RP10 - Decay

• What is the first step in investigating the effect of temperature on the rate of decay of milk?

  Place full-fat milk and cresol red in a test tube
• Why is lipase added to the milk in the decay investigation?

  To catalyze the breakdown of lipids
• What should you do after placing the test tubes in the water bath?

  Allow the temperature to equilibrate
• What is the purpose of stirring the solution during the experiment?

  To ensure even distribution of lipase
• What is recorded after the solution turns yellow?

  The time taken for the reaction
• What does plotting a graph of temperature against time taken show?

  The relationship between temperature and decay rate
• How does lipase accelerate the decay of milk?

  It provides an alternative reaction route
• What does lipase break down lipids into?

  Fatty acids and glycerol
• Why does the pH of the solution change during the reaction?

  Fat is broken down into fatty acids
• What color does cresol red turn in acidic solutions?

  Yellow
• What color does cresol red turn in alkaline solutions?

  Purple
• Why does an increase in temperature increase the reaction rate?

  Particles collide more frequently with higher energy
• What happens to enzymes at very high temperatures?

  They become denatured and lose function
• How does denaturation affect enzyme activity?

  Active site changes shape and cannot catalyze