• 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

How varying the substrate concentration (hydrogen peroxide) when reacting with an enzyme catalyse (potato) affects the volume of oxygen produced.

Extracts from this document...

Introduction

Enzymes are biological catalysts. They increase the rate of chemical reactions taking place within and around living cells without suffering any overall change. There are 3 known factors that affect the rate of reaction in accordance with predictable interactions between enzyme and substrate molecules: Temperature - The affects of temperature may be explained on the basis of kinetic theory. Increased temperature increases the speed of molecular movement and thus the chances of molecular collisions. It is often said that an enzyme's rate of reaction doubles for every 10� C rise in temperature. pH - Changes in the pH affect the attraction between the substrate and enzyme, and thus the efficiency of the conversion process. Often there is an optimum pH, near pH 7 (neutral) in intracellular enzymes, and in the acidic range between pH 1-6 and in the alkaline ranges between pH 8-14. Concentration - There are two types of concentration, concentration of substrate and concentration of enzyme. Substrate concentration can alter the rate of reaction as the higher concentration the more frequent collisions with enzymes and therefore a higher rate of reaction. The concentration of enzymes is similar, as if there is a higher concentration of enzymes then there will be more frequent collisions and therefore a faster rate of reaction. AIM: How varying the substrate concentration (hydrogen peroxide) when reacting with an enzyme catalyse (potato) affects the volume of oxygen produced. BACKGROUND KNOWLEDGE: The reactants of enzyme-catalysed reactions are termed substrates and each enzyme is quite specific in character with a unique 3 dimensional shape shared by all its molecules. Within the shape there is an area called the active site where the chemical reactions occur. In order for this reaction to occur only a small amount of enzyme (catalyse) added to the substrate is required. As according to the Lock and Key theory, the substrate and catalyse molecules are continuously on the move and providing that the substrate is complementary to the active site of the enzyme, every so often they will collide so the substrate molecule(s) ...read more.

Middle

7. Repeat stages 3-6 again, but stage 3 should be altered so the next range of substrate concentration is experimented. i: this procedure should continue until you have recorded all results up to 50 cm3 water and 0 cm3 hydrogen peroxide. 8. Finally repeat the whole experiment again in order to increase the accuracy of results which will make an average calculation possible for each recording. Before the results are recorded into the final results table, initially this should be converted to the volume of oxygen collected. This can be calculated from simply subtracting the volume of water present in the measuring cylinder after 5 minutes from the volume of water at the beginning of the experiment. There are many elements to ensure a fair test is carried out: All recordings will be repeated twice; this will allow me to identify any recording that doesn't follow the usual trend and furthermore calculate an average, I will use the same set of equipment for each recording, and caution will need to be taken when measuring the volume, as a mere mismatch of measurement may be unreliable. Safety is also a major factor that needs to be kept in mind at all times: Risk Preventative Actions Hydrogen Peroxide irritant Wear goggles, Care when dispensing, Mop up spillages, wash of spillages quickly. Tube breakages Wear goggles; clear up immediately after breakage occurs. All apparatus should be handled with care, and primarily with the glass equipment placed away from the edge of the desk. RESULTS: Length of potato chips - 3cm Temperature - Room temperature VOLUME OF WATER (CM3) CONCENTRATION OF HYDROGEN PEROXIDE (CM3) VOLUME OF OXYGEN COLLECTED (CM3) IN 5 MINUTES -1dp- 1 2 Average 0 50 12.5 12 12.25 10 40 11 11.5 11.25 20 30 10 8 9 30 20 8 7.5 7.75 40 10 5.5 5.5 5.5 50 0 0 0 0 The lengths of the magnesium were all matching in length, and I assured the concentration of hydrogen peroxide used was as precise as possible to the required measurement. ...read more.

Conclusion

This enabled me to calculate an average and gave me the advantage of being able to produce a better analysis overall. In addition to the scopes of errors mentioned above, there are many other incontrollable factors that may have had a form of influence or obstruction. However no significant problems or difficulties were encountered whilst conducting the experiment. My results and conclusion were accurate and reliable enough to verify a relationship that as the concentration of hydrogen peroxide is increased, the rate of reaction also increases, hence agreeing with my set prediction. Improvements: No matter how accurate produced results are, due to the restriction in apparatus provided and the time to complete the investigation, improvements will always be applicable. Possible improvements: * There are methods to ensure the temperature is kept constant throughout the experiment. This could be by adding ice whenever the temperature exceeds the normal room temperature; however it is known that the most productive temperature for enzymes to work is at about 40�C. So therefore the temperature could be kept at this constant with the use of a thermometer, Bunsen burner or kettle. * Instead of simply measuring the length of the potato pieces it would be more accurate if they were weighed also. This would be to ensure the pieces are indistinguishable. * Even though two repeats for each recording was accurate enough to produce a reliable average, increasing this to three or four recordings would produce a range of results which could then be analysed in more detail. Extending the investigation: * There are alternatives to using a potato for catalyse for example cheese or bread. A liquid can also be used, yoghurt, beer or wine to name a few examples. * It would be interesting to observe the results if the concentration of hydrogen peroxide was varied to every 5cm3. * The affect temperature has on the rate of reaction can be investigated by making this the independent variable and making the concentration a constant. SECONDARY SOURCES OF INFORMATION: http://www.8886.co.uk http://www.s-cool.co.uk http://homepage.ntlworld.com/mbradley49/science/amylase_project.html NIKESH PARMAR - 11E 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)

    To control the substrate concentration, identical quantities of the substrate were used for each reading. To ensure that this was measured precisely, 10ml syringes were used to accurately extract the hydrogen peroxide. This was done as the rate of reaction would be affected by the level of substrate concentration in relation to enzyme concentration.

  2. Peer reviewed

    The Journey of a cheese sandwich

    4 star(s)

    In the small intestine there are millions of villi. These are small, but visible to the human eye, finger like structures which line the small intestine and are perfect for absorbing the food. The main reason why villi are so good at absorbing food is that they have a thin layer of outer cells, which act as a cell, called micro-villi.

  1. An investigation into how enzyme concentration (catalyse in a potato) affects the rate of ...

    Therefore the larger the surface area exposed, the faster the reaction rate. Ph Level The majority of enzymes work most effectively at Ph 7. Substrate molecules fit into the enzyme's active site because of the surface electrical charge of amino acids in the enzyme molecule and the charge of the substrate molecule.

  2. Decomposition of Hydrogen peroxide

    I must also make sure that I have diluted the substrate precisely in order to get accurate and reliable results. The temperature has to be constant on room temperature the whole time in order that the results should not be affected.

  1. Enzyme Investigation. How to find the best concentration of hydrogen peroxide that will react ...

    Clean your desk and put all of your equipment away and wash your hands Results for pre-test: Time (seconds) Volume of O� produced (cm�) pH 30 60 90 120 150 180 210 240 4 12 15 21 26 29 34 40 43 14 19 24 29 32 37 43

  2. An experiment to investigate whether a change in the concentration of hydrogen peroxide substrate ...

    They have to be kept the same for the experiment to be a fair test. Increasing the temperature will increase the rate of product produced at first. This is because it increases the energy and frequency of collisions of an enzyme and substrate.

  1. Free essay

    This experiment examines how the concentration of hydrogen peroxide affects the rates of reaction ...

    30 50 37.5 22.5 These are the measurement I will be using in my experiment. Method * First I collected my equipment * Next I put on some gloves and safety goggles to protect my hands and eyes from the chemicals * Then I attached the clamp to the stand

  2. Investigating the Effect of Substrate Concentration on the Rate of a Catalyse Reaction- plan

    Variables Dependant. The variables I will control are temperature and enzyme concentration, in the form of a potato; instead an animal tissue could be used such as liver; pH, which will be controlled using a pH buffer. I need to control these variables so that I can identify what factor changes the rate and volume of oxygen produced.

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