Substrate concentration enzyme concentration
Reaches a plateau because all the Plenty of enzyme molecules to
enzyme molecules are used up so deal with the substrate. substrate
if you add more H2O2 the rate is is constant
unchanged
Preliminary work
For my preliminary work we found three catalase sources and tested them to find the best one for our experiment. The three sources were yeast, apple and liver.
We found that yeast was the fastest and that it released the most oxygen. We also found that the best amount of yeast to use is 0.5g
Planning
The aim of this investigation is to find out the rate of reaction of catalase on H2O2. The variable I am going to change in the experiment is the concentration of catalase.
Here is an annotated diagram to explain the way I am going to carry out the experiment.
I will carry out this experiment with 1,2,3,4,5&6% concentration of H2O2 repeated 6 times. To make my results make my results accurate I will take all the precautions I have pointed out in the planning and make sure I use the same equipment (washed out) every time. I will find out the rate by dividing the mean by the time (3 minutes).
Hypothesis
I predict that the rate of reaction will decline as I add substrate. I think this will happen because if you add more substrate to be broken down with the same amount of catalase, the catalase will have too work harder, slowing the rate.
Results table
Here are the results to the experiment
Analysis
The trend of my results is that the rate of reaction grows steadily as the concentration increases. The results to back this up are:
Rate of reaction
The scientific reason for these results is that as you increase the concentration of H2O2 in the solution there are more H2O2 molecules in the same amount of space, therefore the catalase can breakdown more substrate (because of the fact there is more there).
Evaluation
The limitations in my method were, using 0.5g of yeast (the catalase) if I had’ve used more catalse, the rate of the reaction would steadily get faster as there is plenty of enzyme to deal with the substrate. Also, only doing the experiment with 1,2,3,4,5& 6 % of substrate, if we used more the reaction reach a plateau because the there would be too much H2O2 for the enzyme to deal with.
There are many reasons why I could get anomalous results for example, human error (reaction times, equipment set up wrong). Luckily I did not get any anomalous results.
To extend my investigation I would take the results and try to find any connections e.g. the rate against the mean may be proportional in some way?
Overall the expt went really well and I got fairly accurate results, with witch I investigated the reaction.
