Nitrogen Cycle

Question 1

Nitrogen fixation

Answer 1

Atmospheric nitrogen (N2) is converted to organic (reduced) nitrogen - ammonia (NH3) or ammonium (NH4+)

Question 2

Nitrification

Answer 2

2 step process
1) ammonia oxidized to Nitrite (NO2-)
2) nitrite oxidized to Nitrate (NO3-)

Question 3

Denitrification

Answer 3

Denitrifying bacteroa reduce nitrate to nitrogen gas

Question 4

Nitrogen Cycle

Answer 4

Nitrogen fixing -> Nitrification -> Denitrification

Question 5

PEDs of aerobic nitrification

Answer 5

inorganic ammonia/um and nitrite, using O2 to oxidate into Nitrate

Question 6

annamox

Answer 6

ammonia anaerobically reacting with nitrite to form N2

Question 7

anaerobic carbon fixation using nitrogen, what are PED and TEA?

Answer 7

autotrophic reaction of CO2, nitrite and water to make organic carbon and nitrate
PED = nitrite
TEA = CO2

Question 8

TEA of denitrification

Answer 8

Nitrate

Question 9

PEDs of denitrification

Answer 9

H2, reduced sulfur species, organics

Question 10

hurdles in nitrogen fixation

Answer 10

• N triple bond has enthalpy of 900kJ/mol +
• sensitive to oxygen