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D1.2.10—Elongation of polypeptide

Polypeptide elongation adds amino acids sequentially as ribosomes translocate along mRNA, while polysomes translate one transcript simultaneously in active cells.

Syllabus
First assessment 2025
Objective
D1.2.10
Level
HL

Exam analysis

Chance of appearing3%of analysed past papers
Latest appearanceMay 2019
Most common paperPaper1
Typical marks1

Common command terms

  • Explain

Scoring notes

Common mistake
Describing several ribosomes on one mRNA as several genes rather than one transcript being translated many times.

Recent exam appearances

May 2019Paper1 ["HL"] · TZ128[ 1 ]D1.2.10—Elongation of polypeptide
May 2018Paper1 ["HL"] · TZ128[ 1 ]D1.2.10—Elongation of polypeptide
November 2013Paper1 ["HL"] · TZ027[ 1 ]D1.2.10—Elongation of polypeptide
Practice this objective

Coverage 2013–2019 · Updated 16 Jul 2026

Concept essentials

  • Elongation lengthens a polypeptide one amino acid at a time.
  • Ribosomes translocate along mRNA as translation proceeds.
  • A polysome consists of many ribosomes on one mRNA molecule.
  • Farther-moving ribosomes usually carry longer growing polypeptides.
ConceptIB Biology HL