Chapter 20 Carbohydrates CHEM 2124 – General Chemistry II Alfred State College Professor Bensley

Learning Objectives  Identify the three major types of carbohydrates  Recognize the major structural featurs of carbohydrates  Draw the cyclic forms of monosaccharides and classify them as alpha or beta anomers  Recognize the major structural features of disaccharides  Describe the characteristics of cellulose, starch, and glycogen.

Carbohydrates Polyhydroxy aldehydes or ketones, or compounds that can be hydrolyzed to them. I.Introduction A.Monosaccharides 1.Aldoses vs. Ketoses

Carbohydrates B.Triose vs. Tetrose vs. Pentose vs. Hexose C.Physical Properties

Carbohydrates D.Fischer Projection Formulas E.D vs. L Enantiomers of Monosaccharides

Carbohydrates 1.Glucose 2.Galactose 3.Fructose F. Common Monosaccharides

Carbohydrates Review: What is a hemiacetal? Review: How does a cyclic hemiacetal form? II.The Cyclic Forms of Monosaccharides

Carbohydrates A. Anomeric Carbon / Anomers B.How to draw cyclic forms of monosaccharides (Haworth Projections)

The Cyclic Forms of Monosaccharides HOW TO Draw a Haworth Projection from an Acyclic Aldohexose Example Draw both anomers of D -mannose in a Haworth projection.

Carbohydrates Monosaccharides linked together through formation of an acetal: Known as a glycosidic bond or glycosidic linkage III.Disaccharides A. Introduction

Carbohydrates The glycosidic linkage joining the two rings can be alpha (  or beta ( .

Carbohydrates B. Common Disaccharides 1. Lactose 2. Sucrose

Carbohydrates C. Artificial Sweeteners 1. Aspartame (Equal, Nutra Sweet) = 150 x sweeter than Sucrose 2. Saccharine (Sweet n’ Low) = 350 x sweeter than Sucrose

Carbohydrates C. Artificial Sweeteners 3. Sucralose (Spelnda) = 600 x sweeter than Sucrose 4. Others

Carbohydrates IV. Polysaccharides A.Cellulose B.Starch 1.Amylose

Carbohydrates 2.Amylopectin C.Glycogen