Nitrogen Cycle Processes and Functions

The video explains the nitrogen cycle, highlighting its importance in DNA and proteins. It covers nitrogen fixation by bacteria, the role of nitrogen in ecosystems, and the denitrification process. The interaction between the water and nitrogen cycles is also discussed, emphasizing how precipitation and lightning contribute to nitrogen availability. The video concludes with additional resources for further learning.

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

• 78%

• 19%

• 21%

• 50%

Why can't living cells directly use atmospheric nitrogen?

• It is too rare in the atmosphere.

• It is only found in water.

• It is bonded in a stable form.

• It is too reactive.

What is the role of nitrogen-fixing bacteria?

• They convert nitrates into ammonia.

• They convert atmospheric nitrogen into nitrates.

• They decompose dead plants.

• They produce oxygen.

Which plants are known for having nitrogen-fixing bacteria in their roots?

• Legumes

• Ferns

• Grasses

• Mosses

How do animals primarily obtain nitrogen?

• By drinking water.

• By absorbing it through their skin.

• By eating plants or other animals.

• By breathing it in from the air.

What process converts ammonia into nitrates?

• Nitrification

• Ammonification

• Photosynthesis

• Denitrification

What happens during denitrification?

• Nitrogen is absorbed by plants.

• Nitrogen is fixed into the soil.

• Ammonia is converted into nitrates.

• Nitrates are converted into atmospheric nitrogen.

Which process involves the breakdown of organic nitrogen into ammonia?

• Nitrogen fixation

• Nitrification

• Ammonification

• Denitrification

How does precipitation contribute to the nitrogen cycle?

• It prevents nitrogen fixation.

• It removes nitrogen from the soil.

• It dissolves nitrogen and brings it to the surface.

• It converts nitrogen into oxygen.

What role does lightning play in the nitrogen cycle?

• It fixes nitrogen into the soil.

• It splits nitrogen molecules, allowing them to form nitrates.

• It removes nitrogen from the atmosphere.

• It converts nitrates into ammonia.