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

the effect of catalase concentration on the breakdown rate of h2o2

Extracts from this document...


enzyme coursework: the effect of catalase concentrations on the rate of break down of hydrogen peroxide sara de sousa scientific knowledge and understanding: A rate is a measure of change that occurs in a given time whilst a reaction is the interaction of substances undergoing chemical change. The velocity at which any mix of substances are transformed into a product/s in a given unit of time is the rate of reaction. The speed at which this modification occurs relies on two main factors; the amount of collisions between reacting particles and what portion of these collisions are successful in producing a change within the substances present. Reactions between chemical substances will only occur if the particles collide with enough energy to break their initial bonds. This initial energy is called the activation energy. Collision theory: In order to react, particles must collide with a force sufficient to overcome the activation energy. There are four methods of increasing the rate of a reaction, and all can be explained in terms of increasing the number of collisions between reacting particles; 1. Temperature: when the temperature is increased particles move faster as they have more kinetic energy, encouraged by the heat. The more rapidly particles are moving, the more collisions are going to occur. 2. Pressure (or concentration): the more concentrated a solution, the more particles of a reactant are present. The higher the number of particles present the higher the likelihood of collisions. 3. Surface area: if one of the reactants is a solid then breaking it up into smaller pieces will increase its surface area. This means that particles in the solution around it will have a larger area to work on, so there will be more collisions in a shorter time. If both reactants are dissolved in solution/in a liquid state, surface area does not pertain and they relate directly to pressure/concentration. 4. Catalysts: catalysts work by giving the reacting particles a surface to stick to, where they can bump into each other. ...read more.


As I have increased the concentration of each catalase solution constantly, by the same amount each time, I assume that the initial rate of reaction for each catalase concentration will increase by the same amount each time. I believe that the 55% concentration solution will occur just under half the speed of the 25% concentration and at just over a third of the speed during the 70% concentration. apparatus (and justifications): ? Distilled water; will be used to clean some of the apparatus and to compose the catalase solutions instead of normal tap water, because it has no impurities, which may affect the break down of H2O2, resulting in inaccurate results. ? Celery extracts; will be combined with the distilled water to make the different catalase solutions. ? Hydrogen peroxide; the difference in the rate of break down of H2O2, into water and oxygen, will be observed of different concentrations of catalase solutions. ? 3 10ml and 2 5ml syringes; 1 of the 10ml syringes will be used for the hydrogen peroxide, whilst one of each size is used for both the distilled water and the celery extracts. I will be using syringes rather than measuring cylinder because they are much more accurate in measuring liquids, and are still practical to use, as I will only be using relatively small amounts of each liquid. ? 3 50ml glass beakers; I will pour each of the different liquids into a different beaker, so that they can be 'sucked up' by the syringes. ? 6 25ml glass beakers; to hold each of the catalase solutions. ? Conical flask; the shape of the conical flask allows for the 'swirling' of the liquids which are in it. This is a very important feature, as the H2O2 will need to be stirred with the catalase solution in one way or another to ensure that the enzyme and substrate molecules are evenly dispersed, without any being lost in the process. ...read more.


I concluded that there was no need to carry out the experiment for less than 25% because it would happen too slowly to be bothered with. I decided to choose concentrations that had less of a difference, so that when it comes to plotting my graph I will be able to plot points closer together and get a more accurate line of best fit. During my preliminary investigations I only noted the volume of gas produced every 30 seconds, but found that it was difficult to see the progression, so I decided to shorten the time intervals to 15 seconds for the real experiment so that the difference between the amount of oxygen produced would be more evident. I decided to carry on each experiment for 3 1/2 minutes to end up with 14 results for each concentration. The more results are obtained the easier it is to plot a graph and draw in the line of beat fit. I shortened the time to 3 1/2 minutes from 5, which I did in my preliminary because the volume did not alter very much after 4 minutes and this way I would be able to carry out the same experiment more times, to give me a more accurate average result. safety: Of the apparatus being used some is made of glass, and therefore very fragile. Care must be taken to ensure that none of the apparatus is knocked over/falls and breaks, as the glass would shatter. In the event of any breakages, DO NOT TOUCH ANY BROKEN GLASS, but call the supervising teacher immediately. Hydrogen peroxide must also be handled with caution. It is a corrosive chemical; so a lab coat and goggles must be worn. If contact is made with the skin, wash immediately with soap and water. To reduce the risk of any spillages, the transfer of H2O2 to different vessels should be limited, such as in step 5 of the method where it is transferred from the beaker to the syringe straight to the conical flask. as-level biology coursework, enzyme concentration, sara de sousa ...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

    Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst

    4 star(s)

    Results Ratio of hydrogen peroxide to water (cm3) Concentration of Hydrogen Peroxide (%) Time (secs) Celery (cm3) Volume of gas collected (cm3) Average volume of gas (cm3) Average Rate (cm3 s-1) 10:0 6 30 10 8.5 14.70 2.0 10:0 6 30 10 13.0 10:0 6 30 10 16.5 5:5 3 30 10 8.5 8.80 2.4 5:5 3 30

  2. Marked by a teacher

    How does the concentration of enzymes affect the breakdown of starch by a-amylase in ...

    4 star(s)

    Due to this mixture, a ratio is created of enzyme-water molecules. In a pure sample of enzyme, no water is present, and therefore only enzyme molecules are present. If water is added, however, there will be a certain number of water molecules for every enzyme molecule.

  1. Marked by a teacher

    Beetroot Practical Write up

    3 star(s)

    However a chart is considerable easier to read and the colourimeter is occasionally difficult to make a reading exactly 100% with a water filled cuvette. These readings fluctuate between 98% and 102%, which could possibly cause variations with the rest of the experiment results.

  2. Effects of Copper Sulphate on the Activity of Catalase

    released: The graph (see graph 1) generally shows the trend which occurs when there is no CuSO4 present in the solution. It shows that there is a positive correlation between the amount of oxygen produced and the concentration of the substrate, and as time goes on, more oxygen is produced.

  1. Investigation of the effect of adding different concentrations of NaCl to an enzyme-substrate (amylase-starch) ...

    The volume of NaCl used should also be reduced, because, being a cofactor, it increases the ability of solution to form substrate-enzyme complexes. This in turn increase the rate at which the starch is broken down; therefore this gives justification to reduce the volume used down to 1cm�.

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

    (Diagram obtained from the following source) http://metallo.scripps.edu/PROMISE/CATALASE.html X-axis= time Y-axis= volume of gas produced In non-competitive inhibition the inhibitors interfere with enzyme-catalysed reactions by combining with enzymes at locations outside the active site. These inhibitors, rather than reducing accessibility of the active site to the substrate, cause changes in folding


    In fact, the substrate must enter the cytoplasm of the saccharomyces cerevisiae cells before it can undergo respiration. So the saccharomyces cerevisiae cells initially needs to release digestive enzymes, specifically carbohydrase to extracellularly digest the large carbohydrates such as disaccharides or polysaccharides, because these are simply too large to pass through the membrane of the saccharomyces cerevisiae cells.

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

    7.5 7.5 10 10 10 12 non-immob. 11 11 12 12 12 14 ? R1 = 21 ? R2 = 57 U1 = n1 x n2 + 1/2 n2 (n2 + 1) - ? R2 U1 = 6 x 6 + 1/2 6 (6 + 1) - 57 U1 = 36 + 21 - 57 U1 =

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