Outline the nitrogen cycle in making nitrogen available for plant and animal protein, limited to: (a) decomposition of plant and animal protein to ammonium ions (b) nitrification (c) nitrogen fixation by lightning and bacteria (d) absorption of nitrate ions by plants (e) production of amino acids and protein (f) feeding and digestion of proteins (g) denitrification (the names of individual bacteria are not required)

Explain the importance of nitrate ions for making amino acids, required for the production of proteins

Describe the role of the liver in the assimilation of amino acids by converting them to proteins