Prescribed practical B3 - investigate photosynthesis
Investigating the need for light in photosynthesis
Procedure
- Destarch a plant.
- Cover part of a leaf with lightproof paper/foil.
- Make a drawing of the leaf.
- Place the plant in bright light for several hours.
- Test the leaf for starch using the 4-step starch test.
- Make another drawing of the leaf. In this drawing show the areas of the leaf that tested positive and those that tested negative for starch.
Results
Only the areas that have been exposed to light will photosynthesise and therefore test positive for starch, showing that light is necessary for photosynthesis.