Nitrogen cycle

Question 1

Nitrogen cycle

Answer 1

• nitrogen is important for living things because it’s part of proteins, DNA, and other important molecules
• the nitrogen cycle moves and changes nitrogen in different ways throughout the Earth

Question 2

Atmospheric nitrogen fixation

Answer 2

when lightning separates nitrogen gas into nitric acid and nitrogen dioxide, which then dissolve in water to form nitric acid

Question 3

Nitric acid

Answer 3

strong acid that is used for various purposes such as making fertilizers, cleaning metals, and producing explosives

Question 4

Assimilation

Answer 4

plants and some microorganisms take up ammonium and nitrate ions from the soil to use in cell processes

Question 5

Consumption

Answer 5

animals obtain organic nitrogen by consuming either plants or other animals

Question 6

Ammonification

Answer 6

decomposers break down nitrogen compounds found in dead organisms and other organic matter and convert them into ammonia and ammonium, which are released into the soil

Question 7

Volcanic eruptions

Answer 7

release nitrogen gas into the atmosphere, which undergoes transformation into nitrogen oxides due to the heat and pressure generated, ultimately reacting with water vapor to form precipitation

Question 8

Dendrification

Answer 8

converts nitrate (NO3-) and nitrite (NO2-) ions into nitrogen gas, which is then released back into the atmosphere, making it available for utilization by nitrogen-fixing bacteria.

Question 9

Nitrogen fixation by bacteria

Answer 9

in the soil, special bacteria change the air’s nitrogen into a useful substance called ammonia or ammonium ions

Question 10

Nitrification

Answer 10

• nitrifying bacteria convert ammonia (made from nitrogen fixation) into nitrite ions
• other nitrifying bacteria called Nitrobacter change nitrite ions into nitrate ions