Light-independent reaction
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Overview of the Calvin cycle and carbon fixation
In photosynthesis, the light-independent reactions, also somewhat misleadingly called the dark reactions, are chemical reactions that convert carbon dioxide and other compounds into glucose. These reactions, unlike the light-dependent reactions, do not need light to occur; hence the term dark reactions. These reactions take the products of the light-dependent reactions and perform further chemical processes on them. There are two light-independent reactions: carbon fixation and the Calvin-Benson cycle.
In CAM plants, carbon fixation actually does take place at night.
// Regeneration of the substrate for this reaction requires light. Thus it is not that correct to call this reaction as light-independent reaction.
Carbon fixation
Overview of C4 carbon fixation
The carbon fixation reaction is the first step of the light-independent reactions. Carbon from carbon dioxide is "fixed" into a larger carbohydrate. Three pathways to occur: C3 carbon fixation (the most common), C4 carbon fixation, and CAM (Crassulacean Acid Metabolism). C3 fixation occurs as the first step of the Calvin-Benson cycle in all plants. C4 plants first fix carbon dioxide into malate, which is then used to supply carbon dioxide in the middle of the night to the Calvin-Benson cycle. CAM plants perform a similar process.
Calvin cycle
The Calvin-Benson cycle takes carbon dioxide and converts it to glucose, which the plant uses for energy.External links
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