Photosynthesis experiments

Question 1

How to test a leaf for starch

Answer 1

1) Submerge it in boiling water using forceps to stop any chemical reactions from occurring inside it.
2) Put the leaf in a boiling tube with some ethanol and heat it in an electric water bath-this removes any chlorophyll.
3) Rinse the leaf in cold water and add a few drops of iodine solution.
4) If starch is present the leaf will turn black.

Question 2

The chlorophyll experiment

Answer 2

1) Use a variegated leaf from a plant that’s been exposed to direct sunlight.
2) Record the areas of high/low pigment.
3) Test the leaf for starch using iodine.
4) The areas where starch is present (iodine turns blue/black) has been able to photosynthesis because chloroplasts were present.