what component of Earth’s atmosphere exists entirely as a result of photosynthesis?


Oxygen is primarily produced by photosynthesis. In the beginning, there was no free oxygen available in Earth’s atmosphere. It started to appear about 3.5 billion years ago due to the evolution of photosynthetic bacteria.


Green plants and blue-green algae use photosynthesis to produce oxygen as a side product and carbon hydrates such as glucose and sugar for energy. Most of the oxygen in the atmosphere comes from photosynthesis:

6 CO2 + 6 H2O → C6H12O6 + 6 O2

However, some oxygen is also produced by the decomposition of water in the atmosphere:

2 H2O → 2 H2 + 1 O2

Volcanoes release water vapor, which can be decomposed into oxygen and hydrogen. Kenneth Towe’s research concluded that early Earth likely had an atmosphere that contained free oxygen.

How is Oxygen Produced during Photosynthesis?

During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons.

This transforms the water into oxygen and the carbon dioxide into glucose. The oxygen produced during photosynthesis comes from the splitting of water molecules.

The process of photosynthesis can be divided into two stages: the light-dependent reaction and the light-independent (or dark) reaction. During the light reactions, the primary purpose is to generate energy for use in the dark reactions.

The energy is harvested from sunlight, which is transferred to electrons. As the electrons pass through a series of molecules, a proton gradient is formed membranes. The protons flow back enclosed by the thylakoid membrane. The diatomic oxygen is released and the chlorophyll center binds to new water molecules to repeat the process.

Due to the reactions involved, four electrons must be energized by the chlorophyll to generate a single oxygen molecule.

Importance of Oxygen in the Earth’s Atmosphere

The importance of oxygen production in photosynthesis can be summarized as follows:

  1. Oxygen is released as a byproduct of photosynthesis. This means that plants produce oxygen as a result of the process of photosynthesis.
  2. Oxygen is crucial for cellular respiration in plants and Animals. Plants need oxygen for the process of respiration, which is how they convert stored energy into a usable form.
  3. Oxygen is stored for energy and released as a byproduct. This means that plants can use the oxygen produced during photosynthesis for their own energy needs.
  4. Oxygen is also important for other living organisms. Oxygen is necessary for the survival of many living organisms, including humans and animals. The oxygen produced during photosynthesis helps to maintain the balance of oxygen in the atmosphere, which is essential for life on Earth.

Share On:

Related Posts

What Others Are Asking