Catalysts & Enzymes

• What do catalysts do in chemical reactions?

  Catalysts increase the rate of chemical reactions without changing chemically themselves.
• What are enzymes?

  Enzymes are biological catalysts.
• Why do enzymes catalyse specific reactions?

  Due to the shape of their active site.
• What is the lock and key theory of enzyme action?

  It describes how the specific shape of an enzyme's active site allows it to bind to a specific substrate.
• What are enzymes made of?

  Enzymes are proteins.
• How do amino acid chains relate to enzyme function?

  The amino acid chains are folded to form the shape of a specific substrate molecule.
• What happens when a substrate binds to an enzyme's active site?

  The reaction is catalysed by the enzyme.
• What is metabolism?

  Metabolism is the sum of all the reactions in a cell or in the body.
• What are the types of reactions that enzymes can catalyse?

  1. Build large molecules from smaller ones (e.g., starch from glucose)
  2. Change one molecule into another (e.g., converting sugars)
  3. Break down large molecules into smaller ones (e.g., digestive enzymes)
• What is the act of an enzyme when breaking down hydrogen peroxide?

  The enzyme catalase breaks down hydrogen peroxide.
• How can you investigate the effect of different catalysts on the breakdown of hydrogen peroxide?

  By comparing manganese(IV) oxide and liver containing catalase enzyme.