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EEJ MAIN Chemistry QUESTION #5556
Question 1
In the photosynthesis process, how many ATP molecules are consumed in the synthesis of each glucose molecule?
  • 18 ATP✔️
  • 10 ATP
  • 8 ATP
  • 6 ATP
Correct Answer Explanation
The Calvin cycle (dark reactions) requires 18 ATP and 12 NADPH to fix 6 molecules of $CO_2$ into one glucose molecule: $6CO_2 + 18ATP + 12NADPH \to C_6H_{12}O_6 + 18ADP + 12NADP^+$. Each turn of the cycle uses 3 ATP and 2 NADPH; 6 turns are needed for one glucose.