From Lab to Life: Mighty Mitochondria |
So – why do we need oxygen? And where does it come from?
Oxygen on Earth formed through photosynthesis. Ancient microorganisms called cyanobacteria began releasing oxygen by using sunlight to process carbon dioxide and water, to make glucose and oxygen. They split H2O into hydrogen and oxygen, and then combine carbon, hydrogen and oxygen, to make glucose C6H12O6 , a carbohydrate. Excess oxygen is released as a result.
This oxygen is why we humans – and most other living things — are able to live on earth. This accumulation of oxygen started during the Great Oxidation Event approximately 2.4 to 2.5 billion years........