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

The effect of substrate concentration on Potato Catalase

Extracts from this document...


The Effect of Substrate Concentration on Plant Catalase Aim The aim of this experiment is to investigate how the concentration of the substrate, Hydrogen Peroxide, affects the rate of a chemical reaction with plant catalase. Hypothesis An enzyme is a biological catalyst, which increases the rate of chemical reactions. Catalase is an enzyme, which occurs in the cells of many living organisms. Certain of the energy releasing reactions in the cell produce hydrogen peroxide as an end product. This compound, which is toxic, is split into water and oxygen after reacting with catalase. Hydrogen Peroxide � Water + Oxygen 2H2O2 � 2H2O + O2 I predict that as the substrate concentration increases the rate of reaction will also increase. At the beginning of the reaction there are lots of substrate molecules around, therefore more active sites can bind with them. This shows how the substrate bonds to the active site of the enzyme: If the substrate concentration is constantly increased, and the enzyme concentration remains constant there comes a point where every active site is working continuously. If more substrate is added the enzyme cannot work any faster, because the active sites are saturated. The substrate molecules have to wait until the enzyme-substrate complex (e-s complex) has released the products before it can enter into the active site. ...read more.


so that the pH remains constant. * Cork borer * Knife * Ruler * 45cm� hydrogen peroxide (1 mol concentration) - substrate for dilution * Distilled water - for diluting the hydrogen peroxide * Monometer tube approximately 3mm in diameter * Monometer fluid * Spring clips - to open and close the monometer, which will bring the monometer fluid back down to its original level when opened. * Wax pencil - for marking a gap of 5cm on monometer above the level of monometer fluid. * 2 syringes 5cm� -to increase the accuracy of measurements * 5 boiling tubes * Rubber bung * Forceps * Sticky labels * 5 Beakers 20cm� * Clamp stand * Digital stop clock - for gathering more accurate results Procedure 1. Consider safety precautions - handle dangerous equipment carefully, wear lab coat and goggles 2. Set up the apparatus as shown below 3. Cut 10 potato discs of 1mm thickness. 4. Get five 20cm� beakers, distilled water and 45cm� hydrogen peroxide to prepare dilutions as followed: 5. Label the beakers with their concentrations 6. Put 5cm� of the first prepared substrate concentration into the boiling tube then add 5cm� of the catalase solution to it. 7. Put rubber bung back onto boiling tube as soon as possible because the reaction begins as soon at the two solutions are combined. ...read more.


There are two anomalies in the results at 4vol and 8vol substrate concentrations. The anomalies could have been due any of the variables not remaining constant. It was difficult to maintain accuracy during the procedure. This was because it had to be repeated so many times. It was quite a long procedure and it had to be done in total 15 times. One variable that may have differed was the thickness of the potato discs. As there were 150 discs it was difficult practically to make sure they were all equal in size. Given the time I had to complete the experiment many of the discs were measured subjectively. The time taken to replace the rubber bung, after the substrate had been added to the potato catalase also affected the reliability of the experiment. Once the bung had been replaced on the test tube the reaction had already begun so the time taken was not measured accurately. I also had to predict the rest of the graph because there were not enough results. This was due to there not being higher substrate concentrations available. This experiment could be improved if there was access to higher concentrations of Hydrogen Peroxide. This would have increased the number of results obtained and therefore increased the range of the graph. This would have shown more patterns in the results, which would have produced a more accurate and successful experiment. ...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

    To investigate the effect of substrate concentration on Catalase Activity.

    3 star(s)

    Firstly the bung did not fit our tube so it was impossible to fully close the tube containing hydrogen peroxide and Catalase. This unfortunately allowed some oxygen to escape into the atmosphere. Next the tube didn't stay in the measuring cylinder making it hard to collect the oxygen; most of the oxygen ended up escaping.

  2. Investigating the Effect of Substrate Concentration on Catalase

    The more oxygen produced, the more water will get displaced. I predict that as the substrate (hydrogen peroxide) concentration increases, so will the amount of oxygen produced and therefore, the volume of water displaced will increase too. This is because substrate concentration affects enzyme-catalysed reactions.

  1. The effect of hydrogen peroxide on catalase if you change the temperature.

    2.5 10 28.7 3 10 28.7 3.5 10 28.7 4 10 28.7 4.5 10 28.7 5 10 28.7 TEMPERATURE: 55�C TIME (mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm�) 0.5 5.0 13.7 1 6.3 19.0 1.5 7.1 22.0 2 8.0 24.0 2.5 8.0 25.0 3 8.0 25.7 3.5 8.0 26.0 4 8.0

  2. Structures and functions in living organisms. Revision Notes

    2.68 Recall that the lungs, kidneys and skin are organs of excretion Lungs - carbon dioxide Kidney - Urea + Other waste products Skin - sweat (water + minerals) 2.69 Understand how the kidney carries out its roles of excretion and of osmoregulation The kidney filters blood to remove waste

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