The nitrogen cycle is an important cycle to the atmosphere. Nitrogen is an essential part of the biological molecules such as proteins and nucleic acid, which makes nitrogen essential for all living organisms. Nitrogen makes up 78 percent of the atmosphere. There are five steps in the nitrogen cycle between the abiotic environment and the organisms: nitrogen fixation, nitrification, assimilation, ammonification, and dentrification.Nitrogen fixation is the conversion of gaseous nitrogen to ammonia. This process is carried out my nitrogen-fixing bacteria in soil and aquatic environments. These bacteria find an enzyme called nitrogenase to break up molecular nitrogen and combine it with hydrogen. Nitrogen fixing bacteria must consume the energy in 12 grams of sugar in order to fix a single gram of nitrogen biologically. The second step, nitrification is the conversion of ammonia to nitrate. This is a two step process that is accomplished by soil bacteria. The soil bacteria Nitrosomonas and Nitrococus converts ammonia to nitrate and then the soil bacterium Nitroabcter oxidizes nitrate to nitrate. In the third step assimilation, the plants absorb nitrate or ammonia that was formed in step one and two, therefore the plants now have proteins and nucleic acid. When the animals consume the plants, they are also taking in the plant nitrogen compounds and converting them to animal compounds. The fourth step is ammonification. It is the conversion if biological nitrogen compounds into ammonia. Ammonification is when organisms produce nitrogen-containing waste products, such as urine, decomposing and releasing the nitrogen into the abiotic environment as ammonia. The ammonia that was produced during the process of ammonification enters the nitrogen cycle and is then used for the process of nitrification and assimilation. The fifth and last step of the nitrogen cycle is denitrification. Denitrification is the reduction of nitrate to gaseous nitrog...
