What is the first step of translation called?

The first step of translation is called initiation. During this phase, the ribosome assembles around the mRNA molecule, and the first transfer RNA (tRNA) brings the correct amino acid to start the protein synthesis process. The small subunit of the ribosome binds to the mRNA at the start codon, which typically codes for the amino acid methionine. The large ribosomal subunit then associates with this complex, setting the stage for the elongation phase where amino acids are added one by one to the growing polypeptide chain.

This initial step is crucial because it ensures that translation begins correctly at the appropriate site on the mRNA, thereby determining the correct reading frame for the subsequent amino acid sequence. Understanding initiation is fundamental to grasp how proteins are synthesized in cells, which is a key concept in molecular biology and genetics.