Page 186 - Photosynthesis: The Green Miracle

Adnan Oktar

The Dark Phase
The energy-charged NADPH and ATP molecules that emerged dur-
ing the light phase, in the dark phase convert the carbon dioxide into

foodstuffs such as sugar and starch.
The dark phase is a circular reaction, which begins with a molecule
that needs to be recreated at the end of the reaction in order for the proc-
ess to continue. In the start of this reaction, also known as the Calvin
phase, electrons and hydrogen ions joined to the NADPH, and phospho-
rus joined to the ATP, are used to produce glucose. These processes take
place in the liquid regions of the chloroplast known as stroma, and each
phase is controlled by a different enzyme. The dark-phase reaction needs
the carbon dioxide, which enter the leaves through the pores and disperse

in the stroma. When these carbon dioxide molecules bind to the sugar
molecules known as 5-RuBP in the stroma, they form an unbalanced 6-
carbon molecule, and thus the dark phase is initiated. (See diagram on
Page 185: 1st phase.)
This 6-carbon molecule immediately divides, and two 3-phospho-
glycerate (3PG) molecules emerge. Phosphate is added to both molecules
by ATP; this process is referred to as phosphorylation. (See diagram on

Page 185, 2nd phase.) As a result of phosphorylation, two bisphospho-
glycerate (BPG) molecules form. These in turn are broken down by
NADPH, giving rise to two glyceral-3-phosphate (G3P) molecules. (See
diagram on Page 185, 3rd and 4th stages.) This final product is now at the
junction point and part of it abandons the chloroplast in order to partici-
pate in glucose production by entering the cytoplasm. (See diagram on
Page 185, 5th phase.) The other part continues with the Calvin phase, is
again subjected to phosphorylation, and is thus transformed into the 5-
RuBP molecule at the beginning of the phase. (See diagram on Page 185,

7th and 8th phases.) This phase has to be repeated six times for the pro-
duction of the G3P molecule needed to form one glucose molecule.
As in all the other stages of photosynthesis, the enzymes undertake

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