Core Practical 12

• 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 reaction rate with a 10-degree increase
• How is Q10 calculated?

  Rate at T + 10 degrees / Rate at T
• What reaction does the enzyme catalase facilitate?

  Breakdown of hydrogen peroxide into water and oxygen
• What equipment is used to measure the volume of gas produced?

  Gas syringe
• What is the method for measuring the rate of reaction using catalase?

  1. Grind peas in distilled water.
  2. Add hydrogen peroxide solution.
  3. Fit syringe and delivery tube.
  4. Place in water bath at known temperature.
  5. Measure gas volume at intervals.
  6. Repeat at different temperatures.
• What are the risks associated with the experiment and their precautions?

  • Biohazard: Use disinfectant; wash hands.
  • Broken glass: Handle carefully; seek medical help if injured.
  • Hot liquids: Use tongs; run burns under cold water.
  • Hydrogen peroxide: Wear eye protection; wash off immediately.
• How is the rate of reaction calculated?

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

  About 2; rate doubles every 10 degrees
• Up to what point can Q10 be used?

  Up to optimum temperature