Photosynthesis is the conversion of sunlight into usable and storable energy. Autotrophs (such as plants) use carbon dioxide, water, and energy harnessed from sunlight to generate glucose and oxygen through photosynthesis, thus providing a major energy source in the food web.
Plants produce pigments, such as chlorophyll that allow them to absorb energy from sunlight. For example, light energy excites the electrons of the pigment molecule. This energy is later harnessed and converted into chemical bonds of simple sugars.
The chloroplast— which contains pigments in its innermost membrane layer known as thylakoids—is primarily responsible for carrying out photosynthesis.
During photosynthesis, carbon dioxide is used to generate simple sugars. This carbon dioxide is sequestered or removed from the atmosphere, therefore this process is known as carbon sequestration.
Plants get carbon from CO2, a greenhouse gas and contributor to global warming. During photosynthesis, plants remove CO2 from the atmosphere, which has a cooling effect on the earth.