What Kind of Reaction Is Photosynthesis?

By Maria Woehr; Updated April 25, 2017
Plants appear green because of the chemical reaction in photosynthesis.

Photosynthesis is a series of chemical reactions inside plants, algea and bacteria, during which carbon dioxide is converted into sugar or glucose. The chemical reactions take place inside chloroplasts within an organism. There are two chemical reactions that occur: a light and a dark reaction. The byproduct of the chemical reaction is oxygen, which is released into the atmosphere and upon which animals and fungi depend.

Let There Be Light

Light is the catalyst of the first chemical reaction in photosynthesis. Chlorophyll is a substance within the thylakoid membrane, located inside chloroplasts, that absorbs blue and red light, according to "Science Educators." The thylakoid is a sac within the chloroplast. Its main function is to convert light into chemical energy. Within the thylakoid are chlorophyll molecules that absorb light. Chlorophyll molecules are made up of several rings of carbon and nitrogen and a magnesium ion, according to "Science Educators."

Forming ATP

The energy from the light reaction is converted to a chemical called adenosine triphosphate, also known as ATP, which is used to store energy and fuel the second chemical reaction in photosynthesis. According to "Science Educators," ATP is "made of the nucleotide adenine bonded to a ribose sugar, and that is bonded to three phosphate groups." ATP is the primary energy source for biological reactions in all organisms, according to "The True Origin Archive."

Making Sugar

During photosynthesis ATP is used to covert carbon dioxide to sugar. This second chemical reaction does not need light to occur and is often referred to as a dark reaction but is formally called the Calvin cycle. The final product of the reaction is a glucose molecule. The chemical reaction involved in photosynthesis has a molecular formula, which most scientists use. "Chemical Formula" breaks down the equation into an easily understandable formula:

carbon dioxide + water ==> glucose + oxygen 6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2

C-3 and C-4 Plants

Most plans are 3-C plants, which means they put carbon dioxide directly into the Calvin cycle and produce a compound made up of glyceraldehyde 3-phosphate. These plants have a harder time with photosynthesis during the summer months, when it is very hot and dry. Weeds, corn and some other plants that have an easier time surviving dry conditions are C-4 plants. These plants have an extra enzyme, which helps them use carbon dioxide to produce oxaloacetate, according to "Science Educators."

About the Author

Maria Woehr is a journalist with over 10 years of professional writing experience. She started editing in 2006 and has been published in "The Westfield Leader Times," "Insurance & Technology Magazine," "InformationWeek," "Positive Thinking Magazine," "Go Magazine," "The Deal," "The Financial Times" and many other outlets. She is a graduate of Boston University and has a master's degree from Drew University.