• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10

Effect of enzyme concentration on initial rate of reaction

Extracts from this document...


Effect of enzyme concentration on initial rate of reaction The objective of this experiment is to determine how differentiating the concentration of the enzyme catalase affects the initial rate of reaction, in the decomposition of Hydrogen Peroxide (H2O2) The equation of this reaction is: Hydrogen Peroxide(aq) --> Water(l) + Oxygen(g) 2H2O2(aq) + catalase(aq) --> 2H2O(l) + O2(g) The source of the enzyme Catalase in this experiment will be yeast, specifically the Saccharomyces Cerewisea strain, as it is easy to obtain and very safe with no harmful effects to the environment. The technique used to obtain a set of results will be the downward displacement method, where evolved oxygen product from the reaction is passed through a delivery tube and into a water filled burette, pushing the water out of the burette, leaving obtainable results of Oxygen collected. These results will be taken every 5 seconds for two minutes and will give the rate of reaction. My Equipment will be: * Burette * Side-arm Conical Flask * Bung * Tubing * Yeast * Hydrogen peroxide * Water Bath * Water/Margarine Tub * Distilled water/pH7 buffer * Stopwatch I chose to have a burette to collect the evolved Oxygen, as it has a great degree of accuracy. The gas can be measured to 0.05ml or 0.5cm3. I chose to have a side arm conical flask to provide a source for the evolved oxygen to travel through easily. ...read more.


quickly into the side-arm conical flask, and then the 5ml yeast into the same flask, and quickly bung the top. * Measure the oxygen that has evolved every 5 seconds for two minutes, as to gain a value for the initial reaction. * If reaction too fast, half the concentration of hydrogen peroxide (to 10, then 5vols). * Repeat this for the 5 specific temperatures. Precautions: It must be assured that all equipment is washed between experiments where variables are changed, such as the conical flask, graduated pipette etc. also, making sure that they are dried thoroughly is important as any excess water could increase the dilution of the reactants and affect the results. It is also imperative that the stopwatch is started exactly at the same time in each experiment; as soon as the bung is put in. There are a couple of minor safety issues that must be addressed to assure 100% safety. Hydrogen peroxide can be corrosive, and can act as an irritant to the skin, eyes and clothing if spilled and not washed off thoroughly. All enzymes are potential allergies and can irritate membranes found in the eyes nose, or any other cavity. They can also cause asthmatic attacks. Spills of any substance should be washed immediately to obtain the safe environment. A lab coat and goggles should be worn to ensure these safety conditions, however inexplicit they may be. ...read more.


33.4 33.0 33.7 45 32.1 31.7 32.7 50 30.5 30.1 30.8 55 29.5 29.1 29.6 60 27.6 27.4 27.8 This also gave relatively similar to the above experiments but seems a little bit slower. However, it cannot be ruled out until the graph is completed. The last temperature to be tested was 50�C The results are below: Time (seconds) Burette reading (test 1,2,3) Average O2 evolved (cm3) 0 49.5 49.3 49.1 5 47.0 46.6 46.8 10 44.5 44.2 44.3 15 43.1 43.0 43.0 20 41.2 41.2 41.0 25 39.2 38.8 38.9 30 38.0 37.7 37.6 35 36.7 36.4 36.6 40 35.4 35.2 34.8 45 34.1 33.8 34.0 50 32.7 32.4 32.6 55 31.4 31.1 31.2 60 30.7 30.2 30.4 Once again, these resultsare similar to the above, so will again be determined via the graph. Method final experiment: * Set up the apparatus like in the diagram drawn * Place 5ml Yeast containing Catalase and 10ml hydrogen peroxide in water bath (in different vessels), which will be at the specific optimum temperature. * Mix the hydrogen peroxide (10ml/5vols) quickly into the flask containing yeast (5ml), when at required temperature, and bung the top. * Measure the oxygen that has evolved every 5 seconds for two minutes, after the first bubble has evolved as to gain a value for the initial reaction. * Repeat this 3 times for the specified enzyme concentrations, and work out the rate of reaction for each, and then an average for each concentration. ...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

Here's what a teacher thought of this essay

3 star(s)

*** Plan and initial experiments only. This mark is awarded only for the planning section.
The inclusion of many different trial experiments means that this experiment has been thoroughly planned experimentally to find the optimum values for the temperature and concentration of Hydrogen Peroxide.
The hypothesis is testable and is explained using relevant biological background material. The key variables are considered well.
To improve:
The inclusion of more relevant background material to inform the plan would be helpful. The material from textbooks or websites should be referenced at the end.
The risk assessment is not adequate to be awarded marks under the newest marking schemes and needs to considered much more carefully.
The writer needs to ensure that all graphs and table headings are fully labeled with a heading and unit. This should also include sketch graphs used to illustrate a point.

Marked by teacher Stevie Fleming 29/05/2013

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

    Isotonic Point of Potatoes

    5 star(s)

    A tissue paper must first be used to wipe off the water from the potato cylinders. * Make sure all test tubes are kept together so that the surrounding conditions are the same * The same potato should be used for the experiment as different types of potato may have

  2. Marked by a teacher

    Plan: The effect of the end product, phosphate, on the enzyme phosphatase

    5 star(s)

    which produces phenolphthalein and phosphate when reacts with phosphotase in a buffer solution. The reaction was carried out in 5 test tubes with different concentrations of sodium phosphate added to the buffer in each beaker and incubated in the same water bath for 20 minutes.

  1. Marked by a teacher

    The Effect of Temperature on Amylase

    3 star(s)

    After this, at the 60?C it is shown on the graph that the line shows a negative correlation because now the rate decreases to 0.22. Firstly, the rate increases because the enzyme and the substrate molecules both have kinetic energy which makes them collide more often and also because more molecules have sufficient energy to overcome the activation energy.

  2. Investigating the effect of changing the concentration of an acid on the rate of ...

    1.0 5 100% 0 0% To do this I would need a 10cm3 measuring cylinder, to measure out both ingredients, and the boiling tube I would be using in the experiment. Method to get 0.2moldm-3 acid 1. Using a pipette, I would collect some water, and squirt it into the

  1. A investigation into the effect of inhibitor concentration on the enzyme catalase.

    Catalase- This is the enzyme in the experiment; it is used to speed up reaction. The experiment is dependent on the concentration of Catalase because if I were to increase my enzyme concentration the rate of reaction would also increase.

  2. See the effects of amylase on starch at different temperatures and to find at ...

    The rate of reaction increases because of the increasing temperature, this causes the particles to vibrate and collide into each other more and more, this speeds up the break down of starch. As the temperature increases, the collisions per second increase, as the temperature gets too high many of the

  1. The Effect of Solute Concentration Upon the Rate of Osmosis

    This same process will occur after another 10 minutes in their solution, and again after 10 more minutes. After this has been done, I will have a full set of collected results for the potato cubes in the 0.0M, 0.2M and the 0.4M solutions.

  2. The aim of this experiment is to demonstrate that the substrate Hydrogen Peroxide will ...

    RISK ASSESSMENT: Having previously prepared a 'Risk Assessment' of the experiment, I followed the safety procedures, as identified in Annex A, so that I was able to conduct the experiment safely. I firstly tied back my long hair back.

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