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• Metabolism


  The chemical processes that occur within a living organism to maintain life
• Metabolism


  • Involves chemical reactions that break down complex molecules into simpler ones (catabolism)
  • Involves chemical reactions that build up complex molecules from simpler ones (anabolism)
• Anabolism


  Chemical reactions that build up complex molecules from simpler ones
• Catabolism


  Chemical reactions that break down complex molecules into simpler ones
• Enzymatic reaction


  1. Substrate binding

  2. Enzyme-substrate complex formation

  3. Catalysis

  4. Product release
• Activation energy


  The minimum energy required for a chemical reaction to occur
• Enzyme presence


  Reduces the activation energy required for a reaction
• Enzymes catalyse reactions in the body and increase the rate of reactions without being consumed or permanently altered
• Active site of an enzyme

  • Has a specific shape that fits the substrate molecule
  • Binds the substrate molecule
• Anabolic enzymatic reaction


  1. Substrates enter active site

  2. Enzyme-substrate complex forms

  3. Products are released
• Catabolic enzymatic reaction


  1. Substrate enters active site

  2. Enzyme-substrate complex forms

  3. Products are released
• Lock-and-key hypothesis


  The substrate molecule is the 'key' that fits into the 'lock' of the enzyme's active site
• Enzymes


  • They are biological catalysts
  • They are specific to the reactions they catalyse
  • They can be reused
  • Only small amounts are needed
  • They are proteins
• Temperature increase


  Increases the rate of enzymatic reactions up to the optimum temperature

  
• Temperature above optimum


  Causes enzyme denaturation and decreases the rate of enzymatic reactions

  
• pH change from optimum

  Decreases the rate of enzymatic reactions
• Different enzymes have different optimum pH values

  
• Inhibitors


  Chemicals that can decrease the rate of enzyme reactions
• Enzyme inhibitors


  • Cyanide
  • Heavy metals like mercury, lead, copper