This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
All are ketogenic & glucogenic amino acids except 
Select and explain. 
A. Tyrosine, B. Isoleucine, C. Phenyalanine, D. Serine
D: Serine
Answer: D: Serine 
Explanation: Serine is a glucogenic amino acid.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 245.fig 18.16.