Question

Oxygen during photosynthesis evolved in which processes?

Answer 1

In the photosynthesis process, the light energy from the sun is converted into the chemical energy that is used for plant growth. The water absorbed by the root is split into the protons and the oxygen molecule by the process of photolysis.

Complete answer:
Photosynthesis mainly occurs in the chloroplast. It is also known as a plastid. The end product of photosynthesis is sugar and the obtained sugar is converted into starch and stored. In chloroplast, the thylakoid membrane is there, into which the starch is stored in the stroma. The substance utilized by the photolysis step constitutes 70% of the human body.

These substances are utilized to produce oxygen and glucose. During the light reaction of photosynthesis, oxygen gets released. The water molecule splits during the light reaction into oxygen as well as protons and electrons. The water is broken into component atoms when the electrons are taken away from the water molecules. The oxygen atoms which are released from the two water molecules combine to form diatomic oxygen.

During the process of photosynthesis, the plant absorbs carbon dioxide and water and in the presence of sunlight releases oxygen as a by-product. In the initial phase of photosynthesis, sunlight excites the chlorophyll in the plant, in the presence of this exciting chlorophyll, water undergoes the photolytic oxidation reaction(splitting of the water molecule in the presence of sunlight) to generate $H^+$ ions, electrons, and free oxygen species. The $H^+$ ions and electrons are required for further steps to produce ATP and reduce $NADP^+$ to NADPH, while the oxygen is released into the surrounding area.

Note:
The oxygen released during photosynthesis is from the water. The plants absorb water molecules as well as carbon dioxide during photosynthesis. Later these water molecules converted into oxygen and sugar. The oxygen is then released into the atmosphere whereas the sugar molecules are stored for energy.