Nitrogen Cycle

What is ammonification?

The production and release of ammonia from organic compounds containing nitrogen (including urea, proteins, and nucleic acids)

What is nitrification?

The conversion of NH₄ ⁺ to NO₃^- through redox reactions (so releases energy)

How is nitrification carried out?

By nitrifying bacteria in soil

What are the 2 stages of nitrifying bacteria?

1. Oxidation of NH₄⁺ to nitrite ions (NO₂^-)

2. Oxidation of NO₂^- to nitrate ions (NO₃^-)

What is Nitrogen fixation?

When N_{2 (g)} is converted into nitrogen-containing compounds by nitrogen-fixing bacteria in soil

What are the 2 type of nitrogen fixing bateria?

1. Free-living nitrogen-fixing bacteria: These reduce N₂ to NH₃ which are then used to make amino acids

2. Mutualistic nitrogen-fixing bateria: These acquire carbohydrates from root nodules of legumes while root nodules gain amino acids from bacteria

What is denitrification?

denitrifying bacteria convert soil nitrates to N_{2 (g)}, reducing the availability of nitrogen-containig compounds for plants

In what conditions does denitrification occur?

Waterlogged soil with low [O₂]