text: what are the three key elements that are required in assembling the protein chain?   you need minimum  1. mrna that acts as a template 2. ribosomes to catalyze the reaction 3. transfer rnas carrying amino acids. the amino acids are the building blocks of the protein chain and the trna is needed so that the system knows which amino acid to use.  but also gtp to provide the energy for the elongation of the chain, elongation factors, etc.