Effect of pH on Amylase (PRACTICAL)

• What is the first step ?

  • you need to put one drop of iodine into each well of a spotting tray
• What is the second step?

  2cm^3 startch solution in a test tube

  2cm^3 amylase in another test tube

  2cm ^3 pH 5 buffer solution in another test tube
• What is buffer solution used for ?

  to control the pH
• What is the third step ?

  place all three test tubes in a water bath at 30* for 10 minutes
• What is the fourth step ?

  combine all three solution into one test tube and mix with a stirring rod.

  Put is back in the water bath and start a stopwatch
• What is the fifth step ?

  after 30 seconds using the stirring rod transfer one of solution onto one of the wells containing iodine
• If the iodide turns blue-black,what does that mean ?

  means the starch is present
• What is the sixth step ?

  take a sample every 30 seconds till the remaining iodide is orange
• What problems could there be with this practical ?

  • we take samples every 30 secs meaning we only have approximate time for the reaction to complete (could solve this by taking it every 10 seconds )
  • looking for the time the solution does not go blue-black (solve this by having several people looking at the spot tile )
• What do you do when you finish with the first practical ?

  you repeat all the steps but with different pH buffers e.g pH 6,7,8