Unit 5 Nutrient Cycles

Question 1

Why is the nitrogen cycle important and what are the stages

Answer 1

•Is important to create nitrogen containing substances such as DNA, RNA, ATP, NADPH, NADH, FADH and Amino acids

• nitrogen fixation
• ammonification
• nitrification
• denitrification

Question 2

What happens in the nitrogen fixation

Answer 2

Nitrogen fixing bacteria (from soil or root) converts nitrogen from the air to ammonium ions
N2➡️NH4

Question 3

What happens in ammonification

Answer 3

Converts nitrogen from decomposition of protein/DNA to ammonium ions

Which is released into soil this is carried out by saprobionts
NH3➡️NH4

Question 4

What happens in the nitrification

Answer 4

Ammonium ions in soil are oxidised to nitrites then to nitrates by nitrifying bacteria
NH4➡️NO2-➡️NO3-

Question 5

What happens in denitrification

Answer 5

Converts nitrogen in compounds back to nitrogen gas
Usually anaerobic denitrifying happens bacteria
NO3-➡️N2