Calvin cycle
Britishnoun
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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.
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See more at photosynthesis
Etymology
Origin of Calvin cycle
C20: named after Melvin Calvin , who elucidated it
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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
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
These energy- carrying molecules travel into the stroma where the Calvin cycle reactions take place.
From Textbooks ● Apr. 25, 2013
Keep in mind that the purpose of the light-dependent reactions is to convert solar energy into chemical carriers that will be used in the Calvin cycle.
From Textbooks ● Apr. 25, 2013
When these molecules release energy into the Calvin cycle, they each lose atoms to become the lower-energy molecules ADP and NADP+.
From Textbooks ● Apr. 25, 2013
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
