[Campbell Biology P.399] According to the text, what is a key difference in the initiation o... | Practice Question

According to the text, what is a key difference in the initiation of translation between bacteria and eukaryotes?

  • A: In bacteria, the small subunit binds to the 5' cap of the mRNA, while in eukaryotes, it binds to a specific RNA sequence.
  • B: In eukaryotes, the small subunit with initiator tRNA binds to the 5' cap of the mRNA and scans, whereas in bacteria, it binds at a specific upstream RNA sequence.
  • C: Only eukaryotic initiation requires GTP hydrolysis for energy.
  • D: Bacterial initiation brings together an mRNA, a tRNA, and both ribosomal subunits simultaneously.

Explanation

The text details the difference: 'In bacteria, the small subunit can bind the two in either order; it binds the mRNA at a specific RNA sequence, just upstream of the AUG start codon. In eukaryotes, the small subunit, with the initiator tRNA already bound, binds to the 5' cap of the mRNA and then moves, or scans,'.