calvin cycle (dark rxn)

[joonkimdds]

DAT destroyer says 6 cycle is required to make 1 glucose.
I am wondering why it takes 6 cycle instead of 2 cycle.

1 cycle = 3 CO2, 9ATP, 6NADPH added to Rubisco and 3RuBP.

It becomes 6 of 3PGA ==> 6 of G3P and only 1 of them is used to make glucose.

Since G3P is 3carbon, and glucose is 6 carbon, we need to repeat this cycle one more time to make 2 of G3P = 2 of 3 carbon = 6 carbon = glucose.

so I think only 2 cycles are required to make 1 glucose instead of 6 cycle.



Another question I have is, what do the concentration of H and Mg2+ stored in chlorophyll have something to do about this cycle?

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[Svart Aske]

Each cycle only starts with 1 CO2 and 1 RuBP (not 3), so it takes 6 cycles to produce a glucose.

I don't have my textbook with me, but I think Mg is just a component of the chlorophyll pigment, while the H+ concentration difference across the lumen and thylakoid membrane of the chloroplast creates an electrochemical gradient that makes chemiosmosis, and hence ATP production, possible.