Practice question · Multiple choice
The Great Oxidation Event was caused by a metabolic waste product, yet it enabled the emergence of complex multicellular life. What explains this apparent paradox?
Hints
- What metabolic advantage did oxygen afford organisms over anaerobic fermentation?
- How did atmospheric oxygen physically alter the terrestrial environment for early organisms?
Show the answer
B. Oxygen enabled high-yield aerobic respiration and UV-shielding ozone
Why
Treating oxygen solely as a toxin misses that its high redox potential allowed roughly 15 times more ATP production per glucose than fermentation, while atmospheric chemistry generated the protective ozone layer needed for terrestrial life.
Practise Photosynthesis and the Oxygen Revolution
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More questions on Photosynthesis and the Oxygen Revolution
- Why does the Calvin cycle stop within minutes of darkness, despite being called light-independent?
- Aerobic respiration yields about 30 ATP per glucose, while fermentation yields 2. Set how many times more…
- The oxygen released by photosynthesis comes from carbon dioxide.
- Arrange these events in the order they occurred in Earth’s history.
- Sort each consequence by whether the Great Oxidation Event caused it directly.
- Match each molecule to its role in photosynthesis.