1. Initiation of translation- involves
the binding of mRNA to the ribosome and its
accessory proteins. The cap structure is synthesized at the 5' end to insure that
translation begins at the proper AUG start codon.
2. Elongation- tRNA molecules read
successive mRNA codons to properly place
amino acids along the growing polypeptide chain.
3. Termination- Poly(A) polymerase
adds approximately 200 adenine residues to
the 3' end of the mRNA transcript. Ribosomes stop translation
when they encounter one of the stop codons (UAA, UAG, or UGA) prior to the
Mutant tRNAs called suppressor tRNAs can bind to a stop codon and add an amino acid, preventing termination of translation. These can help overcome mutations in the DNA which result in mRNA transcripts having stop codons placed incorrectly in the mRNA transcript of an essential protein.