Enzymes are proteins that catalyse the speed of biochemical reactions in the body. They are responsible for all metabolic functions and are absolutely vital for life itself. Without enzymes, reactions would take place too slowly to keep you alive. These proteins are highly specific regarding what they do and under what conditions they do it in. Like a lock and key, the enzyme and substrate must fit correctly in order for the enzyme to work properly. The reaction we are investigating is the breakdown of hydrogen peroxide catalysed by the enzyme catalase. Five trials will be run at pH levels 4,7 and 10.
From prior knowledge, I know that pH is a measure of the concentrations of hydrogen ions in a solution. The higher the hydrogen ion concentration, the lower the pH. A change in pH above or below will affect the enzyme rate of reaction and the actual activity of the enzyme. Changes in pH lead to the breaking of the ionic bonds that hold the tertiary structure of the enzyme in place. As a result, the active site of the enzyme denatures resulting in the substrate not being able to fit like a "lock and key" mechanism.
Hypothesis.
I predict that the outcome is that when the enzyme is catalysing at the pH 7, the volume of oxygen gas produced will be greatest as we already know that the enzyme catalase is at its most active when exposed to its pH optimum (pH 7). Extremely high or low pH values generally result in complete loss of activity for most enzymes. Values outside of pH 7, that are, pH 4 and 10, catalase will produce far lower volumes of oxygen gas than pH 7. Overall, enzymes are sensitive to changes in pH.
Independent Variable.
The independent variables of this investigation are the buffers we will be using ranging from pH 4, 7 and 10; with us testing an acidic pH buffer solution, neutral pH and alkali pH. (10cm3).
Dependent Variable.
The dependent variable of this investigation is the volume of oxygen produced from the reaction itself which will be measured using a gas syringe and measured after 30 seconds in my groups specific experiment.
