Sources of the nitrogen in urea cycle are the following:: (A) Aspaate and ammonia, (B) Glutamate and ammonia, (C) Arginine and ammonia, (D) Uric acid
Answer is A. The 2 nitrogen atoms of urea are derived from two sources, one from ammonia and other from alpha amino group of aspaic acid. Ref: Textbook of Biochemistry By DM Vasudevan, 3rd Edition, Pages 163-5