Nitrogen Cycle

Question 1

nitrogen fixation

Answer 1

Atmospheric nitrogen is “fixed” or transformed by bacteria living
symbiotically on plant roots of legumes or in blue green algae (cynobacteria). The bacteria
change the N2 into ammonia

Question 2

nitrification

Answer 2

A different set of bacteria break down the ammonia by combining it with oxygen
to create nitrites and then finally nitrates

Question 3

assimilation

Answer 3

The plants then incorporate the nitrogen into organic molecules (DNA, amino
acids, proteins, etc)

Question 4

ammonification

Answer 4

Dead plants and organic waste (like cow dung) convert their stored nitrogen
back into ammonia with the help of decomposers

Question 5

dentrification

Answer 5

Some of the nitrates can be converted back into atmospheric N2 through the
help of bacteria

Question 6

sources of nitrogen

Answer 6

fertilizers

Question 7

molecule that relates to nitrogen fixation

Answer 7

ammonia/ammonium

Question 8

molecule that relates to nitrification

Answer 8

nitrates

Question 9

molecule that relates to assimilation

Answer 9

protein

Question 10

molecule that relates to ammonification

Answer 10

ammonia

Question 11

molecule that relates to

Answer 11

nitrogen gas