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 dark reactions). These reactions take the products of the light-dependent reactions and perform further chemical processes on them. The light-independent reactions are two: carbon fixation and the Calvin cycle.
In CAM plants, carbon fixation actually does take place at night.
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 (processes) exist for this reaction to occur: C3 carbon fixation (the most common), C4 carbon fixation, and CAM. C3 fixation occurs as the first step of the Calvin cycle in all plants. C4 plants first fix carbon dioxide into malate , which is then used to supply carbon dioxide to the Calvin cycle. CAM plants perform a similar process.
Calvin cycle
The Calvin cycle takes carbon dioxide and converts it to glucose, which the plant uses for energy.