What is the function of the large ribosomal unit in translation?

The large ribosomal unit plays a critical role in the process of translation by catalyzing the formation of peptide bonds between amino acids. This is essential for synthesizing proteins, as it allows the amino acids brought to the ribosome to be linked together in a specific sequence determined by the mRNA template. The large subunit contains enzymatic sites, including the peptidyl transferase center, which facilitates the formation of these covalent bonds, thereby elongating the nascent polypeptide chain.

In contrast, other functions attributed to the different parts of the ribosome or processes of translation involve different roles. For instance, the initiation of the assembly of amino acids primarily involves the small ribosomal unit and various initiation factors instead of the large subunit itself. Similarly, while mRNA is transported to the cytoplasm, this is not a function performed by the ribosomal units but rather is associated with mRNA processing and export mechanisms. Additionally, unwinding the mRNA strand for translation is not a function of the ribosomal units; instead, it is carried out by helicase enzymes during the initial stages of translation complex assembly.