- The ribosome binds to the mRNA at the start codon (usually AUG).
- A tRNA molecule carrying the amino acid methionine (Met) binds to the start codon.
2. Elongation:
- The ribosome moves along the mRNA in a 5' to 3' direction.
- Each new codon on the mRNA codes for a specific amino acid.
- A tRNA molecule carrying the corresponding amino acid binds to the codon.
- The amino acid is transferred from the tRNA to the growing polypeptide chain.
- The tRNA is released from the ribosome.
3. Termination:
- The ribosome reaches a stop codon (UAA, UAG, or UGA) on the mRNA.
- There is no tRNA molecule that recognizes a stop codon.
- A release factor binds to the stop codon.
- The polypeptide chain is released from the tRNA.
- The ribosome dissociates from the mRNA.