Describe the nitrogen cycle - KCSE Biology Essays

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Plants absorb nitrogen in the form of nitrates and then assimilate it into vegetable proteins; animals obtain nitrogen from vegetable proteins by supplying plants.

When an animal dies and decomposes, they release nitrogen into the soil in the form of ammonia; the free atmosphere nitrogen is converted to nitrate by a process called nitrogen fixing; there are two processes: biological and abiotic Target.

Nitrogen biofiction by nitrogen-fixing bacteria, whether free or symbiotic; symbiotic bacteria belong to the genus Rhizobium; and are present in nodules of legumes (such as peas, clovers and alfalfa); bacteria contain nitrogen in the atmosphere Convert to ammonia; legumes are used directly to form nitrogen-containing organic compounds (amino acids, nucleic acids, proteins).

When the plant dies, tuberculosis releases the ammonium compound to the soil, it is converted to nitrite, nitrification bacteria are nitrosomonas and nitrite (nitrous bacteria), and nitrifying bacteria are nitrate (nitrate). Free-living microorganisms that fix nitrogen include putrefactive / spoilage bacteria (eg, some algae such as Azobacter spp, Clostridium and Anabaena, Chlorella and Nostoc).

The organism fixes the nitrogen in ammonia by decomposing the proteinaceous matter in the dead organism; ammonia is converted to nitrite; then nitrate; but denitrification

Degradation / reduction of bacteria (eg Pseudomonas aeruginosa or Thiobacillus denitrificans), nitrates, nitrites, ammonium compounds, even gaseous nitrogen; a process called denitrification; nitrogen useful in air is recirculated to the atmosphere The non-biological nitrogen fixation due to lightning during thunderstorms, lightning energy combines nitrogen and oxygen in the atmosphere to form nitrogen oxides and dissolves in rainwater to form nitrous acid / nitric acid . In the soil, nitric acid formed reacts with other compounds dissolved in soil water to form nitrates, and nitrate is used by plants.

Nitrogen circulation is an important cycle for the atmosphere. Nitrogen is an important constituent of biomolecules such as proteins and nucleic acids, making nitrogen essential to all creatures. Nitrogen accounts for 78% of the atmosphere. Nitrogen circulation between abiotic environment and organism has five steps: nitrogen fixation, nitrification, assimilation, ammoniation and deacidification. Nitrogen fixation is the conversion of gaseous nitrogen to ammonia. This process is nitrogen fixed bacteria performed in soil and aquatic environments. These bacteria have discovered an enzyme called nitrogenase that breaks down nitrogen and binds it to hydrogen. Nitrogen-fixing bacteria must consume 12 grams of sugar to biologically immobilize monogram nitrogen. In the second stage, nitrification is the conversion of ammonia to nitrate. This is a two-step process carried out by soil bacteria

In the nitrogen cycle, bacteria convert nitrogen to ammonia in a process called nitrogen fixation. Bacteria also convert nitrogen to nitrate and nitrite. These forms of nitrogen can be consumed by primary producers to form nucleic acids and proteins. And consumers consume these nitrogen and make their own nitrogen compounds. Other bacteria get energy by converting nitric acid to nitrogen. And it is released to the atmosphere during the process called denitrification. Humans also add nitrogen to the biosphere by manufacturing and using fertilizers.