Effect of Substrate Concentration on Rate of Reaction Essay Example
Investigation
Aim:
The aim of the investigation was to investigate the effect of substrate concentration Hydrogen Peroxide H O (in %) on the rate of reaction of the enzyme catalase (in 1/mean time).
Prediction:
As the substrate concentration (hydrogen peroxide) in % increases the rate of reaction in 1/mean rate increases until the solution becomes saturated with the substrate hydrogen peroxide. When this saturation point is reached, then adding extra substrate will make no difference. The rate steadily increases when more substrate is added because more of the active sites of the enzyme are being used due to more collisions between the substrate and enzyme because there are more molecules of hydrogen peroxide, so there will be an increase in enzyme-substrate complexes formed which results in more reactions so the required amount of oxygen is made more quickly. Once the amount of substrate molecules added exceeds the number of active sites available then the rate of reaction will no longer increase, as the maximum number of reactions has already taken place. This means that any extra substrate molecules will not to bind to the active site to form E-S complexes as there are limited active sites, in which by this point all the active sites would have been used up.
Experimental Design –
Independent Variable:
The independent variable, is the variable that is changed, this was the substrate concentration in potato discs. The dilutions of Hydrogen Peroxide were 0.2%, 0.4%, 0.8%, 1.2%, 1.6% and 2.0%.
Dependent Variable:
The dependent variable is the variable that is measured, in this experiment the dependent variable was time taken for disc to reach the surface. Rate = 1/mean time.
Controlled Variables:
The controlled variables were volume of hydrogen peroxide which was 10cm³, concentration of hydrogen peroxide of 2% stock concentration. Also same size discs of the potato which were 2mm. The enzyme concentration has to be kept constant because if
Aim:
The aim of the investigation was to investigate the effect of substrate concentration Hydrogen Peroxide H O (in %) on the rate of reaction of the enzyme catalase (in 1/mean time).
Prediction:
As the substrate concentration (hydrogen peroxide) in % increases the rate of reaction in 1/mean rate increases until the solution becomes saturated with the substrate hydrogen peroxide. When this saturation point is reached, then adding extra substrate will make no difference. The rate steadily increases when more substrate is added because more of the active sites of the enzyme are being used due to more collisions between the substrate and enzyme because there are more molecules of hydrogen peroxide, so there will be an increase in enzyme-substrate complexes formed which results in more reactions so the required amount of oxygen is made more quickly. Once the amount of substrate molecules added exceeds the number of active sites available then the rate of reaction will no longer increase, as the maximum number of reactions has already taken place. This means that any extra substrate molecules will not to bind to the active site to form E-S complexes as there are limited active sites, in which by this point all the active sites would have been used up.
Experimental Design –
Independent Variable:
The independent variable, is the variable that is changed, this was the substrate concentration in potato discs. The dilutions of Hydrogen Peroxide were 0.2%, 0.4%, 0.8%, 1.2%, 1.6% and 2.0%.
Dependent Variable:
The dependent variable is the variable that is measured, in this experiment the dependent variable was time taken for disc to reach the surface. Rate = 1/mean time.
Controlled Variables:
The controlled variables were volume of hydrogen peroxide which was 10cm³, concentration of hydrogen peroxide of 2% stock concentration. Also same size discs of the potato which were 2mm. The enzyme concentration has to be kept constant because if