Nitrogen cycle

    Cards (12)

    • What are the three cycles that are constantly being recycled in nature?
      Nitrogen, carbon, and water cycles
    • Why can't nitrogen gas in the atmosphere be used directly by plants or animals?
      Because nitrogen gas is very unreactive
    • How do plants obtain nitrogen?
      Plants get their nitrogen from the soil in the form of nitrates
    • What role do decomposers play in the nitrogen cycle?
      Decomposers break down proteins and urea into ammonia, returning nitrogen to the soil
    • What is nitrogen fixation?

      Nitrogen fixation is the process of turning nitrogen gas from the air into nitrogen compounds in the soil
    • What are the two main ways nitrogen fixation occurs?
      • Lightning: Energy from lightning makes nitrogen react with oxygen to form nitrates.
      • Nitrogen-fixing bacteria: These bacteria convert atmospheric nitrogen into nitrogen compounds in the soil.
    • What are the four types of bacteria involved in the nitrogen cycle?
      Decomposers, nitrifying bacteria, nitrogen-fixing bacteria, and denitrifying bacteria
    • What do nitrifying bacteria do in the nitrogen cycle?
      Nitrifying bacteria turn ammonium ions in decaying matter into nitrates
    • What is the role of denitrifying bacteria in the nitrogen cycle?
      Denitrifying bacteria turn nitrates back into nitrogen gas
    • Where are denitrifying bacteria commonly found?
      Denitrifying bacteria are often found in waterlogged soils
    • Why are legume plants effective at putting nitrogen back into the soil?
      Because they have nitrogen-fixing bacteria in nodules on their roots
    • What is the mutualistic relationship between legume plants and nitrogen-fixing bacteria?
      • The bacteria receive sugars from the plant.
      • The plant receives nitrogen compounds from the bacteria to make proteins.
      • This relationship benefits both the plant and the bacteria.
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