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Definition

noun

The synthesis of complex organic material using carbon dioxide, water, inorganic salts, and light energy (from sunlight) captured by light-absorbing pigments, such as chlorophyll and other accessory pigments.

Supplement

This process can be simplified in this equation: 6CO₂+12H₂O+energy=C₆H₁₂O₆+6O₂+6H₂O. It means photosynthesis is a process in which carbon dioxide (CO₂), water (H₂O) and light energy are utilized to synthesize an energy-rich carbohydrate like glucose (C₆H₁₂O₆) and to produce oxygen (O₂) as a by-product.

Photosynthesis is a vital process among photoautotrophs, like plants, algae and some bacteria that are able to create their own food directly from inorganic compounds using light energy so that they do not have to eat or rely on nutrients derived from other living organisms. Photosynthesis occurs in plastids (e.g. chloroplasts), which are membrane-bounded organelles containing photosynthetic pigments (e.g. chlorophyll), within the cells of plants and algae. In photosynthetic bacteria (cyanobacteria) that do not have membrane-bounded organelles, photosynthesis occurs in the thylakoid membranes in the cytoplasm.

Word origin: from the Greek photo-, "light", and synthesis, "putting together".
Related forms: photosynthetic (adjective).

Compare: chemosynthesis.
See also: autotrophy.