What Are the Functions of Photosynthesis?

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Photosynthesis is the process of converting energy from the sun into chemical energy or sugar. In addition to fueling the earth's ecosystem, the photosynthetic process recycles carbon dioxide into oxygen.

Equation for Photosynthesis

Photosynthesis converts water and carbon dioxide into sugar and oxygen using sunlight as the catalyst.


Specialized plant cells called chloroplasts, which contain the green pigment chlorophyll, facilitate the photosynthetic process.


The primary function of photosynthesis is to convert the energy from the sun into chemical energy for food. With the exception of certain plants utilizing chemosynthesis, all plants and animals in Earth's ecosystem are ultimately dependent on the sugars and carbohydrates produced by plants through photosynthesis.


A byproduct of the photosynthetic process is the release of oxygen into the atmosphere. Like nature's air filter, photosynthesis takes in harmful carbon dioxide, a byproduct of animal respiration, and produces oxygen that can than be used for animal respiration.

The Big Picture

Photosynthesis converts sunlight into chemical energy in the form of sugar. That sugar is then broken down through cellular respiration to fuel life at the cellular level. We breathe oxygen and exhale carbon dioxide, while plants breathe carbon dioxide and exhale oxygen. Photosynthesis is therefore the ultimate source of the food we eat and the air we breathe.