Question

How oxygen is formed in photosynthesis?

Answer 1

Hint: Photosynthesis occurs in plants, algae and bacteria majorly to extract energy from the sunlight, which is the light energy and convert it into the chemical energy which is required for different physiological functions as well as for proper channeling of energy into the ecosystem.

Complete answer:
The process can happen in two ways either oxygenic or anoxygenic. At the time of oxygenic photosynthesis the light energy from the Sun transfers the water electrons to the carbon dioxide molecule to produce some carbohydrates. Due to the gain of electrons by carbon dioxide it is considered to be reduced while the loss of electrons from the water molecule makes it oxidised. The ultimate product is Oxygen and carbohydrates.
This oxygenic photosynthesis is really necessary for the exchange of gases. When the byproduct of respiration carbon dioxide is given out it is utilised in the process of photosynthesis and oxygen produced in the photosynthesis process is utilised by the breathing organisms.
On the other hand, anoxygenic photosynthesis is carried out by the usage of some other electron donors which are not water. This type of photosynthesis occurs in the purple and green sulphur bacteria which are present majorly in aquatic habitats. Unlike oxygenic photosynthesis anoxygenic photosynthesis does not produce any oxygen.

Note:
6CO₂ + 12H₂O -----------> C₆H₁₂O₆ + 6O₂ + 6H₂O
The above reaction states that when 6 molecules of carbon dioxide combine with 12 molecule of water in the presence of light results in the formation of one molecule of glucose and 6 molecules of oxygen and water