Question

Component of Ornithine cycle are

• A. Ornithine, citrulline and arginine
• B. Omithine, citrulline and fumaric acid
• C. Amino acids are not used fumaric acid
• D. Ornithine, citrulline and alanine

Answer 1

Answer: (A)

Ornithine, citrulline and arginine

The urea cycle also known as Ornithine cycle, is a biochemical reaction resulting in the formation of urea from ammonia. It is seen in the ureotelic organism, to convert the toxic ammonia waste to less toxic urea. This reaction takes place when ammonia combines with carbon dioxide forming carbamoyl phosphate, which enters into the cycle and combines with ornithine to form citrulline, at this stage aspartate changes into fumarate, and citrulline to argininosuccinate, which further changes to arginine. Arginine decomposes to give urea out and ornithine. This complete cycle operates at the expense of 4 ATP.

Hence, the correct answer is option A.