Materials
Method
- Collect materials.
- Weigh three (3) approximately cube shaped pieces of fresh liver to be the same weight of 4.00g
- Prepare the liver into its three different conditions
- Ground- Crush Liver in the mortar and pestle until juice is present.
- Sliced- Using a scalpel
- Whole
- Using the marker, indicate on one (1) test tube the ground liver
- Fill the test tube with 20mL of Distilled water.
- Add 5mL of 3 % Hydrogen Peroxide to the test tube
- Add 10 drops of the dishwashing liquid to the test tube using the pipette
- Lightly swirl the test tube to combine the two solutions.
- Place the ground liver into the test tube and begin timing on the stop watch
- At thirty second intervals record the height of the bubble column, continue this for two minutes or until bubbles cease to grow
- Record all results in table
- Repeat steps 4- 11, replacing the liver with the sliced, then whole liver
- Repeat steps 2-11 three separate times for trials
Data Collection
Results:
Raw Data
Figure 1: Total volume of measuring cylinder throughout reaction of whole liver in Catalase-hydrogen peroxide solution over 120sec.
Note: start at approximately 25mL solution
Figure 2: Total volume of measuring cylinder throughout reaction of sliced liver in Catalase-hydrogen peroxide solution over 120sec.
Note: start at approximately 25mL solution
Figure 3: Total volume of measuring cylinder throughout reaction of ground liver in Catalase-hydrogen peroxide solution over 120sec.
Note: start at approximately 25mL solution
Qualitative Observations:
-
On contact with the solution, small O2 bubbles began to form on the surface of the Liver.
- These bubbles quickly floated to the top where they began forming larger bubbles with the assistance of the Detergent.
- The detergent wall of bubbles began to climb the side of the test tube and eventually filled up in the center.
- The bubbles were murky grey, and had a thicker than normal texture.
- As time progressed the liver seemed visibly softer, though the size remained the same
- No other physical characteristics observed throughout reaction
Data Processing
Sample Calculation Average:
Mean(x) = Ʃ(x) (min) / (Number of x)
Where
Mean= the average value of the selected data
X= data values
Ʃ= the total sum of the data values
Number of x= the number of values in the x data series
e.g. Mean = (17 + 20 + 25) / 3
= 63/3
= 21mL
Sample Calculation Rate of Reaction
Speed = Distance / Time
Speed (mL/sec) = Δ Amount of Total Volume of Solution (mL) / Δ Time(sec)
Calculation [Whole Average]
Rate = (56 – 25)/ 120
= 31 / 120
= 0.26mL/sec
Sample Calculation Experimental Total Volume
Total Volume O2 Detergent bubbles= Total Volume solution – Original Volume solution
Total= Total Solution – 25
Total= 50 – 25
= 25mL
Volume Detergent Bubbles
Figure 4: Total volume of bubbles throughout reaction of whole liver in Catalase-hydrogen peroxide solution over 120sec.
Figure 6: Total volume of bubbles throughout reaction of sliced liver in Catalase-hydrogen peroxide solution over 120sec.
Figure 6: Total volume of bubbles throughout reaction of ground liver in Catalase-hydrogen peroxide solution over 120sec.
Figure 7:Average total volume of bubbles throughout reaction liver in Catalase-hydrogen peroxide solution over 120sec.
Average Results
Figure 8:Average rate of reaction in Catalase-hydrogen peroxide solution over 120sec.
Average Rate
Graphs:
Figure 9: Average total volume of bubbles throughout reaction liver in Catalase-hydrogen peroxide solution over 120sec.
Conclusion
Statement:
The rate of the liver and hydrogen peroxide reaction increased proportionally to the surface area. The greater the surface area the more active sites were exposed to the substrate and the faster oxygen was produced. Therefore the ground liver was the fastest reaction, then the sliced liver and the slowest to react was the whole liver.
Explanation:
The purpose of this investigation was achieved, as it was determined that the surface area of the liver did affect the action of the enzyme. The hypothesis is accepted as the data in Graph 1 shows that the ground liver had the fastest rate of reaction. This can be seen by its steeper gradient and higher maximum. This was followed by the sliced liver which had a shallower gradient and a lower maximum. Last was the whole liver which produced a similar gradient to the sliced, though slightly less steep, nevertheless it was still reacting after 120seconds. The gradient is, in figure 9 a measure of Oxygen output of the system over time. Accordingly, it is representative of the rate of oxygen production per second.
Both the ground and the sliced liver seem to plateau after 90 seconds of reaction time which would suggest that this is the point at which all of the substrate molecules have been acted upon by the Catalase. This should not occur at the same time as the ground supposedly reacts much faster than the whole. The plateau does not account for the fact that the maximum number of active sites on the enzymes are being used up by substrates, because the volume of gas being produced should sill increase despite the rate staying the same, this is not the case for this experiment. The reason for this error becomes evident when considering the results of the sliced liver which indicate that the volume decreases over 30 sec. It is evident that the bubbles have burst and are skewing the datas collected. To account for error due to measuring falsities and equipment interaction the graph of time vs. bubble amount was drawn and a curve of best fit chosen to model the data most effectively. This curve was a polynomial function and when extrapolated could be used to give accurate approximation of the relationship between time and oxygen production.
Evaluation
