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

Investigation on how the temperature affects the activity of the enzyme catalase in the decomposition of hydrogen peroxide.

Extracts from this document...

Introduction

Investigation on how the temperature affects the activity of the enzyme catalase in the decomposition of hydrogen peroxide PLANNING Aim - the aim is to find out the effect of temperature on the rate of reaction of an enzyme (catalase) by investigating the rate of decomposition of hydrogen peroxide. Three main factors will be measured: 1. Temperature - the optimum temperature of the enzyme (temperatures from 10�C to 60�C). 2. Oxygen - the amount released from the hydrogen peroxide, H2O2 (in cm3). 3. Time - the duration of the reaction (300 seconds). Scientific Knowledge Enzymes are complex three-dimensional globular proteins and acts as a biological catalyst, which alters the rate of a chemical reaction without itself undergoing a permanent change. They have a great significance involving the metabolic activities in living organisms. As the enzyme molecule is usually larger than the substrate molecule it acts upon, only a small part of the enzyme molecule comes into contact with the substrate. This region is called the active site. Catalase is an enzyme found in food such as potato and liver. It is used for decomposing hydrogen peroxide from cells, as it is a poisonous by-product of metabolism. Catalase speeds up the decomposition of hydrogen peroxide into water and oxygen, this is because the shape of the active site on the enzyme matches the shape of the hydrogen peroxide molecule so is able to bind with it. This type of reaction where a molecule is broken down into smaller pieces is an anabolic reaction. Hydrogen peroxide Water + Oxygen 2H2O2 (aq) ...read more.

Middle

Put the hydrogen peroxide in a beaker. Remove 10cm3 of the solution using a 10cm3 syringe. 6. Place the syringe into the hole in the bung and add the hydrogen peroxide to the potato discs in the conical flask. 7. Immediately start the stop clock. Record the volume of oxygen gas produced in the gas syringe every 30 seconds for a total of 300 seconds. 8. Repeat this method and increase temperature by 10�C each time until readings for 60�C is collected. Equilibration of the water in waterbath is very important because the temperature is known to fluctuate. For example there may be a temperature difference within the waterbath, therefore to ensure that the temperature of the water is the same in the waterbath, the water must be left for a period of time to come into balance. Using a couple of thermometers on either side can help in determining whether temperature is the equalised and stabilised. It is important to find out whether the hydrogen peroxide will react even when no enzyme is present and to see if any oxygen is given off - this will be the control. Diagram Variables 1. Independent Variable: - Temperature of solution, - Temperature of the water in the waterbath measured in �C using thermometers. 2. Dependant variable: - The volume of oxygen gas produced by the breakdown of hydrogen peroxide, which will be measured in cm3 in a gas syringe for 300 seconds. 3. Control Variables: - These variables, which can alter the rate of reaction, need to be kept constant all the time: Concentration of enzyme catalase: the higher the concentration, the higher the rate of decomposition of hydrogen peroxide. ...read more.

Conclusion

cannot be formed for a reaction to occur. When the enzyme (protein) is denatured it becomes less effective as a catalyst and soon the enzyme activity gets slower and then finally it stops. EVALUATION Limitation - It is quite different to make sure each and every potato disc is of the same size even though a ruler is used. Improvement - Vernier callipers, or a micrometer screw gauge can be used to measure the diameter of the potato discs- this would be more accurate than a ruler. Limitation - there were a few anomalies (see results table on page 7 highlighted in orange). Possible reasons might have been due to human error or contamination in the substrate. It could also be the temperature of the room. The experiment carried out on different days, some times the temperature in the room varied, from 23�C to 30�C. Improvement - Repeating the whole experiment - to eliminate anomalies and ensure the corrections of the optimum temperature. Limitation - Even though there were only a few anomalies, there was no way of determining the pH. Knowing the pH is essential as hydrogen ions are involved. Improvement ph meter could be used to determine the pH of the substrate hydrogen peroxide. A buffer solution could also be used, I can improve my method to give me better results by using a wider range of concentration of hydrogen peroxide. This would then give me more results in which I can use to draw up a better conclusion Temperature close to the optimum temperature, which is 40�C, could be investigated such as 39�C or 41�C to ensure the correct optimum temperature. A thermometer with a high resolution could be used for accuracy. Shimona Madalli The effect of temperature on catalase 4359 ...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

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

    The effects of Hydrogen Peroxide concentration on the activity of Potato Catalase

    4 star(s)

    1:6 (1cm3 of H2O2 to 5 parts of diluted water.) This means I can get a variety of different concentrations. Potato Catalase (5g per experiment) Used to break down Hydrogen Peroxide Can break down Hydrogen Peroxide Buffer Solution (10 cm3 per experiment)

  2. Marked by a teacher

    Enzymes - investigate how the substrate concentration (H2O2) affects the activity of catalase on ...

    3 star(s)

    To avoid this error when carrying out this experiment again I will put plasticine around the syringe and delivery tube. By doing this I can ensure that the top of the bung is air tight, and no gas is escaping.

  1. Marked by a teacher

    The effect of temperature on catalase activity

    3 star(s)

    Each enzyme has an optimum pH at which its active site best fits the substrate. Variation either side of pH results in denaturation of the enzyme and a slower rate of reaction. In this experiment, the pH should be kept constant using a pH 7 buffer, selected to maintain a

  2. The effect of Copper Sulphate concentration on Catalase activity on Hydrogen Peroxide.

    To measure out the solutions a pipette could be used for a good degree of accuracy. This variable must be kept constant in order to abide by the fair test criteria. o The Volume of the equipment - The same equipment should be used.

  1. An Investigation Into the Effect of Substrate Concentration On the Rate of Enzyme Activity.

    bead to travel from the bottom to the top of the test tube. The next temperature of hydrogen peroxide was meant to be 70oC. The catalase enzyme was expected to have been denatured by 65oC, but the speed of the reaction was still increasing.

  2. for this experiment my main aim is to investigate the effect of temperature on ...

    Inverted method * Lubricate inside of syringe to reduce friction when oxygen is being displaced during experiment. * Measure 8cm3 of Hydrogen peroxide using the pipette and pour into the conical flask. Make sure no air bubbles are introduced as this may affect the volume used, which will then affect the overall result.

  1. To investigate the rate at which hydrogen peroxide is broken down by the enzyme ...

    air being expelled when the bung is placed in the conical flask, causing the air to be displaced into the gas syringe. From my results I am able to see that my procedure has gone to plan, as the results I have achieved are as I had expected.

  2. How does a change in temperature effect the activity of the catalase enzyme on ...

    Diagram Pilot Test After taking the information above into account, I expect to see froth to appear of the surface of the solution if I use pure hydrogen peroxide. But I only want to measure the amount of oxygen given off.

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