My question: Sucrose consists but of one Molecule of glucose and one fructose Molecule, right? The molecular formula for glucose and fructose is C6H12O6. But then would have the molecular formula for sucrose C12H24O12 loud. But you is C12H22O11! Have I misunderstood something? Why is molecular formula for sucrose C12H22O11? My ideas: Maybe it has something to do with the bond? Daniel35 darcy Joined: 10/09/2012 Beitrge: 1073 Posted: 30 January 2013 09:52 Title: carbohydrates are verknpft by glycosidic bonds. The formation of the bond is a condensation reaction, in the monosaccharide verknpft Molekle with elimination of small Molekle, for example water (in the plant phosphate is cleaved as glucose-1-phosphate and glucose is not used). Fr any glycosidic bond so you need to add the sum formulas of the building blocks, but also just subtract each H2O. Conversely, darcy the cleavage of sucrose is a so called hydrolysis. Here, a Molecule H2O is "consumed". Sugar Guest Posted: 30 January 2013 10:55 Title: Oh. So at the glycosidic bond a H2O Molecule is delivered so subtracted? And in the cleavage of sucrose is a H2O Molecule "drangehngt" So to add? Daniel35 Joined: 10/09/2012 Beitrge: darcy 1073 Posted: 30 January 2013 11:43 Title: Exactly. In disaccharides 1 H2O in trisaccharides 2 H2O, etc.. And for the empirical formula of a-amylose Molekls from 298 glucose units you draw 297 H2O from the molecular formula of 298 Glucosemolekle from. Sugar Guest Posted: 30 January 2013 19:13 Title: Why is at the glycosidic bond at all a H2O Molecule-free? Does this have to do with the fact that two OH groups react with each other? magician4 Moderator Joined: 05/10/2009 Beitrge: 8272 Location: darcy Hamburg Posted: 30 January 2013 19:35 Title: if you do not rumtreibst degree in sugar chemistry, this education of the glycosidic bond is called everywhere else "vollacetalbildung" mark of this reaction is that a molekuel water per knotted connection is free, yes greeting ingo _________________ a month spared in the laboratory a smooth but ne quarter of an hour at the library! Sugar Guest Posted: 30 January 2013 19:52 Title: What about in terms of the Vollacetalbildung in glycogen? Glycogen consisting darcy of units of glucose. But how many units of glucose darcy is glycogen? Would have to be the monomer of glycogen not C6H10O5 C6H12O6 Helen instead? magician4 Moderator Joined: 05/10/2009 Beitrge: 8272 Location: Hamburg Posted: 30 January 2013 20:31 Title: Glycogen is a highly polymeric veraenderlicher monomer-number (such as it is indeed resistant and disassembled) from investigations it is known that focuses on key so about 50,000 glucose darcy units are joined there per molekuel, the links in the glycoside did are (1.4, at the junction also 1.6) with monomeric you are always on the complete monomer-molekuel, without prejudice to the Tasache that it possibly in of the later operation (condensation in this case underwater spin-off ) then-OH groups, proton o.ae. will lose the sum formula of the so glycogenpolymer monomer remains the glucose greeting ingo _________________ one month in the laboratory saves a smooth but ne quarter of an hour at the library! Daniel35 Joined: 10/09/2012 Beitrge: 1073 Posted: 30 January 2013 22:51 Title: Sugar wrote: Why in the glycosidic bond at all a H2O Molecule-free? Does this have to do with the fact that two OH groups react with each other? Because darcy H2O is just a relatively good leaving group. It is energetically gnstig, split H2O to can. However, do not gnstiog, because then the reaction wre very difficult to reverse. Daniel35 Joined: 10/09/2012 Beitrge: 1073 Posted: 30 January 2013 22:57 Title: Sugar wrote: What about in terms of the Vollacetalbildung in glycogen from? Glycogen consisting of units of glucose. But how many units of glucose is glycogen? That depends on whether you have just eaten or played sports. Glycogen storage in the liver and muscles is highly dynamic. An hour of exercise, and glycogen is depleted. However, glycogen is phosphorolytisch to the 1,4-compounds and dismantled. Here it is not water that is eliminated or deposited, but phosphate.
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