Question

In living beings ammonia is converted into urea through:

• A. ornithine cycle
• B. citrulline cycle
• C. fumarine cycle
• D. arginine cycle

Answer 1

Answer: (D)

arginine cycle

Answer 2

Ornithine combines with one molecule of $NH _{3}$ and $CO _{2}$ to produce citrulline. Citrulline combines with another molecule of $NH _{3}$ to form arginine. Arginine is broken down into urea and ornithine which repeat the cycle. This cycle known as ornithine cycle.