Question

Correct registration of mRNA on the ribosome requires 1) alignment of Pyr-rich sequence on the 3' end of 16S RNA with a Pu-rich part of 5'-end of mRNA 2) The purine-rich segment - the ribosome-binding site (RBS) - is known as the Shine-Dalgarno sequence 3) Initiation factor proteins, GTP, N-formyl-Met-tRNAifMet, mRNA, and 30S ribosome combine to form the 30S initiation complex. The 50S subunit then binds to form a 70S initiation complex.

A. Translation initiation
B. Transcription initiation
C. DNA replication
D. RNA splicing

Answer 1

The process outlined in the question is translation initiation, which involves aligning the mRNA with the ribosomal subunits, relying in part on the Shine-Dalgarno sequence in prokaryotes. The 30S and 50S ribosomal subunits combine with other components to form the initiation complex that starts protein synthesis.

Step-by-step explanation:

The process being described in the question is translation initiation, which is essential for protein synthesis in cells. Firstly, the small ribosomal subunit must align with the messenger RNA (mRNA). In prokaryotes like E. coli, the pyrimidine-rich sequence at the 3' end of 16S ribosomal RNA (rRNA) aligns with the purine-rich Shine-Dalgarno sequence, situated on the 5'-end of the mRNA, allowing the ribosome to properly bind to the mRNA. This ensures the correct positioning for the start of translation. Initiation factors, GTP, N-formyl-Met-tRNAifMet, mRNA, and the 30S ribosomal subunit then associate to form the 30S initiation complex, to which the 50S subunit subsequently binds, resulting in the formation of the 70S ribosomal initiation complex, ready for translation to begin.