Nitrogen Cycle Concepts and Processes

The video explains the nitrogen cycle, starting with atmospheric nitrogen (N2), which is converted by nitrogen-fixing bacteria into ammonia. This ammonia is then transformed into nitrite and nitrate by nitrifying bacteria. Plants assimilate nitrate, and animals obtain nitrogen by consuming plants. Decomposers break down dead organisms, releasing nitrogen back into the soil as ammonia. Denitrifying bacteria complete the cycle by converting nitrate back to atmospheric nitrogen, allowing the cycle to restart.

What is the primary form of nitrogen found in the atmosphere?

• NO2

• NO3

• N2

• NH3

Which organisms are primarily responsible for fixing atmospheric nitrogen?

• Fungi

• Nitrogen-fixing bacteria

• Algae

• Protozoa

What is the product of the nitrogen fixation process?

• Nitrite

• Nitrate

• Ammonia

• Nitrogen gas

During nitrification, ammonia is first converted into which compound?

• Nitrate

• Ammonium

• Nitrite

• Nitrogen gas

Which form of nitrogen can plants directly assimilate?

• Nitrate

• Ammonia

• Nitrogen gas

• Nitrite

What role do decomposers play in the nitrogen cycle?

• Convert ammonia to nitrate

• Break down organic matter to release ammonia

• Convert nitrate to nitrite

• Fix nitrogen

What is the process called when nitrate is converted back to atmospheric nitrogen?

• Assimilation

• Ammonification

• Denitrification

• Nitrification

Which bacteria are responsible for converting nitrate back into nitrogen gas?

• Denitrifying bacteria

• Decomposing bacteria

• Nitrifying bacteria

• Nitrogen-fixing bacteria

What is the significance of the nitrogen cycle in ecosystems?

• It recycles nitrogen, making it available for plant and animal use.

• It provides oxygen to organisms.

• It produces energy for plants.

• It removes carbon dioxide from the atmosphere.

Which of the following is a shortcut loop in the nitrogen cycle?

• Assimilation

• Nitrification

• Denitrification

• Nitrogen fixation by legumes