Nitrogen Cycle Concepts and Processes

The video explains the nitrogen cycle, a vital natural process that circulates nitrogen through the atmosphere, living organisms, and back. It covers nitrogen fixation, where atmospheric nitrogen is converted into ammonia by bacteria or industrial processes. Nitrification follows, converting ammonia into nitrite and nitrate, which plants absorb. Decomposition leads to ammonification, releasing ammonia back into the soil. Finally, denitrification returns nitrogen to the atmosphere, completing the cycle. This cycle is crucial for maintaining ecosystem balance and supporting life on Earth.

What percentage of the Earth's atmosphere is made up of nitrogen gas?

• 50%

• 78%

• 95%

• 21%

Why can't most organisms directly use atmospheric nitrogen?

• It is too hot.

• It is too cold.

• It has a triple bond that is hard to break.

• It is too dense.

Which process converts nitrogen gas into ammonia?

• Nitrification

• Denitrification

• Ammonification

• Nitrogen fixation

What role do nitrogen-fixing bacteria play in the nitrogen cycle?

• They convert ammonia into nitrite.

• They decompose organic matter.

• They convert atmospheric nitrogen into ammonia.

• They convert nitrate into nitrogen gas.

Which industrial process is an example of non-biological nitrogen fixation?

• Krebs cycle

• Calvin cycle

• Haber-Bosch process

• Photosynthesis

What do nitrifying bacteria convert ammonia into?

• Nitrate

• Ammonium ions

• Nitrite

• Nitrogen gas

During assimilation, what do plants convert nitrates into?

• Lipids

• Carbohydrates

• Amino acids

• Proteins

What process involves the breakdown of organic nitrogen compounds by decomposers?

• Denitrification

• Ammonification

• Nitrogen fixation

• Nitrification

Which bacteria convert nitrate ions back into atmospheric nitrogen gas?

• Decomposing bacteria

• Nitrogen-fixing bacteria

• Denitrifying bacteria

• Nitrifying bacteria

What is the final step in the nitrogen cycle that returns nitrogen to the atmosphere?

• Ammonification

• Denitrification

• Assimilation

• Nitrification