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C2.1.4 (HL)—Chemical diversity

Signalling chemicals vary chemically, including peptide or protein hormones that are hydrophilic and steroid hormones that are lipid-soluble, linking signal detection to a specific target-cell response.

Syllabus
First assessment 2025
Objective
C2.1.4
Level
HL

Exam analysis

Chance of appearing3%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper3
Typical marks1–2

Common command terms

  • State
  • Distinguish

Recent exam appearances

May 2024Paper3 ["HL"] · TZ223(a)[ 2 ]C2.1.4 (HL)—Chemical diversity
May 2014Paper3 ["HL"] · TZ114(a)(i)[ 2 ]C2.1.4 (HL)—Chemical diversity
May 2013Paper3 ["HL"] · TZ214(a)[ 1 ]C2.1.4 (HL)—Chemical diversity
Practice this objective

Coverage 2013–2024 · Updated 15 Jul 2026

Concept essentials

  • Protein and peptide hormones include insulin, glucagon, ADH, growth hormone and leptin.
  • Steroid hormones include oestrogen, progesterone and testosterone.
  • Peptide hormones are generally hydrophilic and act through membrane receptors.
  • Steroid hormones are lipid-soluble and can act through intracellular receptors.
ConceptIB Biology HL