Final answer:
The process in question is the elongation stage of protein synthesis during translation, which involves the movement of the 70S ribosome along the mRNA strand, requiring a peptidyl-tRNA complex, aminoacyl-tRNAs, and GTP under the influence of elongation factors.
Step-by-step explanation:
Protein Synthesis and Translation
The process being described is protein synthesis, specifically the elongation stage of translation, which occurs within the ribosome of a cell. During this stage, the 70S ribosome moves along the mRNA molecule. It requires several key elements, namely a mRNA template, peptidyl-tRNA complex positioned at the P site, aminoacyl-tRNAs, elongation factors (EFs), GTP, and ribosomal subunits (30S and 50S forming the 70S complex in prokaryotes like E. coli).
As part of this process, the ribosome moves along the mRNA towards the 3' end by the length of one codon (three bases). This action, known as translocation, requires elongation factor-G (EF-G) — also referred to as translocase — in conjunction with G protein and GTP. Through translocation, a dipeptide is moved from the A site to the P site with its attached tRNA. The deacylated tRNA, without an amino acid, is then released into the cytosol.
The energy for this process comes from the hydrolysis of GTP, which is facilitated by elongation factors. The amino acid sequence of the growing polypeptide chain is determined by codons on the mRNA, with the ribosome catalyzing peptide bond formation at each step of the translation process as it reads the mRNA transcript.