Experiments

• What is starch?


  Starch is a polysaccharide made up of glucose molecules and is the primary storage form of energy in plants.
• Describe a test for starch


  Requires two test tubes

  Label A "starch solution" and B "water"

  Add 2cm3 of starch to test tube A using dropper

  Add 2cm3 of water to test tube B (control)

  Add two drops of iodine solution to both tubes, yellow-brown colour

  Observe and record results
• Conclusion of test for starch

  Tube B remains yellow-brown, Tube A turns blue-black
• Test for Lipid


  Label two greaseproof pieces of paper A and B

  Rub butter on paper A

  Add water to paper B (control)

  Leave paper to dry for 30 minutes

  Hold both pieces to light source
• Result of test for lipid

  Control has no translucent spot after dryng, paper A does
• Test for reducing sugar ie. glucose


  Label tubes A and B

  Ad 2cm3 of glucose to tube A

  Add 2cm3 of water to tube B (control)

  Add 2-3 drops of benedict's solution to both

  Place tubes in water bath and heat to 60c for 5 minutes
• Result of test from reducing sugar

  Tube B will remain blue from Benedict's solution, tube A will have turned brick red
• Test for Protein


  Label two test tubes A and B

  Add 2cm3 of protein solution to A and 2cm3 of water to B

  Add 2-3 drops of Biuret solution to both
• Result of test for protein

  Tube A turns from blue to lilac, tube B remains blue