• 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

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

Extracts from this document...


A Investigation into the Effect of Inhibitor Concentration on the Enzyme Catalase Aim: To investigate how the concentration of inhibitor (lead nitrate) affects the rate of reaction of the enzyme Catalase. Hypothesis: In my hypothesis I state that Hydrogen Peroxide (H O ) will breakdown to oxygen and water in the presence of catalase from the potato. The rate of reaction will decrease with increasing inhibitor (lead nitrate) concentration when molecules of Hydrogen Peroxide are freely available. However, when molecules of the inhibitor are in short supply, the increase in the rate of reaction is limited and therefore will have little affect. Predicted Graph: Background Knowledge: Enzymes- Enzymes are complex 3-D globular proteins, some of which have other associated molecules. Enzymes are catalysts which alters the rate of chemical reaction without itself undergoing a permanent change, and therefore can be used over and over again. Enzymes help reactions speed up which would otherwise take place very slowly. While the enzyme molecule is relatively larger than the larger than the substrate molecule it acts upon, only a small part of the enzyme molecule actually comes into contact. This region is called the ACTIVE SITE. The active site of an enzyme is the region that binds the substrate and contributes the amino acid residues that directly participate in the making and breaking of chemical bonds. However, all enzymes operate only on a specific shape and therefore fits only complementary locks, so only substrates of a particular shape will fit the active site of an enzyme. Substrate Concentration- For a given amount of enzyme, the rate of an enzyme controlled reaction increases with increasing substrate concentration-up to a point. At low substrate concentrations, the active sites of the enzyme molecules are not all used- there simply are not enough substrate molecules to occupy them all. As the substrate concentration increases, more and more sites come into use. ...read more.


We do this to provide us with the enzyme catalase for the experiment. 2. Once this is done separate 4ml of the crushed potato into burette 1, (leaving the rest if the potato for the other burettes) using a syringe. We use a syringe to do this as it is easy to measure with and is accurate. 3. Next add 20cm of pH7 buffer solution with a different syringe. This is added to keep conditions constant during the experiment. 4. Then add the pre-made lead nitrate solution and add the amount required into burette 1 as shown on the table above (i.e. burette 1 would have 10cm distilled water and 0 lead nitrate solution). 5. Finally put your safety goggles on, and add 2cm of hydrogen peroxide (H O ). 6. To ensure everything is mixed in properly for the experiment to occur successfully remove the burette from the wooden clamp stand, place your thumb at the top end so the contents don't spill out and tip upside down two or three times so the contents are shuffled properly. 7. After the burette is safely placed back in to the wooden clamp start the stop clock and take readings of the increase in froth level every 30 seconds for 10 minutes. 8. Repeat steps 2-7 for burettes 2-6. Concentration of lead nitrate will differ for each burette, check on table to see what proportion of distilled water to add to each lead nitrate concentration in each burette. Results: 10cm Distilled Water 0cm Lead Nitrate Solution TIME FROTH LEVEL VOLUME OF FROTH LEVEL 0 20.3 24.36 30 +1.2 +1.44 60 +1.8 +2.16 90 +2.4 +2.88 120 +3.4 +4.08 150 +4.5 +5.4 180 +5.6 +6.72 210 +6.7 +8.04 240 +7.7 +9.24 270 +8.8 +10.56 300 +9.3 +11.16 330 +9.9 +11.88 360 +10.5 +12.6 390 +11.1 +13.32 420 +11.5 +13.8 450 +12.0 +14.4 480 +12.3 +14.64 510 +12.6 +15.12 540 +12.9 +15.48 570 +13.1 +15.72 600 +13.2 +15.84 Total Increase =+13.2 Total Increase =+15.84 8cm of Distilled ...read more.


This was used to maintain the pH level in the experiment. However if I had varied the pH level, it may have resulted in an increase or decrease in rate of reaction. This is because pH is a measure of hydrogen ion concentration. By breaking the hydrogen bonds which give enzyme molecules their shape, any change in pH can effectively denature enzymes. Each enzyme works best at a particular pH- (7 being a neutral point), and deviations from this optimum may result in denaturation. Another precaution was taken with safety equipment. As I was handling hydrogen peroxide, the safety precaution I had to take was to wear safety goggles, especially when pouring it into the burette. To further my investigation, certain experiments could be carried out into the effect of inhibitor on rate of reaction. The major one being to carry out repeats at each inhibitor change, this will enable me to get more reliable and more accurate results, as I will be able to work out he average of this and be able to draw a graph of error bars, which may portray my present obtained results in a different but precise way. I could also test at even more narrower inhibitor changes, to give me more accurate results. Perhaps I could use also try and use a different source to provide me with the enzyme catalase, this is because the desired amount of catalase from the potato may be less or more than what I want it to be. I t was quite hard to measure and there wasn't really a quick way of knowing- making my results negotiable. Consequently, maybe using catalase from yeast would've been easier to use and handle. Specific amounts could be measured much more precisely, and may give more precise results. Another way could also be to use a gas syringe instead of a burette, as this would increase time availability and be easier to record the froth level, because it saves time calculating the froth level increase and gives exact readings. Answers won't need to be rounded by the calculator. 14 1 ...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

    Plan: The effect of the end product, phosphate, on the enzyme phosphatase

    5 star(s)

    From the graph, they decreased by a constant value (about 3.54 unit of absorbance per 0.1M sodium phosphate increased) when the moles of sodium phosphate increased. That's to say the amount of sodium phosphate has a linear relationship with the rate of reaction and had a negative effect on it.

  2. Marked by a teacher

    The aim of this investigation is to find out what effect pH has on ...

    4 star(s)

    Using this method allowed me to get the accurate results that I got, which helped me reach the an appropriate conclusion. Looking at the graphs that I produced I can see all results are close to the line of best fit.

  1. The aim of this experiment is to demonstrate that the substrate Hydrogen Peroxide will ...

    Evaluation Issue Number 4: * If I were to do the experiment again I would measure the potato pieces using a micrometer, which would provide far more accurately sized pieces and mean a much more accurate set of results. Suggested Improvement: Use a micrometer, to accurately record the potato pieces.

  2. Osmosis investigation

    Whilst waiting for the reactions to take place, clear up unnecessary apparatus and wipe down the benches. Remember to leave the chips in their solutions for over an hour. 11. After an hour, remove the pins from each potato chip.

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

    The graph can be divided into three sections. The first of these sections is 2-8 potato discs along the X-axis when the number of bubbles produced on average in two minute rises from 3.5 to 19; this therefore is an increase of 1bubble every ten seconds on average.

  2. Investigating the Effect of Substrate Concentration on Catalase

    2cm3 catalase was then added, the bung was placed on the conical flask and the stopwatch was started. (Preliminary Results Table, Discussion and Evaluation) pH Time/s Volume of Oxygen Produced/cm3 2 0 0 15 4 30 4 45 4 60 4 75 4 90 4 105 4.9 120 4.9 7

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

    The stop clock will be reset, and upon placing the potato core into the boiling tube, and placing the bung into the top, the clock will be started. 4. As the reaction takes place, the gas produced will make the gas syringe rise due to the pressure within the boiling tube.

  2. Investagating the Action of the Enzyme Catalase On the Surface Area of a Potato.

    experiment is 7, neutral so that the catalase enzyme is not affected by the pH of the substances the experiment uses. * The experiment will be conducted at room temperature so that the temperature does not affect the amount of oxygen made in each experiment because certain temperatures either increase the time taken to produce the oxygen or decrease it.

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