Macromolecules

• All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids
• Macromolecules are large molecules composed of thousands of covalently connected atoms
• Polymer

  a long molecule consisting of many similar or identical building blocks that are linked by covalent bonds
• Monomers

  The building blocks of polymers
• Lipids are not polymers or macromolecules
• Polymerization

  • The chemical mechanisms by which cells make polymers
  • Facilitated by enzymes
• Condensation Reaction

  A reaction which two molecules are covalently bonded to each other with the loss of a small molecule

  If a water molecule is lost, it is known as a dehydration reaction
• Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction
• Hydrolysis

  A chemical reaction that breaks bonds between two molecules by the addition of water

  Disassembles polymers into monomers
• Dehydration reactions and hydrolysis can also be involved in the breakdown of molecules that aren't polymers such as lipids
• Carbohydrates are a source of energy and provide structural support
• Nucleic Acids store genetic information and function in gene expression
• Proteins have a wide range of functions such as catalyzing reactions and transporting substances into and out of cells
• Lipids are not polymers or macromolecules
• Lipids are a group of diverse hydrophobic molecules. Their key functions include

  • Providing energy
  • Making up cell membranes
  • Acting as hormones
• Macromolecule: A giant molecule formed by the joining of smaller molecules

  ex. polysaccharides, proteins, nucleic acids
• Polymer: A long molecule consisting of many similar or identical building blocks linked by covalent bonds
• Monomers: Building blocks of polymers

  • In addition to forming polymers, some monomers have functions of their own
• Polymerization: The chemical mechanisms by which cells make polymers

  • Polymerization is facilitated by enzymes
• Enzyme: A macromolecule that serves as a catalyst, a chemical agent that increases the rate of reaction without being used up; Most enzymes are proteins
• Dehydration Synthesis: A reaction in which two molecules are covalently bonded together with the loss of water; Assembles monomers into polymers
• Condensation Reaction: A reaction in which two molecules are covalently bonded together with the loss of a small molecule

  • If a water molecule is lost, its known as a dehydration reaction
• Hydrolysis: A chemical reaction that breaks bonds between two molecules by the addition of water; Disassembles polymers into monomers