Factors Affecting Enzyme Activity

Gianna Maestranzi- 5th period Naranjo

Introduction

Enzymes are responsible for almost all chemical activities in all living organisms as they act as catalysts. Catalysts are substances that speed up chemical reaction without being altered or destroyed throughout the process. Temperature and pH levels are both very important because organisms have a preferred environment to be able to go through the chemical reaction. If an environment is too acidic or too basic for an enzyme it could end up denaturing-where it no longer has the right shape to properly function.

Research Question

How do different levels of pH in a chemical reaction affect the rate of enzymatic activity?

Hypotheses

Explanatory Hypothesis: A change in the pH levels in an enzyme will affect the rate of enzymatic activity.

Prediction: A change in the pH levels will increase the rate if enzymatic activity.

Null Hypothesis: A change in the pH levels will have no affect on the rate of enzymatic activity.

Alternative Hypothesis: A change in the pH level will have an affect on the rate of enzymatic activity.

Claim

I predict that the lower the pH level is, the higher the rate of enzymatic reaction will be.

Methods

My lab group and I began by taking 3 test tubes and placing 3 mL of water and 3 mL of yeast catalase in each. We set up our LabQuest and connected the Vernier Gas Pressure Sensor. We labeled each pH 4, pH 7, and pH 10. For each trial we dropped 2 drops of H2O2 in each test tube through a pipette and immediately capped it with the gas pressure sensor while carefully swirling the contents around and measured the pressure each trial produced.
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Results

The test tube with the pH 4 handled inside of it had the highest pressure and the test tube with pH 10 had the lowest pressure. This is also seen in the bar graphs with the average rates of reaction where pH 4 is the highest as it is the optimal point in the bell curve for reactions to occur. pH 7 was in the middle of both other levels and is about the average of the two levels.

Discussion

The pH 4 has the highest rate of reaction and therefore proves that it is the optimal point for reaction as we only have half of the bell curve where 4 is the peak. So therefore it proves that that any more basic and any more acidic than pH 4 will not have the as high of a rate of reaction. Our data also proved our claim which was "I predict that the lower the pH level is, the higher the rate of enzymatic reaction will be." The line graph showed the gradual decline of the pressure as the pH level increased or became more basic. We may have ran into a few errors because we were only able to run the experiment once so my lab group and I could not get incredibly accurate results. We also only tested 3 different levels instead of all 10 to see which level specifically is actually the best. We also may have not gotten the most accurate results because we had to cap the test tube ourselves and may have let out a bit of missed pressure in each trial.