The nitrogen cycle (copy)

Nitrogen fixation

Nitrogen fixing bacteria convert atmospheric nitrogen (N2) into ammonium (NH4+)

Nitrification

Nitrifying bacteria convert ammonium (NH4+) into nitrites (NO2-), then into nitrates (NO3-)

Nitrogen fixing vs ammonification

Nitrogen fixing is atmospheric nitrogen to ammonium; ammonification is nitrogen-containing compounds into ammonium. Nitrogen fixing is carried out by nitrogen fixing bacteria; ammonification is carried out by decomposers, which break down urea, proteins, nucleic acids, and vitamins.

Denitrification

The conversion, by denitrifying bacteria, of soil nitrates into atmospheric nitrogen

Haber process

An industrial process which combines atmospheric nitrogen and hydrogen to form ammonia

Atmospheric fixation

The conversion of atmospheric nitrogen to nitrates by lightning

Why is atmospheric nitrogen inert

Because of the triple covalent bonds in nitrogen molecules

Why are legumes important in the nitrogen cycle

They have a symbiotic relationship with nitrogen-fixing bacteria that live in their root nodules, which convert atmospheric nitrogen into nitrates, to be used for the plant. The plant provides them with glucose for respiration.