The process of translation, essential for protein synthesis, unfolds in three key stages: initiation, elongation, and termination. Each of these stages mirrors the steps found in transcription, beginning with the initiation phase, which marks the start of translation.

During the initiation of translation, the small ribosomal subunit first binds to the messenger RNA (mRNA). This mRNA contains codons, which are three-nucleotide sequences that specify amino acids. The very first codon, known as the start codon, is AUG, which codes for the amino acid methionine (abbreviated as MET). Following the binding of the small ribosomal subunit to the mRNA, a transfer RNA (tRNA) molecule, carrying the corresponding amino acid methionine, associates with the mRNA. The tRNA has an anticodon that is complementary to the start codon, ensuring the correct amino acid is added to the growing polypeptide chain.

After the small ribosomal subunit and the tRNA are in place, the large ribosomal subunit joins the complex, completing the formation of the intact ribosome. This assembly is facilitated by several proteins known as initiation factors, which play a crucial role in the process. Additionally, the initiation of translation requires energy, highlighting the complexity and energy demands of this biological process.

In summary, the initiation of translation sets the stage for protein synthesis by establishing the ribosomal complex on the mRNA and positioning the first tRNA with its attached amino acid, methionine. This foundational step is critical for the subsequent elongation and termination phases of translation, which will be explored further in future discussions.