required practical - pH on amylase activity

• what is the enzyme used for the practical

  amylase
• what is the substrate used for the practical

  starch
• what product is formed from the breakdown of starch

  glucose
• what solution is used to test for the presence of strach

  iodine solution
• stage 1 - set up temperature and test tubes

  water bath used to maintain 37 degrees as amalayse work in the body - leave measured tubes in water for 10 mins to adjust

  
• what is pH buffer

  solution which maintains a set pH
• stage 2 - spotting tile

  place a few drops of iodine into each well of a spotting tile
• stage 3 - mixture

  mix the starch , amylase and buffer together and keep in water bath
• stage 4 - mixure

  start a timer and every 30 seconds take a sample from the mixture and place a drop into one of the wells of iodine
• what happens when iodine solution is added to starch solution

  starch is present - blue/black

  amylase broken starch down - orange/yellow
• stage 5 - time

  see how long it takes for the iodine to stop turning blue/black and become orange/yellow indicating that the starch has been fully broken down by the amylase
• how can the experiment be repeated to give conclusive results

  use a range of buffers to see which one causes the amylase to break down starch fastest
• what is the dependant variable

  time taken for iodine to stop turning blue black
• what is the independept variable

  the pH of the buffer solution (use a range of 5 different pH's)
• what are the control variables

  temerature

  concentration of enzymes

  concentration of substrates

  time

  volume
• how to calculate rate of reaction

  1 divided by time average (for starch to be broken down)

  e.g. 1/191 = 0.005
• typical graph results of practical 


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