At what point does translation begin during protein synthesis?

Translation begins when the 5' end of mRNA binds to the small ribosomal unit. This process is crucial as it sets the stage for the assembly of the ribosome and the initiation of protein synthesis.

The binding of the mRNA to the small subunit of the ribosome allows for the recognition of the start codon (usually AUG), which is essential for the recruitment of the initiator tRNA carrying the first amino acid (methionine). This step establishes the proper reading frame for translation and ensures that the subsequent amino acids are added correctly to the growing polypeptide chain.

Without the initial binding of the mRNA to the ribosomal subunit, translation would not be able to commence, making this step a key event in the overall process of protein synthesis.