• 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
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15
  16. 16
  17. 17

Factors effecting enzyme activity

Extracts from this document...


Biology Coursework Factors effecting enzyme activity Aim: To investigate the effect of temperature on the rate of catalase activity. Enzymes are proteins that act as catalysts, which are made in the cells. A catalyst is a chemical substance that speeds up a reaction but does not get used up in the process. Enzymes can be used over and over. There are two types of enzyme reactivity, these are called anabolic and catabolic reactions. An anabolic reaction is where large molecules are built up from smaller molecule. A catabolic reaction is where reactions split large molecules into smaller ones. Enzymes work by a method called the lock and key method: Basically it works by the enzyme meeting the substrate and they both fit together well to make an enzyme-substrate complex. This works well because enzymes have a definite three dimensional shapes which is complementary to the shape of the substrate. In the enzyme-substrate complex, the substrate attaches to an area on the enzymes known as the active site. The enzyme is then free to react again with any available substrate. Catalase can be found, not just in humans but in potatoes, apples and the liver. During my preliminary work, I will be investigating which of these gives off the most oxygen. The one which gives off the most oxygen will be the catalase that I use during my experiments. This way it will give me the best results as it has produced the most oxygen. The rate of catalase activity can be measured by measuring the amount of oxygen given off by reacting catalase with hydrogen peroxide. Hydrogen peroxide is a harmful by-product of the process of cellular respiration especially if it builds up in concentration in the cells. The oxygen could be collected by using an upside down measuring cylinder. Hydrogen peroxide is a by-product of fatty acid oxidation. White blood cells produce hydrogen peroxide to kill bacteria. ...read more.


After every 10 seconds record the amount of oxygen that has been produced. Record your results in a table like the one below and repeat three times for accurate results. Below is a blank results table to show how I am going to record my results: Temperature/�C Time/secs Oxygen produced (1)/cm� Oxygen produced (2)/cm� Oxygen produced (3)/cm� Average Obtaining Evidence: During the biology coursework day, I carried out a series of experiments to investigate how temperature affects the rate of catalase activity. Using my method I got the results below: Firstly, I am going to measure the rate of reaction at 20oC. However, the closest that I could get to 20oC was 21oC as the temperature fluctuated quite a bit. Here is the table of results that I obtained from doing that experiment: Temperature/�C Time/secs Oxygen produced (1)/cm� Oxygen produced (2)/cm� Oxygen produced (3)/cm� Average 21.0 10.0 28.5 28.3 28.9 28.6 21.0 20.0 34.5 33.5 33.1 33.7 21.0 30.0 35.6 35.1 35.5 35.2 21.0 40.0 36.6 36.1 35.6 36.1 21.0 50.0 36.8 36.3 36.7 36.3 21.0 60.0 37.0 36.3 35.7 36.3 I then increased the temperature from 21oC to 29oC, to see whether increasing the temperature affected the rate of reaction, recorded my results in this table: Temperature/�C Time/secs Oxygen produced (1)/cm� Oxygen produced (2)/cm� Oxygen produced (3)/cm� Average 29.0 10.0 33.1 34.7 35.0 34.3 29.0 20.0 35.0 35.2 37.1 35.8 29.0 30.0 35.5 35.3 37.5 36.1 29.0 40.0 35.8 35.4 37.8 36.3 29.0 50.0 36.0 35.5 38.0 36.5 29.0 60.0 36.0 35.5 38.1 36.5 I then increased the temperature again to 38oC to see how increasing the temperature affected the rate of reaction, here is a table to show my results: Temperature/�C Time/secs Oxygen produced (1)/cm� Oxygen produced (2)/cm� Oxygen produced (3)/cm� Average 38.0 10.0 31.0 31.0 31.0 31.0 38.0 20.0 31.1 32.0 32.5 31.9 38.0 30.0 31.2 33.5 33.0 32.6 38.0 40.0 31.3 34.0 33.5 32.9 38.0 50.0 31.6 34.1 33.6 33.1 38.0 60.0 31.6 34.1 33.6 33.1 I then increased the ...read more.


Also given more time I would have repeated any set of readings that after evaluation appeared to be anomalous and a poor fit. Despite the anomalous readings at 38oC, I consider my results were good enough to show clearly how rate of reaction of catalase changes with temperature, the more detailed investigation between 35 and 40oC also showed clearly that the optimum temperature for enzymes to work in is 37oC. I now know how temperature affects the rate of catalase activity. That the rate of reaction is speeded up as the temperature increases until its optimum at 37oC and then it rapidly drops again as fast as it increased, resulting in a bell shaped graph. However, there are several other factors that affect the rate of reaction, such as varying the concentration of catalase. To do this I would set up the apparatus like in the diagram I drew earlier in my coursework. I would need to ensure that the temperature stayed constant at 30 degrees, to ensure a fair test. First of all, take the 2% concentration of catalase. Test the pH of the solution using universal indicator. Then write down these two variables into a table, to ensure that the two variables are the same throughout the experiments. Once you have ensured that these two variables are right then add 0.2cm� of catalase into the side arm boiling tube with the 1cm� syringe. Then seal the side arm boiling tube with a bung. Through the hole in the syringe-adapted bung inject 5cm� of hydrogen peroxide (10vols) with the 5cm�, into the side arm boiling tube, and then start the stop clock as soon as the hydrogen peroxide has been dropped in. Record how much oxygen is collected in the gas tube cylinder every 10 seconds for the next 60 seconds into your table of results. Repeat this method 3 times for each concentration, 2%, 4%, 6%, 8% and 10%, of catalase and a control with 0% catalase, distilled water. ...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

Here's what a teacher thought of this essay

4 star(s)

This is a well written and very detailed report.
1. The running commentary that runs throughout the report should be removed
2. The sources of information should be referenced
3. The analysis should quote data from the investigation to back up the patterns

Marked by teacher Luke Smithen 17/09/2013

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 AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    How does the pH affect the activity of amylase

    3 star(s)

    * Add 80ml of boiling distilled water and dissolve the starch within the water. add 15ml of cold distilled water to cool the solution down, but still keep the solution in a water bath to make sure it all dissolves and also stir * Measure out 0.1g of amylase then

  2. Effects of Copper Sulphate on the Activity of Catalase

    Otherwise, the cause of particular trends will be indistinguishable. This means that the only variable in this experiment will be the H2O2. To ensure that it will be a fair test, I will have to carry out all experiments under the same conditions, i.e. same concentrations (except for the variable)

  1. An experiment to investigate the effect of temperature on the action of the enzyme ...

    The difference between the two results mainly lay in their optimum temperature. As they found different temperatures I was unable to say how wrong my prediction was. Even though, I was still able to come to the firm conclusion that an enzyme has an optimum temperature where its rate of

  2. The Effect of Concentration on Pectinase Using Apple

    apple pulp is the length of time the pectinase is in contact with it. If one test tube was left to stand for 10 minutes longer with the pectinase in it than another test tube, then it will have more time to react and therefore more pectin will be broken down.

  1. An experiment to show how protease enzymes are affected by temperature

    Conclusion: The first step in this experiment was to prove that the milk actually does need enzymes to be digested in the body. The control experiment proved this and the water in all 6 cases had no reaction with the milk.

  2. Type - 1 Hypersensitivity Reaction

    These helper cells are derived from virgin/naive T4 and T8 -lymphocytes and are triggered through the recognition of cell-associated antigens, which have several subtypes including helper T cells T4 (regulatory cells), or cytotoxic T cells CD4, which destroy virally infected cells and tumour cells and suppressor T-cells.

  1. Free essay

    Investigating the effect of PH on the activity of the enzyme catalase.

    It has strong oxidizing properties and is therefore a powerful bleaching agent that is mostly used for bleaching paper, and can also be found in rocketry. The oxidizing capacity of hydrogen peroxide is so strong that the chemical is considered a highly reactive oxygen species.

  2. Experiment 3 : Identification Of Food Constituents In Milk

    Several variants on the test have been developed. The Biuret reaction can be used to assay the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide. The intensity of the colour, and hence the absorption at 540 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law.

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