The plant or animal organelle that was involved in this experiment was peroxisomes. The enzyme which acted as the catalyst was catalase, located in peroxisomes.
When the liver was pulped, the big piece of liver was mashed into several smaller pieces. As the size of the liver pieces decreases, the surface area exposed increases and the amount of enzyme in the liver available to react increases. Hence, the overall enzyme activity increases, where the amount of bubbles and gas released in the reaction increases.
When the liver was boiled, the surrounding temperature was beyond 60`C, which was too high for enzyme to react. This is because at high temperature, the 3-dimensional shape of the enzyme is being changed and their active sites are destroyed. Hence, substrates can no longer fit into the active sites of the enzymes. Therefore, enzymatic reaction stops. No bubbles and gases were released when H2O2 was reacted with the boiled liver.
In the reaction of fresh liver with H2O2, more bubbles and gas were released compared to the reaction of potato cubes with H2O2. This shows that the reaction in fresh liver is more than the reaction in potato cubes as the amount of catalase in liver is more than the amount of catalase in potato cubes. Fresh liver contains animal cell, while potato cubes contains plant cell. H2O2 is a metabolic by product, which is poisonous to animal. Therefore, it must be removed from body. One of the function of liver is detoxification. Liver is responsible in removing poisonous substances from our body, which includes H2O2. Hence, liver has many enzyme against H2O2.
When the boiled fresh liver was reacted with H2O2, no reaction occured. However, when the heated manganese dioxide was reacted with H2O2, reaction occured. This is because fresh liver contains organic catalyst while maganese dioxide contains inorganice catalyst. Organic catalyst will be denatured at high temperature, while