27. Investigation of the digestion of starch agar using germinating seeds

  • 00:22 What is the name of the enzyme which hydrolyses starch?
  • 00:34 What colour does iodine-potassium iodide solution turn in the presence of starch?
  • 00:45 Why do you place the seed cut face downwards on the starch agar?
  • 00:53 Why do you incubate the plate at 25oC?
  • 00:57 Is there a clear zone on either plate?
  • 01:05 How would you precisely measure the area of any clear zone? What has caused this clear zone? 
  • soaked maize seeds

  • starch agar plates

  • white tile

  • scalpel

  • iodine-potassium iodide solution

  • boiling tube

  • water bath at 80oC

Hazard Risk Control measure

Iodine-potassium iodide solution - irritant

Contact with eyes and skin

Eye: flood with tap water (10min) Skin: drench with water. Flood with tap water (10min)

Starch agar - growing fungi
Growing pathogens

Risk of allergic reaction
Risk of infection

Aseptic techniques used throughout. Incubate plates at 25oC


Cuts to skin

Cut downwards and away from body