Disaccharide - wikipedia Disaccharide Sucrose, a disaccharide formed from condensation of a molecule of glucose and a molecule of fructose A disaccharide ( also called a double sugar or bivose ) is the sugar formed when two monosaccharides ( simple sugars ) are joined by glycosidic linkage. Like monosaccharides, disaccharides are soluble in water. Three common examples are sucrose, lactose, and maltose. Disaccharides are one of the four chemical groupings of carbohydrates ( monosaccharides, disaccharides, oligosaccharides, and polysaccharides ). The most common types of disaccharides -- sucrose, lactose, and maltose -- have twelve carbon atoms, with the general formula C H O. The differences in these disaccharides are due to atomic arrangements within the molecule. The joining of simple sugars into a double sugar happens by a condensation reaction, which involves the elimination of a water molecule from the functional groups only. Breaking apart a double sugar into its two simple sugars is accomplished by hydrolysis with the help of a type of enzyme called a disaccharidase. As building the larger sugar ejects a water molecule, breaking it down consumes a water molecule. These reactions are vital in metabolism. Each disaccharide is broken down with the help of a corresponding disaccharidase ( sucrase, lactase, and maltase ). Contents 1 Classification 2 Formation 3 Properties 4 Assimilation 5 Common disaccharides 6 References 7 External links Classification There are two functionally different classes of disaccharides : Reducing disaccharides, in which one monosaccharide, the reducing sugar of the pair, still has a free hemiacetal unit that can perform as a reducing aldehyde group ; cellobiose and maltose are examples of reducing disaccharides, each with one hemiacetal unit, the other occupied by the glycosidic bond, which prevents it from acting as a reducing agent. Non-reducing disaccharides, in which the component monosaccharides bond through an acetal linkage between their anomeric centers. This results in neither monosaccharide being left with a hemiacetal unit that is free to act as a reducing agent. Sucrose and trehalose are examples of non-reducing disaccharides because their glycosidic bond is between their respective hemiacetal carbon atoms. The reduced chemical reactivity of the non-reducing sugars in comparison to reducing sugars, may be an advantage where stability in storage is important. Formation The formation of a disaccharide molecule from two monosaccharide molecules proceeds by displacing a hydroxyl radical from one molecule and a hydrogen nucleus ( a proton ) from the other, so that the now vacant bonds on the monosaccharides join the two monomers together. The vacant bonds on the hydroxyl radical and the proton unite in their turn, forming a molecule of water, that then goes free. Because of the removal of the water molecule from the product, the term of convenience for such a process is `` dehydration reaction '' ( also `` condensation reaction '' or `` dehydration synthesis '' ). For example, milk sugar ( lactose ) is a disaccharide made by condensation of one molecule of each of the monosaccharides glucose and galactose, whereas the disaccharide sucrose in sugar cane and sugar beet, is a condensation product of glucose and fructose. Maltose, another common disaccharide, is condensed from two glucose molecules. The dehydration reaction that bonds monosaccharides into disaccharides ( and also bonds monosaccharides into more complex polysaccharides ) forms what are called glycosidic bonds. Properties The glycosidic bond can be formed between any hydroxyl group on the component monosaccharide. So, even if both component sugars are the same ( e.g., glucose ), different bond combinations ( regiochemistry ) and stereochemistry ( alpha - or beta - ) result in disaccharides that are diastereoisomers with different chemical and physical properties. Depending on the monosaccharide constituents, disaccharides are sometimes crystalline, sometimes water - soluble, and sometimes sweet - tasting and sticky - feeling. Assimilation See also : carbohydrate digestion Digestion involves breakdown to the monosaccharides. Common disaccharides Disaccharide Unit 1 Unit 2 Bond Sucrose ( table sugar, cane sugar, beet sugar, or saccharose ) Glucose Fructose α ( 1 → 2 ) β Lactulose Galactose Fructose β ( 1 → 4 ) Lactose ( milk sugar ) Galactose Glucose β ( 1 → 4 ) Maltose ( malt sugar ) Glucose Glucose α ( 1 → 4 ) Trehalose Glucose Glucose α ( 1 → 1 ) α Cellobiose Glucose Glucose β ( 1 → 4 ) Chitobiose Glucosamine Glucosamine β ( 1 → 4 ) Maltose, cellobiose, and chitobiose are hydrolysis products of the polysaccharides starch, cellulose, and chitin, respectively. Less common disaccharides include : Disaccharide Units Bond Kojibiose two glucose monomers α ( 1 → 2 ) Nigerose two glucose monomers α ( 1 → 3 ) Isomaltose two glucose monomers α ( 1 → 6 ) β, β - Trehalose two glucose monomers β ( 1 → 1 ) β α, β - Trehalose two glucose monomers α ( 1 → 1 ) β Sophorose two glucose monomers β ( 1 → 2 ) Laminaribiose two glucose monomers β ( 1 → 3 ) Gentiobiose two glucose monomers β ( 1 → 6 ) Turanose a glucose monomer and a fructose monomer α ( 1 → 3 ) Maltulose a glucose monomer and a fructose monomer α ( 1 → 4 ) Palatinose a glucose monomer and a fructose monomer α ( 1 → 6 ) Gentiobiulose a glucose monomer and a fructose monomer β ( 1 → 6 ) Mannobiose two mannose monomers either α ( 1 → 2 ), α ( 1 → 3 ), α ( 1 → 4 ), or α ( 1 → 6 ) Melibiose a galactose monomer and a glucose monomer α ( 1 → 6 ) Melibiulose a galactose monomer and a fructose monomer α ( 1 → 6 ) Rutinose a rhamnose monomer and a glucose monomer α ( 1 → 6 ) Rutinulose a rhamnose monomer and a fructose monomer β ( 1 → 6 ) Xylobiose two xylopyranose monomers β ( 1 → 4 ) References Jump up ^ Biose on www.merriam-webster.org Jump up ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. ( the `` Gold Book '' ) ( 1997 ). Online corrected version : ( 2006 -- ) `` disaccharides ''. Jump up ^ Biology - A course for O Level. p. 59. ISBN 9810190964. Jump up ^ `` Nomenclature of Carbohydrates ( Recommendations 1996 ) 2 - Carb - 36 Disaccharides ''. Jump up ^ `` Disaccharides and Oligosaccharides ''. Retrieved 2008 - 01 - 29. Jump up ^ Whitney, Ellie ; Sharon Rady Rolfes ( 2011 ). Peggy Williams, ed. Understanding Nutrition ( Twelfth ed. ). California : Wadsworth, Cengage Learning. p. 100. ISBN 0 - 538 - 73465 - 5. Jump up ^ `` Glycosidic Link ''. OChemPal. Utah Valley University. Retrieved 11 December 2013. Jump up ^ F.W. Parrish ; W.B. Hahn, G.R. Mandels ( July 1968 ). `` Crypticity of Myrothecium verrucaria Spores to Maltose and Induction of Transport by Maltulose, a Common Maltose Contaminant '' ( PDF ). J. Bacteriol. American Society for Microbiology. 96 ( 1 ) : 227 -- 233. PMC 252277. PMID 5690932. Retrieved 2008 - 11 - 21. Jump up ^ Matsuda, K. ; Abe, Y ; Fujioka, K ( November 1957 ). `` Kojibiose ( 2 - O - alpha - D - Glucopyranosyl - D - Glucose ) : Isolation and Structure : Chemical Synthesis ''. Nature. 180 ( 4593 ) : 985 -- 6. doi : 10.1038 / 180985a0. PMID 13483573. Jump up ^ T. Taga ; Y. Miwa ; Z. Min ( 1997 ). `` α, β - Trehalose Monohydrate ''. Acta Crystallogr. C. 53 ( 2 ) : 234 -- 236. doi : 10.1107 / S0108270196012693. External links Disaccharides at the US National Library of Medicine Medical Subject Headings ( MeSH ) Sugar ( as food commodity ) List of sugars and sugar products Chemistry Monosaccharide Fructose Galactose Glucose Xylose Disaccharide Lactose Maltose Sucrose Trehalose Free sugar Reducing sugar Sources Sugar beet Sugarcane Agave nectar Birch Coconut Date Honeydew Maple Palm Products Syrups Candi sugar Cheong Maesil - cheong Mogwa - cheong Yuja - cheong Corn syrup Glucose syrup Golden syrup High - fructose corn syrup High - maltose corn syrup Honey Inverted sugar syrup Kuromitsu Maple syrup Molasses Pine honey Steen 's cane syrup Treacle Solid forms Brown Peen tong Chancaca Crystalline fructose Gelling Gula melaka Jaggery Misri Mizuame Molasses sugar Muscovado Nib Non-centrifugal cane sugar Panela Plantation Reserve Powdered Preserving Rock candy Sucanat Sugar candy Barley sugar Butterscotch Candy Hard Toffee Sugar glass Sugarloaf Wasanbon Other forms Caramel Cotton candy floss Maple sugar foods Rum Sugar alcohol Sugar confectionery Sugarcane juice Tuzemák Unrefined sweeteners Industry Production Boilery Plantation Casa grande Refinery Sugar bush Sugar cane mill Engenho Batey Zafra By region ( current ) Cuba Caribbean Philippines Sri Lanka U.S. Sugar Program By region ( historical ) Danish West Indies Fiji Hawaii History Amelioration Act 1798 Blackbirding Colonial molasses trade Demerara rebellion of 1823 Holing cane Molasses Act Reciprocity Treaty of 1875 Slavery in the British and French Caribbean Sugar Act Sugar Duties Act 1846 Sugar Intervention Taiwan Sugar Railways Triangular trade Culture Crop over Sugar house Sugaring Sugar nips Sugar packet Sucrology Sugar people Sugar tit Sugar sculpture Treacle mine Related Added sugar Australian Aboriginal sweet foods Bagasse Barley malt syrup Brown rice syrup Cane knife Flavored syrup Fruit syrup Date honey Grape Jallab Health effects Nectar Sugar addiction Sugars in wine Residual sugar Sugar substitute Sweetened beverage Sweetener Sweetness Vinasse Yacón syrup Category Production Types of carbohydrates General Aldose Ketose Furanose Pyranose Geometry Anomer Cyclohexane conformation Mutarotation Monosaccharides Dioses Aldodiose Glycolaldehyde Trioses Aldotriose Glyceraldehyde Ketotriose Dihydroxyacetone Tetroses Aldotetroses Erythrose Threose Ketotetrose Erythrulose Pentoses Aldopentoses Arabinose Lyxose Ribose Xylose Ketopentoses Ribulose Xylulose Deoxy sugars Deoxyribose Hexoses Aldohexoses Allose Altrose Galactose Glucose Gulose Idose Mannose Talose Ketohexoses Fructose Psicose Sorbose Tagatose Deoxy sugars Fucose Fuculose Rhamnose Heptoses Ketoheptoses Mannoheptulose Sedoheptulose Above 7 Octoses Nonoses Neuraminic acid Multiple Disaccharides Cellobiose Isomaltose Isomaltulose Lactose Lactulose Maltose Sucrose Trehalose Turanose Trisaccharides Maltotriose Melezitose Raffinose Tetrasaccharides Stachyose Other oligosaccharides Acarbose Fructooligosaccharide ( FOS ) Galactooligosaccharide ( GOS ) Isomaltooligosaccharide ( IMO ) Maltodextrin Polysaccharides Beta - glucan Oat beta - glucan Lentinan Sizofiran Zymosan Cellulose Chitin Chitosan Dextrin / Dextran Fructose / Fructan Inulin Galactose / Galactan Glucose / Glucan Glycogen Hemicellulose Levan beta 2 → 6 Lignin Mannan Pectin Starch Amylopectin Amylose Xanthan gum Carbohydrates portal Category Retrieved from `` https://en.wikipedia.org/w/index.php?title=Disaccharide&oldid=862015831 '' Categories : Disaccharides Carbohydrate chemistry Talk Contents About Wikipedia Bân - lâm - gú Беларуская Беларуская ( тарашкевіца ) ‎ Български Bosanski Català Čeština Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Frysk Gaeilge Galego 한국어 Հայերեն Hrvatski Bahasa Indonesia Íslenska Italiano עברית Қазақша Kurdî Кыргызча Latina Lietuvių Magyar Македонски Bahasa Melayu Nederlands 日本 語 Norsk Occitan Oʻzbekcha / ўзбекча Polski Português Română Русский Scots Shqip සිංහල Simple English Slovenčina کوردی Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் ไทย Українська Tiếng Việt 粵語 中文 50 more Edit links This page was last edited on 1 October 2018, at 16 : 42 ( UTC ). 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Question: what kind of bond is formed between 2 monomers of sugar to create a di- or poly-saccharide
Answer: glycosidic bond