How do plants and cyanobacteria produce net positive oxygen if they need to also metabolize oxygen for energy production?

Question

As I understand, plants use 6 carbon dioxide molecules to make 6 Oxygen molecules and 1 glucose molecule. However, to metabolize that glucose to use as an energy source requires using up another 6 Oxygen molecules, with no net production of oxygen. How did the Great Oxidation Event happen if oxygen produced by photosynthesis needs to also be burned when metabolizing the glucose?

In: 2

Answer 1

Plants and phytoplankton produce sugars from CO2. Some of those sugars, they later burn for energy, but some of them are used to grow the plant or propagate the plankton.

So, the sugars that