Nitrogen Cycle Processes

These flashcards cover key concepts related to the nitrogen cycle, including the processes of nitrification, denitrification, nitrogen fixation, and their biological significance.

What is nitrification?

The addition of oxygen to soil, commonly as nitrite (NO₂⁻) and nitrate (NO₃⁻) ions.

Which bacteria are involved in nitrification?

Nitrosomonas converts ammonia to nitrite, and Nitrobacter converts nitrite to nitrate.

What process occurs during decomposition/ammonification?

Proteases digest proteins into amino acids, and deaminases remove -NH₂ groups, converting them back to ammonia.

What is denitrification?

The loss of nitrogen from soil, where anaerobic bacteria convert nitrate ions (NO₃⁻) to nitrogen gas (N₂).

Which bacteria are known for denitrification?

Pseudomonas and other anaerobic bacteria.

What is nitrogen fixation?

The reduction of nitrogen atoms in N₂ into ammonium ions by prokaryotes, such as Rhizobium.

Where is Rhizobium found?

In the root nodules of legumes.

What role does leg-haemoglobin play in nitrogen fixation?

It binds to O₂ in nodules, preventing oxidizing reactions that could poison nitrogen reduction.

What is a consequence of the overuse of fertilizers?

Eutrophication, which is the excessive growth of algae in water bodies due to nutrient runoff.