Final answer:
A ribosome attaches near the 5' end of an mRNA strand, moving toward the 3' end as it translates the mRNA into a polypeptide. The process includes initiation at the AUG start codon, elongation as tRNAs bring amino acids, and termination at a stop codon. Translocation moves the ribosome along the mRNA, assisted by EF-G.
Step-by-step explanation:
A ribosome attaches near the 5' end of an mRNA strand and moves toward the 3' end, translating the mRNA as it goes. In the translation process, the ribosome binds to mRNA in the cytoplasm and moves along from the 5' to 3' direction. The ribosome assembles at the AUG start codon and then recruits methionine-tRNA to begin protein synthesis. The protein synthesis process includes the steps of initiation, elongation, and termination. During elongation, tRNAs bring the appropriate amino acids to the ribosome, matching their anticodons with the codons on the mRNA. The ribosome catalyzes the bonding between the new amino acid and the growing polypeptide chain, shifting along the mRNA by one codon at a time. This process repeats until a stop codon is reached, signaling the end of translation and releasing the finished polypeptide.
Ribosomes move along the mRNA by a process called translocation, which involves an elongation factor called EF-G or translocase. As the ribosome progresses, it adds amino acids to the nascent polypeptide chain, eventually leading to a complete protein once a stop codon is encountered on the mRNA.