Factors Effecting Enzymes

How pH Levels can Effect the Activity of an Enzyme


Enzymes are used to catalyze chemical reactions in the body. But, there are many different factors that can change how fast the rate of those reaction occur, like temperature, concentration, and pH levels. In this presentations, we will be focusing on how pH levels effect how fast enzyme can catalyze chemical reactions.

Research Question

How does pH level effect the reaction rate of an enzyme?


Bar Graph:

  • Independent: Different pH Levels
  • Dependent: Rate of Reactions

Line Graph:

  • Independent: Time
  • Dependent: Pressure

Constants for Both Graphs:

  • Amount of yeast, water, and hydrogen peroxide in the mixture
  • Temperature
  • Amount of pH added to mixture
  • Environment


Explanatory: There is an optimum pH level which will produce the maximum rate of reaction.

Null: The pH level will have no effect on the rate of reaction because the optimal rate will stay the same, despite pH.

Alternative: The pH level will effect the reaction rate the pH can change specific bond interactions that will effect the reaction rate.


I believe that the optimum pH level will be seven, because 7 is the median of the pH levels. I believe that 4 will be to low for a substantial reaction to occur, and I believe that 10 will be to high.


To represent the enzyme, we will use a yeast and water mixture, and we added hydrogen peroxide.. We will be using a LabQuest and a Vernier Gas Pressure Sensor to record the pressure of the mixture as it reacts to the different pHs over time. For each pH, we will add 2 drops of each to separate containers of the yeast-water mixture and record the pressure over time. Once you add the pH drops to the mixture, you quickly cap the mixture with the pressure sensor and you use LoggerPro to record the pressure over time.


Big image
Big image


The optimum pH level for an enzyme is 7.


If you look at the bar graph, the pH of 7 has the highest rate of reaction, at approximately 0.067. On the line graph, the pH level of 7 has the highest pressure consistently over time, and reaches the maximum the fastest.


Since pH 7 has the highest rate of reaction, it has the most effect on the enzyme catalyzation. The pH 7 also reaches the maximum rate of reaction the fastest, which means it must be the optimum pH level. pH 7 has the greatest effect on the bonds between the substrate and the enzyme, and created a more effective, productive reaction in order for the product to be produced faster.

How Experiment Could Have Been Improved

I feel that the experiment would have been improved if we had conducted more trials and acquired more accurate data. We also should have been more accurate with the data if the pressure sensor had a been more consistent when attaching to the beaker after the pH was added.