Effect of Substrate Concentration on Enzyme Activity

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Background
An enzyme is a biological catalyst which speeds up biochemical reactions, such as digestion and respiration, but they remained unchanged at the end of the process (Walpole, Merson-Davies, and Dann 53).

Problem Question
What is the effect of the substrate concentration on enzyme activity?

Hypothesis
As the concentration of the substrate increases, the rate of reaction also increases until it reaches its maximum point where all enzyme molecules are already active due to the solution becomes saturated with the hydrogen peroxide. Therefore, when the rate of reaction is finally at its maximum point, adding more substrate will not make any difference to the rate of reaction.
The rate of reaction increases when the substrate is added it caused the oxygen to be produced quickly. When the substrate molecules go beyond the number of active sites that is available, the rate of reaction will stop increasing. This is because the maximum point of reactions have been reached and are being done at once so if there is any additional substrate molecules in the process, they need to wait until the active sites are available for them.

Variables

Factors Variables How it is conducted
Independent Concentration of H2O2. Set up using syringe with the following concentration of H2O2;

1%
5%
10%
15%
20%
Dependent Rate of reaction - volume of O2 released by each concentration of H2O2. Make sure to be at the right eye level with the bottom of the meniscus to read the long graduated tube.

Controlled Variables WHY it must be controlled HOW it was controlled
1 Volume of the yeast suspension The experiment was done to investigate is the effect of the substrate concentration on enzyme activity. Always take 5mL of the yeas...

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...he one that was measured. Use a better quality burette than can help the experimenter to see the reading of the initial and final oxygen released better or the experimenter may ask for other’s assistance in the reading of the measurement.
Uncontrolled variable Although the temperature was controlled, trial 1 and trial 2 were done on a different day as trial 3, trial 4 and trial 5. Do all trials in the experiment on the same in order to make everything as similar as possible prior to beginning testing.
Human/experimenter error There might be a slight delay when the experimenter was injecting the syringe into the boiling tube while the experimenter also started and stopped the stopwatch. In order to make it more accurate, perhaps ask for another person’s assistance for doing one of the tasks; timing for 30 seconds or injecting the syringe into the boiling tube.

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