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Find out how the temperature affects the action of amylase on starch.

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Introduction

INVESTIGATING THE EFFECT OF TEMPRATURE ON THE ACTION OF AMYLASE ON STARCH AIM: I am trying to find out how the temperature affects the action of amylase on starch. BACKGROUND KNOWLEDGE: Enzymes are composed of amino acids, they act as catalysts to regulate the speed of chemical reactions in living organisms. Hydrolytic enzymes speed up reactions; amylase is one of these. Enzymes regulate the speed of chemical reactions by building up or breaking down substances, this is done by the 'lock and key' sequence. All enzymes have their own specific shape- like all locks, like a lock it has a specific 'key' that fits into the specific substance, that is exclusive to its appropriate enzyme. Enzymes have an optimum temperature and pH to work in, when the temperature is too high for an enzyme it will become deformed and will cease to function, but if temperature is too low it will function but at a low rate to a point where again it will cease to function; until the heat has been regained. Starch is a carbohydrate made up of a chain of glucose. Starch is an insoluble, complex molecule and is titled a polysaccharide. A substance called Iodine detects starch. If Starch is present it turns a blue/black color, if none is present is stays an orange/red color. Starch rich foods include: bread, pasta etc.

Middle

- See variables: Controlled Measurement - Range of measurements - 0 to 60°C - Interval - Rise by 10°C Equipment List - Thermometer (measures temperature) - Measuring Cylinder (measures volume) - Stop watches (measures time) - Water Bath - Iodine - Pipits - Test Tube - Amylase - Starch - Iodine - White Tile - Universal Indicator PLAN Preliminary Work: This is an experiment I have done previous experiment:- Amount of Starch (ml) Amount of Amylase (ml) Temperature Time taken for Starch to Disappear (Mins) 10 1 40°C 17 9 1 40°C 15 8 1 40°C 13 7 1 40°C 10 6 1 40°C 6 5 1 40°C 3 4 1 40°C Less than a min. I am not using 10ml of starch to 1ml amylase because it takes far too long to breakdown. I am not using 3ml of starch to 1ml of amylase because it breaks down too quick. The best choice would be to use 5ml of starch to 1ml of amylase, however because I am taking drops out to test whether the solution has starch I am going to double this to 10ml starch and 2ml amylase so it does not run out. Two different measuring cylinders will be used for measuring starch and amylase.

Conclusion

* 40°C is the optimum temperature because it is closed to body temperature (37°C) where amylase is found. This is why the rate of reaction is at its peak. * Though more heat gives more energy any temperature above 40°C (optimum) causes the amylase to become deformed. Also see scientific explanation. EVALUATION My experiment went exactly to plan and I had not real problem with it. I feel my best results were at 0°C, 10°C, 40°C and 60°C because all three results were the same so I presume they were most accurate e.g. 0°C results were 00, 00, 00 and 40°C results were 20, 20, 20. The results of 0°C and 60°C were assumed infinite (00) after 15 minutes however, I am not sure if it was enough to assume infinite. May be another 15 minutes would have helped me to confirm the results. I still believe they were correct because at 0°C there is no energy and t 60°C the enzyme active site is denatured disabling the substrate from fitting. A high percentage of the points on my graph was close to the line of best fit. The anomalous result was 20°C. It is rear room temperature yet the results from this water both were very unstable. Reasons for this may include contaminations to solution. pH may have changed or an inaccurate amount of substance (amylase and starch). Trevor Palmer 10/N Candidate No: Exam Centre No:

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