explain the nitrogen cycle
Answers
The Nitrogen Cycle
Since earth's atmosphere contains about 78% nitrogen, this makes it the largest pool of nitrogen. In other words, we can say that the reservoir pool of nitrogen is the atmosphere which contains about 78.08% of nitrogen in gaseous state. Since nitrogen is essential for many biological processes to takes place, it plays a crucial role on the life of earth. Nitrogen is an essential component of amino acids, proteins, enzymes and nucleic acids of the protoplasm. But it cannot be used directly and is changed into nitrites and nitrates and then utilized. In plants, the nitrogen is used in chlorophyll molecule which helps in photosynthesis and growth.
In order to obtain nitrogen from air, it is necessary to convert gaseous nitrogen into forms usable by living organisms. This process is called nitrogen fixation. Generally fixation takes place by free- living or symbiotic bacteria. These bacteria have the nitrogenase enzyme that combines gaseous nitrogen with hydrogen to produce ammonia, which is then further converted by the bacteria to make its own organic compounds. The nitrogen fixing bacteria includes Rhizobium which lives in the root nodules of legumes (such as peas or beans). Legume plants can be planted on nutrient-poor soil to enrich them with nitrogen. Sometimes, nitrogen fixation occurs during lighting.
The nitrogen cycle is thus a complex biogeochemical cycle that describes the transformations of inert atmospheric nitrogen into useful nitrogen. It is a cycle which includes gaseous components. Let us discuss the steps involved in the nitrogen cycle.
Steps Involved in Nitrogen Cycle
The steps involved in nitrogen cycle are :
(a) Nitrogen fixation
(b) Nitrification
(c) Assimilation
(d) Ammonification
(d) Ammonification
(e) Denitrification
