Photosynthetic Production of Starch

Procedure:

Part I:

1. Using a 10 mL graduated cylinder, add 3 mL of distilled water and 3 mL of starch solution to two separate test tubes.

2. Add four drops of iodine to each tube.

3. Record your results.

Part II:

1. Make a boiling water bath by heating 200 mL of water in a 400 mL beaker.

2. Add 40 mL of ethanol to a 100 mL beaker and place it inside the boiling water bath.

3. Remove a leaf from the plant exposed to light and place it in the boiling water for 3 seconds and then in the boiling alcohol

for 5 minutes or until the pigment disappears completely from the leaf.

4. Immerse the leaf again in the boiling water for 3 seconds.

5. Place the leaf in an open petri dish and carefully spread it out.

6. Using a medicine dropper, cover the leaf with iodine. Make a sketch of the leaf showing the areas that contain starch.

7. Repeat the procedure with the leaf that has been kept in darkness.