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Investigation: To find the effect of the concentration amylase on the rate of breakdown of starch

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Introduction

. Investigation: To find the effect of the concentration amylase on the rate of breakdown of starch. PREDICTION The lower the concentration of amylase, the slower the breakdown of starch will be. If you double the amount of amylase, the breakdown of starch will be quicker because there are twice as many active sites. I expect to see a graph like: Rate of Breakdown Concentration of amylase RESEARCH Enzymes are made of long protein molecules, which are folded up so they have an irregular globular shape. One part of the surface is the active site and fits exactly into the substrates, which then reacts. When a substrate molecule collides with an enzyme it becomes attached to the active site of the enzyme and the reaction then takes place. The products then leave the active site, which can be used again. Temperature effects the efficiency of the enzymes. The higher the heat the greater the proportion of damage on the enzyme. The enzyme will no longer fit in the active site. Below normal temperatures, enzymes become less and less active, due to reductions in speed of molecular movement, but this is reversible, so enzymes work effectively when returned to normal temperature. ...read more.

Middle

3. Add the concentration of amylase and water to the starch in one of the test tubes. Immediately after this start the stopwatch and stir the solution. 4. Every 30 seconds add a drop of the solution to the iodine solution, using a petite pipette. 5. Once the iodine solution is no longer black and has changed to the chosen shade of brown, I will record the results. 6. If the iodine solution turns brown before the 30 seconds the concentration of amylase is too strong and if it takes over 3 minutes to breakdown the starch then the solution is too weak. PILOT EXPERIMENT RESULTS Total volume Volume of 100% amylase Volume of 100% starch Time taken for breakdown 10cm3 4cm3 6cm3 1 minute 10cm3 2cm3 8cm3 2 minutes 10cm3 6cm3 4cm3 Less than 30 seconds The Pilot experiment was carried out to determine the volumes of starch and amylase that were going to be used in the final experiment. The results above show that the higher the volume of 100% amylase to the volume of 100% starch then the quicker it takes to breakdown. Other volumes of amylase to starch were used, but these took to long to breakdown. ...read more.

Conclusion

This would ensure that the final result was as accurate as possible. Also with more time, more concentrations could have been created. All in all with more time allowed for this investigation, more results would have been gained. In terms of the graph, the more replicates being made and the more concentrations being tested would have meant that it would have been easier to see a pattern, as there have been more results. Another problem which may have made the results vary would have been the fact that the starch was left out so long. Being left out for a while meant that the starch became viscous and stuck to the sides of the boiling tube. This could have resulted in a variation of the volume of starch being mixed together with the different concentrations of amylase. In the future a more accurate measuring cylinder could be used because the measuring cylinder used in this investigation was only to the nearest 0.1 cm3. The colour of the iodine solution could have also caused some inaccuracies because different shades of brown could have been chosen. This would have made the time taken for the starch to break down different. Overall, I think I used my time well, I followed my method and gained fairly accurate results in the time given. My prediction was supported by the results. 1 26/04/07 10:56 ...read more.

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