Nitrogen is the most abundant element on the earth but is the least available one. The nitrogen cycle is how naturally the chemical nitrogen is made available in biological and living processes.
Approximately 78% of the earth’s atmosphere is covered by nitrogen gas. However, this complete amount is not available for use by biological processes.
It gives structure and support to living beings by being components of proteins and nucleic acids.
Animals get nitrogen through the plant and animal diet they consume. Plants require nitrogen gas for their growth and reproduction. Plants tap into CO2 and light energy to form energy resources. Likewise, plants also tap into the nitrogen gas in the atmosphere to make it part of the life processes.
Let us look at the basic components that define the nitrogen cycle.
A simple nitrogen cycle consists of five steps that are of biological importance.
- Nitrogen fixation:
The fixation of atmospheric nitrogen to the soil and the plants. - Nitrogen fixation can be a physical, chemical, or biological process, of which biological process is of great significance. Cyanobacteria and other bacteria fix nitrogen in the soil and the root zone environment. - A group of bacteria called Rhizobium lives in the roots of bacteria in specialized structures called nodules which fix the nitrogen directly to the plants. - Nitrogenase is the enzyme involved in the process of nitrogen fixation. This process does not require oxygen and occurs in an anaerobic environment.
The process of conversion of reduced nitrogen compounds (mainly ammonia) to nitrate and nitrite - Nitrification is an oxygen-requiring process occurring in the soil mediated by soil bacteria Nitrosomonas and Nitrobacter.
The process of incorporation of nitrates and ammonia into the tissues of the plants and animals as components of protein and nucleic acids
The process of conversion of organic nitrogen to ammonia
The process of reducing ammonia to nitrogen gas released back into the atmosphere -Denitrification is also an anaerobic process in the soil converting nitrate to nitrogen gas. This is the soil checkpoint for nitrogen loss back to the atmosphere as nitrogen gas.
1. What are the 5 stages of the nitrogen cycle?
The five stages of the nitrogen cycle are nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.
2. How do you explain the nitrogen cycle?
The nitrogen cycle is the process of converting the atmospheric nitrogen to be used for plants in the soil by the process of nitrogen fixation and nitrification, which are assimilated into plants and animals, brought back to the soil as organic nitrogenous products through the process of ammonification, and then converted back to nitrogen gas to be released into the atmosphere through the process of denitrification.
3. What are the 7 steps of the nitrogen cycle?
The seven steps of the nitrogen cycle are nitrogen fixation, assimilation, ammonification, nitrification, denitrification, dissimilatory nitrate reduction to ammonia, anaerobic ammonia oxidation, and other processes.
4. What is the function of the nitrogen cycle?
The nitrogen cycle is the biogeochemical cycle. The atmospheric free nitrogen molecules are converted into inorganic and organic forms of nitrogen products fixed into the plants and animals as part of the macromolecular compounds like proteins and nucleic acids.
5. What is the order of the nitrogen cycle?
The order of the nitrogen cycle is nitrogen fixation, assimilation, ammonification, nitrification, and denitrification.
6. What is the first step in the nitrogen cycle?
The first step in the nitrogen cycle is nitrogen fixation carried out in the soil in the absence of oxygen by soil bacteria and cyanobacteria.
7. What are biological nitrogen fixers?
The biological nitrogen fixers are nitrogen-fixing soil bacteria, rhizobium bacteria, blue-green algae, and lightning.
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