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The Effect of temperature on the denaturation rate of fungal amylase

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Introduction

UNIT 3 BIOLOGY COURSEWORK DENATURATION RATE OF FUNGAL AMYLASE The Effect of temperature on the denaturation rate of fungal amylase Nature of the Problem Wild mushrooms grow in grassy meadows in all parts of the world. Warm and damp weather suits them best, hence the reason why they grow more rapidly in autumn, than in any other season. Fungi, for example, mushrooms, fulfil important ecological functions. Mushrooms are saprophytic, decomposing fungi. Saprophytic fungi are basically recyclers of organic material. Mushrooms secrete enzymes and acids which break down large organic molecular complexes into simpler compounds which are then absorbed. All ecosystems depend partly upon fungi's ability to decompose organic plant matter, such as, leaves falling from trees, other organic debris and excretory products from animal and plant sources. The result of the decomposition of the organic matter is the return of carbon, hydrogen, nitrogen, and minerals back into the soil in forms which can be useful to plants, insects and other organisms. Fungi are one of the most important groups of organisms on the planet. Fungi are eukaryotes, which are organisms with a distinct nucleus. Fungi comprise the moulds of yeast, mildews, mushrooms, puffballs and rusts. They can be saprophytic, feeding on dead organic matter or parasitic. The main body of most fungi is made up of fine, branching, and usually colourless threads called hyphae, which are 5-10 um in diameter. Each fungus will have vast numbers of these hyphae, all intertwining to make up a tangled web called the mycelium. In a specialised part of the mycelium, spores are produced in vast numbers and dispersed. The mycelium is generally too fine to be seen by the naked eye, except where the hyphae are very closely packed together. The tangled mycelial mass is usually hidden deep within its food sources, such as rotting matter in the soil, leaf litter, rotting wood or dead animals. ...read more.

Middle

3. Leave both the starch solution and the enzyme extract for 5 minutes to equilibrate to the temperature of the water bath. 4. Pipette 5cm3 of distilled water into a cuvette and add 0.25cm3 of standard iodine solution. Mix well. 5. When you are ready to begin the experiment, pour the 10cm3 of enzyme extract into the beaker of starch solution, leaving the beaker into the water bath. Mix thoroughly and immediately start a stopwatch. 6. After 1 minute, remove one 0.25cm3 sample from the enzyme-starch mixture and add to the cuvette containing iodine solution. Mix by inverting the cuvette and measure the absorbance in the colorimeter. Record both the time and the absorbance. 7. Discard the contents of the cuvette, rinse with distilled water, then replace with iodine solution as in step 4. 8. Take further 0.25cm3 samples of the enzyme-starch mixture add to the iodine solution and record the absorbance at suitable time intervals such as 2, 5, 10, 12 and 20 minutes from the start of the experiment. 9. Remember to check zero periodically during the experiment, using the blank prepared for the calibration curve. Analysing Evidence In order to show the effectiveness of the enzyme rather than the time it takes to digest the starch, the inverse of the time taken to digest the starch was plotted on the y-axis, with temperature on the x-axis: The graph shows that, between temperatures of 20oC and 40oC, the efficiency of the enzyme increases with temperature. However, the graph between these points is a curve so the efficiency of the enzyme is not proportional to the temperature. Between 40oC and 60oC, the efficiency of the enzyme decreases with temperature, mirroring the first part of the graph. The graph shows that the optimum temperature of the amylase tested was 40oC. The graph supports my prediction that the optimum temperature of the enzyme would be around 40oC, and would have decreasing efficiency towards 0oC, at which the amylase would be unable to break down the starch at all. ...read more.

Conclusion

At current I do not have enough reliable evidence to draw any conclusions more specific than the rate of reaction is proportional to the temperature until 55OC is reached and after this point the temperature is inversely proportional to the rate of reaction. Note: "Optimum operating temperature/pH" means this is the temperature/pH where the enzyme (amylase) operates the fastest.Evaluating Evidence I believe that the experiment was successful but some of the results were unexpected/unreliable. The time taken for the amylase to digest the starch at 40 OC was far too fast (see Graph 1) it should have been between 4 and 4.5 minutes. All the other results seemed to fit into the trend on the graphs. I believe that the experiment was designed well but there were a few problems. The optimum temperature for the amylase was too high. I believe that all the results were skewed because the enzyme was not given enough time at each particular temperature to be fully affected before it was added to the starch. Because of time restraints they were only left in the water bath for 10 minutes before starting the experiment. However, they should have been left in the water bath for about 30 minutes so that the amylase had been completely affected by the temperature before the experiment was started. I decided to conduct the experiment at 10 OC intervals instead of 5 OC because there was not enough time. When the results were collected I plotted them on a rough graph to find the optimum temperature and then conduct the experiment at this temperature to ensure it was the optimum temperature. I also conducted all three experiments for each condition at the same time to save time. Additional work, which could be carried out, is to repeat the experiment using, a wider range of temperatures and pH levels, a range of different starch solution concentrations or using different enzymes such as protease with a protein. Mukwinda Phiri Lower Sixth Abbey College Guilly Lassman Cambridge 1 ...read more.

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