The nitrogen cycle

• What is the nitrogen cycle?

  A process of recycling nitrogen in nature
• Why can't plants and animals use nitrogen from the air?

  Because it is in gas form
• What role do bacteria play in the nitrogen cycle?

  They convert nitrogen into usable forms
• What are the main steps in the nitrogen cycle?

  1. Nitrogen-fixing bacteria convert nitrogen gas to ammonia.
  2. Nitrifying bacteria convert ammonia to nitrates.
  3. Plants use nitrates to make proteins.
  4. Animals obtain nitrogen by eating plants and each other.
  5. Decomposers break down dead matter, releasing ammonia.
  6. Denitrifying bacteria convert nitrates back to nitrogen gas.
• What do nitrogen-fixing bacteria do?

  They convert nitrogen gas into ammonia
• What do nitrifying bacteria do?

  They turn ammonia into nitrates
• How do plants use nitrogen from nitrates?

  To make proteins necessary for growth
• How do animals obtain nitrogen?

  By eating plants and other animals
• What is the role of decomposers in the nitrogen cycle?

  They break down dead matter and release ammonia
• What do denitrifying bacteria do?

  They convert nitrates back into nitrogen gas
• What is a mutualistic relationship in the nitrogen cycle?

  • Some nitrogen-fixing bacteria live in soil.
  • Others live on roots of peas and beans.
  • Bacteria get food from plants.
  • Plants receive nitrogen compounds from bacteria.
  • Both benefit from the relationship.
• What do nitrogen-fixing bacteria living on plant roots provide to the plants?

  Nitrogen compounds
• Why is the nitrogen cycle important for ecosystems?

  It recycles nitrogen for living organisms
• How does the nitrogen cycle illustrate the concept of recycling in nature?

  Nitrogen is transformed and reused by organisms
• What happens to nitrogen in dead leaves?

  • Decomposers break down dead leaves.
  • This process releases ammonia.
  • Ammonia is converted into nitrates.
• What is the significance of the phrase "What goes around comes around" in the context of the nitrogen cycle?

  It emphasizes the recycling nature of nitrogen