NITROGEN CYCLE

Question 1

What is the process of the nitrogen cycle? (steps 1 -> 3)

Answer 1

1. Most air in the atmosphere is nitrogen gas, but can’t be used in its unreactive, natural state
   Nitrogen is used for proteins for growth.
2. Plants get their nitrogen from the soil; this nitrogen has to be turned into nitrogen compounds before it can be used
3. Animals get proteins by eating plants or other animals

Question 2

What is nitrogen fixing?

Answer 2

Nitrogen fixation - turning nitrogen in the air into nitrogen compounds usable by plants:
1. Nitrogen-fixing bacteria in the soil and roots of some plants…
2. Lightning - the energy allows nitrogen and oxygen to react in the air forming nitrates

Question 3

What are the bacteria involved in the nitrogen cycle?

Answer 3

1. Decomposers: break down proteins in dead organic matter, and urea in animal waste - turning these into ammonia, a nitrogen compound, and then ammonium ions in the soil
2. Nitrifying bacteria - turns ammonium ions in decaying matter into nitrates (nitrification)
3. Nitrogen-fixing bacteria - turns nitrogen in the atmosphere into nitrogen compounds usable by plants
4. Denitrifying bacteria - turns nitrates into nitrogen gas, unusable by any organisms.

Question 4

What is the process of the nitrogen cycle?

Answer 4

Nitrogen fixation (bacteria/lightning) turn nitrogen gas into nitrate ions, that are absorbed by plants by active transport.
The nitrogen is used to make amino acids/proteins, and this goes along the food web until the organisms die
Decomposers turn the proteins in dead organic matter into ammonium ions
These ammonium ions are turned into nitrate ions, by nitrifying bacteria
Denitrifying bacteria turns those nitrates into nitrogen gas (back to start)

Question 5

Why does burning biomass release nitrous oxides into the atmosphere?

Answer 5

Biomass contains DNA, proteins and other nitrogen containing compounds
When burned, oxides of nitrogen are produced
This is a greenhouse gas