SBI 4U: Enzyme Lab

Sonia Pereira
March 6 2013
Ms. Farrell
Lab Partner: Danielle Luciani
Sources of Error:

As the liver for the experiment in test tube C was cooked by the teacher, we had no control over the duration it was cooked at effecting it’s effervescence when placed in the test tube containing hydrogen peroxide. If the liver was over cooked the extreme heat would denature the catalyze enzymes in the meat resulting in little to no reaction. Though if the liver was undercooked and not exposed to much heat, the catalyze enzymes would be very little effected and therefore when placed in hydrogen peroxide you would yield inaccurate results.
Temperature the hydrogen peroxide was stored at. If the hydrogen peroxide was stored in a very cold container it is possible that with slower moving particles within it that there would be less of a reaction when the liver is introduces. Although if the peroxide was stored at a warmer temperature (ideally room temperature) there should be accurate results.
Cross contamination was a big factor that could effect the results. After the tweezers were used to relocate the raw liver, even after a thorough cleaning it is possible that catalyze still remained on the tweezers. When the tweezers were then used to relocate the cooked meat, the catalyze from the raw meat may have gotten on the raw meat, effecting the results.

Discussion:

What was the purpose of each test tube?
Test tube A: To observe and record the reaction between hydrogen peroxide and raw liver, allowing the tester to compare the results (specifically the effervescence) of the following three reactions.
Test tube B: To observe and record the reaction (specifically the effervescence) between hydrogen peroxide and grounded up raw liver which has less viable catalyze, comparing it’s results to that of test tube A.
Test tube C: To observe and record the reaction (effervescence created) between hydrogen peroxide and cooked meat, which has denatured catalyze enzymes due to extreme heat conditions, comparing it’s results to that of test tube A.
Test tube D: To observe and record the reaction (effervescence created) between hydrogen peroxide and raw meat soaked in strong acid for the duration of 15 minutes.As the pH level is changed within the raw meat allowing it to be more acidic, the enzymes are denatured and become useless. The results are compared tot hat of test tube A.

Explain the results obtained in each tube.
Test tube A: The effervescence on a scale of 1-10 was rated a 10. During the reaction, bubbles had formed reaching right to the top of the test tube. Closest to the raw meat the bubbles were very small and fizzy while closer to the top of the test tube the bubbles were very large. The level of hydrogen peroxide has rose notably, and had turned a yellow, cloudy, opaque colour. After a few minutes the reaction seemed to have completely stopped.
Test tube B: The effervescence on a scale of 1-10 was rated a 7. During the reaction, bubbles formed approximately two thirds up the test tube. Closest to the grounded raw meat the bubbles were very small and fizzy while closer to the top of the test tube the bubbles were very large. The hydrogen peroxide turned into a faded yellow opaque colour. The reaction continued for several minutes (fizzing).
Test tube C: The effervescence on a scale of 1-10 was rated a 4.