Biogeochemical Cycles
Chapter Name : Natural Resources |
Sub Topic Code : 103_09_14_05_02 |
Topic Name : Biogeochemical Cycles |
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Sub Topic Name : The Nitrogen -Cycle |
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Introduction
Nitrogen is very important for all life forms. Atmospheric nitrogen is not used directly but converted to nitrites and nitrates by some life forms. This entire process is known as the nitrogen cycle.
Pre-Requisites:
• Components of atmosphere. • Proteins, amino acids and nucleic acids.
Real Life Question:
Can life on earth sustain without nitrogen? If nitrogen is required then how it is used by the living organisms?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Importance of nitrogen | Nitrogen constitutes 78% of the atmosphere. It is a part of essential compounds like proteins, nucleic acids, some vitamins, alkaloids, urea, etc. |
| Nitrogen fixing bacteria | They may be free or associated with dicot plants. They are present in the root nodules of leguminous plants and convert atmospheric nitrogen into nitrites and nitrates. |
| Physical conversion of nitrogen | During lightning, nitrogen in the air converts into oxides of nitrogen. These oxides dissolve in water to give nitric and nitrous acids and come down along with rain and are then utilized by various life forms. |
| Nitrogen cycle | The process in which nitrogen passes from its elemental form in the atmosphere into simple molecules in the soil and water, which get converted to more complex molecules into living beings and back again to the simple nitrogen molecule in the atmosphere. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Encyclopedia and internet | Try to find how many different types of amino acids are present in all the animals and plants. |
Real life uses :
Like oxygen, nitrogen is also essential for survival of life on the earth.
Practical examples around us
| Examples | Explainations |
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What you learn in Theory:
The conversion of elemental nitrogen into different forms and its uptake by the living forms and its conversion back to elemental nitrogen.
What you learn in Practice:
How nitrogen cycle takes place and the importance of nitrogen in living beings.