This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemistry of Nucleotides , Subject name: Biochemistry
N1 of purine ring is derived from - 
Select and explain. 
A. Glycine, B. Aspartate, C. Glutamine, D. Asparagine
B: Aspartate
Answer: B: Aspartate 
Explanation: Ans. is 'b' i.e., Aspartate i) Glycine provides C4, C5 and N7ii) Aspartate provides N1iii) Glutamine provides TV3 and N9iv) Tetrahydrofolate derivatives furnish C2 and C8v) Carbon dioxide provides C6Precursors for pyrimidine denovo synthesisi) Glutamine provides N3ii) Aspartic acid furnishes C4, C5, C6 and N1iii) CO2 provides C2