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The Effect of Temperature on Amylase

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The Effect of Temperature on Amylase Experiment 1 Aim The aim of the experiment is to measure the rate of disappearance of starch from the reaction mixture by using the enzyme amylase. Method * Firstly, the water baths were set at temperatures of 20, 30, 50 and 60C. 0C was set within a beaker of ice water. * Thereafter a boiling tube was taken and 4ml of 1% starch solution was placed inside it. Also 2ml of 0.1% amylase solution was placed in a test tube. * The labelled pair of tubes were placed in the water bath and kept there for 10 minutes to reach the required temperature. * During the 10 minutes, 2 drops of iodine solution was placed into each depression of a spotting tile. * Next the amylase was tipped into the starch and the boiling tube was shaken gently to mix the contents. * A dropping pipette was used to immediately withdraw a sample of the solution and one drop of it was placed into a spot of iodine on the spotting tile. ...read more.


Buffers will be used to provide solutions at different pHs. Apparatus and Chemicals. * Amylase 1% (or 0.5%) * Starch 1% (or 0.5%) * Buffer solutions covering a range of pH, each with a labelled syringe/ plastic pipette * Syringes, 5 cm3, 2 (1 for starch, 1 for amylase) * Iodine solution in a dropper bottle * Test tube rack * Test tube, 1 for each pH to be tested * Dimple tile or white tiles * Teat pipette * Stop clock * Marker pen Health & Safety * Wear eye protection must be worn when handling iodine solution. * Hazards of buffers are varied. Method 1. A fresh starch suspension was made. 2. A solution of 5 g soluble starch was produced in cold water. 500 cm3 of boiling water was poured in and stirred. 3. This was boiled until a clear solution was produced. Modified starch was not used. 4. Sodium hydroxide was within the universal buffer at approximately 0.25 M was labelled an irritant. ...read more.


15. This was left for another 10 seconds . Remove a second drop of the mixture was removed to add to the next drop of iodine. 16. These steps were repeated until the iodine solution and the amylase/ buffer/ starch mixture remained orange. Results pH Time taken(s-1) for starch to disappear & Colour 0�C 0.00 - Orange - blue/black 20�C 0.0025 - Orange - blue/black 40�C 0.0043 - Orange - blue/black 60�C 0.00046- Orange - blue/black Analysis When the pH is changed, or the concentration of the hydrogen ions is modified, the reaction rate decreases rapidly. This is because the shape of the enzyme molecule is altered which in turn changes the shape of the active site. Enzymes are not denatured by minor changes in pH. If the pH is changed then it returns to its optimum then the bonds that have been broken can be re-formed. Therefore the chemical formula of the enzyme molecule is also affected by the pH. Evaluation This is a straightforward practical that gives reliable, unambiguous results. The main errors will be in the order of mixing the enzyme/ substrate/ buffer, or a delay in sampling so that the reaction time is underestimated. ...read more.

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Response to the question

The response to the question is done well. The experiment is explained clearly and the analysis and evaluation of the results are to a high standard. The candidate should provide a conclusion and perhaps explain the science behind the procedure ...

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Response to the question

The response to the question is done well. The experiment is explained clearly and the analysis and evaluation of the results are to a high standard. The candidate should provide a conclusion and perhaps explain the science behind the procedure in greater detail to gain higher marks.

Level of analysis

A range of basic investigations involving the different properties of amylase are investigated, such as the temperature if works best at and how long it takes for amylase to completely break down starch. The analysis of the experiments is described to an accurate and detailed level. The main errors are pointed out in the experiments but to improve the experiments the candidate should consider possible confounding factors and offer solutions to the major problems posed.

Quality of writing

Spelling, grammar and punctuation are to a high level of accuracy throughout the piece. Decimal places are inconsistent in the tables and should all be rounded to to the same number of significant figures to maintain accuracy.

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