• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11

For my coursework I will be performing an investigation into an experiment using hydrogen peroxide (2H2O2) as a substrate and Catalase as the enzyme, which will be produced by a potato.

Extracts from this document...

Introduction

Science Coursework. Skill P - Planning my Investigation (8 marks) Aim For my coursework I will be performing an investigation into an experiment using hydrogen peroxide (2H2O2) as a substrate and Catalase as the enzyme, which will be produced by a potato. The enzyme Catalase is present in all aerobic tissues and catalyses the breakdown of hydrogen peroxide into water and oxygen. Hydrogen peroxide is a toxic by-product of many bio-chemical reactions within organisms, including aerobic respiration. The equation for this is: Catalase Hydrogen peroxide oxygen + water + Catalase (2H2O2) (2O2) (2H2O) This reaction can be discussed in terms of the activation energy and its effect on the rate of a chemical reaction. In order to get this reaction started, either some energy or a catalyst is required. Without it, the reaction would be much slower. In the case of my experiment, the Catalase will bind temporarily to the hydrogen peroxide particles they catalyse. In doing so, they lower the amount of activation energy needed and therefore speed up the reaction. Reactions can only happen when the hydrogen peroxide particles collide with Catalase molecules, but most collisions are not successful in forming product molecules. The 2H2O2 molecules must collide with enough energy to break the original bonds so those new bonds in the product molecules can be formed. All the rate-controlling factors are to do with the frequency of reactant particle collision. In the case of temperature, the energy of the collision is even more important than the frequency effect. I need to change ONE factor in my experiment to measure the rate of reaction between the 2H2O2 and Catalase, and to see if a change in the chosen factor will affect the rate of the reaction in any way. Here is a list of the factors I can change and their effects on the experiment: Surface area of the Potato: If a solid reactant or in this case a solid catalyst (Catalase in Potato) ...read more.

Middle

I also washed and dried all the equipment between each section of the experiment. 4. To ensure my results were as accurate as possible I used a digital stopwatch, graduated measuring cylinders and measuring tube. The Catalase enzyme in a potato was used for this investigation. I kept the following variables the same: * 5 pieces of potato * Each weighing 3.4gms * Volume of the 2H2O2 was 20ml * Concentration of 2H2O2 was 20V * Ph of the 2H2O2 was 8 (alkaline) * Volume of water in the measuring cylinder will be 100.0ml * Room temperature is 25�C approximately 5. When all the apparatus was set up, and I had started the experiment, I started of by using a knife to cut my potato into 1-inch thick strips. The strips were placed on a ceramic tile and a knife was used to cut them into 3cm in length. 6. The weight and lengths of the strips were measured as accurately as possible by placing the strips against a ruler with millimetre units marked on, and then weighed on the electronic scales. 7. A tub was filled half way with water, and a plastic measuring cylinder was also filled with water and placed up side down into the tub to hold the water inside. The stand, clamp and boss were used to hold the cylinder in place, and the bung was removed from the flask. The rubber delivery tube was placed inside the measuring cylinder, and the other end was fitted into the bung with a hole, free to collect the oxygen being produced in the flask. 8. A small measuring tube was used to place 20cm� of hydrogen peroxide solution at pH 8 into the glass flask. This was then put into a water bath, to increase the temperature to 27�C. 9. Care was taken to count 5 potato pieces and add them to the flask. ...read more.

Conclusion

To overcome this problem I could keep the flask containing the hydrogen peroxide in a hot water bath for all the temperatures making sure that the water bath was the suitable depth. This would ensure constant temperature throughout the whole experiment. Looking back at my results I found some anomalous results in my findings. When averaging I used these results, which could of made the average either lower or higher than it should be. To improve this I should have missed these results. Not including some sets of results when making averages may have led to better values. My results are in line with those I predicted. Graphs indicate rise in temperature up a point leads to an increase in oxygen production. This is in line with kinetic theory. However it is very clear that after a certain temperature is reached the enzyme actually virtually stops. This supports my theory of lock and key fit. However optimum activity of enzyme is at about 37�C this is as we expected. But at 50�C the enzyme is still not denatured according to my results. This is a higher temperature than I would expect. Possible not allowing solutions to reach temperatures selected has led to an inaccuracy. It may be that in fact that many temperatures of solutions were lower than we stated. Overall, due to reliable repeats and in general predictions being confirmed I feel my results are reliable enough to make a conclusion. The obvious thing I would improve about the measurements I made would be to increase the range of temperatures used, maybe have gone up to about 60�C. In this way it may be clearer at the temperature which denaturing took place, and would possibly give a graph that resembled the graph in background knowledge. Another way of improving this investigation is to change the method. I measured the time taken to produce 30cm� of oxygen, when I could have measured volume of oxygen that was produced. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. A investigation into the effect of inhibitor concentration on the enzyme catalase.

    This means only a very general, overall trend can be identified across the results. Patterns between these values can only be approximated and are not necessarily very reliable or accurate. Another limitation may have been that I may have used different amount of surface area of potato-due to human error,

  2. Investigating the effect of enzyme catalase concentration on hydrogen peroxide.

    The experiment begins normally and expectedly with the rate of reaction increasing at a steady rate and as the experiment reaches between 6-8 discs the rate of reaction which is still increasing begins to fall, so this starts a decline from 8-10 potato discs.

  1. Factors affecting the activity of potato catalase on hydrogen peroxide.

    By mixing the concentration of H2O2 with water this will decrease the rate of reaction This is because the enzymes found in the potato chip which are the catalyse produce water and oxygen and as I mentioned in the formula above because water molecules are now in there as well,

  2. Investigate the effect of enzyme concentration on the activity of catalase in potato tuber ...

    x 1.2) r = 0.6 cm = 17.342 cm2 = 17.34 cm2 I am working out the surface area of the potato because it is directly proportional to the amount of enzyme in contact with the substrate (H2O2) and therefore is a good measure of the enzyme concentration.

  1. An investigation into how enzyme concentration (catalyse in a potato) affects the rate of ...

    This is shown by the position of the trends. The steepness of the curve in graph 1 shows the rate of the reaction, so the graph shows the three most concentrated mixtures have a fast rate of reaction. The position of the trends and the steepness of the curves show

  2. Investigate the effect of temperature on the activity of catalase (from potato)

    The PH of the reactants should be kept constant. This will not be hard to ensure as the PH of the reactants does not vary significantly during the course of the reaction. 2. The temperature of the reactants will have to be kept constant during the reaction. This is a variable which will be harder to control.

  1. What I will be investigating is the average height of foam that is produced ...

    occurs when the enzyme catalase reacts with the substrate hydrogen peroxide, I will measure my results in millimetres (but this can also be measured in Centimetres.) While the independent variable that I am going to change is the temperature, I will use the temperatures - 20�C 30�C 40 �C 50

  2. Osmosis investigation

    The scales I used were sensitive enough to be able to detect changes of 2 decimal points, which increased precision and accuracy of results. 4. By getting repeated measurements (the 3 different chips) I reduced the effects of random errors because I made an average of the 3. 5.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work