Question

Given below are the steps of protein synthesis. Arrange them in. correct sequence and select the correct option.
(j) Codon-anticodon reaction between mRNA and aminoacyl tRNA complex.
(ii) Attachment of mRNA and smaller sub-unit of ribosome.
(iii) Charging or aminoacylation of tRNA.
(iv) Attachment of larger sub unit of ribosome to the mRNA-tRNAMet complex.
(v) Linking of adjacent amino acids.
(vi) Formation of polypeptide chain.

• A. (ii) $\to$ (i) $\to$ (iii) $\to$ (v) $\to$ (iv) $\to$ (vi)
• B. (v) $\to$ (ii) $\to$ (i) $\to$ (iii) $\to$ (iv) $\to$ (vi)
• C. (iii) $\to$ (ii) $\to$ (iv) $\to$ (i) $\to$ (v) $\to$ (vi)
• D. (iii) $\to$ (ii) $\to$ (i) $\to$ (iv) $\to$ (v) $\to$ (vi)

Answer 1

The correct option is D (iii) $\to$ (ii) $\to$ (i) $\to$ (iv) $\to$ (v) $\to$ (vi)

Aminoacyl tRNA synthetase is an enzyme that attaches the appropriate amino acid onto its tRNA. This step is called as the charging of the tRNA with appropriate amino acid to the anti-codon arm. The mRNA is hence attached to the tRNA and a small sub unit of the ribosome is assembled primarily which is the cellular factory that is responsible for the translation of mRNA to proteins.For initiation the ribosome binds to the mRNA at the start codon that is recognized by the initiator tRNA. The larger sub-unit of the ribosome has two sites for subsequent amino acids to bind and thus be close enough to each other to form a peptide bond. Hence, acting as a catalyst for the peptide bond formation. This linking is the process of the peptide bond formation between two successive amino acids and the formed polypeptide chains with multiple peptide bonds exits from the ribosome.

So, the correct option is, (iii) → (ii) → (i) → (iv) → (v) → (vi)

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