Practice question · True or false
The oxygen released by photosynthesis comes from carbon dioxide.
Hints
- Trace the oxygen atoms through the reaction.
- The light reactions split water, not carbon dioxide.
Show the answer
False
Why
False, the oxygen comes from water, split in the light reactions. This was settled by isotope labelling: label the oxygen in water and it appears in the released O₂; label it in CO₂ and it appears in the sugar instead.
Practise Photosynthesis and the Oxygen Revolution
The app has 4 more questions on this lesson, and keeps your place in the course. Biology I is free to start.
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