1 Macromolecules –Are large molecules composed of a large number of repeated subunits –Are complex in their structures Figure 5.1

2 Macromolecules MacromoleculeSubunit Complex Carbohydrates (e.g. starch) Simple sugar (e.g. glucose) Lipid (triglycerides)Glycerol and fatty acids ProteinAmino Acids Nucleic Acids (DNA or RNA) Nucleotides

3 A polymer –Is a long molecule consisting of many similar smaller building blocks called monomers –Specific monomers make up each macromolecule –E.g. amino acids are the monomers for proteins

4 The Synthesis and Breakdown of Macromolecules Monomers form larger molecules by condensation reactions called dehydration synthesis (a) Dehydration reaction in the synthesis of a polymer HOH H H H2OH2O Short polymer Unlinked monomer Longer polymer Dehydration removes a water molecule, forming a new bond Figure 5.2A

5 Condensation Reactions Requires energy because new bonds are being formed Are also called a anabolic reactions because smaller molecules join together to form larger molecules small  LARGE

6 The Synthesis and Breakdown of Macromolecules Polymers can disassemble by –Hydrolysis (addition of water molecules to lyse or “break apart” the macromolecule) (b) Hydrolysis of a polymer HO H H H2OH2O H Hydrolysis adds a water molecule, breaking a bond Figure 5.2B

7 Hydrolysis Releases energy because bonds are being broken Are also called a Catabolic reactions because larger molecules are being broken down into smaller subunits LARGE  small

8 An immense variety of polymers can be built from a small set of monomers