Initiation of translation requires which combination?

• A. DNA polymerase and helicase
• B. mRNA, tRNA, and the first amino acid
• C. Ribosome and tRNA only
• D. mRNA alone

Answer: (B)

Translation initiation hinges on the template provided by mRNA and the delivery of the first amino acid by a charged initiator tRNA. The mRNA shows which codons will be read and in what order, while the initiator tRNA brings the first amino acid (typically methionine) to the start codon, establishing the reading frame and providing the starting point for polypeptide synthesis. The ribosome then assembles around this complex to begin elongation. So including the mRNA, the initiator tRNA, and the first amino acid correctly reflects the minimal components needed to start translation. Without any of these, translation cannot begin because there would be no template, no initiator to start the chain, or no amino acid to form the first peptide bond.