醛糖）
OH
Ribose（核糖, 戊醛糖）
Glucose （葡萄糖）
Enantiomer: 镜像对称（手性 分子）
L-Glucose(葡萄糖)
D-Glucose(葡萄糖) predominant structure
Section 1
Structure, digestion and absorption of carbohydrates
(糖的结构、消化与吸收)
1. What’s carbohydrates/saccharides?
• 糖(carbohydrates)即碳水化合物，其化学本质为多羟醛或多羟酮
类及其多缩聚体化合物，也称saccharides. 结构式Cn(H2O)n，n≥3. – 单糖(monosaccharides)：葡萄糖、果糖、半乳糖
烟草专业英语考试总结
Chapter 1 单词翻译：单词翻译：Nicotian 烟草属烟草属 combustion ：燃烧. Solanaceae 茄科茄科 combustibility 可燃性度可燃性度 nicotine 尼古丁，烟碱尼古丁，烟碱 pest resistance 抗虫害抗虫害agronomic performance 农艺性能农艺性能 Chinese －Style Cigarette ：中式卷烟：中式卷烟Chinese-style cigarette ：中式卷烟：中式卷烟 Virginian-type cigarette ：烤烟型卷烟：烤烟型卷烟blended cigarette ：混合型卷烟：混合型卷烟 tar content ：焦油含量：焦油含量：焦油含量 aromatic 芳香的芳香的 limit regulation’：限焦令. Virginia tobacco ：弗吉尼亚烟：弗吉尼亚烟Flue-cured tobacco ：烤烟：烤烟 Bright tobacco ：浅色烟：浅色烟 Burley tobacco ：白肋烟：白肋烟Oriental tobacco 东方烟东方烟 Aromatic tobacco ：香料烟：香料烟 Maryland tobacco ：马里兰烟：马里兰烟 Cigar tobacco ：雪茄烟：雪茄烟 disease resistance ：抗病性：抗病性 plant's physiology ：植物生理：植物生理thresh ：打叶：打叶 redrying ：复烤：复烤 aging ：老化，(陈化、醇化) fermentation 发酵发酵cigarette manufacture ：卷烟生产：卷烟生产 smoke chemistry ：烟气化学：烟气化学 cigar 雪茄雪茄cigarillo 小雪茄小雪茄 smokeless tobacco ：无烟烟草：无烟烟草 botanical 植物的植物的air-curing 晾制晾制 sun-curing 晒制晒制 fire-curing 熏制fiue-curing 烤制烤制the State Tobacco Monopoly Administration ：STMA officially ：国家烟草专卖局：国家烟草专卖局2. 长句子翻译长句子翻译Tobacco (Nicotiana (Nicotiana tabacum tabacum L.) L.) is is is a a a kind kind kind of of of special special special plant plant plant containing containing containing nicotine, nicotine, nicotine, belong belong belong to to Solanaceae, Nicotiana. Tobacco differs from other crops in that it is used mostly for combustion. Variables of botanical, physical and chemical characteristics of leaf tobacco determine degrees of combustibility, smoke composition, taste and aroma and, thus, product acceptability. 烟草是一种特殊的含有尼古丁的植物，属于茄科烟草属。
糖的生理功能
ATP -2 2×2 2×2 或2×3 2×3 2×3×3 2×2 2×1 36或38
（五）三羧酸循环的生理意义：
氧化供能。 是糖、脂、蛋白质三大物质分解的最终
代谢通路。 是糖、脂、蛋白质三大物质互相转变的
共同途径。
五、有氧氧化的调节
（1）第一阶段：前述。 （2）第二阶段：关键酶是丙酮酸脱氢酶系。 （3）第三阶段：关键酶是异柠檬酸脱氢酶、 α-酮戊二酸脱氢酶。
第六章 糖 代 谢
chapter 5 Metabolism of carbohydrate
第一节 概述 一、糖的生理功能 二、糖的消化吸收 三、糖代谢概况
一、糖的生理功能
糖类是指多羟基醛或酮及其衍生物。 糖类在生物体的生理功能主要有： 氧化供能,提供碳源,作为结构成分.
二、糖的消化与吸收
（胰腺）
ATP
(8)
2-磷酸甘油酸
磷酸甘油酸变位酶
3-磷酸甘油酸
2-磷酸甘油酸
丙酮 酸
⑼
H2O
烯醇化酶
磷酸烯醇式丙酮酸
ADP
⑽
丙酮酸激酶＊
ATP
⑾
自发
烯醇式丙酮酸
4．还原(reduction)-乳酸的生成：
利用丙酮酸接受酵解代谢过程中产生的 NADH，使NADH重新氧化为NAD+，以确 保反应的继续进行。
四、糖酵解的调节
糖酵解代谢途径的调节主要是通过各种变构 剂对三个关键酶进行变构调节。
五、糖酵解的生理意义
1. 在无氧和缺氧条件下，作为糖分解 供能的补充途径
2. 在有氧条件下，作为某些组织细胞 主要的供能途径。
第三节 糖的有氧氧化
一、有氧氧化的概念：葡萄糖在有氧条件 下 彻 底 氧 化 分 解 生 成 CO2 和 H2O ， 并 释 放出大量能量的过程称为糖的有氧氧化 （aerobic oxidation)。
生化：名词解释大全
生化：名词解释大全生化学是一门研究生命体系化学成分和化学过程的学科。
在这个领域中，蛋白质和核酸是两个重要的研究对象。
下面是一些与蛋白质和核酸相关的重要术语和定义。
第一章：蛋白质1.两性离子（n）是指在特定pH值下，蛋白质分子的某些氨基酸会同时带有正负电荷。
2.必需氨基酸（essential amino acid）是指人体无法自行合成的氨基酸，必须从食物中获得。
3.等电点(isoelectric point,pI)是指蛋白质分子带有零电荷的pH值。
4.稀有氨基酸(rare amino acid)是指在自然界中含量较少的氨基酸，如色氨酸和甲硫氨酸等。
5.非蛋白质氨基酸(nonprotein amino acid)是指不属于蛋白质结构的氨基酸，如肽类和生物碱等。
6.构型(n)是指蛋白质分子中氨基酸的空间排列方式。
7.蛋白质的一级结构(protein primary structure)是指由氨基酸序列构成的线性结构。
8.构象(n)是指蛋白质分子中氨基酸的三维空间排列方式。
9.蛋白质的二级结构(protein secondary structure)是指由氢键和其他键连接的多肽链的局部折叠形成的结构，如α-螺旋和β-折叠等。
10.结构域(domain)是指蛋白质分子中具有独立结构和功能的部分。
11.蛋白质的三级结构(protein tertiary structure)是指由各种键连接的多个结构域的整体折叠形成的结构。
12.氢键(hydrogen bond)是一种弱键，通常用于连接蛋白质分子中的氨基酸。
13.蛋白质的四级结构(protein quaternary structure)是指由多个蛋白质分子相互作用形成的复合物。
14.离子键(ionic bond)是一种强键，通常用于连接蛋白质分子中的离子。
15.超二级结构(super-secondary structure)是指由多个二级结构域相互作用形成的结构。
电子教案 糖代谢(英文版)
Section I Introduction: the fate of absorbed glucose
Model of a mammalian glucose transporter. The hydrophobicity profile of the protein indicates 12 transmembrane helices.
1. Basic process of glycolysi 1-1 The degradation of glucose to pyruvate 1-2 Conversion of pyruvate to lactate “Glycolysis” is derived from Greek words glycos (sugar, sweet) and lysis (dissolution)
－
Pi
AMP
Citrate
Next
PFK-2
The domain structure of the bifunctional enzyme phosphofructokinase 2. The kinase domain (purple) is fused to the
phosphatase domain (red). The knase domain is a P-loop NTP hydrolase domain, as indicated by the purple shading. The bar represents the amino acid sequence of the enzyme.
H3PO4
CHO P
CHOH
end
glycerate 2-phosphate
生化英文名词解释
名词解释Glossary第一章蛋白质的结构与功能Chapter 1 Structure and Function of Proteinpeptide bond（肽键）：a covalent bond linking the α- amino group of one amino acid and theα-carboxyl group of another in a protein molecule.peptide（肽）：a molecule containing two or more amino acids linked by peptide bond. primary structure of protein（蛋白质的一级结构）：the amino acid sequence of a polypeptide.secondary structure of protein（蛋白质的二级结构）：the spatial arrangement of local portions of a polypeptide chain.tertiary structure of protein（蛋白质的三级结构）：the spatial arrangement of all the atoms of a protein or a subunit.quaternary structure of protein（蛋白质的四级结构）：the spatial arrangement of a protein that consists of more than one folded polypeptide chain or subunit.subunit（亚基）：an individual polypeptide chain that associates with one or more separate chains to form a complete protein.motif（模序）：a substructure formed with two or more secondary-structure peptide segments that are drawn close to each other.domain（结构域）：a region within a protein, particularly within a large polypeptide, that functions in a semi-independent manner.positive cooperativity（正协同效应）：an effect that the binding of one ligand to a protein facilitates the subsequent ligand binding.allosteric effect（变构效应）：an effect that a small molecule, called an effector, noncovalently binds to a protein and alters its activity.isoelectric point（pI）of protein （蛋白质的等电点）：the pH at which a protein has an equal number of positive and negative charges and hence bears no net charge. denaturation of protein（蛋白质变性）： the disruption of the natively folded structure of a protein caused by exposure to heat, radiation, or chemicals, or change in pH, that leads to an alteration of chemical, physical and biological properties of the第二章核酸的结构与功能Chapter 2 Structure and Function of Nucleic Aciddenaturation of DNA（DNA的变性）：the disruption of the native conformation of DNA by separation of the DNA double helix into its two component strands, due to heat, chemicals, or change in pH, etc.hyperchromic effect（增色效应）：the increase in ultraviolet absorbance of a DNA while the DNA is denatured.melting temperature（Tm, 融解温度）：the temperature corresponding to half the maximal increase in ultraviolet absorbance of a thermally denatured DNA.annealing（退火）：the process of returning a thermally denatured DNA to its original native structure when it is cooled gradually.第三章酶Chapter 3 Enzymessimple enzyme（单纯酶）：an enzyme that consists of only polypeptide chain(s). conjugated enzyme（结合酶）：an enzyme with its polypeptide portion(apoenzyme) linked to one or more substance other than amino acids, such as metals or small organic molecules.holoenzyme（全酶）：a complete enzyme consisting of the apoenzyme portion plus the cofactor component.essential group（必需基团）： a chemical group on the side chain of amino acid residue of an enzyme that is closely related to the activity of the enzyme.active center / active site（活性中心）：the region of an enzyme molecule that contains the substrate binding site and the catalytic site for converting the substrate(s) into product(s).activation energy（活化能）：the threshold energy that must be overcome to produce a chemical reaction.absolute specificity（绝对特异性）：the extreme selectivity of an enzyme that allows it to catalyze only the reaction with a single substrate in the case of a monomolecular reaction, or the reaction with a single pair of substrates in the case of a bimolecularrelative specificity（相对特异性）：the relative selectivity of an enzyme that allows it to catalyze the reaction with one type of reactants or one type of chemical bond. stereospecificity（立体异构特异性）：the selectivity of an enzyme for a particular stereoisomer.zymogen（酶原）：the inactive precursor of an enzyme.zymogen activation（酶原激活）：the process in which a zymogen is converted to an active enzyme by limited proteolysis and subsequently the active center of the enzyme is formed or exposed.isoenzyme（同工酶）：multiple forms of an enzyme that catalyze the same reaction but differ from one another in one or more of the properties, such as structural, physical, chemical and even immunological properties.第四章糖代谢Chapter 4 Carbohydrate Metabolismglycolysis（糖酵解）： the anaerobic degradation of carbohydrate whereby a molecule of glucose is converted to two molecules of lactic acid.substrate-level phosphorylation（底物水平磷酸化）：the synthesis of ATP from ADP by the phosphorylation of ADP coupled with exergonic breakdown of a high-energy organic substrate molecules.Pastuer effect（巴斯德效应）：the phenomenon that the glycolytic pathway is inhibited under aerobic conditions.glycogen（糖原）： a highly branched polymer of glucose residues primarily in 1,4 linkage but with 1,6 linkage at branchpoints.gluconeogenesis（糖异生）： the synthesis of glucose or glycogen from noncarbohydrate molecules, i.e., lactic acid, glycerol, glucogenic amino acids, etc.第五章脂类代谢Chapter 5 Lipid Metabolismessential fatty acids（必需脂肪酸）： the fatty acids, including linoleic acid, linolenic acid, and arachidonic acid, which can not be synthesized in the mammalian body and must be obtained from diet.mobilization of fat（脂肪动员）： a process of lipolysis in which the fat stored in adipose tissues is converted to free fatty acids and glycerol, which are consequently released into blood so that they can be used in other tissues.β-oxidation of fatty acid（脂肪酸的β-氧化）： a process in which a fatty acid is degraded through a sequential removal of two-carbon fragments from the carboxyl end and therefore acetyl CoA is formed as the bond between the α- and β-carbon atoms is broken.ketone bodies（酮体）： a group of molecules, i.e., acetone, acetoacetate, and β–hydroxybutyrate, that are synthesized in the liver from acetyl CoA.第六章生物氧化Chapter 6 Biological Oxidationrespiratory chain （呼吸链）/ electron transfer chain（电子传递链）： a series of electron carriers responsible for the transport of reducing equivalent from metabolite to molecular oxygen, with the net results of capturing energy for use in ATP synthesis, and of the reduction of oxygen to water.P/O ratio（P/O比值）： the number of molecules of Pi consumed in ATP formation for each oxygen atom reduced to H2O.oxidative phosphorylation（氧化磷酸化）： the process in which the phosphorylation of ADP to yield ATP is coupled to the electron transport through respiratory chain. uncoupler（解偶联剂）： a molecule, such as dinitrophenol, that uncouples ATP synthesis from electron transport.第七章氨基酸代谢Chapter 7 Amino Acid Metabolismessential amino acids（必需氨基酸）： the amino acids，including valine, leucine, isoleucine, threonine, phenylalanine, tryptophan methionine and lysine, that cannot be synthesized by animal body and must therefore be supplied by diet. transdeamination（联合脱氨基作用）： the coupled action of an aminotransferase and a glutamate dehydrogenase involved in deamination of the majority of amino acids. transamination（转氨基作用）： a reaction catalyzed by an aminotransferase, in which an amino group is transferred from an amino acid to a keto acid.ketogenic amino acids（生酮氨基酸）： the amino acids that can be converted to ketone bodies, i.e., leucine and lysine.glucogenic and ketogenic amino acids（生糖兼生酮氨基酸）： the amino acids, i.e., isoleucine, phenylalanine, tyrosine, threonine and tryptophan, that can be converted to either ketone bodies or carbohydrates.one carbon units（一碳单位）/ one carbon groups（一碳基团）： organic groups, including methyl(—CH3), methylene(—CH2—), methenyl(—CH＝), formyl(—CHO) and formimino(—CH＝NH) groups, each containing only one carbon atom generated through catabolisms of some amino acids.第八章核苷酸代谢Chapter 8 Nucleotide Metabolismthe de novo pathway of nucleotide synthesis（核苷酸的从头合成途径）： a pathway through which nucleotides are synthesized by using simple molecules, such as ribose 5-phosphate, amino acids, one carbon units and carbon dioxide.the salvage pathway of nucleotide synthesis（核苷酸的补救合成途径）： a pathway through which nucleotides are synthesized by using the existing nitrogenous bases or nucleosides.第九章物质代谢的联系与调节Chapter 9 Integration and Regulation of Metabolismkey enzyme（关键酶）/ pacemaker enzyme（限速酶）/ regulatory enzyme（调节酶）：an enzyme that sets the rate for the entire biochemical pathway, usually catalyzes the slowest and irreversible step, and can be regulated by a number of metabolites and effectors in addition to its substrates.allosteric regulation（变构调节）： a regulatory mechanism through which a specific low-molecular-weight molecule, called an effector or a modulator, noncovalently binds to a regulatory site outside the active center of a regulatory enzyme and alters the conformation and activity of the enzyme.chemical modification（化学修饰调节）： a regulatory mechanism through which enzyme activities are regulated by means of reversible interconversion between the active and inactive forms of the enzyme resulted from enzyme-catalyzed covalent modificationto a specific amino acid residue.第十章 DNA的生物合成（复制）Chapter 10 Biosynthesis of DNA (Replication)replication（复制）：a process in which an exact copy of parental DNA is synthesized by using each polynucleotide strand of the parental DNA as templates. semiconservative replication（半保留复制）： duplication of DNA after which the daughter duplex carries one parental strand and one newly synthesized strand.DNA polymerase（DNA聚合酶）：any of various enzymes, with the full name of DNA dependent DNA polymerase, that catalyzes the formation of polynucleotides of DNA using an existing strand of DNA as a template.point mutation（点突变）：a mutation that causes the replacement of a single base pair with another, including nonsense mutation, missense mutation and silent mutation. frameshift mutation（框移突变）：a mutation of insertion or deletion of a genetic material that leads to a shift in the translation of the reading frame, resulting in a completely different translation.reverse transcriptase（逆转录酶）：any of various enzymes, with the full name of RNA dependent DNA polymerase, that catalyzes the formation of polynucleotides of DNA using an existing strand of RNA as a template.telomeres（端粒）： structures that occur at the ends of eukaryotic chromosomes that prevent the unraveling of DNA.第十一章 RNA的生物合成（转录）Chapter 11 Biosynthesis of RNA (Transcription)RNA polymerase（RNA聚合酶）：any of various enzymes, with the full name of DNA dependent RNA polymerase, that catalyzes the formation of polynucleotides of RNA using an existing strand of DNA as a template.promoter（启动子）： a DNA sequence immediately before a gene that is recognized by RNA polymerase and signals the start point of transcription.intron（内含子）： a noncoding intervening sequence in a split or interrupted gene that is missing in the final RNA product.exon（外显子）： the region in a split or interrupted gene that codes for RNA which endup in the final product (e.g., mRNA).ribozyme（核酶）：ribonucleic acid with catalytic ability whose substrate is ribonucleic acid.第十二章蛋白质的生物合成（翻译）Chapter 12 Biosynthesis of Proteins (Translation)reading frame（阅读框）： a group of three nonoverlapping nucleotides that is read asa codon during protein synthesis. The reading frame begins with the initiator codonAUG.molecular chaperon (分子伴侣)：a sort of intracellular conservative protein, which can recognize the unnatural conformation of peptide and assist in the accurate folding of domains or the whole protein.signal peptide（信号肽）： a sequence of amino acid residues located at the N-terminal portion of a nascent secretory protein, which marks the protein for translocation across the rough endoplasmic reticulum.第十三章细胞信息转导Chapter 13 Cell Signalingprimary messenger（第一信使）： an extracellular signaling molecule that is released from the signaling cell and can regulate the physiological activity of the target cell.secondary messenger（第二信使）： a small intracellular molecule, such as Ca2+,cAMP, cGMP, diacylglycerol (DAG), inositol triphosphate (IP3), ceramide, or arachidonic acid (AA), etc., that is formed at the inner surface of the plasma membrane in response to a primary messenger.receptor （受体）： a molecular structure on the surface or interior of the target cell that specifically binds signaling molecule and initiates a response in the cell. ligand（配体）： a biologically active molecule that can bind to its specific receptor.G protein （G蛋白）/ guanylate binding proteins （鸟苷酸结合蛋白）：a trimeric guanylatebinding protein in the cytoplasmic side of plasma membrane that acts as a switch to turn activities on and off by interconversion between its monomeric GTPase andtrimeric GDP binding form.hormone response element （激素反应元件，HRE）：a specific DNA sequence that binds hormone-receptor complex; The binding of a hormone-receptor complex either enhances or diminishes the transcription of a specific gene.第十四章血液的生物化学Chapter 14 Biochemical Aspects of Bloodnon-protein nitrogen（非蛋白氮）：nitrogen contained in urea, creatine, creatinine, uric acid, bilirubin, and ammonia.acute phase protein（急性时相蛋白质）：a protein whose plasma concentration can be altered when acute inflammation or a certain type of tissue damage occurs.2,3-bisphosphoglyerate shunt（2,3-二磷酸甘油支路）：the pathway in erythrocyte glycolysis in which glycerate 1,3-bisphosphate(1,3-BPG) is isomerized to 2,3-bisphosphoglyerate(2,3-BPG) and the latter is consequently hydrolyzed to form 3-phosphoglycerate. The importance of 2,3-BPG in the erythrocyte lies in its ability to alter the extent to which hemoglobin binds with oxygen.第十五章肝的生物化学Chapter 15 Biochemical Aspects of the Liverbiotransformation（生物转化）： a series of enzyme-catalyzed processes through which non-nutritional molecules, which are usually hydrophobic, are converted into more soluble metabolites.jaundice（黄疸）： a clinical manifestation of hepatic disease, featuring yellow discolration of the plasma, skin, and mucous membranes, caused by bilirubin accumulation and staining.欢迎您的下载，资料仅供参考！致力为企业和个人提供合同协议，策划案计划书，学习资料等等打造全网一站式需求。
碳水化合物的好处和坏处英文作文
碳水化合物的好处和坏处英文作文全文共6篇示例，供读者参考篇1The Pros and Cons of CarbohydratesHey there! Today we're going to talk about carbohydrates, which are a type of nutrient found in many of the foods we eat. Carbohydrates are really important for our bodies, but we also need to be careful not to eat too many of them. Let me explain!What are Carbohydrates?Carbohydrates, also called "carbs" for short, are nutrients that provide energy for our bodies. They are found in foods like bread, pasta, rice, potatoes, fruits, and sugary items like candy, cookies, and soda. There are two main types of carbs - simple carbs and complex carbs.Simple carbs are found in sugary foods and drinks. They give us a quick burst of energy, but that energy doesn't last very long. Complex carbs are found in foods like whole grains, vegetables, and beans. They provide longer-lasting energy for our bodies.The Benefits of CarbohydratesCarbs are important for many reasons. Here are some of the main benefits:Energy Source: Carbs are our body's main source of energy. When we eat carbs, they are broken down into glucose, which is used by our cells for energy. This energy helps us to walk, run, play, and do all the activities we love!Brain Power: Our brains need a lot of energy to function properly. Carbs provide the fuel our brains need to concentrate, learn new things, and stay sharp.Fiber: Many carb-rich foods, like fruits, vegetables, and whole grains, are also excellent sources of fiber. Fiber is really good for our digestive system and helps us feel full for longer.Nutrient Delivery: Some carb-rich foods, like fruits and vegetables, also provide important vitamins, minerals, and antioxidants that our bodies need to stay healthy.The Drawbacks of CarbohydratesWhile carbs are essential for our health, eating too many of them, especially the wrong types, can cause some problems. Here are some of the main drawbacks:Weight Gain: Eating too many simple carbs, like sugary snacks and drinks, can lead to weight gain. These carbs arequickly broken down and converted into fat if we don't burn off the energy they provide.Blood Sugar Spikes: Simple carbs can cause our blood sugar levels to spike rapidly and then crash, leaving us feeling tired and sluggish. This can be especially problematic for people with diabetes.Nutrient Deficiencies: If we eat too many refined carbs like white bread, pasta, and pastries, we might miss out on important nutrients found in more nutrient-dense foods.Tooth Decay: Sugary carbs can contribute to tooth decay by feeding the bacteria in our mouths that produce acid, which can erode our tooth enamel over time.The Balanced ApproachSo, what's the solution? It's all about balance and making smart choices when it comes to carbs. Here are some tips:Choose Complex Carbs: Focus on getting most of your carbs from nutrient-rich sources like whole grains, fruits, vegetables, and beans. These provide longer-lasting energy and important vitamins, minerals, and fiber.Limit Simple Carbs: Try to limit your intake of simple carbs like sugary snacks, candies, and sweetened drinks. These can cause blood sugar spikes and contribute to weight gain.Portion Control: Even with complex carbs, it's important to watch your portion sizes. Too many carbs of any kind can lead to weight gain if you're not burning off the energy they provide.Stay Active: Regular physical activity is key to using up the energy we get from carbs and maintaining a healthy weight.Balanced Diet: Remember that carbs are just one part of a balanced diet. We also need to include plenty of protein, healthy fats, fruits, and veggies to get all the nutrients our bodies need.So there you have it! Carbs are an essential part of our diet, providing us with energy and important nutrients. However, we need to be mindful of the types and amounts of carbs we consume. By making smart choices and balancing our carb intake with physical activity and other nutrient-rich foods, we can reap the benefits of carbs while avoiding the potential drawbacks.篇2The Pros and Cons of CarbohydratesHave you ever wondered what carbohydrates are and if they are good or bad for you? Carbohydrates are one of the three main types of nutrients found in food, along with proteins and fats. They are made up of sugar molecules that give our bodies energy.There are two main types of carbohydrates: simple and complex. Simple carbohydrates are also called simple sugars. They are found naturally in foods like fruits, vegetables, milk and honey. Complex carbohydrates are made up of long strings of simple sugars. Starchy foods like bread, pasta, rice and potatoes are examples of complex carbs.So are carbs good or bad? Well, like most things in life, they have both pros and cons. Let me start with the good stuff first!The Pros of CarbohydratesThey give us energy! Carbs are the main source of fuel for our bodies. When we eat them, they get broken down into simple sugars that our cells can use for energy to do things like run, jump, think and grow. How cool is that?They help our brains work better. Our brains actually need a lot of energy from carbs to concentrate, learn new things, and remember stuff. Have you ever felt "fuzzy-brained" when youskip a meal? That's because your brain wasn't getting enough carbs!They keep our guts healthy. The fiber found in complex carbs like whole grains, fruits and veggies is really important for keeping our digestive systems running smoothly. Fiber helps us go to the bathroom regularly and prevents constipation. Ew, I know, but it's important!They taste delicious! From sweet treats like cookies and ice cream to comforting dishes like mac and cheese, some of our favorite foods are carb-filled. Enjoying these foods helps make eating fun!Those all sound like pretty good reasons to eat carbs, right? But as with most things, it's possible to have too much of a good thing. And that brings me to the potential downsides of carbohydrates.The Cons of CarbohydratesThey can lead to weight gain if we eat too many. Our bodies only need a certain amount of carbs each day for energy. Any extra carbs get stored as fat. That's why eating tons of sugary or starchy foods can pack on the pounds over time.The wrong carbs can spike our blood sugar. Simple carbs like sugar, honey, syrups and white bread raise our blood sugar levels really quickly. Getting too much of these fast-acting carbs, especially if you have diabetes, can be unhealthy.Some carb-heavy foods lack nutrients. You've probably heard of "empty calories" before. Foods like candy, soda, white bread and chips are high in simple carbs but low in important vitamins, minerals and fiber that our bodies need.They can cause cavities and tooth decay. The natural and added sugars found in many carb-rich foods feed the bacteria in our mouths that cause tooth decay and cavities. That's why it's so important to brush and floss regularly!As you can see, carbs definitely have their upsides and downsides. The key is to try and get most of your carbs from nutritious sources like whole grains, fruits, veggies, beans and low-fat dairy rather than sugary snacks and drinks.Our bodies can't function properly without any carbs at all. But eating way too many of the wrong kinds of carbs can lead to weight gain, blood sugar spikes, and other health issues down the road. It's all about finding that happy, balanced middle ground!Moderation is so important when it comes to carbs. As long as you don't go overboard, they can absolutely be part of a healthy, energizing diet. Just think about choosing your carbs wisely by reaching for foods like oatmeal, brown rice, quinoa, sweet potatoes and other high-fiber options more often. And don't forget to keep treating yourself to your favorite carb-filled indulgences here and there too - that's part of what makes eating so fun and enjoyable!So what do you think? Do the pros of carbs outweigh the cons for you, or vice versa? Whether you're team carb oranti-carb, it's always good to understand both sides so you can make informed choices. Who knew learning about nutrition could be so interesting?篇3The Ups and Downs of CarbohydratesDo you love eating bread, pasta, rice, potatoes, and sweet treats like cookies and candy? If so, you're getting a lot of carbohydrates in your diet! Carbohydrates are one of the three main types of nutrients found in foods, along with proteins and fats. But what exactly are carbs, and are they good or bad for you? Let's take a closer look!What Are Carbohydrates?Carbohydrates are compounds made up of carbon, hydrogen, and oxygen atoms. The word "carbohydrate" comes from the prefix "carbo-" meaning carbon, and "hydrate" meaning water. There are two main types: simple carbs and complex carbs.Simple carbs are also called simple sugars. They include substances like glucose, fructose (found in fruits), sucrose (table sugar), and lactose (milk sugar). Simple carbs taste very sweet and give you a quick burst of energy, but that energy doesn't last very long.Complex carbs are made up of long chains of simple sugars linked together. Starches found in foods like potatoes, whole grains, corn, peas, and lentils are complex carbs. Your body takes longer to break down and digest complex carbs, so they provide longer-lasting energy.The Benefits of CarbsYour body needs some carbohydrates to function properly. In fact, carbs should make up 45-65% of your total daily calories! Here are some of the main benefits of getting enough carbs:Energy BoostThe primary role of carbs is to provide your body with energy in the form of glucose. Glucose is the main source of fuel for your cells, tissues, and organs. Without enough glucose, you would feel tired and sluggish.Brain PowerYour brain runs almost entirely on glucose! It has no way to store glucose, so it relies on a steady supply of carbs to keep your mind sharp for learning, thinking, memory, and concentration.FiberMany complex carb foods like whole grains, beans, fruits, and veggies are excellent sources of fiber. Fiber is important for keeping your digestive system regular and healthy. It also helps you feel fuller for longer after eating.NutrientsIn addition to carbs, many carb-rich plant foods provide valuable vitamins, minerals, and antioxidants that are essential for growth and development. For example, fruits and veggies are packed with vitamin C, potassium, folate, and plant compounds that protect your cells.The Downsides of Too Many CarbsWhile carbs serve vital roles in your overall health andwell-being, eating too many—especially the wrong types of carbs—can also cause some problems.Weight GainSimple carbs like white bread, pastries, sodas, and candy provide calories from sugar with very few other nutrients. Eating too many of these "empty calorie" foods can lead to excess weight gain and even obesity over time.Blood Sugar SpikesSimple sugars are digested quickly and rapidly absorbed into your bloodstream, causing a spike in blood sugar levels. Over time, this can increase your risk of insulin resistance and developing type 2 diabetes.Tooth DecayThe bacteria in your mouth feed on the sugars from carbs, producing acid that can erode and damage your tooth enamel. This can lead to cavities and other dental problems when you eat too many sugary carbs.Health RisksResearch has linked diets high in refined carbs and added sugars to increased risks of heart disease, high cholesterol, high blood pressure, fatty liver disease, and even some types of cancer.So what's the solution? It's all about choosing the right balance and types of carbs!The Best Carbs to EatThe key is to focus on getting most of your carbs from nutrient-rich whole food sources like:•Whol e grains (whole wheat bread, brown rice, oats, quinoa)•Fruits (apples, berries, oranges, bananas)•Veggies (sweet potatoes, peas, corn, carrots)•Beans and lentils•Milk and yogurtThese complex carb foods give you lasting energy along with beneficial fiber, vitamins, minerals, and antioxidants. Simple sugars should be limited in your diet. Only eat small amounts of foods like:•White bread, crackers, and pastries•Sweetened cereals•Cookies, cakes, and candy•Sodas and fruit juicesBy making wise carb choices and keeping your portions in check, you can get all the great benefits of carbohydrates while avoiding the downsides. A balanced diet with the right kinds of carbs is the healthiest way to go!篇4The Ups and Downs of CarbohydratesHey there, friends! Today, we're going to talk about something that's a big part of our daily diets – carbohydrates! You might have heard grown-ups using this big word, but do you know what it really means? Well, let me break it down for you.Carbohydrates, or "carbs" for short, are a type of nutrient found in many of the foods we eat. They're like little bundles of energy that help our bodies function properly. When we eat carbs, they get broken down into glucose, which is a kind of sugar that our cells use for fuel. Pretty cool, right?Now, let's talk about the good stuff first – the awesome benefits of carbohydrates!Energy BoostersAs I mentioned earlier, carbs are fantastic sources of energy. When we eat foods like bread, pasta, rice, or fruits, our bodies convert those carbs into glucose, providing us with the energy we need to run, jump, play, and learn. Can you imagine trying to keep up with your friends at the playground without any energy? No way!Brain PowerNot only do carbs give us physical energy, but they also help our brains work better. Our brains rely heavily on glucose to function properly. Without enough carbs, we might feel tired, grumpy, or have trouble concentrating in class. Who wants that?Fiber FriendsSome carbohydrates, like those found in whole grains, fruits, and vegetables, are packed with fiber. Fiber is like a superhero for our digestive system! It helps keep things moving smoothly and makes us feel fuller for longer. That means we're less likely to overeat or snack on unhealthy foods.Now, let's talk about the not-so-good side of carbohydrates:The Sugar RushWhile carbs can give us energy, some types of carbs, like sugary snacks and drinks, can provide too much energy too quickly. This sudden spike in blood sugar can leave us feeling energized for a short time, but then we might experience an energy crash afterward. That's no fun at all!Weight Gain WorriesIf we consume too many carbs, especially refined or processed carbs like white bread, pastries, and candy, the excess calories can lead to weight gain. This is because our bodies store any extra energy (from carbs or other nutrients) as fat. Too much weight gain can be unhealthy and make it harder to run and play.Blood Sugar BluesFor some people, consuming too many carbs, particularly those with a high glycemic index (a fancy way of saying they raise blood sugar levels quickly), can cause problems with blood sugar control. This is especially true for those with conditions like diabetes.So, what's the bottom line? Carbohydrates are an important part of a balanced diet, but we need to be mindful of the types and amounts we consume. The key is to focus on getting ourcarbs from nutrient-dense sources like whole grains, fruits, vegetables, and legumes. These types of carbs are packed with fiber, vitamins, and minerals that are great for our bodies.On the other hand, we should try to limit our intake of refined and processed carbs, like sugary snacks, white bread, and pastries. These carbs are often high in calories and low in nutrients, which can lead to weight gain and other health issues.Remember, everything in moderation is the way to go! By making smart choices and balancing our carb intake with other healthy foods, we can enjoy the benefits of carbohydrates while avoiding the potential downsides.So, the next time you're reaching for a snack, think about whether it's a nutrient-rich carb source or a treat that should be enjoyed in moderation. And don't forget to listen to your body –it's pretty good at letting you know when you've had enough or when you need a little energy boost from some healthy carbs.That's all for now, friends! I hope you've learned something new and exciting about carbohydrates. Remember, a balanced diet and an active lifestyle are the keys to staying healthy and happy. Now, go out there and make wise choices when it comes to carbs!篇5The Great Carb DebateHi there! My name is Jamie and I'm a 5th grader. Today I want to talk about something that comes up a lot when people discuss healthy eating - carbohydrates. You've probably heard of carbs before, but what exactly are they? And are they good or bad for you?Let me start by explaining what carbohydrates are. Carbs are one of the three main types of nutrients found in food, along with proteins and fats. They are the sugars, starches and fibers found in things like grains, fruits, vegetables, beans, and dairy products. When you eat carbs, your body breaks them down into simple sugars that are used for energy.So now that we know what they are, let's look at some of the pros and cons of eating carbohydrates:The Good Things About CarbsEnergy BoostOne of the biggest benefits of carbs is that they give you energy! The sugars from carbs get released into your bloodstream and give your body's cells a nice kick of fuel to keepyou feeling energized throughout the day. This extra energy can help you concentrate better in school, play harder on the sports field, and just generally feel good. Who doesn't want more energy?FiberMany carb-rich foods like fruits, veggies, whole grains, and beans also contain fiber, which is really important for keeping your digestive system regular and healthy. Fiber helps push food through your body so things keep moving smoothly. It can also help you feel full for longer after eating.NutrientsWhile simple carbs like white bread and pastries don't have many nutrients, complex carbs like whole grains, fruits, and vegetables are packed with important vitamins, minerals, and antioxidants. These nutrients help build strong bones, heal cuts, and protect your body from disease.The Not-So-Good ThingsWeight GainOne of the biggest downsides of eating too many carbs, especially simple carbs and sugars, is that it can lead to weight gain over time. When you consume more calories from anysource than your body can burn off, the extras get stored as fat. Sugary drinks, candy, baked goods, and other carb-heavy foods are very easy to overindulge in.Crashes in EnergyWhile carbs can give you an initial burst of energy, that energy can burn off quickly, especially from simple carb sources. This can lead to a "crash" in energy levels, where you feel really sluggish and tired after the initial high wears off. It's kind of like getting a super burst from a rocket booster, but then running out of fuel mid-flight!Blood Sugar SpikesEating a lot of simple carbs and sugars can cause unhealthy spikes in your blood sugar levels. Your body has to release a lot of insulin to process that sugar rush, and frequent big spikes can lead to insulin resistance down the road. This makes it harder for your body to regulate blood sugar properly.The Bottom LineSo as you can see, carbs have both positive and negative effects on the body. They give you an energy boost but can lead to crashes. They provide fiber and nutrients, but too many canpack on extra pounds. The key, like with most things when it comes to healthy eating, is balance and moderation.The best approach is to focus on getting your carbs from nutritious sources like:Whole grains like oats, brown rice, quinoa and whole wheatFruits like apples, bananas, and berriesVeggies like sweet potatoes, peas, and cornBeans, lentils, and peasThese complex carbs digest more slowly to providelonger-lasting energy, are packed with fiber, and contain plenty of important vitamins and minerals. Simple carbs like white bread, pastries, soda, and candy should be limited since they are low in nutrients and fiber and digested very quickly.So in the end, carbs aren't all good or all bad. They can be an important part of a balanced, healthy diet when the right kinds and amounts are chosen. As long as you're smart about getting your carbs mostly from wholesome, fiber-rich sources and don't go overboard, feel free to enjoy them as a delicious source of energy and nutrients!There you have it - the great debate over whether carbs are good or bad for you. What do you think about carbs after reading this? I'd love to hear your thoughts! Thanks for reading, and stay healthy!篇6The Pros and Cons of CarbohydratesHave you ever wondered why your mom or dad tells you to eat your veggies and not too many sweets? It all has to do with carbohydrates! Carbohydrates are a type of nutrient found in many foods we eat. They provide us with energy to play, study, and grow. But not all carbohydrates are created equal. Some are better for us than others. Let me explain!The Good CarbsYou know those yummy fruits and vegetables your parents always want you to eat? Well, they're packed with good carbohydrates called complex carbs. These carbs are like little powerhouses that give us long-lasting energy. They're also full of fiber, which helps keep our tummies feeling happy and healthy.Some examples of complex carbs are:Whole grains like brown rice, oats, and whole wheat breadBeans and lentilsFruits like apples, bananas, and berriesVeggies like broccoli, spinach, and sweet potatoesComplex carbs are awesome because they take a long time to break down, so they keep us feeling full and energized for hours. They also have lots of vitamins, minerals, and fiber that our bodies need to grow strong and smart.The Not-So-Good CarbsNow, let's talk about the carbs that we should have in moderation – the simple carbs. These are the sugary, processed foods that taste super yummy but don't really do much good for our bodies.Simple carbs are found in:Candy, cookies, and cakeSoda and other sugary drinksWhite bread and pastriesHoney and syrupThe problem with simple carbs is that they get broken down really quickly by our bodies. This means we get a quick burst ofenergy, but then we crash and feel tired and hungry again soon after. Simple carbs also don't have many nutrients or fiber, so they don't keep us feeling full for very long.Too many simple carbs can also lead to problems like weight gain, tooth decay, and even diabetes if we have way too much sugar.The Balancing ActSo, what's the solution? It's all about balance! We need both complex and simple carbs in our diets, but we should focus on getting most of our carbs from the complex, nutrient-rich sources.Here's an example of a balanced day of carbs:Breakfast: Oatmeal with fresh berries and a sprinkle of honeySnack: An apple and a handful of nutsLunch: A whole wheat sandwich with lean turkey, lettuce, and tomatoSnack: Carrot sticks and hummusDinner: Brown rice, grilled chicken, and roasted veggiesDessert: A small piece of dark chocolate or a few bites of birthday cake (it's okay to indulge sometimes!)By eating a variety of complex carbs throughout the day and limiting our intake of simple carbs, we can have all the energy we need while still getting the nutrients our bodies crave.So, the next time your parents encourage you to eat your veggies or choose whole grain bread over white, remember –they're just looking out for your health and happiness! Carbs are an important part of a balanced diet, but it's all about choosing the right ones and enjoying them in moderation.。
6糖代谢
R－酶 降解 （1 →6 ）苷键，去除分支，也称为脱支酶 麦芽糖酶（ －葡萄糖苷酶 ） 水解产物中的麦芽糖
淀粉在-淀粉酶、--淀粉酶、 R－酶、麦芽糖酶共同作用下， 水解为葡萄糖
第六章 糖代谢
2. 磷酸解：催化酶：淀粉磷酸化酶
酶催化特点：a.从非还原端开始，催化 （1→4） 苷键磷酸解 ，其产物为G－1－P。 淀粉+Pi → G-1-P
H2O
H2C COOH H C COOH
H2O
H2C COOH HC COOH HO C COOH H 异柠檬酸
H2C COOH 顺乌头酸酶
HC COOH 顺乌头酸酶
柠檬酸
顺乌头酸
第六章 糖代谢
+ NAD H2C COOH HC COOH HO C COOH H
NADH+ H
+
H2C COOH HC COOH
产物：葡萄糖和果糖
CH 2OH H O H H OH H OH H OH CH 2OH O CH 2OH H H H OH
+
H2O
+
OH
OH
蔗糖酶
OH
蔗糖 +66.5°
葡萄糖 +52.2° -20.4 °
果糖 -93°
旋光度发生了变化，产物总称为转化糖，蔗糖酶也叫 转化酶
第六章 糖代谢
二、淀粉、糖原的酶促降解
第六章 糖代谢
O C ~ S CoA CH2 CH2 COOH
GDP+Pi
GTP
COOH CH2 CH2 COOH
+
HS CoA
琥珀酰CoA合成酶
琥珀酰CoA
琥珀酸
COOH CH2 CH2 COOH
Carbohydrate(二)
D -G lu c o s e
D -G a la c to s e
Glucose and Galactose半乳糖 are therefore epimers.
2. Ring structure
Mutarotation 变旋现象：interconversion of αand β-anomers
•The α- and β- anomers of carbohydrates are typically stable solids. However, in aqueous solution, they quickly equilibrate to an equilibrium mixture of the two forms. •For example, in aqueous solution, glucose exists as a mixture of 36% α- and 64% β- (>99% of the pyranose forms exist in solution). •The equilibration occurs via the ring opening of the cyclic sugar at the anomeric center with the acyclic无环的 form as the intermediate.
They may also be divided into trioses, tetroses, pentoses, hexoses, and so forth, depending on how many carbon atoms they contain.
Carbohydrate生化
Carbohydrates and GlycobiologyCarbohydratesCarbohydrates represent a great class of biomolecules. More than half of the organiccarbon on Earth is stored in just two carbohydrate molecules--starch and cellulose, both of which are polymers of glucose.They are such termed because their general formulas can all be written in a simple form as (CH2O)n or derivatives of it. Another term used to describe sugar-based molecules is rooted in the word "saccharide" (from the Latin, saccharum, meaning sugar).Carbohydrates as food & structural elementsThe major energy cycle of the biosphere depends largely on carbohydrate metabolism. Ribose and deoxyribose sugars form part of the structural framework of RNA and DNA. Polysaccharides are structural elements in the cell walls of bacteria and plants. They are involved in cell-cell recognition. They are linked to many proteins and lipidsMajor classes of carbohydrates1. Monosaccharides: glucose,fructose 2. Oligosaccharides: sucrose, lactose 3. PolysaccharidesHomopolysaccharides: cellulose, glycogen Heteropolysaccharides: bacterial cell wall, with more than one monosaccharide in the repeating unit.Cotton fiber consists of cellulose that is a polysaccharide with physical and chemical properties desirable qualities for textiles.Aldoses and KetosesAldehyde vs. KetoneThe smallest sugar--trioseThe carbonyl group is at an end of the carbon chain, or in an aldehyde group, the monosaccharide is an aldose; anywhere else, a ketose.ChiralityChiral carbons or chiral centers stereoisomersKey point: One carbon center with four different side groups.Three-carbon sugar (aldose) has one chiral centerAldoses with two chiral centersThree chiral centersStereoisomers with n chiral centers=2n Four chiral centers can yield 16 isomers of D- and Lforms together.Ketose with three carbonsKetose withD or L is determined by the chiral center with highest numberMutual epimers: differ only around one carbon D-mannose vs. D-glucose D-glucose vs. D-galactoseenantiomersSome sugars can exist in their Lforms. L-Arabinose is one example.Review of the terminology of sugar stereoisomersEnantiomers: D and L forms of a monosaccharide are nonsuperimposable mirror images Anomers: stereosiomers that differ only in configuration at the anomeric carbon, e.g., α- and β-D-glucose Conformational isomers: they differ in three-dimensional conformation, such as boat and chair formsCyclic structures in monosaccharidesFor simplicity, sugars are presented as aldoses or ketoses in straight chain forms, as shown above. However, in aqueous solution, monosaccharides with five or more carbon atoms in the backbone occur predominantly as cyclic structures.(α-D-glucose)Formation of hemiacetals or hemiketalsPyranoseFuranoseHaworth projection and Fisher ProjectionSubstituent drawn to the left in Fisher’s is drawn above the ring.Formation of cyclic glucose creates an additional chiral carbon. Two anomeric isomers: α and β α: hydroxyl group on the same side of highest numbered asymmetric carbonSummary: Main features of carbohydrates1. the existence of at least one asymmetric center 2. linear or ring structure 3. Formation of polymers through glycosidic bonds 4. the ability to form hydrogen bonds with water or other moleculesGlycosides and glycosidic bondsα-D-Glcp (1−>2) β-D-FrufGlycosidic BondSucrosePyranose Carbon 1 in α-D-glucose Carbon 2 in β-D-fructoseFuranoseLactoseGalβ(1Æ4)GlcDisaccharidesα1 1α linkageSugar derivativesSugar acids Sugar alcohols Deoxy sugars Sugar esters Amino sugarsDeoxy sugarSugar esters: important in metabolismcarbonyl group of a sugar to hydroxyl group. The resulting polyhydroxy compounds are called alditols. Important ones include erythritol, D-mannitol, and Dglucitol (sorbitol).Alditols: They are made by reducing theSorbitolWhen sorbitol accumulates in the lens of an diabetic’s eyes, it can lead to the formation of cataracts. This explains why diabetics can have blind symptom. Sorbitol cannot be digested by bacteria, so it can be used to keep foods fresh. It can cause diarrhea— for ease of constipation.Sugar acidsThe production of a red precipitate of Cu2O is a classic sugar test---Fehling’s test that was used to test for excess sugar in urine of diabetics. The sucrose does not react with Fehling's reagent. Sucrose is a disaccharide of glucose and fructose. Most disaccharides are reducing sugars, sucrose is a notable exception, for it is a nonreducing sugar. The anomeric carbon of glucose is involved in the glucose- fructose bond and hence is not free to form the aldehyde in solution.Fehling’s testFehling’s Reaction with cupric ion (CuSO4) as catalyst, yielding cuprous ion Cu2O). Oxidation of the aldehyde group yields gluconateWhy fructose, and the ring form of monosaccharides can be a reducing sugar?Although fructose does not contain an aldehyde group, it can isomerise into an aldose. Because they're in equilibrium with the open form, any monosaccharide molecule that's in a ring form will, within a fraction of a second, be in the open form and, thus, be able to react with the oxidizing agent.Acidic sugarsAmino sugars and their derivatives。
Carbohydrates
Principles of Biology
Carbohydrates
Figure 5 Disaccharides.
Maltose and sucrose are disaccharide sugars made up of two monomers.
Principles of Biology
Carbohydrates
• Monosaccharides are relatively bulky and are therefore inefficient to store, so organisms convert those not immediately needed into polysaccharides. • A covalent bond called a glycosidic linkage connects structures made of multiple monomers. • The simplest polymer is two linked monosaccharides-a disaccharide. • Glycosidic linkages are formed when a hydroxyl (OH) group is lost from one monomer and a hydrogen (H) atom is lost from the other, resulting in the release of a water (H2O) molecule (a dehydration or condensation reaction), creating polysaccharides.
生物化学英语单词读音2
Chapter 12 DNA Biosynthesis 第十二章 DNA生物合成
Bidirectional replication 双向复制 Endonuclease 内切核酸酶 Exonuclease 外切核酸酶 Gene expression 基因表达 Polymerases 聚合酶类 Primase 引发酶 Primosome 引发体 Proliferating cell nuclear antigen 增殖细胞核抗原 Recombination repairing 重组修复 Replicon 复制子 Reverse transcriptase 逆转录酶 Semiconservative replication 半保留复制 Single stranded DNA binding protein 单链DNA结合蛋白 Telomerase 端粒酶 Telomere 端粒 DNA topoisomerase DNA拓扑异构酶
Chapter 11 Metabolic Regulation 第十一章 代谢调节
Chemical modification 化学修饰 Diabetes mellitus 糖尿病 Inducer 诱导物 Rate limiting enzymes 限速酶 Repressor 阻遏物 Serine/threonine protein phosphatase 丝氨酸／苏氨酸蛋白磷酸酶
Chapter 13 RNA Biosynthesis 第十三章 RNA生物合成
Cis-acting element 顺式作用元件 Hybrid duplex 杂化双链 Posttranscriptional processing 转录后加工 Promoter 启动子 Small nuclear RNA 小核RNA Splicesome 拼接体 Template strand 模板链
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1-磷酸葡萄糖
H 2 O 3 POH 2 C H HO CH 2 OH HO OH
6-磷酸葡萄糖
H 2 O 3 POH 2 C H HO OH HO CH 2 OPO 3 H 2
O
O
6-磷酸果糖
1，6-二磷酸果糖
6、成苷反应
单糖的半缩醛羟基(称苷羟基)，与其他含羟 基的化合物形成环状缩醛，在糖化学中叫糖苷。 糖苷中，非糖部分叫配糖基，连接配糖基 与糖苷基的键叫苷键。
2. 构型：D-、L-构型 3. 构象：椅式构象
4. 理化性质
分类
按含碳原子的数目，单糖可分为丙糖、丁糖、 戊糖和己糖等；根据分子中是含醛基还是酮基， 单糖又可分为醛糖和酮糖。这两种分类方法常结 合起来使用。
CHO CH2 H OH H OH C H 2O H CHO OH H OH OH C H 2O H C H 2O H C=O H HO H OH H OH C H 2O H
左上右下
C H 2O H O H OH
C H 2O H OH
α-D-葡萄糖
CHO
C H 2O H O OH H
β-D-葡萄糖
果糖的Haworth式
H O H 2C H
O
C H 2O H OH
O C H 2O H
α-D-呋喃果糖
H O H 2C H O OH C H 2O H
C H 2O H O
OH
土伦试剂（银氨离子）
斐林试剂（Cu2＋即CuSO4酒石酸钾钠的NaOH溶液）
为什么酮糖也是还原糖？因为在碱性条件下，醛糖和 酮糖可通过形成烯醇负离子和烯二醇而相互转化。葡 萄糖和甘露糖及果糖在碱性条件下相互转化的过程如 下：
（2）与溴水的反应 溴水可与醛糖发生反应，选择性地将醛基氧化成羧基。 由于在酸性条件下（溴水pH=6.00）糖不发生差向异 构，因此溴水不氧化酮糖。可用于鉴别酮糖与醛糖。
化合物
乌本(箭毒)苷 a-L-rhamnose 鼠李糖
Collective Names of Monosaccharides 单糖名称汇总
Monosaccharides
阿拉伯糖 果糖 岩藻糖 半乳糖 葡萄糖 来苏糖 甘露糖 鼠李糖 核糖 木糖
CHO H OH C H 2O H
H HO H H
D-(+)-甘油醛
D型糖
自然界存在的单糖大多是D型糖
单糖的几种简写式
CHO OH OH OH C H 2O H CHO
HO
C H 2O H
CHO CHO HO H C H 2O H
L-(-)-甘油醛
CHO
C H 2O H O
C H 2O H
C H 2O H
丙醛糖
旋光异构体的数目 （2n）
丙酮糖
己醛糖
己酮糖
* * * * H O C H 2C H C H C H C H C H O OH OH OH OH * * * H O C H 2C H C H C H C C H 2O H OH OH OH O
24=16
23=8
单糖的构型和标记法
在糖的化学中，采用D/L法标记单糖 的构型。 单糖构型的确定以甘油醛为标准。
ZnCl
C H 2O C O C H 3 O
2
0 C
o
C H 3O C O
OCOCH
3
OCOCH3
OCOCH3
生物体内，糖在酶的作用下形成一些单酯或 二酯。其中最重要的是磷酸酯，它们在生物代 谢过程中起着重要的作用。
C H 2O H O HO OH OH O P O 3H 2
C H 2O P O 3H 2 O HO OH OH OH
α-D-吡喃果糖
O OH C H 2O H
C H 2O H
D-果糖
ß -D-呋喃果糖
ß D-吡喃果糖 -
单糖的构象式
六元环不是平面型的，透视式仍不能真实地反映 单糖的三维空间结构。吡喃糖六元环与环己烷相似， 优势构象也是椅式。
CH2OH HO HO O OH OH CH2OH HO HO O
OH
衍生物的总称。
糖类的生物学功能
1.是一切生物体维持生命活动所需能量的主要来源； 2.是生物体合成其它化合物的基本原料（前体分子）； 3.充当结构性物质； 4.糖链是高密度的信息载体，是参与神经活动的基本物质； 5.糖类是细胞膜上受体分子的重要组成成分，是细胞识别和 信息传递等功能的参与者。
糖的分类
单糖的重要衍生物
糖醇：较稳定，有甜味。甘露醇、山梨醇 糖醛酸：由单糖的伯醇基氧化而得。葡萄糖醛酸、半乳糖醛酸 氨基糖：糖中的羟基为氨基所取代。D-氨基葡萄糖 糖苷：单糖的半缩醛上羟基与非糖物质（醇、酚等）的羟基 形成的缩醛。洋地黄苷、皂角苷
Ouabain 乌本(箭毒)苷
Highly toxic cardiac glycoside found in the bark and root of the ouabaio tree 在乌本树的树皮和树根中存在一种对心脏具有高毒性的糖苷类
OH
β-D-葡萄糖
HO CH2OH O OH
α-D-葡萄糖
CH2OH O HO OH HO OH OH
HO
α-D-半乳糖
α-D-阿洛糖
OH OH CH2OHO
船式
OH OH
葡萄糖的构象
HO HO
CH2OH
O OH OH
椅式
HO HO
CH2OH
O
OH
OH
单糖的性质
物理性质： 1. 旋光性：糖分子中有不对称碳原子，具有能使偏 振光的平面向左（-）或向右（+）旋转的能力。
CHO H OH H OH H OH C H 2O H
H HO H H
核糖
2-脱氧核糖 戊醛糖
葡萄糖 己醛糖
果糖 己酮糖
单糖的旋光异构体 最简单的单糖是丙醛糖和丙酮糖。除 丙酮糖外，其它单糖分子都有旋光异构体。
* H O C H 2C H C H O OH H O C H 2C C H 2O H O
CH 2 OH CH NNHC 6 H 5 NNHC 6 H 5
HC
NNH C 6 H 5
CH 2 OH
C H 2O H O + H 2 N N H C 6 H 5 过量 C H 2O H
CH
N N H C 6H 5 N N H C 6H 5
C H 2O H
C H 2O H N N H C 6H 5
（3）与稀硝酸的反应 硝酸是比溴水强的氧化剂。它不但可以氧化糖的醛基 还可以氧化糖的伯醇羟基。生成二元羧酸，称为糖二 酸。例如D-葡萄糖经硝酸氧化，生成D-葡萄糖二酸 (glucaric acid)。
3、还原反应
H2/Ni NaBH4 LiAlH4 还原产物叫糖醇
CHO
H2 Ni
CH 2 OH
葡萄糖醇
单糖 ：不能水解的最简单糖类，是多羟基的
醛或酮的衍生物（醛糖或酮糖）
糖类化合物
寡糖 ：有2~10个分子单糖缩合而成，水解
后产生单糖
同多糖
杂多糖 多糖：由多分子单糖或其衍生物所组成，水 解后产生原来的单糖或其衍生物。 结合糖
§6.1 单糖(Monosaccharides) 1. 结构：丙、丁、戊、己糖
CH 2 OH O HO OH OH OH
CH 2 OH O
+ CH 3 OH
干 HCl
HO
OH OH
α-苷键
O CH 3
甲基-α-D-葡萄糖苷
α-D-葡萄糖甲苷
自然界存在的重要单糖及其 衍生物
The most common monosaccharides最常见单糖
Outline of Sugar derivatives and their related deriving ways
Sugar derivatives 糖衍生物 Sugar acids 糖酸
Sugar alcohols 糖醇 Deoxy sugars 脱氧糖 Amino sugars 胺基糖 Sugar esters 糖酯
Deriving ways 衍生方式 Oxidation
(?)reduction (?) Amidolation (酰胺基化) Phosphorylation (磷酸化)， alkylation (烷基化)
HO H C O CHO H OH C O
C H 2O H
β-D-葡萄糖（63%）
C H 2O H
0.1%
C H 2O H
α-D-葡萄糖（37%）
α-D-葡萄糖和β-D-葡萄糖，二者互称异头物。
CHO 多羟基 醛的开 环形式 HCOH HOCH HCOH HCOH CH2OH
CH22OH CH OH
C H 2O H
L型糖
D型糖与L型糖是对映体，根据D型糖 可写出相应的L型糖。
H HO H H CHO OH H OH OH C H 2O H HO H HO HO CHO H OH H H C H 2O H
CHO
CHO
C H 2O H
C H 2O H
D-葡萄糖
CHO CHO
L-葡萄糖
C H 2O H O
半乳糖
C H 2O H O
C H 2O H
C H 2O H
C H 2O H
C H 2O H
甘露糖
果糖
单糖的环状结构 问题的提出 (1) (2) (3) (4) 不与饱和的NaHSO3溶液反应. 仅与1摩尔CH3OH反应. 变旋光现象 在它们的红外光谱中却找不到羰基的特 征峰值。
物理及化学方法证明，结晶状态的单糖是 以环状结构存在的。
CHO H OH C H 2O H