• 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

Investigation into the initial rate of hydrogen peroxide decomposition when the enzyme catalase is used.

Extracts from this document...

Introduction

Investigation into the initial rate of hydrogen peroxide decomposition when the enzyme catalase is used. When Hydrogen Peroxide is broken down there are two products, Oxygen and water. However, the breakdown of Hydrogen Peroxide requires the enzyme catalase which catalyses the reaction. Catalase is found in microbodies and in this experiment the source of catalase is yeast. The formula for the decomposition of Hydrogen peroxide is: (Catalase) H2O --> H2O + O2 The reaction is an anaerobic one, meaning it happens in the absence of oxygen. To measure the rate of the enzyme reaction I will collect the oxygen produced in the reaction over a two-minute period. Also, I will vary the concentration of the hydrogen peroxide each time. So my experiment will look at how the concentration of H2O2 affects the speed of an enzyme controlled reaction. Enzymes, such as catalase, are used to speed up a specific reaction. Each enzyme has an active site in which the break down of the substrate occurs. However, each enzyme's active site is shaped to fit one type of substrate and is said to be specific to the substrate. The specificity of an enzyme to its substrate is known as the 'Lock and Key' theory. Enzymes are globular proteins made up of amino acids and s in any globular protein; there are four types of bonding that give the protein its three-dimensional structure. The four types of bond are disulphide bond, hydrogen bond, ionic bond and hydrophobic interactions. When it has been shaped the amino acids that make up the enzyme's active site and called catalytic amino acids. The aim of this investigation is to find out how substrate concentration will affect the initial rate of reaction. Substrate concentration is an independent variable while the rate of reaction is a dependent variable. An independent variable is a variable that the values have already been chosen for, while the dependent variable is the result or measurement taken that would relies upon the value of the independent variable. ...read more.

Middle

If H2O2 is spilled then it should be covered with a mineral absorbent and then diluted with water. My results are as follows: O2 Collected (cm3) H2O2 (ml) H2O (ml) Time (sec) 1st 2nd 3rd Average 1 4 10 7 6 5 6 1 4 20 8 7 6 7 1 4 30 8 8 8 8 1 4 40 9 9 8 8.7 1 4 50 9 9 9 9 1 4 60 9 10 9 9.3 1 4 70 9 10 9 9.3 1 4 80 9 10 10 9.7 1 4 90 9 10 10 9.7 1 4 100 9 10 11 10 1 4 110 9 11 11 10.3 1 4 120 9 11 11 10.3 O2 Collected (cm3) H2O2 (ml) H2O (ml) Time (sec) 1st 2nd 3rd Average 2 3 10 4 7 12 7.7 2 3 20 4 9 16 9.7 2 3 30 8 11 18 12.3 2 3 40 9 14 20 14.3 2 3 50 12 17 24 17.7 2 3 60 15 22 28 21.7 2 3 70 19 26 33 26 2 3 80 22 28 36 28.7 2 3 90 25 31 40 32 2 3 100 27 33 43 34.3 2 3 110 28 35 46 36.3 2 3 120 29 36 47 37.3 O2 Collected (cm3) H2O2 (ml) H2O (ml) Time (sec) 1st 2nd 3rd Average 3 2 10 8 11 12 10.3 3 2 20 11 14 15 13.3 3 2 30 13 16 18 15.7 3 2 40 15 18 19 17.3 3 2 50 16 19 21 18.7 3 2 60 17 20 22 19.7 3 2 70 18 21 23 20.7 3 2 80 22 22 24 22.7 3 2 90 27 23 25 25 3 2 100 33 23 26 27.3 3 2 110 35 24 27 28.7 3 2 120 37 25 27 29.7 O2 Collected (cm3) ...read more.

Conclusion

Another reason why my results are unreliable is that the surface area was not the same each time. If the yeast in one experiment had a much higher surface area then it was going to have a much faster initial rate of reaction than an experiment where yeast had a small surface area. This is likely to be why my 2ml H2O2 experiment came out higher than my 3ml and 4ml H2O2 experiments On my graphs I have circled what I think are anomalous results. My first anomalies occur on my 2ml H2O2 graph. Between 40seconds and 60seconds the O2 collected is 14.3cm3, 17.7cm3 and 21.7cm3. I think that, although the graph on the whole is unreliable, these are anomalous because they do not fit the best-fit curve. On the 3ml H2O2 graphs I have circled two points as these points dip below the best fit curve and then back up again. At 70seconds and 80seconds the O2 collected is 20.7cm3 and 22.7cm3. A possible reason for this could have been that the tube might have been blocked, maybe by the way that the measuring cylinder was held. It might have been different if the measuring cylinder was clamped so it couldn't move and therefore couldn't squash the tube. By holding the measuring cylinder it was possible that it may have been pressed down on the tube briefly. This would of held the O2 in the tube and then when it was released the O2 would have all come out at once, resulting in the points moving back to the best-fit line. On the 5ml H2O2 graph I have circled one point. This point is after 30seconds and misses the best-fit curve by about 4cm3; it has 30cm3 whereas the curve crosses 30seconds at 34cm3. The reason for this anomaly could have been the same as above or possible because of a reading inaccuracy. Also, when holding the measuring cylinder, it was not always held perfectly upright, and therefore could have given a false reading but this is likely to have been the same throughout the 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 Patterns of Behaviour 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 Patterns of Behaviour essays

  1. Factors Affecting the Rate of Catalytic Decomposition of Hydrogen Peroxide.

    Temperature of Catalyst (Manganese Dioxide) If the temperature of the catalyst was increased, then the heat energy would spread to the reactant (the H202 particles which are colliding). These particles would therefore gain energy and more would be able to reach their activation energy, as explained on the previous page.

  2. The Decomposition of H2O2 using Catalase, in yeast as a catalyst.

    Volume of O2 (cm3) 0.15 22.0 0.30 25.0 0.45 28.0 1.00 29.5 1.15 32.0 1.30 32.0 1.45 34.0 2.00 35.0 I used double the volume of H2O2 this meant that the O2 was given off much fast. This made it difficult to take accurate readings because the gas was being given off so quickly.

  1. The aim of the investigation is to examine the kinetics involved in the reactions ...

    This proved to be a key factor in the validity of the results obtained from the experiment. It is important to understand the consequences of failing to keep a constant length of magnesium ribbon in the experiment i.e. smaller than 2.0cm.

  2. Free essay

    Close Your Eyes

    My bed was already in place with my duvet and pillows neatly arranged. That would soon change. I got into my pyjamas and jumped onto my bed. Switched on the laptop and waited for it to load. Username - Mrs Jones Password - Bolton_Queen Guitarist and Vocalist of McFly, Danny Jones was my god.

  1. Investigation On The Enzyme Trypsin

    Here are my results: A Table showing the relationship between the Incubation Time period, and the % decrease in the rate of reaction Incubation Time (minutes) % Decrease in rate of reaction 5 - 6 4 6 - 7 6.7 7 - 8 4.5 8 - 9 8.5 9 -

  2. Factors Affecting Enzyme Activity

    This is because the enzyme would denature, losing its shape and therefore making the active site unsuitable to accept the substrate. This is better explained in the further theory section. I would expect a graph of rate of reaction against temperature to look like the one on the next page.

  1. THE EFFECT OF BILE SALT ON THE ACTION OF THE ENZYME LIPASE

    Chemicals required * Distilled water. * Sodium hydroxide. * Lipase (enzyme). * Full-fat cream, lipid (substrate). * Bile salt. Concentration of bile salt Table two below, demonstrates how to maintain the different concentrations of bile salt, which is essential once conducting the experiment, in order to observe the affect of bile salt on the activity of lipase on lipids.

  2. To determine the rate law for a chemical reaction among hydrogen peroxide, iodide and ...

    Part II - Reaction Rate Measurements The information necessary to determined the effects of the concentration of H2O2, I- and H+ on the rate of reaction by six reaction mixtures, as well as the effect of temperature and a catalyst.

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