Question

State in brief the role of photosynthesis and respiration in carbon cycle in natue

Answer 1

1. Carbon enters life forms through the process of photosynthesis. During photosynthesis, carbon dioxide and water combine to produce glucose and oxygen. This changes the atmospheric carbon into glucose molecules.
Glucose, which is a source of food, is utilized by organisms to produce energy during respiration. During this process, glucose is broken down in the presence/absence of oxygen to produce carbon dioxide.

2. Oxygen is an important component of life. We cannot survive without oxygen. It comprises about 21% of atmospheric air. It is also present in dissolved form in water bodies and helps in the survival of aquatic life. In combined form, it is found both in Earth’s crust and in the air. In the air, it occurs as carbon dioxide. In the crust, it is present as oxides of most metals and silicon and also as carbonate, sulphate, nitrate and other minerals.

Oxygen is also a part of several essential bio-molecules such as carbohydrates, proteins, nucleic acids and fats.

Oxygen cycle

There are processes that utilize atmospheric oxygen. At the same time, the balance of oxygen in the atmosphere is also maintained. 

Oxygen is utilized during respiration, combustion and formation of oxides of nitrogen.Oxygen is returned to the atmosphere in only one major way, and that is photosynthesis.