3.3 - Enzymes and Activation Energy

• Enzymes help chemical reactions take place at LOWER energy levels
• What do enzymes not do?

  They do not supply energy for reactions
• Enzymes speed up the rate of reactions without being consumed by the reaction
• Enzymes allow your body to use less energy to drive reactions
• Enzymes are almost always proteins
• What’s the enzyme that is used as a catalyst for this reaction?

  Maltose + Water --?--> glucose + glucose


  Maltase

  • helps to catalyze the reaction
• Activation Energy - The minimum amount of energy required for a reaction to take place.
• Transition State - A temporary, unstable state between reactants and products ( before new bonds are formed )
• Activation Energy is when it requires a certain amount of energy to help break the bonds of chemicals
• Transition State occurs when enough energy is required to begin reaction (available to break the bonds holding the reactants together).
• Explain this diagram

  
• Net Energy = amount of energy requires to start reaction (activation energy) - amount of energy released by reaction
• What provides Activation Energy?

  1. Thermal Energy

  • often causes more and more reactions to take place as more and more energy is released
  • hard to regulate

  
  

  2. Catalyst (Enzymes)

  • allows reactions to occur using less energy
  • can be regulated to control rates of reactions
• What type of reaction is this?

  Energy is released = Exothermic reaction

  
• What type of reaction is this?

  Energy is Absorbed = Endothermic Reaction

  
• How can Enzymes lower Activation Energy?

  1. BRINGS REACTANTS TOGETHER

  • orients molecules into positions so they can bind

  2. CHARGED ENZYMES HELP BREAK BONDS

  • charged functional groups help to attract reactants and break bond

  3. ENZYME CHANGES SHAPE OF SUBSTRATE

  • enzyme changes shape to change the shape of the substrate and break bonds