NEETBotanyPhotosynthesis in Higher Plants
During the biosynthetic phase of photosynthesis in a typical C₃ plant, if exactly 72 molecules of ATP are consumed, how many molecules of glucose are synthesized and how many molecules of NADPH are oxidized simultaneously?
Options
- A4 molecules of glucose and 48 molecules of NADPH
- B4 molecules of glucose and 24 molecules of NADPH
- C2 molecules of glucose and 48 molecules of NADPH
- D6 molecules of glucose and 72 molecules of NADPH
Correct answer
A. 4 molecules of glucose and 48 molecules of NADPH
Step-by-step solution
In the biosynthetic phase of a C₃ plant, the synthesis of one molecule of glucose requires the fixation of 6 CO₂ molecules. The fixation of one CO₂ molecule in the Calvin cycle consumes 3 ATP and 2 NADPH. Thus, one glucose molecule requires 6 3 = 18 ATP and 6 2 = 12 NADPH. If 72 molecules of ATP are consumed, the number of glucose molecules synthesized is 72 18 = 4 molecules. Since each glucose molecule requires the oxidation of 12 NADPH molecules, the total number of NADPH molecules oxidized is 4 12 = 48 molecules