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During translation initiation in prokaryotes, a GTP molecule is needed in the:

Correct answer: C. Association of 30S mRNA with formyl­-mett-RNA

  • A. Formation of formyl-­met­t-RNA
  • B. Binding of 30S subunit of ribosome with mRNA
  • C. Association of 30S mRNA with formyl­-mett-RNA
  • D. Association of 50S subunit of ribosome with initiation complex.

Explanation

During translation initiation in prokaryotes, a GTP molecule is needed in the association of 30S mRNA with formyl-mett-RNA.This is because the GTP molecule is used to power the movement of initiation factor 2 (IF-2) to the ribosome. IF-2 brings with it the formyl-methionine-tRNA (fMet-tRNA), which is the first amino acid that is incorporated into the growing polypeptide chain. The other options are incorrect because: Methyl-methionine-tRNA (Met-tRNA) is formed during translation elongation, not translation initiation. The binding of the 30S ribosomal subunit to mRNA does not require GTP. The association of the 50S ribosomal subunit to the initiation complex does not require GTP.

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