• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst

Extracts from this document...

Introduction

Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst Variables * Amount of celery * Concentration of celery, more or less watered down. * Concentration of Hydrogen Peroxide (H202) * The amount of H202 * The temperature of H202 I am going to vary the concentration of the hydrogen peroxide. I think that varying the concentration of the liquid will be the best experiment to do and will hopefully give a strong set of results, which will enable me to obtain clear conclusions. Prediction The rate of an enzyme- controlled reaction depends on the temperature, pH, and concentrations of the enzyme and its substrate. The more enzyme molecules produced by a cell, the faster the reaction will proceed. Similarly, an increase in the substrate concentration will speed up the reaction if there are enough enzymes molecules to cope with the additional substrate. Therefore by diluting the hydrogen peroxide with water, this will decrease the rate of decomposition of the H202, and the less gas will be given off. The enzyme in the experiment is catalase. Hydrogen peroxide is poisonous and the catalase works to render the hydrogen peroxide harmless by breaking it down to water and oxygen. If the concentration of H202 is less, then there is more water present, and there are less hydrogen peroxide molecules, so there is less for the catalase to render harmless, so less H2O and O2 is produced. ...read more.

Middle

To make this easier the gas burette will be clamped in place, so it doesn't have to be held. Safety * Eye protection must be worn as H202 is being used, and can cause serious damage to the eye. * Care must be taken when using knives to cut up the celery. * Bags must be tucked under the benches as they may cause an accident. Method * The apparatus was set up as shown in the diagram * 35grams of celery was cut up and mixed with 20cm3 of water, which was blended for 1 minute. * 10cm3 of the celery mush was then placed in a conical flask * The gas burette was filled with water and clamped in place over a bath of water * 10cm3 of the hydrogen peroxide (in whatever concentration) was added to the celery * The stop clock was started * As quickly as possible, the bung was placed in the top of the conical flask and the delivery tube angled so that the gas would be directed up the burette. * After 30 seconds the stop clock was stopped * The amount of gas collected was noted, by reading the scale on the gas burette. * Each concentration was repeated three times to confirm the validity of the data and so an average can be made. Results Ratio of hydrogen peroxide to water (cm3) ...read more.

Conclusion

If I were to carry out the experiment with the hydrogen peroxide at different temperatures, my prediction would be that the higher the temperature, the more gas would be given off. This is because, to make reactions work between the enzyme and H202 there must be a certain amount of force to combine them together, they have to collide to set the reaction off. The total kinetic energy of the reactant molecules must be at least as big as the activation energy. So if the H202 was heated up, the kinetic energy would be larger, so there will be more chance of collisions, so the overall reaction would occur faster. This is true up until a certain point. As enzymes are specific, they work best between a small range of temperatures. If the temperature is too high, then the enzymes are denatured, they change shape and they can no longer combine with the substances. I could also extend the concentration experiment further by looking at the quote " an increase in the substrate concentration will speed up the reaction if there are enough enzyme molecules to cope with the additional substrate." As I put in my analysis, in my experiment there were enough enzyme molecules, but I could do an experiment to find out the specific concentration where the concentration is too high for the enzyme molecules to cope with. Jo Waddell 11M Page 1 5/2/2007 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

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

Here's what a teacher thought of this essay

4 star(s)

This is a good essay that discusses the break down of hydrogen peroxide. The method is clearly laid out and there is a good analysis of the results.

There are areas of discussion about enzymes that are valid and correct but it is lacking in the finer detail. At A level, I would expect more scientific discussion regarding tertiary structure but the writer may not have covered that area. If you were looking for reference to discuss enzymes and rate of reaction - this would seem a good practical to use and build up the explanation.

****

Marked by teacher Sam Morran 08/01/2013

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 AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    Effect of temperature on the enzyme pectinase in fruit juice production.

    3 star(s)

    Despite all this, the results obtained were not 100% accurate. There was a clear trend as temperature increased as I had predicted but towards the temperatures of 70-80 degrees, I had anomalous results, this can be seen looking at the graph.

  2. Effects of Copper Sulphate on the Activity of Catalase

    CuSO4 Without CuSO4 With CuSO4 Without CuSO4 9 ml/min 39 ml/min 11 ml/min 64 ml/min 14 ml/min 80 ml/min 20 ml/min 100 ml/min 25 ml/min 147 ml/min The graph (see graph 3) of the results satisfies my prediction because the two lines are how they were expected.

  1. The Effect of Concentration on Pectinase Using Apple

    2.5ml of 5.00% pectinase is then syringed into the test tube and mixed gently using a glass rod for exactly 10 seconds. A small sheet of clingfilm is placed on the test tube to cover it and prevent the loss of any juice.

  2. Type - 1 Hypersensitivity Reaction

    and blood vessels, which causes vasodilation and an increase in permeability. Egg albumin like histamine works on the H1 receptors, which are located on the cells of longitude and smooth muscle. There are three different histamine receptors extensively located throughout mammalian tissue these are H1 H2 (stimulates gastric secretion and stimulates the heart rate)

  1. Investigating how different concentrations of a antibiotic effects the growth of a bacterium.

    One from each of the antibiotic concentrations should place in each agar plate. X. Once all the small discs have been placed into the dishes, it would be important to seal the lids together with the use of cellotape to ensure that they are not opened and the results destroyed.

  2. Investigating the effect of temperature on the activity of free and immobilised enzymes.

    Once an individual has developed an immune response as a result of inhalation or skin contact with the enzyme, re-exposure produces increasingly severe responses becoming dangerous or even fatal. * Any waste enzyme powder should be dissolved in water before disposal into the sewage system.

  1. DETERMINING THE WATER POTENTIAL OF A POTATO TUBER CELLS USING THE WEIGHING METHOD.

    The equivalent process in animal cells is called crenation. The liquid content of the cell leaks out due to diffusion. Plasmolysis only occurs in extreme conditions and rarely happens in nature. It is induced in the laboratory by immersing cells in strong saline or sugar solutions to cause exosmosis, often using Elodea plants or onion epidermal cells, which have coloured cell sap so that the process is clearly visible.

  2. To Investigate an Enzymes Reaction.

    Apparatus To be able to conduct my experiment I will need: * Peas - (soaked, peeled and split) * Pestle & mortar (to breakdown the peas) * 6 test tubes & rack (labelled with the amount of H2O2 they contain)

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