29. In photosynthesis how many water molecules does it take to manufacture a single glucose molecule?
A total of 12 waters (H20) are needed. That means six pairs of hydrogens from 6 waters (each pair generates three ATPs) will produce a total of 18 ATPs needed in the Calvin Cycle to produce the glucose molecule. The other six molecules of water (6H2O)will be used to supply hydrogens to make glucose (C6H12O6) in the Calvin Cycle.