Scientific Methodology & Enzyme Activity

Laboratory 2: Scientific Methodology & Enzyme Activity

Objective:

The purpose of this experiment was to simply measure oxygen production rates released from decomposed hydrogen peroxide under different conditions (concentration of enzymes, temperature, and PH level).

Hypothesis:
Part a:
If different amounts of enzyme solution are added to the hydrogen peroxide, then the highest amount of enzymes will have the greatest reaction rate because enzymes catalyze reactions, meaning more oxygen will be produced quicker.

Part b:
If different temperatures are used to catalyze enzyme activity, then the lowest temperature would produce the quickest reaction rate because enzymes can become denaturized at higher temperatures

Part c:
If different amounts of pH are used to catalyze the reaction, then the concentration with pH 7 will have the quickest reaction, because enzymes work best in neutral conditions such as conditions that are neither acidic nor alkaline. Procedures:

Part a:
Connect Gas Sensor to Lab quest
Label 4 test tubes and fill each with 5mL of 3.0% hydrogen peroxide and 5mL of water Add 5 drops of enzyme solution to test tube 1
Pour contents of tube 1 into Nalgene bottle, place O2 Gas Sensor in. Perform linear regression to calculate rate of reaction.
Fine rate of enzyme activity for test tubes 2,3,4
Add 10 drops of solution test tube 2. Repeat steps 6-8
Add 20 drops of enzyme solution to test tube 3. Repeat 6-8
Repeat steps 6-8 without any enzyme drops.

Part b:
Obtain 5 different test tubes. Fill each test tube with 5 mL of 3.0% hydrogen peroxide and 5 mL of water. Place each tube in each of the following water baths for 10 mins 0 degrees C: 400 mL beaker filled with ice water

23 degrees C: No bath
37 degrees C: Place in bath
70 degrees C: Place in bath
100 degrees C: Obtain hotplate and heat water
Add 10 drops of enzyme solution to all test tubes

Part c:
Place three clean test tubes in a rack and label pH 4, pH 7, and pH 10 Add 5 mL of 3% hydrogen peroxide and mL of one of the pH buffers to each tube Add 10 drops to each solution and repeat steps 6-8 from other procedure

Results
Part a:
0 Drops
-0.00027354
5 Drops
0.0033465
10 Drops
0.0055014
20 Drops
0.0073347

From the data collected, the reaction excelled quicker when infused with more enzymes. 20 drops followed by 0 was the order the reaction worked best. The control group was the solution with no enzyme solution that resulted in a negative reaction slope.

Part b:
0 ºC
0.0081987
23 ºC
0.015408
37 ºC
0.020473
70 ºC
0.013858
100 ºC
0.0031956

This data indicates that 37 Cº worked best for the reaction, followed by 23 Cº, 70 Cº, 0 Cº and 100 Cº

Part c:
pH4
0.013847
pH7
0.014491
pH10
0.0082392

This data indicates that a level of pH 7 worked best for the reaction, followed by pH 4 and pH10.

Discussion
Part a:
The results from the lab effectively demonstrate how enzyme (catalase) concentration affected the rates of decomposition in hydrogen peroxide. The independent variable being the amount of solution, and the dependent being the rate of oxygen. The more enzyme solution, the more efficient the rate of oxygen was produced. This was comparable with my hypothesis as I had the same idea. The objective was achieved because we were able to calculate oxygen rates released from decomposed hydrogen peroxide. You can clearly see, when no enzyme solution was used, the reaction rate came out negative. If 30 drops of enzyme solution were to be tested, it would further increase reaction rate as Catalase lowers the activation energy. What I got out of the lab was how effective enzymes are within chemical reactions.

Part b:
These results show how temperature of extreme high, or low affects enzyme activity. The highest rate of enzyme activity occurred at 37 Cº. Anything that was hotter or cold than 37 Cº slowed the reaction rate. As I thought, 100 degrees would denature the enzyme, and that was the case. The data provided shows exactly what temperatures enzymes work best, and worst. The objective was achieved as we discovered the different reaction rates under different temperatures.

The results are reliable, as we know enzymes do not work well when under extreme heat or denaturation occurs. What I learned in this experiment was that enzymes don’t work well under cold temperatures because they tend to move slower. My hypothesis did not quite match, because I thought they work best at lower temperatures.

Part c:
These results shown from this experiment led us to conclude that enzymes work best at certain pH rates. For this particular enzyme, pH 7 worked best. When compared to high levels of pH, the lower levels worked better. The wrong level of pH can denature enzymes; therefore finding the right level is essential. The independent variable was the amount of pH, and the dependent being the rate of oxygen. The results are reliable as they are reinforced by the fact that enzymes typically work best at neutral pH levels.