Question

Do the following events during bacterial translation occur primarily within the 30S subunit, within the 50S subunits, or at the interface between these two ribosomal subunits?

A. mRNA-tRNA recognition
B. Peptidyl transfer reaction
C. Exit of the polypeptide chain from the ribosome
D. Binding of initiation factors IF1, IF2, and IF3

Answer 1

During bacterial translation, mRNA-tRNA recognition and binding of initiation factors occur at the interface of or within the 30S subunit, respectively, while the peptidyl transfer reaction and exit of the polypeptide occur within the 50S subunit.

Step-by-step explanation:

The process of bacterial translation involves specific events that occur at distinct locations within or between the ribosomal subunits. These events are critical to the synthesis of polypeptides from mRNA templates.

• mRNA-tRNA recognition occurs primarily at the interface between the 30S and 50S ribosomal subunits. The initiation codon on the mRNA is recognized by the anticodon of the initiator tRNA.
• The peptidyl transfer reaction, which forms the peptide bond between amino acids, primarily takes place within the 50S ribosomal subunit. This is where the enzymatic activity of the ribosome as a ribozyme is centered.
• The exit of the polypeptide chain from the ribosome occurs through the exit tunnel located in the 50S subunit of the ribosome.
• Binding of initiation factors IF1, IF2, and IF3, which is critical for the translation initiation, occurs at the small 30S ribosomal subunit.