The Nitrogen Cycle: Key Processes and Impacts on Ecosystems

The video explains the nitrogen cycle, highlighting its importance for living organisms. It covers the steps of nitrogen fixation, assimilation, ammonification, nitrification, and denitrification. The video also discusses the role of bacteria and plants in these processes and the problems caused by increased nitrogen levels, such as acid rain and soil acidification.

What percentage of the atmosphere is composed of nitrogen?

• 21%

• 95%

• 78%

• 50%

What is the first step in the nitrogen cycle?

• Nitrification

• Ammonification

• Denitrification

• Nitrogen Fixation

Which organisms are primarily responsible for nitrogen fixation?

• Algae

• Fungi

• Leguminous plants and bacteria

• Insects

What is the process of absorbing nitrates and ammonia into organic nitrogen called?

• Nitrogen Assimilation

• Nitrification

• Denitrification

• Ammonification

What happens during ammonification?

• Conversion of ammonia to nitrites

• Conversion of organic nitrogen to ammonia

• Conversion of nitrates to nitrogen gas

• Absorption of nitrates by plants

Which bacteria are involved in converting ammonia to nitrites?

• Micrococcus

• Nitrosomonas

• Clostridium

• Anabena

What is the final step in the nitrogen cycle?

• Nitrification

• Denitrification

• Ammonification

• Nitrogen Fixation

What environmental issue can result from increased nitrogen levels?

• Acid rain formation

• Global warming

• Deforestation

• Ozone depletion

Which process converts nitrates back into molecular nitrogen?

• Ammonification

• Nitrogen Fixation

• Denitrification

• Nitrification

What is the role of nitrifying bacteria in the nitrogen cycle?

• Fix atmospheric nitrogen

• Convert ammonia to nitrites

• Absorb nitrates into plants

• Convert nitrates to nitrogen gas