Chapter 2

 A compound is a substance that is made of two or more joined elements  Organic compounds contain carbon atoms(along with other elements) that are covalently bonded  Four types of organic compounds among living things are Carbohydrates Lipids Proteins Nucleic Acids

 Key source of energy  Found in most foods  The building blocks of carbohydrates are single sugars called monosaccharides Chains of monosaccharides are called polysaccharides  Contain C, H,O in a 1:2:1 ratio

 Important for structure and function of cell membranes  Nonpolar molecules Not soluble or mostly insoluble in water  Include fats, phospholipids, steroids, and waxes

 Large molecule formed by linked smaller molecules called amino acids Amino acids are the building blocks of proteins

 Long chains of smaller molecules called nucleotides Nucleotide contains a sugar, base, and a phosphate group  Includes DNA and RNA DNA- deoxyribonucleic acid- stores hereditary information RNA- ribonucleic acid- important in making proteins

 Act as a catalyst Substance that increases the speed of a chemical reaction  Most are proteins