Where does the empty tRNA exit the ribosome during elongation?

Where does the empty tRNA exit the ribosome during elongation?

• A. A site
• B. P site
• C. E site
• D. Start codon

Answer: (C)

During elongation, tRNAs cycle through three binding pockets on the ribosome: the A site for the incoming aminoacyl-tRNA, the P site holding the growing polypeptide, and the E site as the exit. After the new peptide bond forms, the ribosome translocates, moving the deacylated tRNA from the P site into the E site, where it exits the ribosome. This leaving from the exit site recycles the tRNA and clears space for the next aminoacyl-tRNA to enter the A site. The start codon is only involved in initiation, not a place for tRNA exit, and the A site is the entry point for new tRNA, not the exit. So the empty tRNA exits from the E site.

During elongation, tRNAs cycle through three binding pockets on the ribosome: the A site for the incoming aminoacyl-tRNA, the P site holding the growing polypeptide, and the E site as the exit. After the new peptide bond forms, the ribosome translocates, moving the deacylated tRNA from the P site into the E site, where it exits the ribosome. This leaving from the exit site recycles the tRNA and clears space for the next aminoacyl-tRNA to enter the A site. The start codon is only involved in initiation, not a place for tRNA exit, and the A site is the entry point for new tRNA, not the exit. So the empty tRNA exits from the E site.