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Biology- enzyme coursework

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Biology Coursework: Enzymes By Kerry Douglas Investigate the Effect of Temperature on the Action of the Enzyme Amylase This expirment was set up to find the effect of different tempetures on the enzyme: Amylase. We had two different variables: Independent and Dependent. Independent Variable: The factor to be changed in the investigation. In the this practical it was the temperature. Using water baths we had a range of six temperatures - 25�C to 50�C with 5�C intervals between each. Dependent Variable: The factor to be measured during the investigation. In this practical it was the time taken for starch to break down. We did this using a stop-clock and we were able to calculate the rate of reaction. Rate of reaction= 1/time taken (s-1) Controlled Variables: These are the factors which must be kept constant to create a fair test. In our investigation we used the: 1. Same enzymes 2. Same substrate 3. Same volume of enzyme and substrate 4. Same time intverals for measurment 5. Same volume of Iodine 6. Same concentration of Amylase Hypothesis : In this invesigation I predict that as the temperature increases, the rate of reaction will increase, but this will only occur up to a certain point and temperature or the enzyme will become denatured- causing the rate to decrease drastically. ...read more.


We chose these temperates because they fall on what we belive to be the optimum temperature. The procedure was repeated three times to ensure the results would be reliable and so we could identify any anomalous results. Rate of Reaction(s) X1000 Temperature �C Method Apparatus/Chemicals: * Six waterbaths * Beakers * Syringes (5 cm3) (5ml) * Spotting Tile * Stop Clock * Saftey goggles * Dropper (pipette) * 1% Starch suspension * 0.1% Amylase solution * Iodine Solution Procedure: 1. Switch on the water baths and allow them to reach the temperatures needed. 2. Place amylase in a beaker and starch in a different beaker into each water bath. The water baths will have different temperatures. 3. Using syringes to measure the volumes, place 5 cm3 starch suspension in one beaker and 5cm3 of Amylase in a separate beaker. Make sure you use different syringes so there is no coss-contamination of substances. 4. Place one drop of iodine in each depression of the spotting tiles using a pipette. Saftey goggles should be worn as iodine is dangerous to the eyes. 5. Pour the contents of one beaker i.e Pour the starch into the amylase, then swirl the liquid to ensure thorough mixing. ...read more.


Sources of Error This procedure was suitable because the iodine test produced results that were easily observed to determine the rate of reaction and results were as expected. The set of results in the replicas are similar but not identical, this is due to sources of error. For example: * Differences in drop size therefore more/less iodine mixture added will affect the colour. * Timimng. It was difficult to start the clock/timer and mix the solutuion at the same time * It is difficult to judge and point due to simiular colour in the last few spots, it was personal interpretations of the colour. Improvments * Use a syringe instead of a dropper to produce equal volume (0.1) ml. * Work in pairs to improve the timing- one person mixes, one person sets the clock. * Use spotting tiles of the same shade (all white or all cream) so the colours will be the same. * Or use a colourmeter machine to judge the colours. Anomalous Results An odd result was 24�C - 660�C. It was faster than the others due to the possiblity that there was too little starch or too much enzyme. At 44�C - 870�C is slower than the others, this may be because there is too much start or too little enzyme. Both of these are accurate for measurment error. ...read more.

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4 star(s)

A good piece of coursework which is well thought out and executed. A few minor issues to be tightened up on and made clearer. 4 stars.

Marked by teacher Louise Star 08/01/2013

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