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

"Enzymes are biological catalysts, which increase the rate of chemical reactions within living cells. They effectively lower the activation energy required for the chemical reaction to start, without undergoing any physical change"

Extracts from this document...


Analysing evidence and drawing conclusions Background information: Enzymes are biological catalysts, which increase the rate of chemical reactions within living cells. They effectively lower the activation energy required for the chemical reaction to start, without undergoing any physical change. They are not used up by the reactants, and therefore do not appear within the products. Enzymes are globular proteins, either in a tertiary or quaternary protein form. The shape is three dimensional, with one area, designed specifically for a particular substrate called the active site. The active site consists of a sequence of amino acids which will chemically bind with a substrate, altering the chemical bonds of the structure and therefore making it easier for a particular reaction to take place. The substrate binds to the active site of the enzyme to form an enzyme substrate complex. This lowers the activation energy, allowing the reaction to take place at a lower temperature. When the products are formed, they leave the active site, leaving the enzyme unchanged. The enzyme can now bond with another molecule of the same substrate and cause another reaction to take place. The enzyme used in this investigation is peroxidase, otherwise known as catalase. It is an enzyme which is found in many living cells, including mammalian liver, and in plants such as potatoes and celery. ...read more.


= 0.67 The statistical tests on the two sets of data show that although they were collected as a result of two individual experiments, they have similarities between them in terms of mean and median. The mean and median are two methods of an average, and it being similar for the two sets of data proves that the data has good consistency. The spread of the data was measured by the standard deviation, and as can be seen from the values, the distributions of the sets of values are different. However, this does not make such a difference in the reliability of the data, as it is the trends and patterns that the data shows that is of importance to me. Overall, the statistical tests have provided me with results showing that they are consistent, and therefore are a good basis for my conclusion. Statistical significance test Statistical significance tests are used to show whether the difference between the means of two sets of data are truly significant. I have decided to use the Mann-Whitney U test, as this is the best significance test to use for independent measures design experiments, which does not take the distribution of the data into consideration. ...read more.


A low number of particles, in a high number of water particles means only a small number of particles will combine with the catalase to be broken down at any one time. In comparison, a high concentration, like the 20 volume concentration contains many more hydrogen peroxide particles available for the catalase to combine with. This results in more particles combined with the active sites of the catalase, causing a larger number of particles being broken down at any one time. Therefore, a higher number of oxygen and water particles are produced at a given time, which results in a larger volume of oxygen given off by the reaction with a higher concentration of the hydrogen peroxide. In conclusion, the increase in oxygen with the concentration supported the idea of an increase in rate of reaction of the breakdown of hydrogen peroxide stated within my hypothesis. This showed that the increase of the amount of hydrogen peroxide substrate caused the enzyme catalase to act upon it at a faster rate increasing the amount of the oxygen product produced. Fundamentally, this supports the biological theory that increasing an amount of substrate will increase the enzyme activity upon it, providing that the amount of enzyme active sites available for that substrate is more than the substrate particles involved. ?? ?? ?? ?? Shakila Chowdhury Analysis Biology Paul Smith 5 ...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

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

    4 star(s)

    The second method would also be much easier to repeat. Apparatus: * Termamyl(r) 60T ?-amylase granules * Distilled water (used to make concentration solutions) * Beaker (250cm�) * Measuring cylinder, 50cm� (accurate to 1cm�, ?0.5cm�) * Balance (accurate to 2d.p.)

  2. Investigate how concentration of the enzyme catalase in celery tissue alters the rate of ...

    of enzyme reaction, and so that the amount of celery can be easily measured. 50 cm3 Distilled Water. The water used to dilute the celery extract must be distilled so that there are no impurities in the water. The water used to dilute the celery extract in all the boiling

  1. To investigate the rate at which hydrogen peroxide is broken down by the enzyme ...

    I will then go on to use 6cm� of enzyme solution with 4cm� of water, then 4cm� of the enzyme solution and 6cm� of water, and finally 2cm� of the enzyme solution and 8cm� of distilled water.

  2. Reaction of Catalase and Hydrogen Peroxide

    After that I will transfer 100 ml of hydrogen peroxide solution from bottle to the beaker using a measuring cylinder. Than I will use the pipette to take 4 ml of hydrogen peroxide from the beaker and put it in the boiling tube.

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

    If I was to explain the course of the reaction in graphical terms, I expect that for the loIst copper sulphate solutions, the curves representing the results will be steepest, showing a fast rate of reaction. For the higher concentrations, up to copper sulphate in its pure state, I expect

  2. An Investigation on the Effect of Enzyme Concentration on rate of hydrogen peroxide breakdown.

    If the temperature is increased above this level then enzyme activity will actually decrease. This is because the molecules which make up the enzyme, which is a protein, gain so much kinetic energy and vibrate with so much vigour that they break the hydrogen bonds holding the molecules together in the secondary and tertiary structures.

  1. This is an experiment to show how different concentration of celery tissue enzyme, catalase ...

    Protease Protein Carbohydrase Carbohydrates Enzymes bind their substrates at active sites. The active site is the location on the surface of the enzyme where the catalysed reaction takes place. Enzymes are specific just like lock and key, they have exactly the Right shape to fit onto their substrates in just the same way a key fits into the locks.

  2. How do temperature and concentration affect the rate of decomposition of hydrogen peroxide by ...

    This means that there is more chance of a reaction occurring so the rate of the reaction increases. However if you increase the temperature too much the rate of reaction decreases, even if the molecules do have a higher kinetic energy and more collisions occur between them.

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