Factors Affecting Enzyme Activity

Group Members: Carrie, Fatima, Raymond, Daphne

Poster By: Carrie Chen

Mrs. Ferguson, 4th Period


Enzymes are proteins with an active-site and substrate complex, and they function to lower activation energy to catalyze reactions. Enzymes have optimal levels that they function in, in the amount of concentration, temperature, and pH levels. Each enzyme has a preferred pH level or temperature range, and if the environment is too extreme, the enzyme will denature. The enzyme hydrogen peroxide is toxic to animals, and organisms seek to destroy the enzyme before it does damage.


Find the rates of reaction in different temperature ranges and determine how it affects enzyme activity.

Research Question:

How does temperature affect enzyme activity?


Explanatory: We hypothesize that an increase in temperature will increase enzyme activity, due to increased movement of molecules.

Prediction: If the temperature increases, then enzyme activity increases.

Null: The increase in temperature does not increase enzyme activity.

Alternative: The temperature determines the likelihood of an increase on the effect of enzyme activity.


Independent Variable:

Temperature of the Reaction

Dependent Variable:

Rate of reaction

Control Variable:

Room Temperature (20-25)


Amount of enzyme used, type of enzyme used, pH level (7)


  • Lab Quest
  • Lab Quest App
  • Vernier Gas Pressure Sensor
  • rubber-stopper assembly
  • 10 mL graduated cylinder
  • 250 mL beaker of water
  • 3% H2O2
  • styrofoam cup to use as a water bath
  • enzyme suspension
  • four 18 x 150 mm test tubes
  • ice
  • test tube rack
  • thermometer or temperature probe
  • four disposable pipettes
  • Logger Pro


1. Use 4 clean test tubes and place it on the test tube rack. Make sure all materials are present for the temperature enzyme lab. Label the test tubes T 0-5, T-20-25, T-30-35, and T 50-55.

2. Add 3% 3 mL H2O2 and 3 mL of water to each test tube.

3. Make sure the LabQuest is set in the proper settings.

4. Measure the enzyme activity at 0-5:

  • a) Prepare an ice bath in a styrofoam cup and keep placing ice until it is within the temperature range. Check with the temperature probe.
  • b) Place the T 0-5 test tube in the cold water bath for 5 minutes until it reaches the 0-5 degrees range. Check with a temperature probe.
  • c) Once it hits the sufficient range, add 2 drops of the enzyme and start the procedure.
  • d) Make sure to gently swirl the substance for 3 minutes to get substantial amount of evidence. If the pressure exceeds 130 kPa, stop swirling and open the stopper to prevent an explosion. Save the data collected in the LabQuest.
5. Repeat step 4 for the T 30-35 and T 50-55 test tubes.

6. Record the data and transfer the information via Logger Pro. Find the pressure v. time curve and find the trendline for the collected data. Combine all the data collected to create one graph.


Big image

Analysis of Results:

As shown in the graph above, the rate of reaction for T 30-35 and T 50-55 is significantly higher; the room temperature and ice bath test tubes did not have a significant slope change. The T 0-5, T 20-25, and T 30-35 maintain a mostly constant, straight slope. The slope steeply increases for T 50-55 in the beginning, and begins to flat line following 20 seconds.



The temperature determines the likelihood of an increase on the effect enzyme activity, because as temperature increased, enzyme activity also increased. As temperature increased, the rate of reaction in the beginning was significantly higher, as the 52 Degrees Celsius Line's slope was significantly steeper in the beginning, and then it leveled out in the second half. Temperature determines the effect of enzyme activity, as the increase in temperature generated higher rats of reactions for the highest temperature, while the lower temperatures remained relatively the same, within the 101-102 kPa area. Each enzyme has an optimal temperature level, where the rates of reactions are the highest; therefore, the rate of reaction is lower for lower temperatures because the enzyme does not have enough energy to catalyze a reaction; the higher the temperature the temperature went, the higher the reaction rate is, until the enzyme denatured. The optimal temperature level was determined to be lower than 50 degrees Celsius.


One error that could have possible occurred is the non-uniform way of the gentle swirling for 3 minutes; one is not able to maintain a constant swirling of the enzymes, which could have contributed to the continual enzyme reaction in the higher temperatures.

One way to improve upon the experiment is to specify a temperature for the test tubes; by providing a range, there could be many variations due to the different temperatures that each group chose within the range. By providing a specific temperature, the graphs would be more accurate and uniform across the groups.


Factors Affecting Enzyme Activity Lab Handout

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