Lab Report #10
Factors Effecting the Rate of the Enzyme Catalase
Introduction:
State the overall purpose of the lab and provide information about enzymes in general and how Catalase functions in our bodies.
H2O2 ¨ H2O + O2
Procedure:
Three factors were examined for their effect on the rate of Catalase: temperature, pH, and concentration of the enzyme itself.
Fresh chicken liver (15-20 grams) was macerated and mixed with approximately 50 ml of distilled water to produce the Catalase extract.
Five water baths were prepared ranging from icy, cool, room, warm, to boiling temperatures. Thermometers recorded the actual temperatures of each bath.
A large test tube with 10.0 ml 3% H2O2 was placed in each water bath along with a second test tube with 5-8 ml of the Catalase extract. A Vernier pressure probe was affixed to a large rubber stopper that was placed in the larger test tube containing the substrate H2O2 immediately after 6 drops of the Catalase extract was added. The resulting pressure buildup brought on by the oxygen evolution was recorded for 90 seconds. Each temperature trial was stored and displayed on a graph that plotted pressure (mm Hg) versus temperature for each treatment.
Five samples of varying pH levels were prepared with a strong acid (acetic), a weak acid (vinegar), a near-neutral pH, a weak base and a strong base. Color pH tabs were used to estimate the actual pH values. 5.0 ml of each varying pH solution was added to 10.0 ml of 3% H2O2 into a large test tube. Six drops of Catalase extract were added to each of the five pH solutions and sealed with the pressure probe bearing rubber stopper. Each trial was stored and displayed on a graph.
Five large test tubes were filled with 10.0 ml 3% H2O2. To each individual test tube, varying numbers of drops of Catalase extract were added, stoppered with the pressure sensor with the ensuing pressure recorded as before. The drops of extract ranged from 3, 6, 9, 12, and 15 drops.
Results:
I will give you a handout of the class data graphs that you can include in your lab report.
Discussion:
Look at the graphs that weÕve prepared. I suggest that you respond to the questions accompanying these graphs to help write your discussion section.