[Campbell Biology P.402] Which of the following events correctly describes the translocation... | Practice Question

Which of the following events correctly describes the translocation step during translation elongation?

  • A: The ribosome moves along the mRNA, shifting the tRNA from the A site to the P site and the empty tRNA from the P site to the E site for release.
  • B: An aminoacyl tRNA binds to the A site, forming a peptide bond with the growing polypeptide.
  • C: The polypeptide chain is released from the ribosome.
  • D: The two ribosomal subunits dissociate from the mRNA.

Explanation

As described in Figure 17.20, step 3, "The ribosome translocates the tRNA in the A site to the P site. At the same time, the empty tRNA in the P site is moved to the E site, where it is released. The mRNA moves along with its bound tRNAs, bringing the next codon to be translated into the A site."