The aim of my experiment is to determine how temperature affects the rate of lipid digestion by lipase. Preliminary experiment Quantities: 3 centimetre cubed of milk. 5 drops of phenolphthalein. 3 centimetre cubed of sodium carbonate (alkaline). 1 centimetre cubed of lipase. Must be added last. My preliminary experiment was extremely essential as it helped me to find out what quantities I shall have to use in the main experiments that was 3 cm of sodium carbonate as shown above. It also gave me a rough outline of how the main experiment would work out. What I am going to do. METHOD:
Set up a water bath as the one shown in the above diagram. Then heat water bath to a desired temperature which are (20,30,40,50,60 C) preferably begin with 20 and work to 60. Next you have to add 3 cm of milk, 5 drops of phenolphthalein and cm of sodium carbonate to the test tube. Measurements must be precise. You must then stir the mixture if completed successfully mixture will transform to a pink colour. The next step is to adjust the temperature to a different one. You should sensibly increase the temperature by 10 C. Once you have calibrated the temperature you must add 1 cm of lipase to the mixture and begin the stopwatch.
Your final step is to stir and time how long it takes for the solution to turn white. You must repeat the following method above three times for each different temperature. My prediction is that the rate of lipid digestion by lipase will increase in speed as the temperature is increased. The scientific explanation for my prediction is that: a higher temperature means more energy specifically more kinetic energy, which therefore means particles move faster which would cause a lot more collisions which would finally result in a faster reaction.
The factors I will need to keep the same each time are the quantities. Which is 3 cm of milk, 5 drops of phenolphthalein, 3 cm of sodium carbonate and 1 cm of lipase. I will also need to remember to put the lipase in last out of all the other items. The reason I need to keep these factors the same is to maintain a fair test and reliable results. If I were to change these quantities then I would be creating a fault, which would be noticeable on my graph and results. If I maintain the same quantities it would show the reaction changing as the temperature does yet it would still fit the pattern.
The factor I am deliberately changing is the desired temperature (variables). The ranges of values I will be required to use for the factor I am varying are 20,30,40,50 and 60 C. We will carry out the experiment all these different values. I will ensure my results are reliable by repeating the experiment three times for each of the above temperatures. This will enlarge my chances of accomplishing a fair test I will also be able to calculate an average for each temperature. Once we had stirred the mixture at all the different temperatures the mixture transformed from pink to white.
The reason for this is that it creates an acid after the reaction happens which is shown by the phenolphthalein in the mixture. My conclusion. My results clearly show that lipid digestions by lipase rates are affected by temperature. You can undoubtedly notice that when you increase the temperature the reaction rate times speed up until it reaches 60 C where it suddenly slows down it should be even quicker. My results almost fit my original prediction perfectly although I never predicted the immediate slow down at 60 C.
The reason for the abrupt reaction rate slowing down in scientific terms is: the high temperatures denature the enzymes and proteins, making them permanently damaged and unable to digest lipids therefore 60 C must have been slightly above the maximum temperature the proteins could handle. This caused the sudden drop in my graph/results. The rest of the data fitted the general pattern as well as 60 C, rate of reaction speeding up as temperature is increased. I now strongly acknowledge the fact that temperature does affect the rate of lipid digestion by lipase.