For photosynthesis to occur, plants need sunlight, water, carbon dioxide and chlorophyll. Through the process of photosynthesis plants convert light energy into chemical energy. They use this energy to make food which they store as sugars.
Photosynthesis occurs in the chloroplasts of the plant, usually in the leaves. The reason that the leaves look green is because of the chlorophyll. Chlorophyll absorbs the red and blue light from the sun, and this is the light the plants use for the process. The leaves also absorb light from the sun and carbon dioxide from the air. Plants get the water needed for photosynthesis from their roots. As they go through the process, they release oxygen into the air. This is one reason that photosynthesis is so important.
There are two stages to photosynthesis: light reactions and dark reactions. During the light reaction, sunlight is converted to chemical energy using the plant's chlorophyll and oxygen is released through the stomata. During the dark reaction, the carbon dioxide is converted to sugars during a process known as the Calvin Cycle. Plants continually go through the process of photosynthesis during their life cycles and continue to create oxygen and filter carbon dioxide out of the air.