This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Structure & Function of Protein, Subject name: Biochemistry
[{'content': 'The optically inactive amino acid is: \nSelect and explain. \nA. Glycine, B. Serine, C. Threonine, D. Valine', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. A. GlycineOptically inactive molecules are those whose mirror images are super imposable and don't have a chiral carbon atom.Out of the 20 standard amino acids glycine is the simplest, optically inactive amino acid.", 'role': 'assistant'}]