Biology Chapter 5: Polymers and Macromolecules

Polymers and Monomers

• Polymers are large biological molecules composed of smaller molecules called monomers
• Monomers are the building blocks of polymers, and different types of monomers form different classes of polymers

Synthesis of Polymers

• Polymerization is the process of forming polymers from monomers
• This process is facilitated by enzymes, which speed up chemical reactions
• The reaction that connects a monomer to another monomer or a polymer is a condensation reaction
• In a condensation reaction, two molecules are covalently bonded to each other with the loss of a small molecule (dehydration reaction)
• Examples of polymer synthesis include carbohydrate and protein polymers

Breakdown of Polymers

• The breakdown of polymers into monomers is called hydrolysis
• Hydrolysis is the reverse of the dehydration reaction
• A water molecule is added to break the bond between monomers, with a hydrogen from water attaching to one monomer and a hydroxyl group attaching to the other
• Examples of hydrolysis include digestion, where enzymes break down polymers into monomers

Diversity of Macromolecules

• The diversity of macromolecules in the living world is vast and effectively limitless
• This diversity is due to the arrangement of monomers, with the linear sequence of units determining the characteristics of the polymer
• Despite being constructed from a limited number of monomers, the possible variety of polymers is enormous

Learn about the molecular differences between individuals and species, and how polymers are formed and disassembled through hydrolysis.