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Nitrogen Excretion Forms


Excess nitrogen that builds up in the cell following the breakdown of amino acids must be excreted to avoid toxicity.

Complete the following statements demonstrating your understanding of the form of nitrogen excreted by each group of organisms indicated.

Animals living in large volumes of water typically excrete nitrogen in the form of

, which can be quickly rendered non-toxic by dilution. Most terrestrial vertebrates excrete nitrogen in the form of

, a less toxic waste product which moves through the blood to the kidneys. Birds and terrestrial reptiles excrete nitrogen as

, a relatively insoluble molecule containing four nitrogen atoms.