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Calvin cycle
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<h2 id="coupling-to-other-metabolic-pathways">Coupling to other metabolic pathways </h2> <p>The reactions of the Calvin cycle are closely coupled to the <a href="/facts/Thylakoid/d9PEe649">thylakoid</a> electron transport chain,<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> as the energy required to reduce the carbon dioxide is provided by <a href="/facts/NADPH/XMgmPQ5t">NADPH</a> produced during the <a href="/facts/Light-dependent_reactions/kBnR8Lcp">light dependent reactions</a>. The process of <a href="/facts/Photorespiration/Dh4p0aCM">photorespiration</a>, also known as C2 cycle, is also coupled to the Calvin cycle, as it results from an alternative reaction of the <a href="/facts/RuBisCO/C8asuQsc">RuBisCO</a> enzyme, and its final byproduct is another <a href="/facts/Glyceraldehyde_3-phosphate/Wy3FMLzJ">glyceraldehyde-3-P</a> molecule. </p> <h2 id="calvin-cycle">Calvin cycle</h2> <p>The Calvin cycle, Calvin–Benson–Bassham (CBB) cycle, reductive pentose phosphate cycle (RPP cycle) or C3 cycle is a series of <a href="/facts/Biochemistry/fa2pWEBp">biochemical</a> <a href="/facts/Redox/Pyd5RVcj">redox</a> reactions that take place in the <a href="/facts/Stroma_(fluid)/AYwQHKSm">stroma</a> of <a href="/facts/Chloroplast/fo8U3yTx">chloroplast</a> in <a href="/facts/Photosynthesis/TMV7w693">photosynthetic</a> <a href="/facts/Organism/j8JkL09u">organisms</a>. The cycle was discovered in 1950 by <a href="/facts/Melvin_Calvin/2PnPFS1n">Melvin Calvin</a>, <a href="/facts/James_Bassham/uEQ8vaXE">James Bassham</a>, and <a href="/facts/Andrew_Benson/4VsKBAud">Andrew Benson</a> at the <a href="/facts/University_of_California%2c_Berkeley/MXVEjklr">University of California, Berkeley</a> by using the <a href="/facts/Radioactive/Ya6FVjt4">radioactive</a> <a href="/facts/Isotope/KD9B1y6o">isotope</a> <a href="/facts/Carbon-14/Ut8SBNNa">carbon-14</a>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> </p><p>Photosynthesis occurs in two stages in a cell. In the first stage, light-dependent reactions capture the energy of light and use it to make the energy-storage molecule <a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a> and the moderate-energy hydrogen carrier <a href="/facts/NADPH/XMgmPQ5t">NADPH</a>. The Calvin cycle uses these compounds to convert <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a> and <a href="/facts/Water/0lkXnJPK">water</a> into <a href="/facts/Organic_compound/gqCNaN45">organic compounds</a><a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> that can be used by the organism (and by animals that feed on it). This set of reactions is also called <i>carbon fixation</i>. The key <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a> of the cycle is called <a href="/facts/RuBisCO/C8asuQsc">RuBisCO</a>. In the following biochemical equations, the chemical species (phosphates and carboxylic acids) exist in equilibria among their various ionized states as governed by the <a href="/facts/PH/RnSv8D7y">pH</a>. </p><p>The enzymes in the Calvin cycle are functionally equivalent to most enzymes used in other metabolic pathways such as <a href="/facts/Gluconeogenesis/Jj5THIHh">gluconeogenesis</a> and the <a href="/facts/Pentose_phosphate_pathway/NbuG6Ffj">pentose phosphate pathway</a>, but the enzymes in the Calvin cycle are found in the chloroplast stroma instead of the cell <a href="/facts/Cytosol/VyXgygWm">cytosol</a>, separating the reactions. They are activated in the light (which is why the name "dark reaction" is misleading), and also by products of the light-dependent reaction. These regulatory functions prevent the Calvin cycle from being respired to carbon dioxide. Energy (in the form of ATP) would be wasted in carrying out these reactions when they have no <a href="/facts/Primary_production/14RzcF5E">net productivity</a>. </p><p>The sum of reactions in the Calvin cycle is the following: </p> 3 CO2 + 6 <a href="/facts/Nicotinamide_adenine_dinucleotide_phosphate/XMgmPQ5t">NADPH</a> + 9 <a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a> + 5 H2O → <a href="/facts/Glyceraldehyde-3-phosphate/Wy3FMLzJ">glyceraldehyde-3-phosphate</a> (G3P) + 6 <a href="/facts/Nicotinamide_adenine_dinucleotide_phosphate/XMgmPQ5t">NADP+</a> + 9 <a href="/facts/Adenosine_diphosphate/JEDnsCjn">ADP</a> + 8 Pi (Pi = inorganic <a href="/facts/Phosphate/FDGVCxUG">phosphate</a>) <p><a href="/facts/Hexose/ooxIWuDL">Hexose</a> (six-carbon) sugars are not products of the Calvin cycle. Although many texts list a product of photosynthesis as C6H12O6, this is mainly for convenience to match the equation of <a href="/facts/Aerobic_respiration/kb6gpsvL">aerobic respiration</a>, where six-carbon sugars are oxidized in mitochondria. The carbohydrate products of the Calvin cycle are three-carbon sugar phosphate molecules, or "triose phosphates", namely, <a href="/facts/Glyceraldehyde-3-phosphate/Wy3FMLzJ">glyceraldehyde-3-phosphate</a> (G3P). </p> <h3>Steps</h3> <p>In the first stage of the Calvin cycle, a CO2 molecule is incorporated into one of two three-carbon molecules (<a href="/facts/Glyceraldehyde_3-phosphate/Wy3FMLzJ">glyceraldehyde 3-phosphate</a> or G3P), where it uses up two molecules of <a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a> and two molecules of <a href="/facts/NADPH/XMgmPQ5t">NADPH</a>, which had been produced in the light-dependent stage. The three steps involved are: </p> <ol><li>The enzyme <a href="/facts/RuBisCO/C8asuQsc">RuBisCO</a> catalyses the carboxylation of <a href="/facts/Ribulose-1%2c5-bisphosphate/1DwB2uHE">ribulose-1,5-bisphosphate</a>, RuBP, a 5-carbon compound, by carbon dioxide (a total of 6 carbons) in a two-step reaction.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> The product of the first step is enediol-enzyme complex that can capture CO2 or O2. Thus, enediol-enzyme complex is the real carboxylase/oxygenase. The CO2 that is captured by enediol in second step produces an unstable six-carbon compound called 2-carboxy 3-keto 1,5-biphosphoribotol (CKABP<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>) (or 3-keto-2-carboxyarabinitol 1,5-bisphosphate) that immediately splits into 2 molecules of <a href="/facts/3-phosphoglycerate/vI3TSY4D">3-phosphoglycerate</a> (also written as 3-phosphoglyceric acid, PGA, 3PGA, or 3-PGA), a 3-carbon compound.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a></li> <li>The enzyme <a href="/facts/Phosphoglycerate_kinase/BpUE8QNw">phosphoglycerate kinase</a> catalyses the phosphorylation of 3-PGA by ATP (which was produced in the light-dependent stage). <a href="/facts/1%2c3-Bisphosphoglycerate/aL6aR6ha">1,3-Bisphosphoglycerate</a> (glycerate-1,3-bisphosphate) and <a href="/facts/Adenosine_diphosphate/JEDnsCjn">ADP</a> are the products. (However, note that two 3-PGAs are produced for every CO2 that enters the cycle, so this step utilizes two <a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a> per CO2 fixed.)</li> <li>The enzyme <a href="/facts/Glyceraldehyde-3-phosphate_dehydrogenase_(NADP%252B)_(phosphorylating)/mqHAAgPy">glyceraldehyde 3-phosphate dehydrogenase</a> catalyses the <a href="/facts/Redox/Pyd5RVcj">reduction</a> of 1,3BPGA by <a href="/facts/NADPH/XMgmPQ5t">NADPH</a> (which is another product of the light-dependent stage). <a href="/facts/Glyceraldehyde_3-phosphate/Wy3FMLzJ">Glyceraldehyde 3-phosphate</a> (also called G3P, GP, TP, PGAL, GAP) is produced, and the <a href="/facts/NADPH/XMgmPQ5t">NADPH</a> itself is oxidized and becomes <a href="/facts/NADP%252B/XMgmPQ5t">NADP+</a>. Again, two <a href="/facts/NADPH/XMgmPQ5t">NADPH</a> are utilized per CO2 fixed.</li></ol> <p>The next stage in the Calvin cycle is to regenerate <a href="/facts/RuBP/1DwB2uHE">RuBP</a>. Five G3P molecules produce three <a href="/facts/RuBP/1DwB2uHE">RuBP</a> molecules, using up three molecules of ATP. Since each CO2 molecule produces two G3P molecules, three CO2 molecules produce six G3P molecules, of which five are used to regenerate <a href="/facts/RuBP/1DwB2uHE">RuBP</a>, leaving a net gain of one G3P molecule per three CO2 molecules (as would be expected from the number of carbon atoms involved). </p> <p>The regeneration stage can be broken down into a series of steps. </p> <ol><li><a href="/facts/Triose_phosphate_isomerase/9dsKLNp0">Triose phosphate isomerase</a> converts one of the G3P reversibly into <a href="/facts/Dihydroxyacetone_phosphate/XsSIJJT9">dihydroxyacetone phosphate</a> (DHAP), also a 3-carbon molecule.</li> <li><a href="/facts/Aldolase/jBS69B6G">Aldolase</a> and <a href="/facts/Fructose-1%2c6-bisphosphatase/3u4SopQe">fructose-1,6-bisphosphatase</a> convert a G3P and a DHAP into <a href="/facts/Fructose_6-phosphate/QQCrNpkT">fructose 6-phosphate</a> (6C). A phosphate ion is lost into solution.</li> <li>Then fixation of another CO2 generates two more G3P.</li> <li>F6P has two carbons removed by <a href="/facts/Transketolase/2bMkMucS">transketolase</a>, giving <a href="/facts/Erythrose-4-phosphate/z1V75Irk">erythrose-4-phosphate</a> (E4P). The two carbons on <a href="/facts/Transketolase/2bMkMucS">transketolase</a> are added to a G3P, giving the ketose <a href="/facts/Xylulose-5-phosphate/6HabNEkz">xylulose-5-phosphate</a> (Xu5P).</li> <li>E4P and a DHAP (formed from one of the G3P from the second CO2 fixation) are converted into <a href="/facts/Sedoheptulose-1%2c7-bisphosphate/eNHmjuAJ">sedoheptulose-1,7-bisphosphate</a> (7C) by aldolase enzyme.</li> <li><a href="/facts/Sedoheptulose-bisphosphatase/eNHmjuAJ">Sedoheptulose-1,7-bisphosphatase</a> (one of only three enzymes of the Calvin cycle that are unique to plants) cleaves <a href="/facts/Sedoheptulose-1%2c7-bisphosphate/eNHmjuAJ">sedoheptulose-1,7-bisphosphate</a> into <a href="/facts/Sedoheptulose-7-phosphate/etV9mj10">sedoheptulose-7-phosphate</a>, releasing an inorganic phosphate ion into solution.</li> <li>Fixation of a third CO2 generates two more G3P. The ketose S7P has two carbons removed by <a href="/facts/Transketolase/2bMkMucS">transketolase</a>, giving <a href="/facts/Ribose-5-phosphate/gMzSE2e1">ribose-5-phosphate</a> (R5P), and the two carbons remaining on <a href="/facts/Transketolase/2bMkMucS">transketolase</a> are transferred to one of the G3P, giving another Xu5P. This leaves one G3P as the product of fixation of 3 CO2, with generation of three pentoses that can be converted to Ru5P.</li> <li>R5P is converted into <a href="/facts/Ribulose-5-phosphate/VnQ2Ngdt">ribulose-5-phosphate</a> (Ru5P, RuP) by <a href="/facts/Phosphopentose_isomerase/mKV3K5pP">phosphopentose isomerase</a>. Xu5P is converted into RuP by <a href="/facts/Phosphopentose_epimerase/zhPxLC9P">phosphopentose epimerase</a>.</li> <li>Finally, <a href="/facts/Phosphoribulokinase/uNM1m7VY">phosphoribulokinase</a> (another plant-unique enzyme of the pathway) phosphorylates RuP into RuBP, ribulose-1,5-bisphosphate, completing the Calvin <i>cycle</i>. This requires the input of one ATP.</li></ol> <p>Thus, of six G3P produced, five are used to make three RuBP (5C) molecules (totaling 15 carbons), with only one G3P available for subsequent conversion to hexose. This requires nine ATP molecules and six NADPH molecules per three CO2 molecules. The equation of the overall Calvin cycle is shown diagrammatically below. </p> <p><a href="/facts/RuBisCO/C8asuQsc">RuBisCO</a> also reacts competitively with O2 instead of CO2 in <a href="/facts/Photorespiration/Dh4p0aCM">photorespiration</a>. The rate of photorespiration is higher at high temperatures. Photorespiration turns RuBP into 3-PGA and 2-phosphoglycolate, a 2-carbon molecule that can be converted via glycolate and glyoxalate to glycine. Via the glycine cleavage system and tetrahydrofolate, two glycines are converted into serine plus CO2. Serine can be converted back to 3-phosphoglycerate. Thus, only 3 of 4 carbons from two phosphoglycolates can be converted back to 3-PGA. It can be seen that photorespiration has very negative consequences for the plant, because, rather than fixing CO2, this process leads to loss of CO2. <a href="/facts/C4_carbon_fixation/2dLTxsae">C4 carbon fixation</a> evolved to circumvent photorespiration, but can occur only in certain plants native to very warm or tropical climates—corn, for example. Furthermore, RuBisCOs catalyzing the light-independent reactions of photosynthesis generally exhibit an improved specificity for CO2 relative to O2, in order to minimize the oxygenation reaction. This improved specificity evolved after RuBisCO incorporated a new protein subunit.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p> <h3>Products</h3> <p>The immediate products of one turn of the Calvin cycle are 2 glyceraldehyde-3-phosphate (G3P) molecules, 3 ADP, and 2 NADP+. (ADP and NADP+ are not really "products". They are regenerated and later used again in the <a href="/facts/Light-dependent_reactions/kBnR8Lcp">light-dependent reactions</a>). Each G3P molecule is composed of 3 carbons. For the Calvin cycle to continue, RuBP (ribulose 1,5-bisphosphate) must be regenerated. So, 5 out of 6 carbons from the 2 G3P molecules are used for this purpose. Therefore, there is only 1 net carbon produced to play with for each turn. To create 1 surplus G3P requires 3 carbons, and therefore 3 turns of the Calvin cycle. To make one glucose molecule (which can be created from 2 G3P molecules) would require 6 turns of the Calvin cycle. Surplus G3P can also be used to form other carbohydrates such as starch, sucrose, and cellulose, depending on what the plant needs.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h2 id="light-dependent-regulation">Light-dependent regulation</h2> <p class="note">Main article: <a href="/facts/Light-dependent_reactions/kBnR8Lcp">Light-dependent reactions</a></p> <p>These reactions do not occur in the dark or at night. There is a light-dependent regulation of the cycle enzymes, as the third step requires NADPH.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p><p>There are two regulation systems at work when the cycle must be turned on or off: the <a href="/facts/Thioredoxin/Up6p35ke">thioredoxin</a>/<a href="/facts/Ferredoxin/1qJJjQHk">ferredoxin</a> activation system, which activates some of the cycle enzymes; and the <a href="/facts/RuBisCo/C8asuQsc">RuBisCo</a> enzyme activation, active in the Calvin cycle, which involves its own activase.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>The thioredoxin/ferredoxin system activates the enzymes glyceraldehyde-3-P dehydrogenase, glyceraldehyde-3-P phosphatase, fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase, and ribulose-5-phosphatase kinase, which are key points of the process. This happens when light is available, as the ferredoxin protein is reduced in the <a href="/facts/Photosystem_I/z9hRH0kt">photosystem I</a> complex of the thylakoid electron chain when electrons are circulating through it.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> Ferredoxin then binds to and reduces the thioredoxin protein, which activates the cycle enzymes by severing a <a href="/facts/Cystine/MmwEHkkI">cystine</a> bond found in all these enzymes. This is a dynamic process as the same bond is formed again by other proteins that deactivate the enzymes. The implications of this process are that the enzymes remain mostly activated by day and are deactivated in the dark when there is no more reduced ferredoxin available. </p><p>The enzyme RuBisCo has its own, more complex activation process. It requires that a specific <a href="/facts/Lysine/CEetgA9L">lysine</a> amino acid be <a href="/facts/Carbamylated/up52qydJ">carbamylated</a> to activate the enzyme. This lysine binds to <a href="/facts/RuBP/1DwB2uHE">RuBP</a> and leads to a non-functional state if left uncarbamylated. A specific activase enzyme, called <a href="/facts/RuBisCO/C8asuQsc">RuBisCo activase</a>, helps this carbamylation process by removing one proton from the lysine and making the binding of the carbon dioxide molecule possible. Even then the RuBisCo enzyme is not yet functional, as it needs a magnesium ion bound to the lysine to function. This magnesium ion is released from the thylakoid lumen when the inner pH drops due to the active pumping of protons from the electron flow. RuBisCo activase itself is activated by increased concentrations of ATP in the stroma caused by its <a href="/facts/Phosphorylation/LXUEEeIL">phosphorylation</a>.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Wood%25E2%2580%2593Ljungdahl_pathway/JPeyzANy">Wood–Ljungdahl pathway</a> – A set of biochemical reactions used by some bacteria</li></ul> <ul><li>Bassham JA (2003). "Mapping the carbon reduction cycle: a personal retrospective". <i>Photosynth. Res</i>. 76 (1–3): 35–52. <a href="/facts/Bibcode_(identifier)/9HtdQSGB">Bibcode</a>:<a href="https://ui.adsabs.harvard.edu/abs/2003PhoRe..76...35B">2003PhoRe..76...35B</a>. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1023%2FA%3A1024929725022">10.1023/A:1024929725022</a>. <a href="/facts/PMID_(identifier)/JlHAvMHt">PMID</a> <a href="https://pubmed.ncbi.nlm.nih.gov/16228564">16228564</a>. <a href="/facts/S2CID_(identifier)/ldJsHa2Y">S2CID</a> <a href="https://api.semanticscholar.org/CorpusID:52854452">52854452</a>.</li> <li>Diwan, Joyce J. (2005). <a href="https://web.archive.org/web/20050316092319/http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/dark.htm">"Photosynthetic Dark Reaction"</a>. Biochemistry and Biophysics, Rensselaer Polytechnic Institute. Archived from <a href="http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/dark.htm">the original</a> on 2005-03-16. Retrieved 2012-10-24.</li> <li>Portis, Archie; Parry, Martin (2007). <a href="https://web.archive.org/web/20120312090903/http://ddr.nal.usda.gov/dspace/bitstream/10113/3976/1/IND43944177.pdf">"Discoveries in Rubisco (Ribulose 1,5-bisphosphate carboxylase/oxygenase): a historical perspective"</a> (PDF). <i>Photosynthesis Research</i>. 94 (1): 121–143. <a href="/facts/Bibcode_(identifier)/9HtdQSGB">Bibcode</a>:<a href="https://ui.adsabs.harvard.edu/abs/2007PhoRe..94..121P">2007PhoRe..94..121P</a>. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1007%2Fs11120-007-9225-6">10.1007/s11120-007-9225-6</a>. <a href="/facts/PMID_(identifier)/JlHAvMHt">PMID</a> <a href="https://pubmed.ncbi.nlm.nih.gov/17665149">17665149</a>. <a href="/facts/S2CID_(identifier)/ldJsHa2Y">S2CID</a> <a href="https://api.semanticscholar.org/CorpusID:39767233">39767233</a>. Archived from <a href="https://ddr.nal.usda.gov/dspace/bitstream/10113/3976/1/IND43944177.pdf">the original</a> (PDF) on 2012-03-12.</li></ul> <h2 id="further-reading">Further reading</h2> <ul><li><a href="http://4e.plantphys.net/article.php?ch=8&id=81">Rubisco Activase, from the Plant Physiology Online website</a> <a href="https://web.archive.org/web/20090218124635/http://4e.plantphys.net/article.php?ch=8&id=81">Archived</a> 2009-02-18 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li> <li><a href="http://4e.plantphys.net/article.php?ch=8&id=80">Thioredoxins, from the Plant Physiology Online website</a> <a href="https://web.archive.org/web/20080616040922/http://4e.plantphys.net/article.php?ch=8&id=80">Archived</a> 2008-06-16 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="https://web.archive.org/web/20050316092319/http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/dark.htm">The Biochemistry of the Calvin Cycle at Rensselaer Polytechnic Institute</a></li> <li><a href="https://www.ncbi.nlm.nih.gov/books/NBK22344/">The Calvin Cycle and the Pentose Phosphate Pathway</a> from <i>Biochemistry</i>, Fifth Edition by Jeremy M. Berg, John L. Tymoczko and Lubert Stryer. Published by W. H. Freeman and Company (2002).</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Silverstein, Alvin (2008). Photosynthesis. Twenty-First Century Books. p. 21. ISBN 9780822567981. <a href="9780822567981" target="_blank">9780822567981</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Cushman, John C. (2001). "A plastic photosynthetic adaptation to arid environments". Plant Physiology. 127 (4): 1439–1448. doi:10.1104/pp.010818. PMC 1540176. PMID 11743087. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1540176" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1540176</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Sainis, Jayashree Krishna; Dani, Diksha Narhar; Dey, Gautam Kumar (2003-01-01). "Involvement of thylakoid membranes in supramolecular organisation of Calvin cycle enzymes inAnacystis nidulans". Journal of Plant Physiology. 160 (1): 23–32. Bibcode:2003JPPhy.160...23S. doi:10.1078/0176-1617-00849. ISSN 0176-1617. PMID 12685042. The results suggested that the integrity of thylakoid membranes may be essential for the organisation of sequential enzymes of the Calvin cycle in vivo and facilitate their functioning. <a href="https://www.sciencedirect.com/science/article/pii/S0176161704703739" target="_blank">https://www.sciencedirect.com/science/article/pii/S0176161704703739</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Bassham J, Benson A, Calvin M (1950). "The path of carbon in photosynthesis" (PDF). J Biol Chem. 185 (2): 781–7. doi:10.2172/910351. PMID 14774424. Archived from the original (PDF) on 2009-02-19. Retrieved 2013-07-03. <a href="https://web.archive.org/web/20090219123745/http://www.jbc.org/cgi/reprint/185/2/781.pdf" target="_blank">https://web.archive.org/web/20090219123745/http://www.jbc.org/cgi/reprint/185/2/781.pdf</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Campbell, Neil A.; Brad Williamson; Robin J. Heyden (2006). Biology: Exploring Life. Boston, Massachusetts: Pearson Prentice Hall. ISBN 0-13-250882-6. <a href="0-13-250882-6" target="_blank">0-13-250882-6</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Farazdaghi H (2009). "Modeling the Kinetics of Activation and Reaction of Rubisco from Gas Exchange". Photosynthesis in silico. Advances in Photosynthesis and Respiration. Vol. 29. pp. 275–294. doi:10.1007/978-1-4020-9237-4_12. ISBN 978-1-4020-9236-7. <a href="978-1-4020-9236-7" target="_blank">978-1-4020-9236-7</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Lorimer, G.H.; Andrews, T.J.; Pierce, J.; Schloss, J.V. (1986). "2´-carboxy-3-keto-D-arabinitol 1,5-bisphosphate, the six-carbon intermediate of the ribulose bisphosphate carboxylase reaction". Phil. Trans. R. Soc. Lond. B. 313 (1162): 397–407. Bibcode:1986RSPTB.313..397L. doi:10.1098/rstb.1986.0046. <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.1986.0046" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rstb.1986.0046</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Campbell, and Reece Biology: 8th Edition, page 198. Benjamin Cummings, December 7, 2007. <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Schulz, L; Guo, Z; Zarzycki, J; Steinchen, W; Schuller, JM; Heimerl, T; Prinz, S; Mueller-Cajar, O; Erb, TJ; Hochberg, GKA (14 October 2022). "Evolution of increased complexity and specificity at the dawn of form I Rubiscos". Science. 378 (6616): 155–160. Bibcode:2022Sci...378..155S. doi:10.1126/science.abq1416. PMID 36227987. S2CID 252897276. <a href="https://www.science.org/doi/10.1126/science.abq1416" target="_blank">https://www.science.org/doi/10.1126/science.abq1416</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Russell, Wolfe et al.Biology: Exploring the Diversity of Life.Toronto:Nelson College Indigenous,1st ed, Vol. 1, 2010, pg 151 <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Schreier, Tina; Hibberd, Julian (1 March 2019). "Variations in the Calvin–Benson cycle: selection pressures and optimization?". Journal of Experimental Botany. 70 (6) (published 27 March 2019): 1697–1701. doi:10.1093/jxb/erz078. PMC 6436154. PMID 30916343 – via Oxford Academic. <a href="/wiki/Julian_Hibberd" target="_blank">/wiki/Julian_Hibberd</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Konwarh, Rocktotpal; Abda, Ebrahim M.; Haregu, Simatsidk; Singh, Anand Pratap (2022-01-01), Khan, Raju; Murali, S.; Gogoi, Satyabrat (eds.), "Chapter 7 - Exemplary evidence of bio-nano crosstalk between carbon dots and plant systems", Carbon Dots in Agricultural Systems, Academic Press, pp. 155–173, ISBN 978-0-323-90260-1, retrieved 2023-04-22 <a href="978-0-323-90260-1" target="_blank">978-0-323-90260-1</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Besse, I; Buchanan, B (1997). "Thioredoxin-linked animal and plant processes: the new generation". Bot. Bull. Acad. Sin. 38: 1–11. <a href="/wiki/Bot._Bull._Acad._Sin." target="_blank">/wiki/Bot._Bull._Acad._Sin.</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Ruuska, Sari A.; Andrews, T. John; Badger, Murray R.; Price, G. Dean; von Caemmerer, Susanne (2000-02-01). "The Role of Chloroplast Electron Transport and Metabolites in Modulating Rubisco Activity in Tobacco. Insights from Transgenic Plants with Reduced Amounts of Cytochrome b/f Complex or Glyceraldehyde 3-Phosphate Dehydrogenase". Plant Physiology. 122 (2): 491–504. doi:10.1104/pp.122.2.491. ISSN 1532-2548. PMC 58886. PMID 10677442. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC58886" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC58886</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> </ol>