predictions of bathed liver ( Cold , warm , hot )
We all predicted that high temperatures to the beef liver would release the catalase. Therefore, when we would add the hydrogen peroxide there would be little to no reaction. We made this prediction by our prior knowledge on enzymes. We knew that extreme conditions of temperature or pH levels would denature, or change the shape and works of an enzyme. Meaning the enzyme wouldn't work as it did before. For the first experiment, we predicted that the cold bath wouldn't do a lot of damage to the catalase, yet still do its job of breaking down H2O2. For the second experiment we place the beef liver in warm water for five minutes. Not much has changed to the physical features or previous state it was in. We predicted that the catalase would work the same and the liver wouldn't change very drastically. As for the third, which is in boiling water, we predicted that the liver would cook and release the catalase making no reaction. We made these predictions based on our prior knowledge, knowing that drastic temperature changes agitate the bonds that create a enzyme and that bind it to it's substrate.
Cold bath In our first experiment, we had two test tubes. One consisted of beef liver and the other, 2 mL of H2O2. We added each test tube into the ice bath and examined as time went on. After three minutes we removed them both and added the hydrogen peroxide to the liver. It took 18 seconds for the catalase to break down the H2O2. The reaction rate for this experiment was a 1.
The prediction we made was almost accurate. The catalase did work the same as it should and the reaction took longer than a normal catalase reaction, but had the exact same reaction. We think this is due to the chilled molecules and chilled liver. When molecules get cold, they tend to slow down, causing the reaction to slow down as well. |
warm bath Our second experiment contained both a test tube of beef liver and a test tube of 2 mL of H2O2. We placed the tubes into a bath of warm water for three minutes straight to make it the temperature of the water itself. When we reached 3 minutes, we took it out and combined what was inside the test tubes. It had a reaction right away. It lasted 9 seconds, which is longer than the normal catalase reaction, so we rated the reaction to be a 4.
The group predicted that the catalase would work the same as a normal catalase reaction. This is correct, but warming the liver actually increased the speed of the reaction. Most enzymes become denatured at a heat of 40 degrees Celsius, so our experiment was in the beginning stages of denaturment. |
hot bath (boiling) This is our third and final experiment for this part. We only had one test tube in this. It was consisted of beef liver and water. We put the test tube into a bath of boiling water for five minutes and when we took it out, we let it cool off for a couple of minutes. When it was cooled enough, we poured out the the water that was with the liver and added 2 mL of H2O2. Absolutely nothing happened. No bubbling of any sort.
We predicted this would happened because we cooked the liver. By cooking or boiling the liver we exposed it to extreme temperatures and we knew that extreme temperatures can denature catalase activity. |