Nitrogen Cycle

key notes:–

🌱 Nitrogen Cycle – Key Notes

🔹 What is Nitrogen?

• Nitrogen is a colorless, odorless gas.
• It makes up about 78% of the Earth’s atmosphere.
• Plants and animals need nitrogen to build proteins and grow.

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🔄 What is the Nitrogen Cycle?

• The Nitrogen Cycle is the process by which nitrogen moves between the air, soil, plants, animals, and back into the air.

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🔍 Steps in the Nitrogen Cycle:

Nitrogen Fixation

Nitrogen in the air (N₂) is converted into a usable form (like ammonia).

Done by:

• Lightning (natural)
• Nitrogen-fixing bacteria (in soil or root nodules of plants like peas, beans).

Nitrification

• Ammonia is changed into nitrates and nitrites by bacteria in the soil.
• These are forms plants can absorb.

Assimilation

• Plants absorb nitrates from the soil.
• Animals eat plants and use nitrogen to build proteins.

Ammonification (Decay)

• When plants and animals die, decomposers (like bacteria and fungi) break them down.
• Nitrogen returns to the soil as ammonia.

Denitrification

• Other bacteria convert nitrates back into nitrogen gas (N₂).
• This gas returns to the atmosphere, completing the cycle.

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🌾 Importance of the Nitrogen Cycle

• Helps in plant growth.
• Maintains balance of nitrogen in the atmosphere.
• Supports food chains and ecosystems.

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🧠 Fun Fact:

• Without the nitrogen cycle, plants wouldn’t grow, and all life on Earth would be affected!

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