Exploring the Nitrogen Cycle: Key Processes and Concepts

The video explains the nitrogen cycle, highlighting its importance for DNA and proteins. Nitrogen, which makes up 78% of the atmosphere, cannot be directly absorbed by humans and must be obtained through food. The cycle involves nitrogen moving from the atmosphere to the soil, where bacteria convert it into forms usable by plants. This process includes nitrogen fixation, nitrification, and assimilation. Not all nitrogen is absorbed by plants; some is returned to the atmosphere through denitrification. Decomposers and bacteria also play a role in recycling nitrogen from animal waste and remains, continuing the cycle.

What percentage of our atmosphere is made up of nitrogen?

• 21%

• 99%

• 50%

• 78%

Why can't humans directly breathe in nitrogen from the atmosphere?

• It is toxic

• It is too light

• It is not in a usable form

• It is too heavy

What process combines nitrogen with hydrogen to form ammonia?

• Nitrification

• Ammonification

• Denitrification

• Nitrogen fixation

Which natural phenomenon can also fix nitrogen in the atmosphere?

• Tsunamis

• Earthquakes

• Volcanic eruptions

• Lightning

What is the toxic form of nitrogen that is converted by bacteria?

• Nitrogen gas

• Nitrite

• Ammonia

• Nitrate

What is the process called when plants absorb nitrogen?

• Ammonification

• Assimilation

• Nitrification

• Denitrification

Tags

NGSS.MS-LS2-1

What process releases nitrogen back into the atmosphere?

• Assimilation

• Ammonification

• Nitrification

• Denitrification

Tags

NGSS.MS-LS2-3

What happens to nitrogen when an animal dies or excretes waste?

• It remains unchanged

• It is absorbed by plants

• It evaporates

• It is broken down by bacteria

Tags

NGSS.MS-LS2-3

NGSS.MS-LS2-4

What is the process called that converts nitrogen in waste or dead animals back into ammonia?

• Ammonification

• Assimilation

• Denitrification

• Nitrification

Tags

NGSS.MS-LS2-3

What is the final step in the nitrogen cycle that allows it to continue?

• Nitrification

• Denitrification

• Assimilation

• Ammonification