The effect temperature has on the activity of Amylase

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Carol Bhaskar

Biology coursework – the effect temperature has on the activity of Amylase

Aim

  • To find out how a temperature change affects the efficiency of amylase in digesting starch.

Planning

        Enzymes exist in all living things.  They are composed of polymers of amino acids and are produced in living cells.  Each cell contains several hundred enzymes, which catalyse a vast number of chemical reactions.  Enzymes are known as biological catalysts  (a substance which accelerates a reaction without being consumed in the process) as they dramatically increase the rate at which reactions occur within living organisms. Enzymes catalysis saves the need for an increase in temperature in order to speed up reactions within living things – such an increase in temperature would be lethal to the organism.  It is these enzymes, which control the metabolic reactions in our human bodies.  

        Amylase is an enzyme; it is present in our saliva and pancreatic juice. Amylase speeds up the break down of long chains of starch molecule into smaller chains of maltose.  Enzyme molecules have an extremely exact shape including a dented part called the active site.  This is exactly the right size and shape for the substrate to fit into (in the case of amylase this is starch), it is the place where the substrate binds and the reaction takes place.  When a substrate inserts into the active site, the enzyme pulls the substrate molecule out of shape thus splitting it into product molecules ( in this case glucose).  High temperatures make enzymes inactive: this is because they are proteins, which are damaged by temperatures above 40°C (although the enzymes I will be using are commercially produced, and so this temperature will be approximately 60°C).  Most enzymes are most affective at a neutral pH, this is also due to them being proteins which are damaged by very acidic, or alkaline conditions.  Any one enzyme can only ever convert any one substrate into a simpler molecule due to the unique active site.      

        

Method

        In order to carry this experiment out we conducted some preliminary trials to find the most efficient method and quantities.  In these trials we used amylase with a concentration of 0.1% and found that this concentration was not dense enough to produce an effective experiment.  This was because the dependent variable (starch) was taking too long to break down, meaning that colour changes were very subtle and hard to record.  Due this the concentration will be increased to 0.8%, and will remained the same throughout the experiment.  The concentration of starch will always be 1%.  These trials also gave us the opportunity to experiment with quantities.  We concluded that equal quantities of both the independent and dependent variables should be used, to ensure that the ratio of starch molecules to amylase molecules was even.  5.0ml of each shall be used; this will be obtained by measuring them in a 10.0ml-measuring cylinder as this is more accurate than a larger 100ml cylinder.

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 The equipment our experiment requires is a spotting dish, a measuring cylinder, test tubes, a pipette, an electrical water bath (this will be more accurate than using a Bunsen burner), a stopwatch and a thermometer.  

        

The above diagram is a summary of our method; this is how we will conduct our experiment into how temperature affects the activity of amylase.    

        

5.0ml of amylase solution and 5ml of starch solution will be measured and each poured ...

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