dark reactions


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dark reactions

Any enzymatically mediated chemical reaction that takes place in the absence of light. One example is the series of light-independent reactions that produce glucose from carbon dioxide and cellular energy sources.

dark reactions

or

light-independent reactions

those processes in PHOTOSYNTHESIS that do not require light energy but which can occur in both light and dark conditions; the reactions involve the reduction of carbon dioxide to carbohydrate in the CALVIN CYCLE using ATP and NADPH2 formed in the LIGHT REACTIONS.
References in periodicals archive ?
Oxygen deficiency was the major limiting factor of decreasing current and voltage during dark reactions. Highest power output was reported during day times when the photosynthesis was at maximum and oxygen was abundant during first week of experiment.
There was a sharp decline of current and power density during night when plants mostly undergo dark reactions.
Once produced, these energy-rich compounds must then migrate to the energy transfer point in the leaf and release their energy to drive the light-independent reactions or dark reaction in the chloroplast stoma to convert carbon dioxide into glucose through a complex series of reactions that all first-year biology students learn as the Calvin Benson cycle.
There are two parts to photosynthesis -- a light reaction and a dark reaction. The light reaction converts light energy to chemical energy and must take place in the light.
"We've been able to separate the light reaction from the dark reaction and instead of using biological photosynthesis, we are using solar panels to convert the sunlight to electrical energy, then to a chemical intermediate, and using that to power carbon dioxide fixation to produce the fuel," Liao said.
The matrix between the grana is called the stroma, and the enzymes involved in the dark reactions are located there.
Photosynthesis consists of two basic light reactions--photolysis and photophosphorylation--followed by the dark reactions of the Calvin cycle.
In the process, water ([H.sup.2]O) is split, releasing oxygen, while the ATP and NADPH are then used to make carbon-to-carbon bonds in the Light Independent Process (Dark Reactions).
Dark reactions use indirect solar absorption, such as in biomass conversion, in which exposure to sunlight is used in synthesis or catalysis reactions.