Translation

Translation can almost be looked at as the continuation of Transcription, where the mRNA is used as a template to make proteins. However, translation tends to differ quite a bit from transcription or replication since it is not making copies of genes, but rather converting genes into proteins. The process includes:

• tRNA (transfer RNA) which includes the 3 nucleotide anticodons
• mRNA, the finished product of Transcription, which includes the codons for tRNA to attach to
• ribosomal subunits to help the process along

                                                               

Just like replication or transcription, Translation includes three processes: Initiation, Elongation and Termination.

Initiation:

• Proteins known as initiation factors assemble all the molecules together for the production of proteins. First, a small ribosomal sub-unit will find the start codon (AUG) in the mRNA, and attach itself there. This will act as a signal for the tRNA.

• After the tRNA has grabbed the corresponding amino acid to the mRNA codon from the cytoplasm, the tRNA comes over to the start codon, it will attach onto the mRNA with its anticodon, which includes the complementary base pair to AUG (UAC) and the corresponding amino acid for AUG, methionine.

• Then, the large ribosomal sub-unit joins the group, gets the process kicking. With the large ribosomal sub-unit, there are three binding sides for the tRNAs: The P (peptide) site, the A (amino acid) site and the E (exit) site.

Elongation:

• The mRNA is established as the reading frame, and the codons are read in sequence from the starting codon.

• The amino acid on the initiator tRNA, methionine, is the beginning of the polypeptide chain. It occupies the P site in the large ribosomal sub-unit. Simutaneously there is another tRNA in the A site, with the complementary anticodon of the subsequent codon sequence on the mRNA, carrying the corresponding amino acid.

• The amino acid of the initiator tRNA then forms a peptide bond with the amino acid in the A site, with the outcome of the a dipeptide attached to the tRNA at the A site.

• Once the initiator tRNA is now robbed of its amino acid, it goes to the E site, where it exits the ribosomal sub-unit. This entire process repeats, as the ribosomes moves one sequence over, putting the tRNA with the amino acids in the P site, and giving room for a complementary tRNA to land in the S site.

                                            

Termination:

• The process of elongation continues until it reaches the stop codon in the mRNA, signified with the codon sequences UGA, UAG or UAA.

• When this happens, a protein will come called the release factor, and cut the polypeptide from the tRNA it is on. 

• Then, the polypeptide is released, and set out to carry out its duties in the cell.