How many ATP molecules are required in the C₄

Solution

In the C₄ pathway (Hatch-Slack pathway), the synthesis of one molecule of glucose requires a total of 30 ATP molecules . Here's a breakdown of how this energy is utilized: ATP Requirements:

1. C₄ Cycle (Initial CO₂ Fixation in Mesophyll Cells):
   • 2 ATP molecules are consumed to regenerate phosphoenolpyruvate (PEP) from pyruvate for every CO₂ molecule fixed in the C₄ cycle.
   • For the production of one glucose molecule, 6 CO₂ molecules are required, so 6 × 2 = 12 ATP are used in the C₄ cycle.
2. Calvin Cycle (C₃ Pathway in Bundle-Sheath Cells):
   • The Calvin cycle requires 18 ATP molecules to synthesize one glucose molecule (as in the C₃ pathway).

• 12 ATP from the C₄ cycle + 18 ATP from the Calvin cycle = 30 ATP molecules.