Calvin cycle

British  

noun

1. botany a series of reactions, occurring during photosynthesis, in which glucose is synthesized from carbon dioxide

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Calvin cycle Scientific  

1. A series of chemical reactions that occurs as part of the dark reactions of photosynthesis, in which carbon is broken away from gaseous carbon dioxide and fixed as organic carbon in compounds that are ultimately used to make sugars and starch as food. The Calvin cycle starts with a five-carbon sugar molecule, to which the carbon of carbon dioxide is attached by a covalent bond. This unstable molecule breaks apart into two three-carbon molecules, which are reduced by the electron-carriers ATP and NADPH (which were created by the earlier light reactions) into three-carbon molecules that are available for the synthesis of sugar and starch. It takes three carbon dioxide molecules to produce enough carbon for the synthesis of one of these three-carbon molecules and to regenerate the five-carbon sugar so the cycle can begin again.

2. See more at photosynthesis

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Etymology

Origin of Calvin cycle

C20: named after Melvin _Calvin , who elucidated it

Example Sentences

Gagrani points to earlier research by Smith and colleagues on the Calvin cycle, the series of reactions in photosynthesis that converts carbon dioxide into glucose.

From Science Daily • Jan. 6, 2026

This wasteful metabolic pathway begins when rubisco, the carbon-fixing enzyme of the Calvin cycle, grabs O2 rather than CO2.

From Textbooks • Jan. 1, 2015

The CO2 is then fixed by rubisco and made into sugars via the Calvin cycle, exactly as in C3 photosynthesis.

From Textbooks • Jan. 1, 2015

In the Calvin cycle, which takes place in the stroma, the chemical energy derived from the light-dependent reactions drives both the capture of carbon in carbon dioxide molecules and the subsequent assembly of sugar molecules.

From Textbooks • Apr. 25, 2013

The carriers that move energy from the light-dependent reactions to the Calvin cycle reactions can be thought of as “full” because they bring energy.

From Textbooks • Apr. 25, 2013