Nitrogen Cycle Flashcard

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What is the nitrogen cycle?

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The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms, including nitrogen gas, ammonia, nitrites, and nitrates, in the environment.

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What is nitrogen fixation?

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Nitrogen fixation is the process of converting nitrogen gas (N2) from the atmosphere into ammonia (NH3) or related compounds in soil, making it available for plants.

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What role do legumes play in the nitrogen cycle?

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Legumes have symbiotic relationships with nitrogen-fixing bacteria, allowing them to convert atmospheric nitrogen into a form that plants can use.

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What is nitrification?

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Nitrification is the biological process in which ammonia is oxidized to nitrites (NO2-) and then to nitrates (NO3-), which plants can absorb.

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What is denitrification?

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Denitrification is the process by which nitrates are reduced to nitrogen gas (N2) or nitrous oxide (N2O), returning nitrogen to the atmosphere.

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What is ammonification?

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Ammonification is the process of converting organic nitrogen from dead plants and animals into ammonia by decomposers.

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Why is ammonia considered toxic?

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Ammonia is toxic to plants and animals at high concentrations because it can disrupt cellular processes and lead to toxicity.

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What percentage of the Earth's atmosphere is nitrogen?

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Approximately 78% of the Earth's atmosphere is nitrogen.

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How do plants obtain nitrogen?

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Plants obtain nitrogen primarily through the uptake of nitrates and ammonium from the soil.

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Can animals use nitrogen gas directly?

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No, animals cannot use nitrogen gas directly; they must obtain nitrogen from the food they eat.