An experiment to investigate how the rate of enzyme reaction is affected by the pH
Aim & Hypothesis/Null Hypothesis
The aim of this experiment is to find out whether pH levels affect the working rate of reaction of the enzyme catalase as it breaks down hydrogen peroxide.
My prediction (hypothesis) is that the rate of reaction depends on the pH of the environment that the enzyme is placed in. I also predict that the enzyme will have an optimum functioning pH that it works best at (i.e. has the highest rate of reaction at a particular pH level). As the pH level approaches this optimum, the rate of reaction will increase, then peak at the optimum pH, then after this point, the rate of reaction will begin to decrease again (see fig.1 below)
My null hypothesis is that the pH level will have no effect on the rate of reaction, and it is against this that I will be testing.
Biological Background Knowledge
Enzymes are substances that act as catalysts, so they increase the rate of chemical reactions. They are specific, so may only catalyse one reaction. They are also not used up during the reaction, meaning they can be used over and over again. This means that only a small amount of the enzyme will be required to catalyse the reaction.
There are two theories to how enzymes function; the 'lock and key' theory, (see fig.2 below) and the 'induced fit' theory. (See fig.3 below)
Most chemical reactions require an initial input of energy before molecules will react together. This is known as activation energy. The way enzymes increase the rate of reaction is by lowering the free energy of activation, i.e. reducing the point at which the reaction will initialise. (See fig.4 below)
Aim & Hypothesis/Null Hypothesis
The aim of this experiment is to find out whether pH levels affect the working rate of reaction of the enzyme catalase as it breaks down hydrogen peroxide.
My prediction (hypothesis) is that the rate of reaction depends on the pH of the environment that the enzyme is placed in. I also predict that the enzyme will have an optimum functioning pH that it works best at (i.e. has the highest rate of reaction at a particular pH level). As the pH level approaches this optimum, the rate of reaction will increase, then peak at the optimum pH, then after this point, the rate of reaction will begin to decrease again (see fig.1 below)
My null hypothesis is that the pH level will have no effect on the rate of reaction, and it is against this that I will be testing.
Biological Background Knowledge
Enzymes are substances that act as catalysts, so they increase the rate of chemical reactions. They are specific, so may only catalyse one reaction. They are also not used up during the reaction, meaning they can be used over and over again. This means that only a small amount of the enzyme will be required to catalyse the reaction.
There are two theories to how enzymes function; the 'lock and key' theory, (see fig.2 below) and the 'induced fit' theory. (See fig.3 below)
Most chemical reactions require an initial input of energy before molecules will react together. This is known as activation energy. The way enzymes increase the rate of reaction is by lowering the free energy of activation, i.e. reducing the point at which the reaction will initialise. (See fig.4 below)
