Editing Photosynthesis (section)

===Calvin cycle===
{{Main|Calvin cycle|Carbon fixation}}
In the [[light-independent reactions|light-independent]] (or "dark") reactions, the enzyme [[RuBisCO]] captures [[carbon dioxide|CO<sub>2</sub>]] from the [[Earth's atmosphere|atmosphere]] and, in a [[Biological process|process]] called the [[Calvin cycle]], uses the newly formed [[NADPH]] and releases [[Triose|three-carbon sugars]], which are later [[Condensation reaction|combined]] to form [[sucrose]] and [[starch]]. The overall equation for the light-independent reactions in [[green plants]] is<ref name="Raven-2005"/>{{rp|128}}

{{block indent|3 CO<sub>2</sub> + 9 ATP + 6 NADPH + 6 H<sup>+</sup> → C<sub>3</sub>H<sub>6</sub>O<sub>3</sub>-phosphate + 9 ADP + 8 P<sub>i</sub> + 6 NADP<sup>+</sup> + 3 H<sub>2</sub>O}}

[[File:Calvin-cycle4.svg|thumb|upright=1.4|Overview of the Calvin cycle and [[Biological carbon fixation|carbon fixation]]]]

[[Carbon fixation]] produces the [[Glyceraldehyde 3-phosphate|three-carbon sugar intermediate]], which is then converted into the final [[carbohydrate]] products. The [[Monosaccharide|simple carbon sugars]] photosynthesis produces are then used to form other [[organic compound]]s, such as the building material [[cellulose]], the [[Precursor (chemistry)|precursors]] for [[lipid]] and [[amino acid]] biosynthesis, or as a fuel in [[cellular respiration]]. The latter occurs not only in [[plant]]s but also in [[animal]]s when the [[carbon]] and [[energy]] from plants is passed through a [[food chain]].

The [[Biological carbon fixation|fixation]] or [[Redox|reduction]] of [[carbon dioxide]] is a process in which carbon dioxide combines with a [[five-carbon sugar]], [[ribulose 1,5-bisphosphate]], to [[Yield (chemistry)|yield]] two [[molecule]]s of a three-carbon compound, [[glycerate 3-phosphate]], also known as 3-phosphoglycerate. Glycerate 3-phosphate, in the presence of [[Adenosine triphosphate|ATP]] and [[NADPH]] produced during the light-dependent stages, is reduced to [[glyceraldehyde 3-phosphate]]. This [[Product (chemistry)|product]] is also referred to as 3-phosphoglyceraldehyde (PGAL) or, more generically, as [[triose]] phosphate. Most (five out of six molecules) of the glyceraldehyde 3-phosphate produced are used to regenerate ribulose 1,5-bisphosphate so the process can continue. The triose phosphates not thus "recycled" often condense to form [[hexose]] phosphates, which ultimately yield [[sucrose]], [[starch]], and [[cellulose]], as well as [[glucose]] and [[fructose]]. The [[sugar]]s produced during carbon [[metabolism]] yield [[carbon skeleton]]s that can be used for other [[metabolic reaction]]s like the production of [[amino acids]] and [[lipids]].