Chapter 4

amylopectin

A branched-chain polysaccharide composed of glucose units.

disaccharides

Carbohydrates composed of two monosaccharide units linked by a glycosidic bond. They include sucrose (common table sugar), lactose (milk sugar), and maltose.

complex carbohydrates

Chains of more then two monosaccharides. May be oligosaccharides or polysaccharides.

polysaccharides

Long carbohydrate chains composed of more than 10 sugar molecules. These can be straight or branched.

aspartame

An artificial sweetner composed of two amino acids. It is 200 times sweeter than sucrose and sold by the trade name NutraSweet.

saccharin

An artificial sweetner that tastes about 300 to 700 times sweeter than sucrose.`

phenylketonuria

An inherited disorder caused by a lack or deficiency of the enzyme that converts phenylalanine to tyrosine.

monosaccharides

Any sugars that are not broken down further during digestion and have the general formula CnH2nOn, where n = 3 to 7. The common ones, glucose, fructose, and galactose all have six carbon atoms (n = 6).

starch

The major storage form of carbohydrate in plants; this is composed of long chains of glucose molecules in a straight (amylase) or branching (amylopectin) arrangement.

fructose

A common monosaccharide containing six carbons that is naturally present in honey and many fruits; often added to foods in the form of high fructose corn syrup. Also called levulose or fruit sugar.

glucose

A common monosacchride containing six carbons that is present in the blood; also known as dextrose or blood sugar. It is a component of the disacchrides sucrose, lactose and maltose and various complex carbohydrates.

lactose

A disaccharide composed of glucose and galactose; also called milk sugar because it is the major sugar in milk and dairy products.

sucrose

A disaccharide compound of one molecule of glucose and one molecule of fructose joined together. Also known as table sugar.

chitin

A long-chain structural polysaccharide of slightly modified glucose. Found in the hard exterior sheletons of insects, crustaceans, and other invertebrates; also occurs in the cell walls of fungi.

galactose

A monosaccharide containing six carbons that can be converted into glucose in the body. In foods and living systems, this usually is joined with other monosaccharides.

amylose

A straight- chain polysaccharide composed of glucose units.

cellulose

A straight-chain polysaccharide composed hundreds of glucose units linked by beta bonds. It is nondigestible by humans and a component of dietary fiber.

pectins

A type of dietary fiber found in fruits.

glycogen

A very large, highly branched polysaccharide composed of multiple glucose units. Sometimes called animal starch, this is the primary storage form of glucose in animals.

ketosis

Abnormally high concentration of keytone bodies in boy tissues and fluids.

dental caries

Destruction of the enamel surface of teeth caused by acids resulting from bacterial breakdown of sugars in the mouth.

gums

Dietary fibers, which contain galactose and other monosaccharides, found between plant cell walls.

ketone bodies

Molecules formed when insufficient carbohydrate is available to completely metabolize fat. Formation of these is promoted by a low glucose level and high acetyl CoA level within cells. Acetone, acetoacetate, and beta-hydroxybutyrate are examples. Beta-hydroxybutyrate is sometimes improperly called a keytone.

glucagon

Produced by alpha cells in the pancreas, this polypeptide hormone promotes the breakdown of liver glycogen to glucose, thereby blood glucose. This secretion is stimulated by low blood glucose levels and by growth hormone.

insulin

Produced by beta cells in the pancreas, this polypeptide hormone stimulates the uptake of blood glucose into muscle and adipose cells, the synthesis of glycogen in the liver, and various other processes.

simple carbohydrates

Sugars are composed of a single sugar molecule (a monosaccharide) or two joined sugar molecules (a disaccharide).