Connecting Photosynthesis to Respiration—Seeing the Big Picture

 

At first, Photosynthesis and Respiration felt like separate worlds. Then I realized they form a continuous cycle: the glucose I wrote down in my Calvin poster becomes fuel for glycolysis in the cytoplasm, generating 2 ATP and 2 pyruvate per glucose. I drew a flowchart:

1. Glycolysis (cytoplasm): Glucose → 2 pyruvate + 2 ATP.
2. Krebs cycle (mitochondrial matrix): Pyruvate → CO₂ + NADH/FADH₂ + 2 ATP.
3. Oxidative phosphorylation (inner mitochondrial membrane): NADH/FADH₂ donate electrons → H₂O + 32 ATP.

By color-coding each stage and linking it back to my Photosynthesis outputs—glucose and O₂—I saw how plants power both their own cells and heterotrophs.

Sample SPM Question
“Compare the location and net ATP yield of glycolysis, the Krebs cycle, and oxidative phosphorylation in respiration.”

My comparison:
• Glycolysis: cytoplasm; net 2 ATP.
• Krebs cycle: mitochondrial matrix; net 2 ATP per glucose.
• Oxidative phosphorylation: inner membrane; ~32 ATP per glucose.