• 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

Catalase Enzyme Coursework

Extracts from this document...

Introduction

Effect of Enzyme Concentration on Hydrogen Peroxide Aim: The aim of this investigation is to find out how varying the number of potato discs affects the rate at which Catalase breaks down Hydrogen Peroxide. Background Information "The fastest known enzyme is Catalase. Found in the liver where it speeds up the decomposition of hydrogen peroxide into water and oxygen, Catalase has a turnover number [the number of substrate molecules which one molecule of enzyme turns into products per minute] of 6 million. Its action can be demonstrated by dropping a small piece of liver into...hydrogen peroxide: the fizzing that ensues as oxygen is given off is a dramatic demonstration of an enzyme in action." -M.B.V. Roberts, from "Biology A Functional Approach" Catalase is also found in a common potato, where it follows the same reaction. This reaction takes place in the potato to ............ Enzyme molecules have a very specific method of converting those molecules upon which they work (the substrate molecules). Enzyme molecules are proteins that act as biological catalysts, so they are not themselves used up when converting substrate molecules into the product. Here it is also used for the break down of hydrogen peroxide into oxygen and water, as shown in the equation below:- Hydrogen peroxide Catalyst oxygen + water 2H2O2 O2 + 2H2O The rate of a reaction means the speed of the reaction, how long it takes for the two reactants to react together to form a new substance called a product. There are many conditions you can add to the experiment to speed up the rate of reaction. In order to speed up the rate of a reaction you can choose these conditions: > Increase the temperature of the reactants. > Increase the concentration of the reactants. > Increase the surface area of the reactants. > Use a catalyst. > Use light. For a chemical reaction to happen the particles involved must collide. The collision also has to transfer enough energy for the reaction to be successful. ...read more.

Middle

* 15 boiling tubes * Distilled water in order to make dilutions * 3 delivery tubes attached to bungs which fit delivery tubes and the gas syringes * Boiling tube racks to place the boiling tubes into * 3 clamp stands to hold the boiling tubes upright * 10 pipettes or 2 measuring cylinders to add the hydrogen peroxide into the boiling tubes * Safety goggles to avoid eyes coming into contact with hazardous chemicals * Rubber gloves to prevent skin from coming into contact with hazardous chemicals * Forceps (tweezers) to place and remove the potato discs from the boiling tubes Method: 1. Collect the apparatus listed and set up the experiment as shown. 2. Using a potato borer with a diameter of 1cm bore the potato on a white tile. Making sure fingers are kept clear of the borer end, so you don't hurt yourself. 3. Using forceps (tweezers), remove the tube of potato from the borer. Forceps should be used to allow minimal exposure of the potato discs to the surrounding environment. 4. Using a knife, cut the tube of potato into equal sized discs with a diameter of 2mm. Make certain that you are careful when cutting the potato and keep your fingers clear of the blade. 5. There are 30 discs need as the first experiment is carried out3 times using 10 discs each time. 6. Into a boiling tube, collect 10cm� of hydrogen peroxide (diluted to 20%vol.) using a pipette or measuring cylinder. 7. Next, collect the rubber bung with delivery tube attached to it. Make sure that the two are well connected to prevent any loss of the oxygen gas that will be produced. 8. The other end of the delivery tube should be attached to the gas syringe. 9. Then add 10 potato discs to a boiling tube containing hydrogen peroxide and close the bung straight away. ...read more.

Conclusion

This prevented oxygen gas being collected in the syringe. This could be overcome by using a conical flask. Conical flask will give a bigger volume to react in would allow maximum oxygen gas to be collected. A good point is that the syringe was held on the clamp stand. There was no contact with it. This would prevent body heat being transferred to the syringe. Having held the syringe at 180 degrees, meant that it was easy to see how much gas had been collected. It made reading of the meniscus straightforward. However there could have been a possibility that I mis-read the meniscus reading. This could have also been true when measuring the hydrogen peroxide. Another positive element was that no kinetic energy was applied to the boiling tube. As you can see that there are many criticism of my method. Overall the method was reliable but may be the way things were used may have lead to inaccuracies. And of course there was human error too. If I was to do this experiment again then I would make sure that all apparatus was cleaned with a disinfectant. This time I would utilise a conical flask rather than a boiling tube. An additional thing I could do is that I can control some of the variable affecting the enzyme activity. For example temperature can be kept constant by carrying out the experiment in a water bath. pH can be controlled by adding an equivalent amount of buffer solution each time. Investigations on enzymes are a very wild field. If I was to make further investigations, I would investigate how the activity of enzyme differs across different potatoes. So I could try a range of potatoes such as canned, frozen dried. I can see hoe the activity of the catalase differs across different potatoes. Also since the aim of my experiment was to research on the concentration of enzymes, I will conduct the further experiment with a much higher range of potato discs, to see the affect of the rate of reaction. ?? ?? ?? ?? ...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

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

    3 star(s)

    * Make sure long hair is tied back. * If there are any breakages or spillages inform the laboratory staff in charge, and take appropriate course of action under their direction. Apparatus Equipment Number required Reason for choice Boiling tube 12 Use as a reaction chamber and to contain dilutions of hydrogen peroxide.

  2. Investigate how concentration of the enzyme catalase in celery tissue alters the rate of ...

    Gently shake the boiling tube to get rid of any bubbles. 12. Sticky label a 5 cm3 syringe 'H2O2'. 13. Record the temperature of the H2O2 in the beaker. 14. Immediately after, take the 'H2O2' syringe and use it to collect 5 cm3 of hydrogen peroxide using the same technique as outlined in step 7.

  1. A2 coursework- The effects of bile salts on digestion of fat

    lipase will not be breaking down the fat as quickly and so temperature will become an independent variable in this experiment. I found from my preliminary work that using a water bath worked well and it will keep the temperature more constant then a Bunsen burner which will also be

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

    is chosen correctly to allow for ease of method, and also accuracy. A preliminary experiment is also important to get an idea of how much of each solution should be used, and then at what strengths to use it. My initial idea was to use 5 different strengths of the

  1. Reaction of Catalase and Hydrogen Peroxide

    Hydrogen peroxide is produced as an intermediate during these chemical processes. And must be removed to prevent damage to cellular machinery. Prokaryotes organisms like bacteria that lack nuclear membrane also lack membrane bound organelles such as peroxisomes. Antioxidant enzymes like Catalase and superoxide dismutase are located in the periplasmic space,

  2. Investigating the effect of the Temperature on the Enzyme Catalase when it reacts with ...

    Below are the factors, which are kept constant. * Concentration of Hydrogen peroxide - use 1% concentration * Concentration of Catalase - use 50eu/cm3 of Catalase * Size of the paper (surface area) * Volume of Catalase - Use the same size and the same thickness of the filter paper

  1. Investigation of how PH affects the action of the enzyme catalase.

    It has been discovered that the substrate and enzyme are only fully complementary when the substrate is "bound" to the active site. The diagram shows that the shape of the substrate is similar to that of the active site, but they are not fully complementary.

  2. An Experiment Into How Temperature Affects the Activity of a Enzyme - Catalase and ...

    The illustration shows the rapid denaturing of an enzyme. Enzymes are also sensitive to pH in a cell there is a neutral level of pH (7) and this is usually when they work best. However enzymes in the stomach work best at a pH of 2.

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