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How does photosynthesis work?

Quick answer

Photosynthesis works in two stages: light-dependent reactions capture sunlight in the chloroplasts to make energy carriers, then the Calvin cycle uses that energy to turn carbon dioxide and water into glucose, releasing oxygen. Chlorophyll in the chloroplasts absorbs sunlight (mainly red and blue light).

Step by step

  1. Chlorophyll in the chloroplasts absorbs sunlight (mainly red and blue light).
  2. Light reactions split water, release oxygen, and store energy in molecules called ATP and NADPH.
  3. The Calvin cycle uses that stored energy to build glucose from carbon dioxide.
  4. Overall: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.

People also ask

What are the two stages of photosynthesis?
The light-dependent reactions (capture sunlight, split water, release oxygen) and the Calvin cycle (build glucose from CO₂ using the captured energy).
Where does photosynthesis happen?
Mostly in the leaves, inside chloroplasts that contain the green pigment chlorophyll.
Why does photosynthesis release oxygen?
Oxygen is a by-product of splitting water molecules during the light-dependent reactions.

Part of the guide: Nature & Earth: Living Things and Rocks →