• 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
  12. 12
    12
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19
  20. 20
    20
  21. 21
    21
  22. 22
    22
  23. 23
    23

The aim of this experiment is to demonstrate that the substrate Hydrogen Peroxide will break down to oxygen and water, in the presence of the enzyme catalase.

Extracts from this document...

Introduction

BIOLOGY AS LEVEL KATHERINE WYATT ANALYSIS AND EVALUATION OF COURSEWORK EXPERIMENT 5 DECEMBER 2002 COURSEWORK EXPERIMENT Further to the 'Coursework Plan' which was submitted to my tutor on 5 December, outlining a plan for conducting an experiment 'to establish that varying the surface area of catalase exposed to the substrate Hydrogen Peroxide will affect the rate of the reaction', all students were given a 'Student Worksheet', which detailed the prescribed apparatus and methodology for conducting the experiment. The following information will outline the evaluation and analysis of this experiment, under the following headings: * Introduction; * Prediction; * Variables; * Preliminary Work; * Method; * Results; * Conclusion; * Interpretation; * Evaluation. INTRODUCTION The aim of this experiment is to demonstrate that the substrate Hydrogen Peroxide will break down to oxygen and water, in the presence of the enzyme catalase. The catalase will be obtained from potatoes. This experiment also aims to investigate and demonstrate that an increase in the surface area of potato (catalase), placed in equal volumes of Hydrogen Peroxide, will increase the activity of catalase and hence increase the level of oxygen production. This will demonstrate an increased rate of catalase reaction. Specifically, with regard to this experiment, Catalase is a biological enzyme, which helps to speed up the reaction between catalase (found in potato) and the breakdown of Hydrogen Peroxide. Most intracellular enzymes work only on one particular substrate. Catalase, for example, acts only on Hydrogen Peroxide, and is ineffective on any other natural substrate. The active site is contained within the enzyme (Lock), and once the substrate (Key) is locked into the active site, the reaction takes place. The products (oxygen and water) will then be released, and the enzyme will move on to another substrate (Hydrogen Peroxide). PREDICTION The experiment, therefore, aims to demonstrate firstly an enzyme reaction between catalase (found in potato) and Hydrogen Peroxide; and secondly, the speed of the reaction when the surface area of the potato is increased. ...read more.

Middle

8. MEAUREMENT OF TIMINGS: Every 30 seconds, I then measured the volume of oxygen that had been released in the experiment, by taking the manometer reading and recording this in the table, for 5 minutes. 9. DISCARD: After each experiment, all contents of the boiling tube were discarded in a central beaker, for use by all students. 10. REPEAT OF EXPERIMENT: In order to enable an average result to be taken, the same experiment was conducted for the same sized potato sample, and accordant results were then inserted into a secondary table. 11. FURTHER SAMPLE SIZES OF POTATO: I then took a secondary sample of potato, utilising the cork borer and cleaned with the distilled water. Utilising the scalpel and tile, I then completed the experiment, as outlined in steps 5 - 10, for pieces of potato as follows: 4 cm x 1 cm; 3 cm and 2 cm; 3 cm and 2 x 1 cm; 5 x 1 cm. 12. RECORDING OF OXYGEN PRODUCTION: When the previous steps has been achieved, the timings and total volume of oxygen collected (cm3), should be noted in a result table, as outlined in 'Results'. If bubbles are still being produced, then oxygen is also still being produced. The clamp was then opened to allow the gas to be released. The manometer fluid was then return to its original level, thus ensuring accurate readings. 13. CLEARING UP: Following the completion of all the experiments, as outlined above, I then disposed of all of the potato and fluids utilised in the experiment, and cleared all the apparatus away and cleaned up the experiment surfaces. RESULTS This experiment provided the volume and rate (in cm3) of oxygen produced at varying times, by identifying the levels of oxygen gas which are given off in the space of 5 minutes for the various concentrations of potato samples, as outlined in the 'Table of Results' (Below). ...read more.

Conclusion

Evaluation Issue Number 7: * The Hydrogen peroxide did not always cover all of the potato, thus reducing the effect of increased surface area Suggested Improvement: In future, I should increase the quantity of Hydrogen Peroxide, ensuring that the same quantity is used for each experiment, however. Evaluation Issue Number 8: * A change in pH may have had an impact upon the results. Suggested Improvement: In order not to disrupt the results, pH 7 buffer should be selected and inserted into the boiling tube, to match the natural pH of the potato tissue and therefore match the enzyme, to ensure that it is able to work effectively. Evaluation Issue Number 9: * I felt clumsy and unconfident in this experiment, due to lack of expertise and previous practice with the experiment equipment. Suggested Improvement: In future, I would like to conduct more experiments, and certainly have a pilot experiment, to ensure that I am confident in the use of all of the equipment. Accuracy of Results Although I have commented (above) on suggested improvement to the experiment, on a more positive note, to conclude, I can confirm that I restricted the variables to only one - being that of the increased surface area of the potato (catalase). This ensured that the experiment was completed as fairly as possible, ensuing that all the variables except for the varying surface area of potato, remained the same for all of the experiments. I can also confirm that completing each different groupings of potato twice, and thus calculating an average for these results, should have guaranteed more reliable results. I also measured the volume of Hydrogen Peroxide very accurately with a pipette and filler, ensuring that that meniscus was accurate. In summary, the experiment did conclude that which I had detailed in the 'Prediction' of the experiment, however, further improvements as outlined (above) would ensure that a repeat of this experiment, would attain more accurate and thus conclusive results. ...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

    Biology Coursework Enzymes

    4 star(s)

    nothing is obstructing me, I will also remove any obstructions that are on the floor for example bags, I will make sure that I wear safety goggles at all times as the iodine solution is irritant. Also I will be very cautious when handling the hot water so I do not suffer from burns.

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

    have achieved it may be due to my earlier assumption, where an error may have occurred in my method and preparation and caused these odd results. From carrying out this investigation, I can see that inhibitors have some degree of effect on rate of reaction- the addition of an inhibitor prevents the normal enzyme- substrate complex being formed.

  1. The Effect of Surface Area on Catalase Activity in Potato

    Heavy metal ions such as mercury and silver, cause disulphide bonds to break. These bonds help to maintain the shape of the enzyme molecule. Once broken, the enzyme molecules' structure becomes irreversibly altered with the permanent loss of its catalytic properties.

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

    Also, results were limited due to a time limit. Apparatus: 10ml Water, 20ml Hydrogen peroxide, potato strips of the same width and from the same source, Stopwatch, Boiling tubes, Boiling tube holder, Measuring tube, Scalpel, Pipette, Ruler, White Tile, Core taking device and Results sheet.

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

    and for 2 potatoes it is 0.13 (ml sec-1). This shows that the rate of reaction has more than doubled from 1 to 2 potato pieces. For 4 potatoes the rate of reaction is 0.34 (ml sec-1) this shows that from 2 to 4 potatoes the rate of reaction has nearly trebled.

  2. Influence of pH on the activity of potato Catalase

    This will affect the averages that is the product form the results, as in some cases there is only 1 result the average will not be entirely true as it have no other readings to compare against. Over the first pH groups, 3 to 7, the time taken shown on

  1. The effect of temperature upon the enzyme catalase

    This would allow me to get nearly the same surface area of potato each time, and therefore the rate of reaction would be more similar for each of the repeats, improving the accuracy of my results, and therefore improving the reliability of my conclusions.

  2. An investigation to compare the reaction rates between potato and hydrogen peroxide against liver ...

    To make sure that I was making my experiment as safe as possible, I had to do a risk assessment of my experiment. First I checked out how hazardous the hydrogen peroxide was.

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