testing for biological molecules

• starch

  • test - add orange/brown iodine solution
  • positive - colours turns blue/black
• sugar

  • test - add blue benedict's solution, place in a boiling water bath for 5 minutes
  • positive - colour turns brick red
• protein

  • test - add blue Biuret solution
  • positive - colours turns lilac/purple
• lipid

  • test - add ethanol and decant into water
  • positive - cloudy white emulsion