• 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

Influence of pH on the Activity of Potato Catalase.

Extracts from this document...

Introduction

Influence of pH on the Activity of Potato Catalase Catalase is found in a vide variety of plant and animal tissues, its use is to break down toxic hydrogen peroxide which is formed as a by-product of biochemical reactions, into the harmless substances, water and oxygen. The rate of activity of many enzymes is largely influenced by changes in the pH level. To show the effect of pH on the enzyme Catalase, an experiment will be conducted where potato-discs of a constant size are placed in solutions of known pH and will react with hydrogen peroxide in the solution. The rate at which oxygen is evolved will be measured using a manometer, thus reflecting the activity of the Catalase in the potato. Requirements for Experiment: - Scalpel/Sharp Cutting Device - Cork Borer - Petri Dish - Boiling Tube (with rubber bung) - Stand (with bosses and clamps) - Manometer Tube (with a select diameter 2mm/3mm) - Beaker - Syringe (5cm�) X2 - Clip - Stop Clock - Pencil - Potato Tubers - Tongs - Test Tube Rack - Hydrogen Peroxide - Citric Acid phosphate buffers, made up as shown below from Na2HPO4 (0.2 mol dm-3) and citric acid (0.1 mol dm-3) to provide 100cm3 of buffer in each case: Buffer pH Na2HPO4 cm3 Hydrogen Peroxide cm3 8.3 5 5 6.3 5 5 4.3 5 5 3.5 5 5 2.8 5 5 Before the experiment it is advised that the pHs should be checked with litmus paper or an electrical pH meter. ...read more.

Middle

4) As the reaction begins and oxygen is produced the manometer fluid should be pushed down the left hand side of the manometer tube. Using the stop clock, time how long it takes for the fluid to rise through a distance of 5cm in the right hand side of the tube. During this period gently agitate the boiling tube to ensure that the reaction is occurring at an optimal level. 5) Open the clip at the top of the boiling tube so that the manometer fluid returns to its idle position. Time the evolution of oxygen twice more and work out an average result. 6) Remove the bung and wash out the boiling tube thoroughly. 7) Repeat steps 1-6 another five times, with a fresh set of five potato discs each time and using differing buffer solutions of the chosen pH in turn. 8) For each of the final readings, divide the rate of reaction by 100 by the time taken in seconds for a 5cm rise in the right-hand manometer tube. This provides larger numbers for graph plotting. 9) Collate the results in a table 10) Plot a graph of the rate of reaction against pH for the results found. Setup: Results Table Results of the experiment are displayed as follows: pH Buffer cm3 Hydrogen Peroxide cm3 Time/Seconds 2.8 5 5 129.31 5 5 84.38 5 5 98.91 3.5 5 5 110.04 5 5 75.79 5 5 65.09 4.3 5 5 92.45 5 5 75.16 5 ...read more.

Conclusion

It therefore competes with the substrate for the active site, so the reaction is slower. A non-competitive inhibitor molecule is quite different in structure from the substrate molecule and does not fit into the active site. It binds to another part of the enzyme molecule, changing the shape of the whole enzyme, including the active site, so that it can no longer bind substrate molecules. Non-competitive inhibitors therefore simply reduce the amount of active enzyme; similar to decreasing the enzyme concentration. In conclusion, the presence of these inhibitors will have altered the reaction by increasing or decreasing the rate at which the products are produced. There will have been limitations in the results as the range of buffer solution pHs used in the experiment were inadequate to determine an exact optimal pH for the enzyme Catalase to function. To find the optimal pH, further tests could have been conducted by using pHs with closer intervals within the range of 4.5 and 6.5, where the rate of reaction increases sharply, as shown on the graph by an arrow. By analysing the results and the graphs that were produced, there are no obvious anomalies in the results achieved; however there may have been a slight discrepancy in one result which is marked on the graph/s with a circle. This could have been a consequence of any of the factors mentioned above in the evaluation section. Adam Darrah A-Level Biology 09/05/2007 Influence of pH on the Activity of Potato Catalase ...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 Patterns of Behaviour 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 Patterns of Behaviour essays

  1. THE EFFECT OF BILE SALT ON THE ACTION OF THE ENZYME LIPASE

    Once the preparation for the experiment was complete, the probe was added to the mixture for readings to be taken. However, the solution was mixed a few times in some of the experiments. This was done to ensure that all the chemicals were interacting together and not settling at the bottom of the beaker.

  2. Effect Of Substrate Concentration On The Activity Of Catalase

    The only anomalies are the results at 8% and 10%. The result at 8% is slightly above the line of best fit and the 10% result is slightly below it. This is probably due to an experimental error involving one of the factors mentioned above.

  1. The Effect of Catalase in the Breakdown of Hydrogen Peroxide

    Average Reading (cm3) Average Volume of Oxygen (cm3) 20 45.9 2.8 30 45.4 2.1 40 42.8 5.7 50 42.7 5.2 60 31.5 10.9 70 32.5 11.49 Percentage of Catalase: 20% 1st Attempt 2nd Attempt Time: Reading (cm3): Volume of Oxygen: Reading (cm3): Volume of Oxygen: AVERAGE Reading: AVERAGE Volume of Oxygen: 0 48.7 0 48.5 0 48.6 0

  2. Experiment to investigate the activity of enzyme catalase at different pHs.

    Apparatus We set up the following apparatus as shown in the diagram. * Test tube rack * 2 boiling tubes * Rubber bung and delivery tube * Stop watch * Top-Hand balance * Measuring cylinder Safety In order to ensure the experiment is carried out safely I must clear all

  1. The effect of concentration on the activity of catalase.

    The molecule must approach each other and collide in the appropriate orientation. This is referred to as the steric factor. The molecules must also contain the minimum amount of energy for the reaction to commence. This is referred to as the activation energy.

  2. Factors Affecting Enzyme Activity

    and concentration of the enzyme solution (catalase solution). I think temperature would affect the rate of enzyme activity as all enzymes have an optimum temperature at which they work best, the reason for this is explained in the further theory section. This temperature is the temperature the enzyme was intended to work at.

  1. To investigate and compare the effect of temperature on the activity of catalase in ...

    Enzymes can break own substances, known as catabolism, or can join substances together, known as anabolism. Together they form metabolism, which is every chemical reaction in the body. Factors affecting the rate of reaction: The rate of an enzyme-controlled reaction is measured by the amount of substrate changed, or the amount of product formed in a given time.

  2. Effect Of Substrate Concentration On The Activity Of Catalase

    Test Tubes 6. Beakers 7. Test Tube Rack 8. Stop Watch 9. Pipette 10. Pipette Filler 11. Tap Water METHOD To test out how the concentration of hydrogen peroxide affects the rate of reaction first set up the apparatus below. 1. Add 2cm3 of yeast to one test tube.

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