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Biology LibreTexts

18.7: Photosynthesis

Photoautotrophs use sunlight as a source of energy and through the process of photosynthesis, reduce carbon dioxide to form carbohydrates such as glucose. The radiant energy is converted to the chemical bond energy within glucose and other organic molecules. Plants, algae, and cyanobacteria are known as oxygenic photoautotrophs because they synthesize organic molecules from inorganic materials, convert light energy into chemical energy, use water as an electron source, and generate oxygen as an end product of photosynthesis. The overall reaction for photosynthesis is as follows:

\[ 6 CO_2 + 12 H_2O \xrightarrow[\text{light}]{\text{chlorophyll}} C_6H_{12}O_6 + 6 O_2 + 6 H_2O\]

Note that photosyntehsis is a redox reaction with carbon dioxide (\(CO_2\)) reduced to produce glucose (\(C_6H_{12}O_6\)) and water (\(H_2O\)) oxidized to produce oxygen (\(O_2\)). Photosynthesis is composed of two stages: the light-dependent reactions and the light independent reactions.

Contributors

  • Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)