Nitrogen Cycle

Question 1

The ______ is a biogeochemical process that describes the continuous movement of nitrogen through the Earth’s
atmosphere, soil, and living organisms.

Answer 1

nitrogen cycle

Question 2

_____is essential for life, as it’s a key
component of amino acids, proteins, and
nucleic acids (DNA and RNA).

Answer 2

Nitrogen

Question 3

However, atmospheric nitrogen (N2), which makes up
about 78% of the air we breathe, is unusable
by most organisms in its gaseous form. The
nitrogen cycle involves several crucial steps
that transform nitrogen into usable forms and
then back again into the atmosphere.

Answer 3

True

Question 4

Give two advantages of nitrogen cycle

Answer 4

Soil fertility
Environmental regulation
Natural fertilization
Sustains ecosystem
Biodiversity support

Question 5

Give two disadvantages of nitrogen cycle

Answer 5

Eutrophication
Greenhouse gas emissions
Soil acidification
Air and water pollution
Disruption by human activities

Question 6

Excessive nitrogen or nutrients , often due to agricultural runoff (from fertilizers), can lead to eutrophication in water bodies.

Answer 6

Eutrophication

Question 7

What are the stages of nitrogen cycle?

Answer 7

S1 Nitrogen Fixation
S2 Nitrification
S3 Assimilation
S4 Ammonification
S5 Denitrification

Question 8

____ is a crucial element for life, but plants
and animals cannot directly use the nitrogen gas
that makes up the majority of the Earth’s
atmosphere

Answer 8

Nitrogen

Question 9

_____is the initial step of the nitrogen
cycle. Here, Atmospheric nitrogen (N2) which is
primarily available in an inert form, is converted
into the usable form -ammonia (NH3), Nitrates
(NO3-), and Nitrites (NO2-).

Answer 9

Stage 1: Nitrogen Fixation

Question 10

What is the symbol of nitrogen?

Answer 10

N2

Question 11

Symbol of -ammonia

Answer 11

NH3

Question 12

Symbol of nitrates

Answer 12

NO3-

Question 13

Symbol of nitrites

Answer 13

N02-

Question 14

Nitrogen fixation occurs through both
biological and non-biological processes.

Answer 14

True

Question 15

The nitrogen fixation occurs through what process?

Answer 15

biological and non-biological processes

Question 16

____the fixation of atmospheric nitrogen into nitrogenous salts with the help
of microorganisms.

Answer 16

Biological Nitrogen Fixation (BNF)

Question 17

Under in biological nitrogen fixation, what are the 2 given examples?

Answer 17

1. Symbiotic nitrogen fixation
2. Non-symbiotic nitrogen fixation

Question 18

Under in Non-biological nitrogen fixation, what are the 2 given examples?

Answer 18

1. Lightning
2. Industrial processes

Question 19

refers to the conversion of atmospheric nitrogen (N2) into usable forms by natural processes, such as lightning, or
industrial processes, rather than by biological
organisms like bacteria.

Answer 19

Non-biological Nitrogen Fixation

Question 20

The ammonia is converted into nitrate by the
presence of bacteria in the soil. Nitrites are
formed by the oxidation of ammonia with the
help of Nitrosomonas bacteria species. Later,
the produced nitrites are converted into nitrates
by Nitrobacter. This conversion is very important
as ammonia gas is toxic for plants.

Answer 20

Stage 2: Nitrification

Question 21

The ammonia is converted into ______ by the
presence of bacteria in the soil. Nitrites are
formed by the ______ with the
help of_______ . Later,
the produced nitrites are converted into ______

Answer 21

1. Nitrate
2. oxidation of ammonia
3. Nitrosomonas bacteria species
4. nitrates by Nitrobacter.

Question 22

What are the reaction involved in the process of Nitrification?

Answer 22

2NH3 + 3O2 → 2NO2– + 2H+ + 2H2O
2NO2– + O2 → 2NO3–

Question 23

______ is the process by which inorganic nitrogen compounds are used to form organic nitrogen compounds such as amino acids, amides, etc. Plants and other organisms, which cannot directly use nitrogen molecules, depend on absorbing nitrogen as nitrates or ammonia.

Answer 23

Stage 3: Assimilation

Question 24

What are the two inorganic compounds that are absorbed by plants during the stage of assimilation?

Answer 24

nitrates or ammonia

Question 25

What are the inorganic nitrogen compounds that are used to form organic nitrogen compounds?

Answer 25

amino acids, amides

Question 27

This process also allows nitrogen to enter the food web, supporting the entire ecosystem by providing essential nutrients for growth and development.

Answer 27

Assimilation

Question 28

What are the Process of Assimilation?

Answer 28

1.Nitrogen Uptake 2. Nitrate Reduction 3. Ammonia Incorporation

Question 29

Plants absorb nitrogen mainly as nitrates (NO3-) and ammonium ions (NH4+) through specialized root transporters.

Answer 29

Nitrogen Uptake

Question 30

•Nitrate (NO3-) → Nitrite (NO2-) (via nitrate reductase in the cytoplasm). •Nitrite (NO2-) → Ammonia (NH3) (via nitrite reductase in chloroplasts or root plastids).

Answer 30

Nitrate Reduction

Question 31

Ammonia is incorporated into amino acids via the glutamine synthetase reaction. Glutamine synthetase combines ammonia with glutamate to form glutamine, which is then converted into other amino acids through transamination reactions.

Answer 31

Ammonia Incorporation

Question 32

____is the process where microscopic organisms like bacteria or other types of decomposing organisms, break down nitrogen-containing chemicals from dead organic matter.

Answer 32

Stage 4: Ammonification

Question 33

____is the final stage of the nitrogen cycle. It is a crucial part of the nitrogen cycle, where microorganisms, primarily bacteria, convert nitrate (NO3-) into nitrogen gas (N2), which is then released into the atmosphere and completing the cycle.

Answer 33

Stage 5: Denitrification

Question 34

Symbol of nitrogen gas?

Answer 34

N2

Question 35

It Returns nitrogen to the air.

Answer 35

Maintains Nitrogen Balance

Question 36

It Removes excess nitrates.

Answer 36

Reduces Water Pollution

Question 37

What are the flow of denitrification process?

Answer 37

Nitrate→Nitrite → Nitric Oxide → Nitrous oxide → Nitrogen gas.

Question 38

What element makes up about 78% of the air he breathe and unusable by most organisms in its gaseous form?

Answer 38

Nitrogen

Question 39

Which stage of the nitrogen cycle involves bacteria converting nitrate (NO3-) into nitrogen gas (N2), which is then released into the atmosphere and completing the cycle.

Answer 39

Stage 5: Denitrification

Question 40

What are the primary products of ammonification?

Answer 40

Ammonia and ammonium

Question 41

What is the process where microscopic organisms like bacteria or other types of decomposing organisms, breakdown nitrogen containing chemicals from dead organic matter?

Answer 41

Ammonification

Question 42

What is the symbol of nitrogen and atomic number?

Answer 42

N num 7