macromolecule
Carbons affinity for covalent bonding means that many distinct and relatively stable organic molecules nevertheless readily form larger, more complex molecules. Any large molecule is referred to as macromolecule macro- = large , and the organic compounds in this section all fit this description. However, some macromolecules are made up of several copies of single units called monomer mono- = one; -mer = part . Like beads in a long necklace, these monomers link by covalent bonds to form long polymers poly- = many . There are many examples of monomers and polymers among the organic compounds. Monomers form polymers by engaging in dehydration synthesis see Figure 2.14 . As was noted earlier, this reaction results in the release of a molecule of water. Each monomer contributes: One gives up a hydrogen atom and the other gives up a hydroxyl group. Polymers are split into monomers by hydrolysis -lysis = rupture . The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other.