Nitrogen Cycle Concepts and Processes

The video explains the nitrogen cycle, highlighting its complexity and importance for life. It covers the role of nitrogen in DNA and proteins, the challenges of atmospheric nitrogen, and the processes of nitrogen fixation, nitrification, and denitrification. The video also discusses how nitrogen moves through the food chain via assimilation and the role of decomposers. Additionally, it explains how lightning contributes to the nitrogen cycle by forming nitrates that mix with soil nitrates.

Why is nitrogen essential for DNA?

• It is part of the nitrogen bases in nucleotides.

• It stabilizes the DNA structure.

• It provides energy for DNA replication.

• It forms the backbone of DNA.

What is the main challenge with atmospheric nitrogen for living organisms?

• It reacts too quickly with other elements.

• It is too abundant.

• It is toxic to cells.

• It is mostly unusable due to its stable triple bond.

What is the process called where soil bacteria convert atmospheric nitrogen into ammonium?

• Denitrification

• Nitrification

• Nitrogen fixation

• Ammonification

During nitrification, what do soil bacteria convert ammonium into?

• Nitrogen gas

• Nitrates

• Nitrites

• Ammonia

What is the role of denitrification in the nitrogen cycle?

• It assimilates nitrogen into plants.

• It decomposes organic matter.

• It fixes nitrogen into the soil.

• It converts nitrates back into nitrogen gas.

How do plants assimilate nitrogen?

• Through their leaves

• By absorbing nitrates through their roots

• By converting nitrogen gas directly

• By consuming other plants

What happens to nitrogen as it moves up the food chain?

• It is converted back to nitrogen gas.

• It is passed from producers to consumers.

• It is lost to the atmosphere.

• It becomes less concentrated.

What process do decomposers use to release ammonium back into the soil?

• Nitrification

• Assimilation

• Denitrification

• Ammonification

How does lightning contribute to the nitrogen cycle?

• It fixes nitrogen directly into plants.

• It breaks down nitrogen gas into nitrates.

• It releases nitrogen gas into the atmosphere.

• It converts nitrates into ammonium.

What is the significance of nitrates formed by lightning?

• They are converted into nitrogen gas.

• They deplete the ozone layer.

• They are a natural fertilizer for the soil.

• They are harmful to plants.