🚀 Translation – Making Proteins One Amino Acid at a Time

Translation is polymerisation of amino acids into a polypeptide chain. The sequence of amino acids follows the base sequence of mRNA, and each new amino acid joins by a 💪 peptide bond. :contentReference[oaicite:0]{index=0}

1. “Charging” the tRNA 🔋

  • Every amino acid first activates in the presence of ATP.
  • The activated amino acid hooks onto its specific tRNA — a step called aminoacylation or charging. :contentReference[oaicite:1]{index=1}
  • If two charged tRNAs sit close together, forming a peptide bond becomes energetically favorable. 🌟

2. The Ribosome – The Protein Factory 🏭

  • Built from structural RNAs plus ≈ 80 proteins.
  • Exists as two sub-units: one large and one small (they unite only during translation). :contentReference[oaicite:2]{index=2}
  • The large sub-unit holds two binding sites so incoming amino acids are side-by-side for quick peptide-bond formation. :contentReference[oaicite:3]{index=3}
  • Its 23S rRNA (in bacteria) acts as a ribozyme — an RNA enzyme that speeds up peptide-bond formation. 🔬

3. The Translational Unit & UTRs 🧩

  • A translational unit runs from the start codon AUG to a stop codon and encodes one polypeptide. :contentReference[oaicite:4]{index=4}
  • Extra sequences at both ends of mRNA, called the 5′ UTR and 3′ UTR, stay untranslated but boost efficiency. 🚦

4. Step-by-Step Flow ⏩

  1. Initiation 🎬 – The small ribosomal sub-unit locks onto mRNA, recognising the AUG start with a special initiator tRNA.
  2. Elongation ➕ – Charged tRNA–amino-acid complexes arrive one after another, matching anticodons to codons. The ribosome slides along the mRNA, stitching amino acids into a growing chain. :contentReference[oaicite:5]{index=5}
  3. Termination 🛑 – A release factor binds the stop codon, the completed polypeptide pops free, and the ribosome sub-units separate. :contentReference[oaicite:6]{index=6}

🎯 High-Yield NEET Nuggets

  • Charging (aminoacylation) of tRNA requires ATP.
  • Start codon is always AUG; stop codons do not have matching tRNAs.
  • The ribosome’s 23S rRNA functions as a catalytic ribozyme.
  • 5′ UTR and 3′ UTR regions increase translation efficiency without encoding amino acids.

Keep practicing codon–anticodon matching, and picture the ribosome as a moving assembly line — it makes remembering translation steps a breeze! 😊