Monomers & Covalent Bonds (College Board AP® Biology): Study Guide

Hydrolysis & dehydration synthesis

• Polymers are large molecules that contain many repeated monomers

  • The term macromolecule is often used to describe biological polymers

• Many metabolic processes involve the breaking and making of biological macromolecules; this occurs via:

  • hydrolysis

  • dehydration synthesis

Hydrolysis

• Hydrolysis is a chemical reaction involving the cleaving of covalent bonds

  • This type of reaction breaks down larger molecules into smaller molecules

• When water is added to the bond between monomers in a polymer, the bond is broken

  • The hydrogen ion from a water molecule is added to one monomer

  • The hydroxyl group of the water molecule is added to the other monomer

Dehydration synthesis

• Dehydration synthesis is a chemical reaction during which covalent bonds are formed

  • This results in the joining of two smaller molecules to synthesize a larger molecule

• A molecule of water is given off as a by-product, hence the term dehydration

  • A hydrogen ion is removed from one monomer

  • A hydroxyl group is removed from the other

• The joining of many monomers via dehydration synthesis results in formation of a polymer; this is known as polymerization