• 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

An investigation to find out how surface area affects the action of the enzyme Catalase.

Extracts from this document...


An investigation to find out how surface area affects the action of the enzyme Catalase Background: An enzyme is a biological catalyst, or a substance that acts as a catalyst in a living organism, regulating the rate at which chemical reactions take place, without itself being altered in the process. The biological processes that occur within all living things are chemical reactions, of which most are regulated by enzymes. Without these enzymes, many of these reactions would not occur at an acceptable rate. An enzyme will only work with one type of substance or group of substances called the substrate, to catalyse a certain kind of reaction. Only a certain region of the enzyme, called the active site, binds to the substrate. The active site is a groove or pocket formed by the folding pattern of the protein. An enzyme is a three dimensional structure, together with chemical and electrical properties of the active site, it permits only a particular substrate to bind to the site. These factors determine the enzyme's specificity. Because the enzymes are not used up in the reactions they catalyse and can be used over and over again, only a very small amount of an enzyme is needed to catalyse a reaction. A reaction will reach its maximum velocity when all the active sites of the enzyme molecules are engaged. A single enzyme can convert around 1000 substrate molecules per second. The rate of reaction will increase as the substrate concentration is increased. When all the active sites available are engaged, the enzyme is said to be saturated. The rate of reaction is determined by the speed at which the active sites can convert substrate to product. In this instance Hydrogen Peroxide to Water and Oxygen. Hydrogen peroxide - symbol equation H2O2 - is a substance that is produced by numerous metabolic reactions. This toxic waste created extensively in mammalian tissues is catalysed by Catalase. ...read more.


If there are sufficient substrate molecules to occupy all of the enzymes' active sites, the rate of reaction is unaffected by further increases in substrate concentration as the enzymes are unable to break down the greater quantity of substrate. * To control the substrate concentration, I will use 40cm� of substrate in each experiment. To ensure that this was measured precisely, I used a measuring cylinder to gauge precisely 40cm� of substrate. * Inhibition - Inhibitors compete with the substrate for the active sites of the enzyme (competitive inhibitors) or attach themselves to the enzyme, altering the shape of the active site so that the substrate is unable to occupy it and the enzyme cannot function (non-competitive inhibitors). Inhibitors therefore slow the rate of reaction. They should not have affected this investigation, however, as none were added. * Enzyme Concentration - Provided there is an excess substrate, an increase in enzyme concentration will lead to a corresponding increase in rate of reaction. Where the substrate is in short supply (i.e. it is limiting) an increase in enzyme concentration has no effect. This last point will not be a problem, as 40cm� of substrate is sufficient to occupy all the catalase molecules from the potato. This factor - enzyme concentration - will help me to answer my aim, as I am trying to find how the surface area and therefore the concentration of the catalase in the substrate affect the rate of reaction. I varied the enzyme concentration by altering the surface area of the potato cuboids that contain the Catalase, in the reaction, the greater the surface area of the potato, the greater the enzyme concentration. The concentration of the catalase molecules in the hydrogen peroxide solution is determined by the amount of molecules per a certain measure. So as the hydrogen peroxide remains constant at a volume of 40cm�, the concentration of the catalase increases as more catalase is present in the H2O2. ...read more.


the gap between the line for 64 and 100cm� is disproportionately large in comparison to the difference, as the increase in reaction rate in relation to surface area is one of exponential increase. This also shows my prediction is correct. A problem I encountered was that I used too much substrate, as the reaction did not finish within an acceptable time limit, or in the time that I had to carry out all the experiments. As there was so much substrate (hydrogen peroxide) it did not all get reacted with the catalase; by using a lesser amount of substrate the catalase would have catalysed the substrate faster. The reaction rate would have remained the same, but oxygen production would finish a lot sooner, and would not reach the same level as when I used 40cm�. I think an acceptable volume of substrate to use would be 5cm�. My results would look like this (5cm� H2O2): Not like this (using 40cm� H2O2): Another factor that may have affected the results was where the potato came from, because if I used a strip of potato from the centre, rather than the edge, there may have been more catalase present. This could account for the anomaly in results at 40cm�. For all the other results, I may have used potato from the edge, then for this reading I may have used potato from the centre. I do no know if this is true, but it is a possibility. One problem with the method of gas collection was that I had to fill the cylinder with water, and then put it into the trough. Sometimes a small amount of air was left in the tube; this would have created a bias result. To over come this I could have used a syringe to collect the gas, but I did not have the resources available. Overall I feel that I answered my aims conclusively and I feel that my prediction was correct to a large extent, although due to inaccuracies in my results I cannot draw totally complete conclusions. ?? ?? ?? ?? Biology.doc Toby Parnell 11G Page: ...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 Life Processes & 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 GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Effects of Surface Area on Catalase Activity in Potato.

    5 star(s)

    Increasing the concentration increases the number of Catalase particles present in the given volume, the increase in enzyme particles will increase the probability of reacting particles to collide and thus creating a higher rate of reaction. A cork borer will be used to obtain a tube of potato with a

  2. A investigation into the effect of inhibitor concentration on the enzyme catalase.

    They alter the shape of the enzyme molecule in such a way that the active site can no longer properly accommodate the substrate. As the substrate and inhibitor molecule attach to different parts of the enzyme, they are not competing for the same sites.

  1. The Effect of Surface Area on Catalase Activity in Potato

    The three-dimensional shape is then changed so much that the active site of the enzyme will no longer fit the substrate molecule. At this point the enzyme is classed as "Denatured" and loses its catalytic properties The optimum temperature of an enzyme varies considerably.

  2. Investigating the effect of enzyme catalase concentration on hydrogen peroxide.

    accurate as they could have been but when one takes into account the limitations and restrictions, I believe that my results were as good as they could have been. Unfortunately, much time was lost to the fact that the stopwatch that I used was very poor and frequently faulted and

  1. Influence of pH on the activity of potato Catalase

    The number of potato slices put in was less than the correct amount that was clearly stated, this would have taken more time and affected the results due to the concentration of potato catalase and the total surface area.

  2. An investigation into the effect of substrate concentration on the activity of the enzyme ...

    the experiment, it will need to be roughly the same as this could affect results. Assuming that all experiments are carried at roughly the same time, then a constant temperature can be more or less assured. * Type of potato - The same batch of potato will be used each

  1. Investigate the effect of enzyme concentration on the activity of catalase in potato tuber ...

    Another way of solving this problem is to try and find a very big potato so you are able to bore out of it 45 potato pieces. Though it is very hard to find a potato that big it will reduce the problem of getting different concentrations of enzymes in different potatoes and different potato sticks taken from different potatoes.

  2. An investigation into how enzyme concentration (catalyse in a potato) affects the rate of ...

    This means there is a higher chance and more opportunities for a substrate colliding into an available active site. The more collisions with the active site, the faster the reaction as explained by the collision theory. Surface Area The larger the surface area, the more enzyme molecules are exposed and able to react and a greater possibility of collision.

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