This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Aminoacyl t-RNA is required for all except - 
Select and explain. 
A. Hydroxyproline, B. Methionine, C. Cystine, D. Lysine
A: Hydroxyproline
Answer: A: Hydroxyproline 
Explanation: Hydroxyproline and hydroxylysine are not represented into genetic code, i.e. they to not have t-RNA capable of accepting them and inserting them into polypeptide chain. Therefore, they have to be synthesized post-translationally from proline and lysine residues in the polypeptides.