Plants depend on water and light to grow. They collect the water through their roots. They collect the light with their leaves. The leaf is the food-making part of a plant. They use the light, water and carbon dioxide (the gas we exhale), to make sugars for growth and seed development – this is photosynthesis.
The plant’s cells have chloroplasts, a specialized organelle containing chlorophyll, a green pigment. Chlorophyll traps the light energy needed for photosynthesis. The cells that contain the most chloroplasts are on the upper surface of a leaf exposed to the sun. The energy absorbed by the chlorophyll helps to change the carbon dioxide and water into sugars, which the plant uses to grow, and oxygen, which the plant releases.
The formula for photosynthesis is: Light + water + CO2 = Sugars + O2
