tRNAs interact with the ribosome only after
A) they bind the free mRNA.
B) the small and large subunits have come together.
C) the first peptide bond in the nascent chain is formed.
D) the AUG start codon is positioned in the E site.

Question

Quizplus · Accepted Answer

tRNAs are recruited to the ribosome and begin interacting with it only after the small and large subunits have come together to form the functional ribosome. This is the correct option. Choice A is incorrect because tRNAs do not bind free mRNA; rather, they are charged with amino acids by aminoacyl-tRNA synthetases and then brought to the ribosome. Choice C is incorrect because the first peptide bond is formed after the interaction between tRNAs and the ribosome has already begun. Choice D is incorrect because the AUG start codon is positioned in the P site, not the E site, and the interaction between tRNAs and the ribosome has already begun by this point.

TRNAs Interact with the Ribosome Only After