Nitrogen Cycle

What are the main forms of nitrogen found in the soil?

• Ammonia, nitrites, and nitrates.

• Urea, phosphates, and sulfates.

• Nitrogen gas, carbon dioxide, and oxygen.

• Ammonium, potassium, and calcium.

What is the significance of the nitrogen cycle in ecosystems?

• It recycles nitrogen, making it available for use by living organisms.

• It helps in the formation of ozone in the atmosphere.

• It increases the acidity of soil, promoting plant growth.

• It prevents the depletion of carbon dioxide in the atmosphere.

What role do nitrifying bacteria play in the nitrogen cycle?

• They convert ammonia into nitrites and then into nitrates.

• They convert nitrates into ammonia.

• They fix atmospheric nitrogen into organic compounds.

• They decompose organic matter into ammonia.

What is nitrogen fixation?

• The process of converting nitrogen gas into ammonia or related compounds in soil.

• The process of converting ammonia into nitrogen gas in the atmosphere.

• The process of absorbing nitrogen from the soil by plants.

• The process of breaking down nitrogen compounds into simpler substances.

How does nitrogen return to the atmosphere?

• Through the process of denitrification.

• By nitrogen fixation in plants.

• Through the process of photosynthesis.

• By evaporation from water bodies.

What is the role of legumes in the nitrogen cycle?

• They host nitrogen-fixing bacteria in their root nodules.

• They absorb nitrogen from the atmosphere directly.

• They decompose organic matter to release nitrogen.

• They prevent nitrogen loss from the soil.

Do bacteria create a form of nitrogen that animals can use directly?

• Yes, they do.

• No, they do not.

• Only in certain conditions.

• Bacteria do not create nitrogen.

Why is nitrogen important for living organisms?

• It is a key component of amino acids, proteins, and nucleic acids.

• It helps in the formation of carbohydrates.

• It is essential for the production of vitamins.

• It acts as a primary energy source for cells.

How do humans impact the nitrogen cycle?

• Through the use of fertilizers, which can lead to excess nitrogen in ecosystems.

• By planting more trees, which absorb nitrogen from the soil.

• By reducing carbon emissions, which helps balance the nitrogen cycle.

• Through industrial processes that eliminate nitrogen from the atmosphere.

What is denitrification?

• The process by which bacteria convert nitrates back into nitrogen gas.

• The process of converting nitrogen gas into nitrates.

• The process by which plants absorb nitrogen from the soil.

• The process of breaking down nitrogen compounds into ammonia.