Question

Which of the following amino acids are present in ornithine cycle?

• A. Valine and cystine
• B. Arginine and citrulline
• C. Glycine and methionine
• D. None of the above

Answer 1

The correct option is B Arginine and citrulline

Ornithine cycle converts two amino groups, one from NH4+ and one from aspartate, and a carbon atom from HCO3, to the nontoxic excretion product urea. Ornithine gets converted into citrulline, which in turn gets converted into arginine with the help of aspartate in the cytosol. Ultimately, arginine is converted back to ornithine.