Oxygen is a By-Product of Photosynthesis in Plants, Algae, and Cyanobacteria
- Have you ever wondered where the oxygen you breathe comes from?
- It’s a by-product of photosynthesis, the process that powers nearly all life on Earth.

Photosynthesis
- Photosynthesis is a crucial biological process that occurs in plants, algae, and cyanobacteria (also known as blue-green algae).
- This process involves the conversion of light energy into chemical energy, resulting in the production of glucose and the release of oxygen.
- One of the key aspects of photosynthesis is that oxygen is produced as a by-product.
- This oxygen is essential for life on Earth, as it supports the respiration of most living organisms.
- It is important to understand that the oxygen released during photosynthesis actually comes from the splitting of water molecules.
Carbon dioxide + water → glucose + oxygen

This equation highlights that oxygen is produced as a byproduct during photosynthesis.
The Source of Oxygen
- The oxygen released during photosynthesis originates from water molecules, not carbon dioxide.



