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
Polar amino acids are all except 
Select and explain. 
A. Glutamic acid, B. Histidine, C. Glutamine, D. Methionine
D: Methionine
Answer: D: Methionine 
Explanation: Amino acids having charged or ionic polar side chains (hydrophilic): C-a. Acidic amino acids: They have a negative charge on the R group: Aspaic acid and Glutamic acid (Tyrosine is mildly acidic). C-b. Basic amino acids: They have a positive charge on the R group: Lysine, Arginine, and Histidine.Ref: DM Vasudevan - Textbook of Biochemistry, 6th edition, page no: 21