Enzyme reactions

• What factors influence the rate of an enzyme-controlled reaction?

  Temperature, pH, substrate concentration, enzyme concentration
• Why is it important to keep all other variables constant in an enzyme reaction experiment?

  To prevent them from influencing the results
• What is measured to determine the initial rate of reaction?

  The concentration of reactants and products
• Why is the initial rate of reaction significant?

  It is when reactant concentrations are known
• What does the temperature coefficient (Q10) indicate?

  Change in rate with a 10 degree increase
• How is Q10 calculated?

  Rate at T + 10 degrees divided by rate at T
• What enzyme is used to break down hydrogen peroxide in the experiment?

  Catalase
• What is produced when catalase breaks down hydrogen peroxide?

  Water and oxygen
• What equipment is needed for the enzyme reaction experiment?

  • Water bath
  • Boiling tube
  • Bung
  • Soaked peas
  • Hydrogen peroxide solution
  • Delivery tube
  • Gas syringe
  • Stop clock
  • Mortar and pestle
• What is the first step in the method for the enzyme reaction experiment?

  Grind a known mass of peas in distilled water
• What should be done after adding hydrogen peroxide to the peas?

  Fit the syringe into the delivery tube
• How long should the experiment be timed for?

  5 minutes
• How is the volume of gas produced measured?

  At regular intervals, e.g., every 30 seconds
• What are the risks and safety precautions in the experiment?

  • Biohazard: Use disinfectant; wash hands
  • Broken glass: Handle carefully; seek medical help if injured
  • Hot liquids: Use tongs; wear eye protection
  • Hydrogen peroxide: Wear eye protection; wash off skin immediately
• What should be done in case of a biohazard contamination?

  Use disinfectant and wash hands
• What is the conclusion regarding the rate of reaction?

  Rate is volume of gas produced divided by time
• What is the Q10 value for catalase?

  About 2
• When can Q10 be used in relation to temperature?

  Only up to optimum temperature
• What is the relationship between temperature and enzyme activity?

  • Rate increases with temperature up to optimum
  • Q10 indicates rate change with temperature increase
  • Enzymes denature beyond optimum temperature