• 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...

Introduction

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.

Middle

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.

Conclusion

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)

    Starting at a lower concentration would mean having to go into fiddly, hard to measure out decimal numbers, to get a good set of different concentrations. Next we tried reducing the celery concentration. The experiment was repeated, in the same way but using 10cm3 of hydrogen peroxide and 5cm3 of water.

  2. Marked by a teacher

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

    4 star(s)

    The idea behind this mechanism is that the substrate molecule fits into the rigid shape of the active site of the enzyme. This helps to explain the specificity of enzymes: a slight alteration in the shape of the active site means a mismatch in the shape of the substrate and the active site.

  1. Marked by a teacher

    The effect of temperature on the enzyme Catalase.

    4 star(s)

    but under room temperature at about 15�C it should work best because it is cool. I also know this because of my preliminary investigations and references off of the Internet. Equipment * Catalase enzyme (48ml) * Hydrogen Peroxide (24ml) * Test tube (3x for each denomination - 10�C, 15�C, 20�C, 25�C, 30�C, 34�C, 45�C, 50�C)

  2. Marked by a teacher

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

    3 star(s)

    The course of a reaction is affected by a number of factors, which are enzyme concentration, substrate concentration, temperature and pH. Temperature Temperature is a factor that affects enzyme activity. At low temperatures, the reaction takes place only very slowly.

  1. 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

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

    The main things that kept the results accurate was the fact that 6 repeats for each temperature were carried out, this meant that a good median average could be made. Secondly a large range of temperatures were used to test the catalase enzyme, this made the whole experiment and results very reliable and thorough.

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

    Apparatus The apparatus provided, as shown below, are the only pieces of equipment and chemicals that will be used in the experiment. � Lab Coat � Goggles � Stopwatch � Pipettes � Syringes � Test Tubes � Test Tube Holder Racks � Spotting Tiles � Beakers � 1% Starch Solution

  2. WHAT EFFECT DOES SUBSTRATE HAVE ON THE RATE OF RESPIRATION IN SACCHAROMYCES CEREVISIAE?

    So maltose is required to be broken down by the saccharomyces cerevisiae extracellularly. So when the maltose solution is added to the saccharomyces cerevisiae, the saccharomyces cerevisiae will secrete enzymes such as maltase, which travel out of the saccharomyces cerevisiae cell via the cell membrane.

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