How does the Rate of a Reaction involving Amylase differ as the Temperature changes?

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How does the Rate of a Reaction involving Amylase differ as the Temperature changes?

Planning:

Our aim is to observe what effect varying the temperature will have on the rate of a reaction involving an enzyme.

I predict that as the temperature increases, from 5oC, the rate of a reaction will increase till it reaches the optimum rate of reaction. After this the rate of reaction will decrease. This is due to the structural format of the enzyme. An enzyme is a globular protein structure which has a very specific primary structure and because of that can fold up into a very specific shape, if shape or amino acid is missing or replaced by another in primary structure the enzyme cannot function. As the temperature increases the enzyme will have more energy so will be able to collide more often with a substrate and bind. This will increase until optimum temperature which is around 37OC - 40oC. After it has reached this temperature the heat energy causes the molecules to vibrate because of the kinetic energy from the heat, this will cause bonds to break particularly hydrogen bonds which are not the strongest bonds made. This will therefore change the globular protein shape, and so the active site, therefore no substrate will fit into the site and the enzyme is no longer useful and is called denatured.

We have chosen to vary the temperature, there are three other variables to change and see what effect they will have on an enzyme, therefore all other variables need to be controlled. We will need to control the pH because the pH scale represents the percentage of hydrogen ions in the solution; these H+ will react with globular protein and make hydrogen bonds with its side chains. Therefore each molecule has its own pH it works best at. At the optimum pH the active site of an enzyme will accept the substrate. Amylases’ optimum pH is around 10. Another variable needed to be controlled is the concentration of the substrate. We will need to use a set concentration, and volume to ensure test is fair. The concentration and volume of the enzyme is another variable that will need to be controlled to be fair.

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Sins we as a class has decided to vary temperatures, each person will do the experiment for each temperature. We all decided to have the temperatures 10oC, 20oC, 30oC, 40oC, 50OC, 60OC. we decided to continue taking a sample every 1 minute until it reached the aromatic point, where the solution had changed the iodine completely from blue-black toe its natural colour orange-red. We all had to also ensure that we equilibrated the enzyme and substrate before we mix the two together to start the reaction. We decided to use amylase as the enzyme and starch as the substrate ...

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