This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
All of the following are require in protein synthesis except 
Select and explain. 
A. el F-1, B. mRNA, C. Mg +2, D. Ca +2
D: Ca +2
Answer: D: Ca +2 
Explanation: Elongation process of Translation has three steps : Binding of amino acyl tRNA to the A site. Peptide bond formation and Translocation of the ribosome on the mRNA. REFERENCE : DM.VASUDEVAN.TEXTBOOK ; SEVENTH EDITION ; PAGE NO :601