This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification and metabolism of amino acids, Subject name: Biochemistry
[{'content': 'Substrate for gluconeogenesis include? \nSelect and explain. \nA. Glycerol, B. Leucine, C. Fatty acids, D. Acetyl CoA', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Only 5 amino acids are both glucogenic and ketogenic. Mnemonic - TTT I P Both glucogenic and ketogenic amino acids: Tryptophan Tyrosine Threonine, Isoleucine, Phenylalanine Note: there is a controversy regarding Lysine, some book says it is purely ketogenic some say it is both Ketogenic and glucogenic serine is only glucogenic amino acid.', 'role': 'assistant'}]