• 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
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14

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

Extracts from this document...

Introduction

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.

Middle

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.

Conclusion

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)

    Variables In this experiment, the only variable I want is the different concentrations of sodium phosphate, so to show its effect on the activity on enzyme, the other factors which affect enzyme working must be controlled, thus giving the same condition for enzyme activation in each test tube.

  2. Marked by a teacher

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

    4 star(s)

    My prediction states that most product will be produced in pH 7-7.5 range and after looking at the results and the evidence I know that my prediction was correct. Evaluation: In my investigation, the method I used involved the pressure sensor in gaining the results.

  1. Marked by a teacher

    effects of substrate concentration on the activity of the enzyme catalase.

    4 star(s)

    So a faster reaction and faster substrate being used up. "My hypothesis is that the higher the substrate concentration the higher the collision rate with substrate enzyme particles, so the faster the substrate would be used up." I believe this because of the collision theory, which states that the higher

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

    However, this proved to be very difficult to Co-ordinate. Suggested Improvement: In future, 2 people should conduct this experiment. Evaluation Issue Number 2: * If bubbles are still being produced at the end of the three minutes time-period, then oxygen is also still being produced.

  1. Investigating the Effect of Substrate Concentration on Catalase

    The concentrations will be made up using 10cm3 syringes and 25cm3 measuring cylinders. Where possible (the less than or equal to 10cm3 volumes) a syringe will be used as this is much more accurate than the measuring cylinder. The concentrations will be made up according to the concentration table to ensure the correct amounts are given.

  2. 'The effect of changing the concentration of the substrate hydrogen peroxide on the rate ...

    I also predict that if you continue to increase the concentration of the substrate the rate of reaction will not continue to increase because all the active sites on the enzyme will be used up. Also I predict that a lot of oxygen will be produced in the first minute,

  1. Osmosis investigation

    For 0.8m, measure 6ml of water and 24ml of sucrose. Pour into boiling tube marked 0.8m and put cling film over top. For 1.0m, measure 0ml of water and 30ml of sucrose. Pour into boiling tube marked 1.0m and put cling film over top.

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

    Also, results were limited due to a time limit. Apparatus: 10ml Water, 20ml Hydrogen peroxide, potato strips of the same width and from the same source, Stopwatch, Boiling tubes, Boiling tube holder, Measuring tube, Scalpel, Pipette, Ruler, White Tile, Core taking device and Results sheet.

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