Photosynthesis Chapter 13

What is photosynthesis? Photosynthesis is the process that green plants use to make their own food using sunlight. Plants need the green chemical called chlorophyll to make food.

The Leaf The leaf is flat and thin so that light can be absorbed. Tiny pores called stomata allow gaseous exchange and water vapour to pass out of the leaf

Equation for photosynthesis. Light Carbon Dioxide + Water Glucose + Oxygen Chlorophyll Chlorophyll traps the light’s energy and uses it to combine carbon dioxide(CO2) and water(H2O) together to form Glucose(C6H1206) and Oxygen(O2).

Photosynthesis

Starch The glucose can be used directly by the plant as a source of energy. The plant may also store the glucose by turning it into starch . Some glucose is converted to protein by combining with nitrates from the soil.

To test a leaf for Starch. 1.Boil the leaf in water to kill the leaf and soften it 2. Boil the leaf in Alcohol to remove the chlorophyll

3.Rinse the leaf in hot water and soften it. 4. Spread the leaf on a white tile and add a few drops of Iodine. Result The leaf turns Blue/ Black. Starch is present in the Leaf.

What would you find if you tested this leaf for starch?