Nitrogen Cycle

Question 1

Step 1 nitrogen to ammonia (Nitrogen fixation)

Answer 1

Nitrogen-fixing bacteria break the nitrogen apart (as nitrogen as a triple bond cannot be easily broken). they add hydrogen atoms to it to form ammonia. this process moves nitrogen from the air to the soil and is called nitrogen fixation.
Ammonia can be taken up from plants to make important biological molecules like DNA. (this is called assimilation)

nitrogen-fixing bacteria are found in the soil or root nodules of legumes

Question 2

step 2 Ammonia to nitrates (nitrification) in soil

Answer 2

nitrifying bacteria add oxygen to ammonia to form nitrites (no2-) then again to nitrates (no3-)

Question 3

Step 3 nitrate to nitrogen gas (denitrifying)

Answer 3

bacteria convert nitrates into nitrogen gas happens best in low oxygen environments and reduces the fertility of the soil.

Question 4

side note

Answer 4

nitrogen is transferred through food webs, when organisms die they get decomposed and nitrogen becomes ammonia.