Sequential steps in translation elongation

Steps:

• tRNA carrying a specific amino acid enters the ribosome's A site (statement 3).
• The tRNA anticodon base-pairs with the mRNA codon to ensure correct matching (statement 2).
• A peptide bond forms between the new amino acid and the growing polypeptide chain (statement 1).
• This sequence reflects the standard elongation cycle in protein synthesis.

Why A is correct:

• It follows the biological order where codon-anticodon binding (2) must occur before peptide bond formation (1), as defined in ribosomal translation mechanisms.

Why the others are wrong:

• B: Places peptide bond (1) before binding (2), which is impossible without proper codon recognition.
• C: References undefined statement 4, making the sequence invalid.
• D: Identical to C, with the same invalid reference to step 4.

Final answer: A