Carbohydrate 2 Flashcards
Differences in anomers in molecules of the same substance and configurations
Molecular weight and boiling point
Maturoration Def
Inverstion between sugar alpha and beta anomers when dissolved in water. In solid forms it caused by ring opening (hemiacteyl/hemiketyl) and reclosing. Dissolution of substance = opening of ring. Equilibrium reaction. 1:1 reaction of anomers
Differences between theoretical and true equilibrium
Theoretical = 1:1 anomers. True equailibrium 1 anomer may be produced more then other. Anomer quantity is measured seeing wheer true euilibrium’s refraction index falls relative to theoretical and 2 individual anomers
Oxidation of Aldoses
Aldoses are oxidised to aldonic acid (carboxylic acid). Br2 is used instead of Tollen’s Reagent due to the alkaline nature of Tollen’s interfers with oxidation
Tollen’s Reagent Outline
Ag+ in aqueous NH3. Positive reducing sugar = shiny silver mirror
Fehling’s Reagent Outline
Cu in sodium tartarate (blue) reduced to Cu2O (red) in presence of reducing sugar
Benedicts’ Reagent Outline
Cu in aq sodium citrate (blue) to Cu2O (red) in presnce of reducing sugar
Acetal (Glycoside) Formation
Hemiacetal and an alcohol reacting in the presence of HCl. Acetal’s rings are less likely to open making them more stable then hemiacetals
Disaccharides Outline
Glycosidic acetal linking between the anomeric C of 1 monosaccharide and an OH on another. Eg Maltose
Maltose Outline
2 Alpha D glucose units joined together by an alpha 1-4 glycosidic bond. Formed by enzyme based hydrolysis of starch. Disaccharide. Contains a hemiacetal group (reducing sugar, undergoes matouration)
Cellobiose Outline
2 Beta D glucose units joined together by a beta 1-4 glycosidic bond. Formed by partial hydrolyses of cellulose. Disaccharide, contains hemiacetal group (reducing sugars, undergoes matuoration)
Lactose Outline
1-4 Beta glycosidic bond between glucose (C4) and galactose (C1). Contains hemiacetal group (reducing sugar, undergoes maturation)
Lactose Intolerance Outline
Low levels of lactase results in an inability to cleave glycosidic bond. Lactose builds up in small intestine, gets fermented by bacteria in small intestine resulting in CO2, H2O and organic acids forming
Galactosemia Outline
After lactose is hydrolysed to glucose and galactose, galactose builds up in blood as galactose-1-phosphate due to insufficient galactose-1-phosaphate uridylyl transferase. Results in kidney, liver and brain damage
Sucrose Outline
Glycosidic bond between glucose (C1) and fructose (C2). Disaccharide, no hemi acetyl group (not reducing, no matuoration)
Sucrose and tooth decay
Streptococcus on sucrose have glucosyl transferase. this enzymes break glycosidic bonds at C1 and C2 and polymerises glucose units to form an insoluble dextrin (alpha 1 to 6). Dextran adheres to tooth enamels, sucrose provides nutrients to bacteria and bacteria produce lactic acid
D-Glucosamine Outline
Component of glycoproteins that recognoise other cells and antigens on foreign matter
Glycoconjugates Outline
Sugar linked molecules that are involved in cell membrane, involved in cell recognition. Different sugars indicate different cells
Polysaccharides Outline
Complex carbohydrates. Thousands of simple sugars combined by glycosidic bonds. No hemiacetyl groups and only 1 free anomeric OH at end of chain. Eg celllose, starch and glycogen
Cellulose Outline
Thousands of glucose units held together by beta 1 -> 4 glycosidic bonds. Imaprts strength into plants. Enzyme cellulase brakes down cellulose (not found in humans)
Starch Outline
2 components amylose and amylopectin. Amylopectin has alpha 1 -> 4 glycosidic bonds and amylopectin has alpha 1 -> 4 glycosidic bonds with alpha 1->6 branches every 25 sugar units
Glycogen Outline
Similar structure to amylopectin. Contains alpha 1 -> 4 bonds with branching of alpha 1 -> 6 every 25 sugar units. Differnt to amylopectin as there are more branches but they are shorter in length
