• 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

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

Extracts from this document...

Introduction

The effect of the end product, phosphate, on the enzyme phosphatase 1. Plan Phosphatase enzymes release phosphates from a variety of substrates for synthesis of nucleotides, phospholipids, etc. They are found in both plant and animal tissues and can be classified as acid or alkaline depending on their optimum pH. In this experiment an acid phosphatase from potato was used. Hypothesis Since phosphate is a product of phosphatase activity, it may act as an end product inhibitor of the phosphatase enzyme, therefore slowing down the enzyme-catalyzed reaction. Background knowledge Enzymes are biological catalysts which speed up the metabolic reaction inside the cells. Enzymes are proteins and therefore can function because of their specific 3D shape. The active site is part of the molecule which allows the substrate to enter and form enzyme-substrate complex. If the shape of the active site changed, the substrate will not fit in, therefore the enzyme cannot function properly. The activity of enzyme is not only affected by temperature, pH, but also by enzyme inhibitors. These are the substances which can reduce the activity of enzymes. There are two types of enzyme inhibitors which refer to competitive and non-competitive inhibitor. Competitive inhibitor is a molecule which has a similar shape to the substrate, competing with the substrate for the active site of the enzyme and the inhibition can be either reversible or irreversible. The reversible inhibition means the inhibitors form a loose association with the enzyme and may become detached to the enzyme later, thus enabling the enzymes to function again. Irreversible inhibition means that the inhibitors combine permanently with the enzymes, making it impossible for substrates to react. Non-competitive inhibitor is a molecule which does not enter the active site of the enzyme but changes its shape by entering the other part of the enzyme, leaving the enzyme unable to work. However, Cells always contain many natural inhibitors which control the rate of metabolism and known as the reversible non-competitive inhibitor. ...read more.

Middle

Then place the two test tubes opposite to each other in the centrifuge, put the lid back and centrifuge for bout 5 minutes. After that, pour the supernatant into a clean test tube. This is used as the enzyme suspension. Label 15 test tubes A1-A5, B1-B5, C1-C5 and add 5 cm3 buffer from beaker 1 to tube A1, B1, C1 by using the same syringe; then using the same syringe add 5cm3 buffer from beaker 2 to tubeA2, B2, C2 and continue this same procedure step wise to beaker5. Add 1cm3 of the 1% phenolphthalein phosphate to each tube by a 1 cm3 syringe. Then use a kettle to make some hot water and then mix with cold water in the 1000ml beaker. Use a thermometer to stir and add any either cold or hot water until the temperature keeps at steady 30?. Then add 1 cm3 of enzyme suspension to each tube and mix them well with 5 different stirring rods, e.g. one rod stir A1,B1,C1and the other one stir A2,B2,C2 and so on. Place them together in the 30? water bath and at the same time start the stop clock. During the incubation, add any hot water if temperature drops. After being incubated for 20 minutes, put all the test tubes out of the water bath and place them back on the rack. Add 5cm3 of 10% sodium carbonate solution to each tube and mix as before. The tubes can now be stored in a fridge until the next day if required. Then record the color of each test tube and measure the intensity of the pink colour using a colorimeter with a 550nm filter. Record the absorbance. Present them in a table with headings. Then calculate the average absorbance for each concentration of sodium phosphate by using the value of A1, B1 and C1 for 0M, A2,B2 and C2 for )0.05M and continue this procedure to A5, B5 and C5. ...read more.

Conclusion

First I will make 7 buffer 5 solution each contains sodium carbonate with concentration 0.0, 0.10, 0.20, 0.30, 0.35, 0.40, 0.45 mol/cm respectively. Label them from A to D. Second I will choose a big potato to extract the enzyme phosphatase in the same way of last experiment. Then I will prepare 4 sets of test tubes each contains 7 test tubes. Label them from A1 to D7. Then add buffer A to test tube sets A, buffer B to test tube sets B and so on. Add 1cm of the 1% phenolphthalein phosphate to each tube by a 1 cm syringe. Stir the enzyme suspension well and add 1cm of it into each test tube and mix them well. Then put all the test tubes in the same water bath of 30?. After 20 min incubation, and assistant and I will take them out of the water bath and add sodium carbonate to each test tube at the same time to stop the reaction. Then use a colorimeter with precise division to quantify the color change in each test tube(from colorless to pink). Calculate the average of A1 B1 C1 and A2 B2 C2 and so on. Draw these 7 values on a graph paper and also the error bar. Deducing from the results of last experiment, I predict that the graph pattern would be a straight line with negative gradient, and between the sodium phosphate concentration 0.35 and 0.45 mol/cm, the rate of reaction will be 0. Investigation 2 To investigate whether the result of the investigation, the end product effect is only specific to phosphatase in the potato, or has a commonness to all the enzymes, I will carry out the following two experiments. One will be the same process as the investigation of end product effect but use the beansprouts to extract the enzyme phosphatase. I predict that the rate of reaction decreases as the concentration of sodium phosphate increases and the pattern of the graph will be the same as the potatoes'. ...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

Here's what a teacher thought of this essay

5 star(s)

This is a very well written report that demonstrates a good understanding of scientific processes and methods.
1. The background knowledge section is well written and concise but should include references.
2. The variables section is well thought through.
3. The method section should be simplified and restructured.
4. The data is presented well.
5. The conclusion is detailed but again needs references.
6. The evaluation is the strongest section in the report and shows good statistical knowledge.
***** (5 stars)

Marked by teacher Luke Smithen 01/05/2013

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 GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Isotonic Point of Potatoes

    5 star(s)

    The length will be kept constant by cutting the potato cylinders of the same length using a ruler. Any major difference in the length would be cut using a knife. This is to ensure a uniform rate of diffusion across the potato cell.

  2. Marked by a teacher

    Investigating Enzymes and the effects of different variables such as temperature on how they ...

    4 star(s)

    Chapter 2 - Method The following lines illustrate our method. They are separated into easy-to-understand steps. Step 1: Attach a clamp to a stand. Step 2: Set up a gas syringe by attaching it to the clamp. Make sure that this is gripped tightly, however make certain that it does not restrict movement of the inner component.

  1. Marked by a teacher

    To investigate the effect of temperature on enzyme activity. The enzyme used will be ...

    4 star(s)

    This supports the prediction. According to learn.co.uk "As the temperature rises the enzyme works much quicker, but if it gets too hot, above 45�C the human enzymes will denature." This also supports the prediction. Apparatus: A 100 cubic centimetre measuring tube, test tube, 4 cubic centimetres hydrogen peroxide, 2 cubic centimetres pH7 buffer, 2

  2. Marked by a teacher

    Agar gel lab report

    3 star(s)

    * While putting the acid from the syringe, in the beaker some of the acid could have stuck to the syringe leading to inaccuracies. * Since the beaker was reused for all the steps it may have not given accurate results as some of the water after being rinsed could have been left over reducing the concentration of the acid.

  1. Investigating the effect of changing the concentration of an acid on the rate of ...

    Results Concentration of HCl (moldm-3) Taken with straw Taken with cork borer Time taken to turn colourless (s) 0.2 Yes No 341 0.2 No Yes 0.4 Yes No 0.4 No Yes 0.6 Yes No 0.6 No Yes 0.8 Yes No 0.8 No Yes 1.0 Yes No 175 1.0 No Yes 707 I originally thought that

  2. What is the difference in Vitamin C content between orange juice and orange squash?

    So orange squash needed 2.5 cm3 more in order to decolourise the DCPIP solution. Also, it took an average of 0.3 cm3 of ascorbic acid in order to decolourise the DCPIP solution. This particular result is very important as it leads to the calculation of how much Vitamin C content each liquid actually has.

  1. To investigate the factors that effect osmosis in living tissue.

    the rate of osmosis, increasing the temperature to 370C will increase the rate of osmosis. This is as osmosis depends on the movement of particles, increasing the temperature of a particle increases it's kinetic energy and so the rate of osmosis is proportional to the increase in temperature.

  2. Experiment to investigate the effect of Temperature on the enzyme activity of Pectinase

    The inhibitor could inhibit the active site which would reduce the working rate of the enzyme. Inhibitors are found naturally, but are also used as drugs. They are used deliberately to make sure the speed of the reaction is not too quick at certain points.

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