This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
[{'content': 'Sulphur containing amino acid is \nSelect and explain. \nA. Cysteine, B. Lysine, C. Arginine, D. Phenylalanine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Cysteine # Sulfur-containing amino acids (cysteine & methionine) are generally considered to be nonpolar and hydrophobic.> In fact, methionine is one of the most hydrophobic amino acids and is almost always found on the interior of proteins.> Cysteine on the other hand does ionize to yield the thiolate anion.', 'role': 'assistant'}]