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HbLee HbLee
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8 years ago Edited: 8 years ago, HbLee
6RuBP + 6CO2 + 18ATP + 12NADPH ———→ 6RuBP + C6H12O6 +18 ADP +16P +12 NADP

Is the overall equation of the Calvin Cycle...

But I don't understand.
3 molecules of CO2 and RuBP make 6 molcules of G3P and one is exported outside the chloroplast to make a glucose and 5 remain. Yet glucose is a six-carbon sugar hence it needs 2 molecules of G3P. Then 2 molecules of G3P are exported and 10 should be used to regenerate RuBP. But why 6 not 5?Neutral Face??


I summarized Photosynthesis.

Light-dependent Reaction
1.   An antenna complex surrounding the reaction center of Photosystem II absorbs light energy and passes it to a reaction center which has a pair of special chlorophyll a molecules.
2.   The light energy excites an electron from the Chlorophyll a pair then the excited electron is transferred to a primary electron acceptor. Meanwhile, water breaks down into (H2O →  2H+ + ½O2 + 2e-) and donates its electrons to the reaction center.
3.   The electron passed to the primary electron acceptor travels through the electron transport chain and is delivered to Photosystem I, making ATP(as non-cyclic photophosphorylation).
4.   Another photon is absorbed by PSI antenna and is transmitted to the reaction center.
5.   The reaction center is oxidized and sends the electron which travels through the shorter chain and reduces NADP to NADPH.
Light-independent Reaction
 
1. Fixation : Ribulose biphosphate carboxylase(RuBisCo) catalyzes a reaction between CO2 and ribulose 1,5-biphosphate(RuBP). Two molecules of 3-phosphoglyceric acid(3-PGA or GP) are formed.     (from one molecule of CO2 and one RuBP)

2. Reduction : These 3-PGA molecules are phosphorylated by ATP into glycerate diphosphate molecules then reduced by NADPH into two molecules of glyceraldehyde 3-phosphate(G3P or PGAL). (The ATP and NADPH are from the light-dependent reactions)

3. Regeneration : 3 molecules of CO2 in turn produce 6 molecules of G3P. Only one molecule
of G3P is exported outside the chloroplast to be associated with the process of making a glucose molecule and the remaining G3P molecules are converted by ATP energy to reform RuBP molecues thus the overall equation of Calvin Cycle is 3RuBP + 3CO2 + 9ATP + 6NADPH ———→ 3RuBP + C3H6O3 +9 ADP +8P +6 NADP

Is there anything to add or correct?

Post Merge: 8 years ago

Oh, now I recall RuBP is a 5-carbon sugar.
Still, I would be appreciated if you leave a comment about my summary.
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psyche360psyche360
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Posts: 453
8 years ago
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