Nitrogen and carbon cycle

Introduction:

CARBON CYCLE-

There are more compounds of carbon, than of all the other elements taken together except hydrogen. This wide variety of carbon compounds is essential for the existence of the complex molecules of life, For example, carbohydrates, fats, proteins, vitamins and nucleic acids. It is extremely important that carbon atoms transfer form the living to the non-living forms and vice-versa. This is not only linked to transfer of energy but also to basic processes by which life survives on the earth. The exchange of carbon between the living and non-living thing centres around two processes, namely respiration and photosynthesis, and one compound, carbon dioxide. This Cycle of carbon in nature is called Carbon cycle.

Nitrogen Cycle-

Nitrogen is essential for all the living things. Proteins and nucleic acids, which are essential for growth and good health, contain nitrogen. Like carbon, there is a global cycle for nitrogen, which is known as the Nitrogen cycle. Nitrogen atoms are cycled between various form of life, and between the atmosphere and the soil, by a series of interlinked chemical changes. Animals feed on plants and other animals for their requirement of nitrogen for making proteins. Most plants obtain the nitrogen they require from the soil. In soil, nitrogen is present as nitrates, which are soluble salts of nitric acid. The solubility of nitrates is of great importance. Plants absorb nitrates from aqueous solutions through their roots. Nitrates come to the soil from the atmosphere with rain water. In the atmosphere, at the time of lightning, nitrogen and oxygen combine to form oxides of nitrogen, which, in turn, form nitrates. Nitrates also enter the soil from the decay of dead plants and animals. Nitrogen-fixing bacteria are found in the soil, which can convert the nitrogen in air directly in to nitrates. Some plants are also capable of fixing atmospheric nitrogen because their roots have such nodules that contain nitrogen-fixing bacteria. These plants are leguminous, known as legumes. Beans plant is an example of a leguminous plant.