Term | Definition |
active site | on an enzyme, the site that attaches to a substrate |
adenosine triphosphate (ATP) | adenosine triphosphate, an organic molecule that acts as the main energy source for cell processes; composed of a nitrogenous base, a sugar, and three phosphate groups |
amino acid | a compound of a class of simple organic compounds that contain a carboxyl group and an amino group and that combine to form proteins |
carbohydrate | a class of molecules that includes sugars, starches, and fiber; contains carbon, hydrogen, and oxygen |
condensation reaction | a chemical reaction in which two or more molecules combine to produce water or another simple molecule |
deoxyribonucleic acid (DNA) | deoxyribonucleic acid, the material that contains the information that determines inherited characteristics |
disaccharide | a sugar formed from two monosaccharides |
enzyme | a molecule, either protein or RNA, that acts as a catalyst in biochemical reactions |
fatty acid | an organic acid that is contained in lipids, such as fats or oils |
functional group | the portion of a molecule that is active in a chemical reaction and that determines the properties of many organic compounds |
hydrolysis | a chemical reaction between water and another substance to form two or more new substances; a reaction between water and a salt to create an acid or a base |
lipid | a fat molecule or a molecule that has similar properties; examples include oils, waxes, and steroids |
macromolecule | a very large organic molecule, usually a polymer, composed of hundreds or thousands of atoms |
monomer | a simple molecule that can combine with other like or unlike molecules to make a polymer |
monosaccharide | a simple sugar that is the basic subunit of a carbohydrate |
nucleic acid | an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information |
nucleotide | in a nucleic-acid chain, a subunit that consists of a sugar, a phosphate, and a nitrogenous base |
organic compound | a covalently bonded compound that contains carbon, excluding carbonates and oxides |
peptide bond | the chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid |
phospholipid | a lipid that contains phosphorus and that is a structural component in cell membranes |
polymer | a large molecule that is formed by more than five monomers, or small units |
polypeptide | a long chain of several amino acids |
polysaccharide | one of the carbohydrates made up of long chains of simple sugars; polysaccharides include starch, cellulose, and glycogen |
protein | an organic compound that is made of one or more chains of amino acids and that is a principal component of all cells |
ribonucleic acid (RNA) | ribonucleic acid, a natural polymer that is present in all living cells and that plays a role in protein synthesis |
steroid | a type of lipid that consists of four carbon rings to which various functional groups are attached and that usually has a physiological action |
substrate | a part, substance, or element that lies beneath and supports another part, substance, or element; the reactant in reactions catalyzed by enzymes |
triglyceride | a lipid made of three fatty acid molecules and one glycerol molecule |
wax | a type of structural lipid consisting of a long fatty-acid chain that is joined to a long alcohol chain |