IntroductionI am going to investigate how the concentration of hydrogen peroxide affects the rate of reaction between the hydrogen peroxide, and it's enzyme, catalase, which is found in yeast. There are many other factors which will affect the speed with which this reaction can take place.These include;-The concentration of the substrate (Hydrogen peroxide)-The concentration of the yeast solution-The temperature of both the substrate and of the yeast solution-The ph of the substrate.Key FactorI am investigating the effect on the speed of the reaction of the concentration of the substrate in this experiment. I will do this by changing the concentration of the hydrogen peroxide, and measur ...view middle of the document...
The hydrogen peroxide particle collides and bonds onto the side of the larger catalase protein, and a reaction within the hydrogen peroxide takes place. However, because the enzyme only catalyses the reaction, it does not take part in the reaction, and so it remains unchanged. Therefore the catalase particles can be reused.Because the particles of catalase and hydrogen peroxide particles have to collide in order for the reaction to take place, the more catalase particles there are, the more likely the hydrogen peroxide particles are to collide with the catalase particles, and to cause the reaction to happen.If a graph were drawn of the number of catalase particles against the rate of reaction with a given number of hydrogen peroxide particles, then the graph would have a steep positive increase, followed by the gradual flattening of the graph, due to the fact that the number of catalase particles had exceeded the number of hydrogen peroxide particles as the hydrogen peroxide was broken down.However, in this experiment, the concentration of yeast solution will only be 5%, and so this will not be enough for the catalase particles to exceed the number of hydrogen peroxide particles in any of the concentrations.TemperatureThe temperatures of both the hydrogen peroxide and the yeast solution will affect the rate of reaction. This is because, as the temperature is increased, the energy given to the particles is increased, and they move around more. This causes many more collisions to occur, and therefore for the rate of reaction to increase. However, because the enzyme can be denatured, once the solutions reach a certain temperature, the reaction ceases to occur. The enzyme has a maximum efficiency temperature, before and after which it does not work as quickly.PHThe pH of the hydrogen peroxide and of the chemical which is being used to dilute the hydrogen peroxide (water) will affect the rate of the reaction. This is because the enzyme (catalase) is affected by the pH, as are all enzymes. The enzyme has a point of maximum efficiency, or 'optimum pH,' and before and after this point, the catalase does work as well, and in extreme acidity or alkalinity, it is denatured.Fair TestBecause the 'Key Variables' described above will affect the rate of the reaction, to measure the effect of one of these variables, the others need to be controlled.Concentration of Yeast SolutionI will control this by using the same amount of yeast throughout the experiment (2cm ). I will also make sure that the concentration of the solution remains the same by using 5% yeast solution (already made up by the laboratory) throughout. This will prevent this variable from affecting the reliability and accuracy of this experiment.TemperatureFor the enzyme to be denatured, the temperature must be relatively high. These temperatures should not be reached in the school laboratory. However, they will also not be at the enzymes point of maximum efficiency. Because heating the ye...
