Amylase Investigation

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GCSE Biology Coursework-Plan

"The enzyme salivary amylase, formerly known as ptyalin, initiates the break down of starch. This is the only chemical digestion that occurs in the mouth. The function of salivary amylase is to break the chemical bonds between some of the monosacchaides in the starches to reduce the long-chain polysaccharides to the disaccharide maltose." This quote is from Principles of Anatomy and Physiology.

The equipment I will be using is as follows-

One Beaker

Two Syringes

One Pipette

Two Test Tubes

One Boiling Tube

One Spotting Tile

One Kettle

One Stop Watch

One Thermometer

I am going to test how quickly amylase breaks down starch at different temperatures. I am going to do this by extracting 10cm3 of starch and 10cm3 of Amylase using a syringe into two separate test tubes. I will then place the two test tubes in a beaker containing water at certain temperatures for five minutes. The temperatures will be 0, 10, 20, 40, 60, 80 and 100 degrees centigrade. To get to the higher temperatures I will use a kettle. I am leaving the test tubes in a beaker for five minutes to allow the starch and amylase to equal that of the water temperature. After five minutes I will mix the starch and amylase together into a boiling tube, and start the stop clock. After every 30 seconds I will extract a drop of the starch/amylase mixture using a pipette into a spotting tile. In each spot of the spotting tile will be iodine solution. I will then record the colour that the drop goes.

To make this experiment fair I am going to do the experiment three times and then take the average result from each test. After each test I will wash the end of the syringe under a tap to prevent the two mixtures from mixing. Each time I do the experiment I will use the same amount of starch and amylase and will take a recording every 30 seconds. The experiment will be made safe by having to wear goggles because iodine is irritant.
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I predict that Amylase will break down starch quickest at around body temperature (37oC). This is because Amylase is found in your mouth so therefore it naturally works at body temperature. Amylase works best at body temperature and at pH between 6 and 7 (nearly neutral). At this temperature amylase uses a lock and key theory.

The molecules on which an enzyme acts are called substrate molecules. The enzyme and substrate molecules fit into each other exactly, rather like the way a key fits into a lock.

I am going to record the colour that ...

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