• 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

The activity of Enzyme Concentration on Hydrogen Peroxide.

Extracts from this document...

Introduction

The activity of Enzyme Concentration on Hydrogen Peroxide. Introduction In this investigation, I will be investigating the activity of the enzyme Catalase on the substrate hydrogen peroxide (H2O2). Scientific Background Enzymes are biological catalysts that speed up the thousands of metabolic reactions that occur in living cells. They are usually large proteins made up of hundreds of amino acids, and often contain a non-proteinaceous group, known as the prosthetic group. This is what is important in the actual catalysis. In an enzyme-catalyzed reaction, the substance to be acted upon, the substrate, binds to the active site of the enzyme. The substrate is held to the enzyme in an enzyme-substrate complex by hydrophobic bonds, hydrogen bonds, and ionic bonds. The enzyme then converts the substrate to the reaction products in a process requiring several steps, and often involves covalent bonds. Finally, the products are released. By allowing this to occur, the enzyme reduces the activation energy required in any chemical reaction. All chemical reactions require energy for them to occur, because there is an energetic barrier that reactants must overcome for them to be converted into the products. Once enough energy is supplied, a position called the transition state takes place, and the reactants can then form the products. This energy is called the activation energy. Enzymes reduce this activation barrier. Each enzyme is specific for a certain reaction due to its unique amino acid sequence, which causes it to have a unique three-dimensional structure. The active site also has a specific shape, therefore only allowing few of the many compounds present to interact with it. ...read more.

Middle

The measuring cylinder is then emptied into the delivery funnel, giving a more accurate amount of substrate used. The tap will have been closed so that no H2O2 will have dripped into the potato discs. * The tap is opened and, simultaneously the clock is started. When all the H2O2 is emptied the tap will be closed, to stop any gas from escaping. The gas then flows through to the gas syringe, which will take the reading of gas evolved. Measurements of the gas evolved are taken, especially at the start to give a more accurate interpretation of the initial reaction, as at that point the substrate in excess, so this gives the most accurate estimation of what the rate of the decomposition is, when the enzyme is involved. * Readings are taken at 5secs, 10s, 15s, 20s, 30s, 40s, 50s, and 60s. * Once the results have been noted the conical flask is removed, and washed using water. Though the enzymes are reusable, new discs of potato are used in their place. This time, maybe a differing amount of discs is used, giving a more varied enzyme concentration. * This method is repeated for until all results are recorded. For each concentration of enzyme, 3 different readings are taken and an average of the results is taken, if they are consistent. Safety Precautions The following safety precautions will be maintained throughout the experiment to maintain a safe working environment. o H2O2 is corrosive, and at 20% is definitely an irritant. o Goggles, lab coat and gloves must be worn at all times. o Care must be taken when using sharp implements. ...read more.

Conclusion

This is why discs are going to be used because they each have the equal amount of exposure of any cylinder, no matter what length. * The measuring cylinder on a beehive was just impractical. It was not stable and the displacement was hard to read off accurately. An alternative was to use a gas syringe. This will be used in the experiment because of the practicality. Results: The following results were obtained: Volume of O2 produced/ml Length of potato/cm 10 seconds 20 seconds 40 seconds 3 3 5 8 5 4 6 6 7 7 8 9 Conclusion From the results table it can be seen that the initial rates do increase with the increase in length. However, eventually all of the cylinders gave off between 8-9ml at the end. Though the amount of O2 being produced increases there should be a decreasing rate. However, this cannot be seen from the graph above for "3cm". This may be due to the cylinder's lack of exposure to the H2O2, and a substantial result could not have been achieved. The 5cm cylinder does show the predicted trend of an increasing rate, then a constant rate. This gives further support for the prediction. The 7cm also portrays the predicted trend. Though it hasn't reached its constant rate, the rate is slowing down. The graph also supports the prediction made that because there is the same exposure of enzymes, no matter what length of cylinder. This is because there is not vast difference between the results. With an exposed surface maybe more dramatic and substantial results will be achieved. Overall the preliminary investigation was an effective way of supporting predictions made and also trying and improving the method. ...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. Marked by a teacher

    effects of substrate concentration on the activity of the enzyme catalase.

    4 star(s)

    I will use the following items in the experiment:- * Ruler * Stop Clock * Test Tube rack * Test tubes * Potato discs * H�O� This experiment would show me which volume of hydrogen peroxide (Substrate) to use, it would show which suitable substrate to use by measuring the height of the froth.

  2. To investigate the effect of enzyme concentration on the activity of catalase in potato ...

    This should be changed to the nearest 0.1ml. Evaluating evidence: - Form doing my experiment I can conclude that I have no anomalous results. I think that the overall accuracy of the measurements was quite accurate. The volume of hydrogen peroxide was measured using a measuring cylinder to the nearest 1ml.

  1. The aim of this experiment is to demonstrate that the substrate Hydrogen Peroxide will ...

    Evaluation Issue Number 4: * If I were to do the experiment again I would measure the potato pieces using a micrometer, which would provide far more accurately sized pieces and mean a much more accurate set of results. Suggested Improvement: Use a micrometer, to accurately record the potato pieces.

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

    However, I tried to compensate for any problems by doing all the readings for the potato discs twice just to confirm that there were no odd results. I believe that my results are accurate if I my justification for the potential rogue result is true, since I was aware of

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

    Preferably you should use completely new equipment each time to prevent contamination and unfair results. It is impossible to precisely measure out the amount of hydrogen peroxide each time. As the scale on the measuring cylinder shows the measurement to the nearest 1ml.

  2. Investigating the Effect of Substrate Concentration on Catalase

    10cm3 Syringe 0.5cm3 To measure out the less than or equal to 10cm3 volumes a 10cm3 syringe will be used.

  1. An Investigation into the effect of surface area on the activity of catalase in ...

    What variable am I going to keep the same, and how? The surface area of a 40mm-1 in height, 8mm-1 in diameter piece of potato chip of 1105.841mm-2 (to 3 decimal places), by slicing it into smaller chips, so that the surface area is increased.

  2. What influence does pH have on the enzyme Catalase?

    enzyme activity is reduced and therefore the rate of reaction should decrease. It suggests that the curve were to continue it is likely it would be bell shaped. Limitations to the conclusion However, there are also some limitations to my conclusion due to the extent of my data, which could affect the confidence I can place in it.

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