Translation Requirements—After Transcription Is Complete Once transcription has produced a mature mRNA, which of the following is NOT required for protein synthesis to proceed?

Introduction / Context:
Translation converts mRNA information into polypeptide sequences. The machinery includes ribosomes, tRNAs, and a suite of protein factors and enzymes. This question asks you to identify which component is not necessary for the translation step once the mRNA transcript is ready.

Given Data / Assumptions:

• A mature mRNA is available in the cytoplasm.
• tRNAs must be charged with amino acids by aminoacyl-tRNA synthetases.
• Ribosomes read the mRNA and catalyze peptide bond formation.

Concept / Approach:
DNA is the template for transcription, but it is not a direct participant in translation. The translation apparatus acts on mRNA. Therefore, among the options, DNA is the one not required at this stage, whereas tRNA, ribosomes, mRNA, and aminoacyl-tRNA synthetases are all essential for peptide synthesis and elongation accuracy.

Step-by-Step Solution:

Verification / Alternative check:
Cell-free translation systems (e.g., rabbit reticulocyte lysate) translate added mRNA without any DNA present, validating that DNA is unnecessary for the translation step.

Why Other Options Are Wrong:

• tRNA/ribosomes/mRNA: core translation components.
• Aminoacyl-tRNA synthetases: required to generate aminoacyl-tRNAs for decoding.

Common Pitfalls:
Assuming that because DNA encodes proteins, it must be present during translation; in reality, transcription and translation are distinct processes.

Final Answer:
DNA