• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15

What influence does pH have on the enzyme Catalase?

Extracts from this document...


Biology Data Analysis What influence does pH have on the enzyme Catalase? _____________________________________________________________________________ Enzymes act as catalysts in the cells of an organism, speeding up a chemical reaction but remaining unchanged itself. Most enzymes break down large molecules into small molecules. However, others can join small molecules together. Enzymes are important in an organism because they regulate the many chemical reactions that take place inside the cells in the process of metabolism. They are proteins, made of long chains of amino acids folded into a complex shape called a globular protein. The molecules in the reaction, called the substrate, must fit exactly into the enzyme in a place called the active site, which is where the reaction takes place, for the enzyme to work. Changes in the environment the enzyme, for example temperature or pH, can affect the active site shape and therefore they change the rate of reaction. This data analysis was to investigate the influence of pH on the rate of reaction of the enzyme catalase in potatoes. Catalase breaks down the highly oxidising hydrogen peroxide, into water and oxygen. 2H2O CATALASE 2H2O + O2 Hydrogen peroxide is formed as a by-product of various other biochemical reactions and would damage cell membranes very quickly if not removed, so catalase is an essential enzyme to work quickly and effectively. Catalase occurs in many plant and animal tissues, but this experiment used the catalase in potatoes. During the experiment, potato discs which naturally contain catalase were placed in a solution of a known pH and hydrogen peroxide. Then the rate at which oxygen produced evolved the manometer liquid within twenty seconds was measured. The oxygen production proved that there was a reaction taking place and the movement reflected the rate of reaction of the catalase in the potato, measured in mm/20s. The class used eight different potatoes at a range of pH values from pH 4 to pH 8. ...read more.


When the pH became so acidic and the whole enzyme's ionic bonds began to be changed and the enzyme active site denature the graph fell steeply as shown between pH 5 and 4. When all the enzymes were completely denatured there would be no reaction at all. Evaluation Evaluation of procedures The experiment had a simple method, which was easy to repeat in the same way again. It was also very safe to conduct, if you followed the explicit safety precautions wearing safety goggles and lab coats and being highly careful with the highly oxidising hydrogen peroxide and dangerous apparatus such as knives or broken glass if a test or manometer tube was broken. It was completed in a reasonable amount of time and it gave a wide set of data that could be studied and analysed. However, it the data was not as reliable as it could be. The range of rate of reaction for each pH was huge. For example at pH 8 the results ranged from 37 to 134 mm/20s. This meant that there was a large degree of overlap between the error bars representing the range of values, and even the boxes in Figure 2 showing the majority of the data in the inter quartile range, at the different pH. This means we cannot be certain in the conclusion as the true value could fall anywhere in the range. It shows that the data collected was not particularly accurate. The fact that the results were not completely accurate could be due to the method as there were several experimental flaws in the investigation and there are a number of improvements that could be made to improve them and therefore get a more accurate set of data to make a reliable conclusion from. These were the main problems and a suggested improvement: 1. Issues with the apparatus/techniques Measuring the rate of reaction by seeing how far the oxygen produced evolved the manometer fluid was an inaccurate method. ...read more.


Therefore, I cannot be certain even if the scientific theory and some of the data show it. There are weaknesses in the techniques, as discussed in the 'Evaluation of Procedures', which would have affected the accuracy of the data, which limits the faith I can place in the conclusion. This included the lack of precision of some of the apparatus, such as the oxygen escaping from the tube you had to hold down and, also the lack of control of variables. The range was not adequate to see the full effect of the whole spectrum of pH, both acid and alkaline. This is why although I am only reasonably confident I cannot place full confidence in the conclusion. However, we could have more confidence if we amended these problems by: * Using the improvements in apparatus and techniques described in the 'Evaluation of Procedures' to make the data more accurate and therefore more reliable. * Extending the range to use more alkaline pH values, such as pH 9, 10, 11, 12 to provide more evidence for the second aspect of the conclusion. It would also help to continue testing more acidic pH values to see when the enzyme was denatured to such an extent that it could not react at all with the hydrogen peroxide. This would display the full effect of pH on catalase for us to base the best conclusion on. * Including pH values at smaller intervals to ascertain the optimum pH more accurately. * Taking further data at each pH 6, where there was a lack of it, as to get a better picture of what the effect of this pH is These ideas would make the data be more accurate and complete, and therefore make the conclusion more reliable and secure. 1 Source: 'Twenty First Century Science GCSE Biology' published by OCR (page 101) 2 Source: 'Twenty First Century Science GCSE Biology' published by OCR (page 101) 3 Source: Chemistry Help Website: http://www.chemguide.co.uk/organicprops/aminoacids/enzymes2.html ?? ?? ?? ?? Anna Broadley BIOLOGY DATA ANALYSIS UVC - 1 - ...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

    Investigating the breakdown of hydrogen peroxide by the enzyme catalyse in potatoes.

    4 star(s)

    However it also shows that the some of the points do not fit exactly and although they have only slight difference, they can indicate possible errors in the investigation. This may have occurred in the measurement of the quantities of the enzyme and substrate and also variations in the room temperature may have led to inaccuracies.

  2. Marked by a teacher

    The Effect of pH on Catalase

    4 star(s)

    Repeat with different pHs. Apparatus: 1 100 cm3 gas syringe (with rubber tubing) 1 boiling tube 1 250 cm3 beaker 1 100 cm3 beaker 1 10 cm3 graduated pipette (with filler) 1 watch glass 1 spatula 2 thermometer 1 2 cm3 plastic syringe 1 10 cm3 measuring cylinder 1

  1. Marked by a teacher

    Biology Coursework: Investigation of How Ph Affects the Rate of Reaction of Catalase

    3 star(s)

    They also did simply not react, such as pH 1 and pH 14. Results: Here the time taken represents the amount of time it took for 10ml of water to be displaced by oxygen gas released from the breaking down of Hydrogen Peroxide to water and oxygen by catalase.

  2. What is the effect of pH on the activity of the enzyme catalase?

    The numbers 0-7 represent an acidic pH, and 7-14 represent a low, otherwise known as a 'basic' pH. The optimum pH for catalase is seven. In this lab, we aimed to test this statement by investigating the effect of pH on the activity of catalase, (which has an optimum pH of 7).

  1. Influence of pH on the activity of potato Catalase

    This means that the results of the experiment are presented in a clear and orderly fashion that allows patterns in the results to become more obvious. The rate of reaction was calculated by dividing 1000 by the time taken for the quantity of gas to be produced from the reaction.

  2. How does the concentration of hydrogen peroxide affect how the enzymes in potatoes work?

    Amount of gas produced (cm�) 20 4.5 16 4 12 3.4 8 2.8 4 1.8 0 0 Averages Final concentration of H�O� (vol.) Amount of gas produced (cm�) 20 5 16 3.83 12 3.2 8 2.87 4 2 0 0 Identifying patterns in the results The obvious pattern that the

  1. Investigating the influence of pH on the activity of potato catalase

    of the active site so that the substrate can no longer fit. The pH will also alter the charge of the active site which can also disrupt the electrical fit of the active site and charged substrate. All enzymes have an optimum pH which they catalyse a reaction at the maximum rate.

  2. Investigating the Effect of Substrate Concentration on Catalase

    Apparatus Item Sensitivity Justification Conical Flask 50cm3 There is no need really to measure anything using the conical flask. It only needs to be large enough to easily be able to hold 24cm3. Trough N/A This is to put water in so that the burette can be turned upside down without losing any water.

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