CHAPTER 18: CARBOHYDRATE STRUCTURE

Most abundant organic compounds on earth; includes cellulose in plants and chitin in arthropods; only about 1% of the mammalian body.

Carbohydrates

Storage carbohydrates such as starch in plants and glycogen in animals; serve as glucose reserves for vital functions.

Complex Carbohydrates

Simple sugars that are basic units of more complex molecules; single chains of carbon atoms with multiple adjacent hydroxyl groups.

Monosaccharides

Five-carbon sugars; important in plant fiber and animal metabolism; constituent of nucleotides, nucleic acids, and coenzymes.

Pentoses

Six-carbon sugars; physiologically important in mammals; glucose, fructose, and galactose are major hexoses.

Hexoses

Two monosaccharides joined by a glycosidic bond; examples include maltose, trehalose, lactose, and sucrose.

Disaccharides

Disaccharide consisting of two glucose molecules in an a-(1,4) glycosidic linkage; found in germinating grains and vegetables.

Maltose

Disaccharide found in milk; consists of galactose and glucose in a b-(1,4) glycosidic linkage.

Lactose

Disaccharide consisting of glucose and fructose linked in an a-(1,2) glycosidic bond; abundant in plants and familiar as table sugar.

Sucrose

Three monosaccharides held together by glycosidic bonds; examples include raffinose and melezitose found in plants.

Trisaccharides