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This experiment is carried out to find the effects of temperature on the activity of lipase by adding honorableness and observes how long it takes to decolonize from pink, because milk is slightly alkaline that change to pink after adding phenolphthalein. In order to enhancing the result and the color, adding sodium carbonate is needed. Principle: The recommend rationale of the volume of enzyme (lipase) to sodium carbonate to substrate (milk) is 1:7:5.
The purpose of adding sodium carbonate is to enhance the result of the experiment and to give an obvious change of the color of phenolphthalein from pink to color which indicated that the lipase is the mixture already breaks down all the fat or lipids into fatty acid and glycerol inside he milk. By timing how long does the enzyme has turn the alkaline mixture into acidic by observing the color change.
Hypothesis: The rate of the lipase activity is affected by the various temperature, as the temperature increase, the activity of the enzyme also increase but when the temperature is at the extreme cold or hot temperature, the reaction of the enzyme stops or take a relativity longer period of this in order to breaking down lipid. There also is a specific temperature range which is the temperature near to the body temperature that the enzyme acts at a fastest rate. Variable tables: Independent variables
Dependent variables Controlled variables Temperature of the mixture pH value changes Time taken in the setup (lipase activity) Volume of milk Volume of enzyme Volume of sodium carbonate Assumption: 1 . Assume that the concentration of the lipid inside every ml of milk are the same. 2. Assume that the concentration of the lipase in every 1 ml are the same. 3. Assume that there are no substances in side the milk will reacts with the sodium carbonate and phenolphthalein.
Apparatus and materials Boiling tube xx Test tube xx Plastic beaker xx ml milk x 4 Stop watch xx pipette filler ml lipase xx ml sodium carbonate xx Thermometer xx ml pipette x 2 ice (for water bath) 100 C hot water (for water bath) phenolphthalein ml pipette XSL Procedures: 1. Measure ml of lipase using ml pipette with pipette filler, ml of sodium carbonate and ml of milk using ml of pipette with pipette filler. Pour the content into the test tube. Repeat the step for 4 times. 2.
Put the test tube containing enzyme, milk, sodium carbonate and an empty boiling tube in water bath in respectively. In order too make all the solutions reach equilibrium. Maintain the temperature. 3. Mix milk and sodium carbonate, in the empty boiling tube then add 5 drops of phenolphthalein. Mix well. The solution should be pink. 4. Pour ml of enzyme in the boiling tube and start timing. Mix well. 5. Through out the processes, keep on shaking the boiling tube to let the enzyme reacts with the milk. . Stop the stop watch when the mixture inside the boiling tube changes to the color of the milk.