- photosynthesis
- 1. The compounding or building up of chemical substances under the influence of light. 2. The process by which green plants, using chlorophyll and the energy of sunlight, produce carbohydrates from water and carbon dioxide, liberating molecular oxygen in the process. [photo- + G. synthesis, a putting together]- bacterial p. a primitive form of p. observed in some bacteria using only one photosystem and some reducing agent other than water.
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pho·to·syn·the·sis .fōt-ō-'sin(t)-thə-səs n, pl -the·ses synthesis of chemical compounds with the aid of light sometimes including the near infrared or near ultraviolet esp the formation of carbohydrates from carbon dioxide and a source of hydrogen (as water) in chlorophyll-containing cells (as of green plants) exposed to light involving a photochemical release of oxygen through the decomposition of water followed by various enzymatic synthetic reactions that usu. do not require the presence of lightpho·to·syn·the·size -.sīz also Brit pho·to·syn·the·sise vi, -sized also Brit -sised; -siz·ing also Brit -sis·ingpho·to·syn·thet·ic -sin-'thet-ik adjpho·to·syn·thet·i·cal·ly -i-k(ə-)lē adv* * *
n.the process whereby green plants and some bacteria manufacture carbohydrates from carbon dioxide and water, using energy absorbed from sunlight by the green pigment chlorophyll. In green plants this complex process may be summarized thus:6CO2 + 6H2O -> C6H12O6 + 6O2* * *
pho·to·syn·the·sis (fo″to-sinґthə-sis) [photo- + synthesis] a chemical combination caused by the action of light; specifically the formation of carbohydrates (with release of molecular oxygen) from carbon dioxide and water in the chlorophyll tissue of plants and blue-green algae under the influence of light. In bacteria, photosynthesis employs hydrogen sulfide, molecular hydrogen, and other reduced compounds in place of water, so that molecular oxygen is not released. Cf. chemosynthesis.
Medical dictionary. 2011.