The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: Summary Metal oxide nanoparticles MONPs are used in a variety of applications including drug formulations, paint, sensors and biomedical devices due to their unique physicochemical properties. One of the major problems with their widespread implementation is their uncontrolled agglomeration.
The average results are all written down to one decimal place because although the stopwatch gives results to two decimal places it is impossible to get accurate times to two decimal places due to the fact that our reaction times are not fast enough to stop the stopwatch precisely.
If you double the concentration of Hydrogen Peroxide then the rate of reaction doubles as well. I would expect the rate to increase two times if the Hydrogen Peroxide concentration is increased two times because there are twice as many substrate molecules which can join onto the enzymes active sites.
There may also be some experimental error which causes the inaccuracies. This is shown by the gradient of the graph going down. At this point virtually all the active sites are occupied so the active sites are said to be saturated with Hydrogen Peroxide.
Increasing the Hydrogen Peroxide Concentration after the point of saturation has been reached will not cause the rate of reaction to go up any more.
All the active sites are being used so any extra Hydrogen Peroxide molecules will have to wait until an active site becomes available. The theoretical maximum rate of reaction is when all the sites are being used but in reality this theoretical maximum is never reached due to the fact that not all the active sites are being used all the time.
The substrate molecules need time to join onto the enzyme and to leave it so the maximum rate achieved is always slightly below the theoretical maximum. The time taken to fit into and leave the active site is the limiting factor in the rate of reaction.
The diagram below shows what happens. I tried to keep all the variables except for the concentration of Hydrogen Peroxide the same for all the experiments. However, in reality it is impossible to keep all the variables precisely the same.
This will slightly affect all the results but as I carried out all the three steps in the same way for all the experiments it should not make any difference to the overall result. As the scale on the pipettes shows the volume to the nearest mm3 the volume of the solutions that I used should be correct to the nearest mm3.
The volume of gas in the test tube to start with is slightly affected by the amount which the bung is pushed down each time, if the bung is pushed down further then the volume in the tube will be less so the 30cm3 of gas is reached faster. Anomolies The plotted results on the graph produce a straight line of best fit to begin with which then goes into a curve of steadily decreasing gradient.
This is probably due to an experimental error involving one of the factors mentioned above. Extension Work This experiment could be improved in a number of ways. It could be repeated more times to help get rid of any anomalies.
A better overall result would be obtained by repeating the experiment more times because any errors in one experiment should be compensated for by the other experiments.
enzyme called catalase breaks down hydrogen peroxide into water and oxygen. In experiment number 3, we are comparing the action of catalase in different tissues by testing this hypothesis: The breakdown of hydrogen peroxide occurs at the same rate in all cells. It is found in the peroxisomes of cells, and it is meant to break down hydrogen peroxide (H2O2), a substance that is toxic for the body, into water and oxygen. To balance equations, for every two peroxide molecules broken down, the enzyme yields two water molecules and one oxygen molecule. Students watch a video and do a quick activity to see that a catalyst can increase the rate of the breakdown (decomposition) of hydrogen peroxide. Students will then use salt as a catalyst in a reaction between aluminum foil and a solution of copper II sulfate.
The problem of the delay between pouring in the Hydrogen Peroxide, bunging the test tube and starting the stopwatch could have been limited by getting another person to start the stopwatch when the hydrogen peroxide was poured into the tube. Disclaimer This is a real A-level school project and as such is intended for educational or research purposes only.
Extracts of this project must not be included in any projects that you submit for marking. Doing this could lead to being disqualified from all the subjects that you are taking.
You have been warned. If you want more help with doing your biology practicals then have a look at 'Advanced Level Practical Work for Biology' by Sally Morgan.
If you want more detailed biology information then I'd recommend the book 'Advanced Biology' by M. If you like this post please consider linking to it using this code:Liver contains the enzyme catalase. It can break down hydrogen peroxide which is harmful to cells into water and oxygen.
Enzymes are organic catalysts and can speed up chemical reactions. This is a simple experiment with which to introduce catalysis. The blood contains the enzyme catalase which on mixing with hydrogen peroxide catalyses its breakdown into water and oxygen via the disproportionation reaction: H 2 O 2 (aq) → H 2 O(l) + ½O 2 (g) ΔH = kJ mol Catalase is very efficient at decomposing hydrogen peroxide.
The Hydrogen Peroxide Breakdown Laying the Foundation in Biology 7 Enzymes work by lowering the energy of activation. For example, hydrogen peroxide decomposes to form water, H2O, and oxygen gas, O2. While this is a catabolic reaction, the rate at which it occurs is slow. Light and temperature affect the reaction rate.
hydrogen peroxide produced in this normal metabolic process would build up and cause oxidative damage to our sensitive cellular components.
Catalase is a large quaternary protein, a tetramer, consisting of four large subunits. The hydrogen peroxide solution that you are using in this experiment is labeled as a 3% solution, mass/volume (3 g H2O2 per mL of water). However, in order to complete the calculations, the concentration must be in molarity.
4. Repeat the experiment with hydrogen peroxide concentrations of 16%, 12%, 10%, 8%, 4% and 0%. The 0% concentration of hydrogen peroxide solution is done as a control solution to show that at 0% concentration no reaction occurs.