Before cellular respiration can take place, glucose must be created. Glucose is created in the Calvin cycle. The Calvin
cycle is a series of reactions that take place in the stroma of a thylakoid cell and uses ATP and NADPH. The Calvin cycle
is divided into three phases; Carbon Fixation, Reduction, and Regeneration of RuBP (ribulose-1,5-diphosphate).
In the first phase, carbon gas is taken from the atmosphere and attaches to RuBP. It creates a six carbon molecule. Almost
immediatly this molecule divides into two 3-carbon molecules called PGA (phosphogylcerate). The enzyme RuBP carboxylase catalyzes
this reaction. It is called C3 fixation; two 3-carbon molecules are produced.
In the second phase, the stroma of the cell allows reactions to reduce PGA into PGAL. First ATP gives off it's phosphates
and PGA gets transformed into PGAP (biphosphogylcerate). Secondly, a molecule of NADPH gives up a hydrogen ion and some of
it's electrons to PGAP, this reduces PGAP into PGAL (phosphogyleraldehyde).
At this point there are six molecules containing three carbon and one phosphate.
In the last phase, one of the molecules (containing three carbon and one phosphate) is taken away. At this point you
are left with five molecules, and it is called G3P. Then three ADP are added and you end up with your begining molecule of
Once this whole cycle is done twice, Glucose is created.