arbohydrates - General Description A. Polyhydroxy Aldehydes or Ketones ARBN AIN B. Serve a variety of functions ARBN AIN ARBN AIN 1. Energy storage (Glucose, Glycogen, Starch) 2. Structural Support (ellulose, hitin) 3. Biochemical ontrol (DNA, Glycoproteins). ydrates of arbon - General formula: n(2)n, n=1,2,3... D. Saccharides - from Latin saccharum (sugar) 1. Monosaccharides - simple sugars 2. Disaccharides, trisaccharides, tetrasaccharides,... 3. ligosaccharides 4. Polysaccharides
arbohydrates - General Nomenclature A. -SE ending - Glucose, Galactose, Sucrose, ellulose B. lassification by Number of arbons 1. 363 - Tri + ose = Triose 2. 484 - Tetra + ose = Tetrose 3. 5105 - Penta + ose = Pentose. lassification by Functional Groups 1. Aldoses contain the aldehyde functional group. 2. Ketoses contain the ketone functional group. D. ombining A, B, and 2 an aldopentose 2 a ketohexose 2
arbohydrates - Simple Structures A. Simple Monosaccharide Structures D-Glyceraldehyde Dihydroxyacetone (A simple aldose) (A simple ketose) B. Note: Glyceraldehyde exists in two enantiomeric forms D
arbohydrates - Simple Structures Important Aldopentoses Important Aldohexoses 2 2 D-ribose 2-deoxy-D-ribose 2 D-glucose 2 D-galactose Glucose and Galactose are epimers
arbohydrates - Simple Structures An Important Ketohexose 2 2 2 2 2 D-fructose D-glucose omparison of the structures of D-fructose and D-glucose D-fructose
arbohydrates - Simple Structures What is L-Glucose? D-Glucose and L-Glucose are enantiomers Most naturally occurring monosaccharides are from the D-series. 2 2 D-Glucose L-Glucose
Absolute onfigurations of the D-Aldoses
Absolute onfigurations of the D-Ketoses
arbohydrates - yclic Structures Previously Studied Reactions of Aldehydes and Ketones
6 arbohydrates - yclic Structures 1 yclic Forms of Glucose 6 6 5 5 1 1 6 6 6 5 5 1 1 anomers
arbohydrates - yclic Structures In solution, glucose exists in a variety of forms.
arbohydrates - Reducing Sugars Glucose is a reducing sugar u 2+ u2 The small amount of aldehyde present in a glucose solution is sufficient to reduce the copper ion from 2+ to 1+.
arbohydrates - yclic Structures yclic Forms of ther arbohydrates
arbohydrates - yclic Structures β-d-glucopyranose β-d-galactopyranose
arbohydrates - Reducing Sugars Because they exist to a small extent in the aldehyde form in solution, most other simple sugars are reducing sugars.
arbohydrates - Reducing Sugars Because they exist to a small extent in the aldehyde form in solution, most other simple sugars are reducing sugars.
arbohydrates - Glycoside Formation
arbohydrates - Glycoside Formation The linkage between the sugar and the alcohol is called a glycosidic linkage and must be designated as α or β. Glycosides of simple monosaccharides are not reducing sugars because the aldehyde functional group is no longer present. The alcohol which attaches through the glycosidic can be another carbohydrate.
arbohydrates - Glycoside Formation
arbohydrates - Sugar Phosphates
arbohydrates - Acidic Sugars 2 D-Glucose D-Glucuronic Acid A building block for hyaluronic acid
arbohydrates - Amino Sugars 2 N 2 2 N 3 D-Glucosamine N-acetyl-D-Glucosamine Building block for chitin, the exoskeleton of crustaceans
arbohydrates - Sugar Sulphates - S - 2 S N - D-Glucuronic Acid 2-sulfate S - N-sulfo-D-Glucosamine 6-sulfate Building blocks for heparin
Monosaccharides - Physical Properties 1) Most monosaccharides are crystalline solids at room temperature and are very soluble in water where they can form highly viscous solutions. 2) Monosaccharides are slightly soluble in alcohols (methanol, ethanol) and are insoluble in less polar solvents (ethers, hydrocarbons). 3) Many monosaccharides taste sweet. 4) A solution of a reducing sugar may contain a mixture of α anomers, β anomers, and acyclic structures. The structures rapidly interconvert to form an equilibrium mixture. (This interconversion is called mutarotation.) 5) Usually, only a single form of a carbohydrate is drawn when drawing a carbohydrate in solution.
Mutarotation of Glucose alpha anomer oxo form beta anomer [α]d = +112º [α]d = +19º Equilibrium Mixture 36% 64% [α]d = +53º
Mutarotation of Glucose