Question

Trace the path of a labeled carbon atom through the biological processes of photosynthesis and respiration. The atom will start its journey inside a carbon dioxide molecule and it will end in the air inside a new carbon dioxide molecule. Your mission is to use your knowledge of photosynthesis and respiration to explain what happens to the carbon atom in these processes.

Answer 1

Cellular respiration and photosynthesis are reverse and complement reactions to each other.

In photosynthesis, carbon dioxide and water yield glucose and oxygen:
CO₂ + H₂O → C₆H₁₂O₆ + O₂

In the opposite reaction - cellular respiration, glucose and oxygen yield water and carbon dioxide:
C₆H₁₂O₆ + O₂ → CO₂ + H₂O