The Effects of Temperature on the Action of Diastase on a Starch Suspension Hypothesis: The practical being carried out is to observe the effects of temperature on starch break down using a synthesized version of salivary amylase, this being Diastase. The starch will be placed into the Diastase and water and then placed in baths of water of different l. temperatures. The test tube containing water will have little or no reaction at all. However, the test tube containing the Diastase will have several different times to which the starch will break down.
Once the Diastase reaches etween 30 – 40 degrees Celsius, the time taken for the starch to break down should decrease and be at it’s lowest to do so. However, in cold solutions the starch will take longer as it will in temperatures beyond 40 degrees. Once it reaches this point, the break down will either take a very long period of time or have no reaction at all as enzymes are denatured at a certain point. Materials: 4 x test tubes 5mL Diastase 5mL Water 10mL 2% Starch Suspension. Pipette 2 x Spotting tiles Large Beaker filled with water of assigned temperature Thermometer Iodine ? Marker Method: 2.
To the tube labelled W, 5mL of water were added and to S, the Diastase. In tubes A and B, 5mL each of 2% Starch Suspension was added. 3. Water was heated to 400C in a kettle and added to a large beaker. 4. The four test tubes were placed in the bath of water for 5 minutes to adapt. 5. Two clean spotting tiles were collected, and in each indentation a drop of iodine was added. 6. The contents of A and B were poured into tubes S and W, respectively. These tubes were then placed back into the water bath, which has been kept constant by adding several drops of warm water to it. . As soon as this took place the procedure was timed.
The pipette was used to place drops from test tube S into the iodine filled indents on the spotting tiles. 8. The same step was repeated using the contents of test tube W, after cleaning the pipette of its former contents. 9. Steps 7 and 8 were repeated every 30 seconds until the solution in the iodine did not turn black, thus indicating that the starch has been completely broken down. 10. The time was taken for the Diastase to break down and recorded in order to share with the class. Diagram: [IMAGE] The following results are ones that would be expected if both classes had successful outcomes.
Neither classes obtained proper results, so the following will be used instead to demonstrate what should have taken place. Temperature (oc) Time taken for starch to break down (minutes) 10 18 20 9 4. 5 2 50 7 70 14. 5 No reaction No Reaction Discussion: Enzymes are specific. A model that helps illustrate this is the Lock and Key Model. The model demonstrates that only certain “keys” (substrates) will fit into the correct “lock (enzymes). The practical carried out illustrates that starch is broken down by Salivary Amylase, which in this case has been substituted with Diastase, a synthesized version of the original substance.
Enzymes are affected by the concentration of the enzyme, the pH of the medium in which the reaction is taking place and the presence of certain ions or non-protein molecules. However, the main factor affecting the rate of reaction in this examination is temperature. Temperature influences enzyme activity. Most chemical reaction rates heighten as the temperature increases. The optimum temperature of an enzyme is the temperature at which it works best. So, although reaction rate may increase, as does he temperature, once it reaches its optimum temperature the enzyme is denatured.
That is, due to the fact that enzymes are proteins, they will change shape once they exceed 45-50 degrees Celsius. The optimum temperature of most enzymes in the human body is between 30 and 40 degrees Celsius. The table above shows that at 10 degrees, the starch took 18 minutes to completely break down. Due to the fact that the temperature is low, the enzyme is far from its optimum temperature and will not work as fast or efficiently. It can be noticed that as the temperature increases, the time taken for the starch to reak down decreases.