Bio1- enzymes (starch + amylase)

Question 1

What is the 8 step method to the enzymes practical?

Answer 1

1. Place 1 dot of iodine solution into each well of a spotting tile
2. Fill three test tubes - 2cm ³ starch solution, 2cm ³ amylase solution, 2cm ³ of pH buffer solution
3. Place test tubes in a water bath at 30°C, leave for 10mins to allow solutions to reach correct temperature.
4. Combine all three into one test tube and stir using a stirring rod. Return to water bath and start stopwatch.
5. After 30secs, use stirring rod to transfer 1drop of solution to a well in the spotting tile.
6. Iodine turns blue-black if starch is present.
7. Repeat step 5 until iodine remains orange- this is when starch is no longer present (completed reaction).
8. Repeat whole experiment with different pH buffers.

Question 2

What colour does iodine turn if starch is present?

Answer 2

Blue-black

Question 3

What colour does iodine change to when starch isn’t present?

Answer 3

Remains orange