H2O comes out of PS?

Gary Hannan bio_hannan at ONLINE.EMICH.EDU
Mon Mar 13 09:31:02 EST 2000


John,

Thanks for the reply.  That seems reasonable to me.  It does look like the
O comes out at the PGA to PGAL step.  I guess the overall formula would
have to be taken as a gross oversimplification of the "real" process.

Thanks again,

Gary HAnnan
>
>I teach that the formula is actually 6CO2 + 12H2O --> C6H12O6 + 6H2O + 6O2
>
>Light is used to split H2O releasing O2 and producing ATP (from ADP + Pi)
>and reduced NADPH2 - this takes place on the thlakoids of the chloroplast.
>
>The NADPH2 is used in the Calvin cycle to reduce CO2 and one of the
>byproducts of one (?) of the stages of the Calvin cycle of reactions is
>H2O.  The H in this water will have come via the NADPH2 and the O in this
>water has come from CO2.  This takes place in the stroma of the
>chloroplast.
>
>I bet this is an oversimplification, but it satisfies me and most 17 year
>olds.
>
>
>Dr. John Hewitson (Oundle School)
>Bramston Garden Cottage, Oundle, Peterborough PE8 4BG UK
>Phone and Fax +44 (0) 1832 272209
>email john_hewitson at breathe.co.uk
>
>---


Gary Hannan
bio_hannan at online.emich.edu
Biology Dept.
Eastern Michigan University
Ypsilanti, MI  48197
(734) 487-4399


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