Answer
Initiation: the tRNA carrying a certain amino acid attaches to the ribosomal subunit. They both bind to the 5' end of the mRNA by identifying the 5' GTP cap. The units move along the mRNA in the 3' direction and stop when the start codon is reached.
Elongation: the initial tRNA begins in the middle spot of the ribosome (P site). A new codon is exposed in another slot (A site) right next to it. The A site will receive the next tRNA, one whose anticodon is complementary to the exposed codon. This process repeats until the polypeptide is ready to be terminated.
Termination: Termination happens when a stop codon enters the A site. Stop codons are recognized by release factors, which fit into the P site and signal the enzyme to add a water molecule to the last amino acid. As a result, the chain separates from the tRNA, and the new polypeptide is released.
Work Step by Step
Initiation: the tRNA carrying a certain amino acid attaches to the ribosomal subunit. They both bind to the 5' end of the mRNA by identifying the 5' GTP cap. The units move along the mRNA in the 3' direction and stop when the start codon is reached.
Elongation: the initial tRNA begins in the middle spot of the ribosome (P site). A new codon is exposed in another slot (A site) right next to it. The A site will receive the next tRNA, one whose anticodon is complementary to the exposed codon. This process repeats until the polypeptide is ready to be terminated.
Termination: Termination happens when a stop codon enters the A site. Stop codons are recognized by release factors, which fit into the P site and signal the enzyme to add a water molecule to the last amino acid. As a result, the chain separates from the tRNA, and the new polypeptide is released.
