Final answer:
To reduce six molecules of CO2 to glucose in photosynthesis, 18 ATP and 12 NADPH molecules are needed. This is because each CO2 molecule requires two NADPH and three ATP molecules to be converted into glucose.
Step-by-step explanation:
To reduce six molecules of CO2 to glucose by photosynthesis, a specific number of NADPH and ATP molecules are required. Each molecule of CO2 fixed in the Calvin cycle necessitates two NADPH and three ATP molecules. Therefore, for six CO2 molecules, you would need 12 NADPH and 18 ATP molecules. During the reduction phase, the 12 NADPH and 12 ATP molecules convert six molecules of 3-PGA into six molecules of G3P. Then, six additional ATP molecules are used to regenerate RUBP, which is necessary for the cycle to continue.
In summary, for the complete process of converting six molecules of CO2 to one molecule of glucose, a total of 18 ATP and 12 NADPH molecules are required. This illustrates the energetic process whereby photosynthesis transforms light energy into chemical energy stored in glucose.