Translation on the ribosomeराइबोसोम पर अनुवादन
NCERT Fig 5.13 · Class 12 Biology · Chapter 5 · interactive diagram
Parts and their functions
- mRNA (mRNA) — Template read codon by codon, 5′→3′.
- 5′ untranslated region (UTR) (5′ अननुवादित क्षेत्र) — Before the start codon; not translated; needed for efficient translation.
- 3′ untranslated region (UTR) (3′ अननुवादित क्षेत्र) — After the stop codon; not translated.
- Start codon AUG (प्रारंभ कोडॉन AUG) — Recognised only by the initiator tRNA (methionine).
- Stop codon (समापन कोडॉन) — UAA, UAG or UGA; no tRNA reads it.
- Large subunit (बड़ी उपइकाई) — Has two sites for tRNAs; its rRNA (23S in bacteria) catalyses the peptide bond — a ribozyme.
- Small subunit (छोटी उपइकाई) — Translation begins when it meets the mRNA.
- Charged tRNA (आवेशित tRNA) — tRNA carrying its amino acid; pairs with the codon by its anticodon.
- Growing polypeptide (बनता पॉलीपेप्टाइड) — Amino acids joined by peptide bonds.
- Release factor (विमोचन कारक) — Binds the stop codon; ends translation and releases the polypeptide.
Steps
- Initiation: ribosome + initiator tRNA (met) at AUG.
- Elongation: tRNAs bring amino acids codon by codon; peptide bonds form.
- Termination: release factor at the stop codon; polypeptide released.
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 5.13. Report a mistake