Powering the Body

Abstract

Food is composed of hundreds of different molecules. Indeed, molecules similar to most of those pictured in this book appear on our dinner plate at one time or another. Meats and vegetables are rich in protein and nucleic acid. Potatoes and corn are rich in starchy carbohydrate, and fruits are naturally sweetened with simple sugars. A specialized cadre of enzymes, secreted into the stomach and intestines, break these diverse food molecules into manageable pieces. Most of these enzymes are hydrolases, which use individual water molecules to break the bonds in their target molecules. Proteins are broken into smaller pieces, then into individual amino acids. Nucleic acids are broken into nucleotides and often further separated into their component phosphates, sugars, and bases. Polysaccharides yield sweet simple sugars.