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B1.1.6—Cellulose structure and function

Cellulose is a beta glucose polysaccharide whose straight unbranched chains and hydrogen-bonded microfibrils strengthen plant cell walls structurally and mechanically.

Syllabus
First assessment 2025
Objective
B1.1.6
Level
HL

Exam analysis

Chance of appearing4%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper2
Typical marks1–3

Common command terms

  • Label
  • Describe
  • Outline
  • Identify

Scoring notes

Common mistake
Describing cellulose as branched or made from alpha-glucose.

Recent exam appearances

May 2024Paper2 ["HL"] · TZ18(a)[ 3 ]B1.1.6—Cellulose structure and function
November 2023Paper2 ["HL"] · TZ25(a)[ 3 ]B1.1.6—Cellulose structure and function
May 2021Paper1 ["HL"] · TZ17[ 1 ]B1.1.6—Cellulose structure and function
May 2019Paper2 ["HL"] · TZ14(c)[ 2 ]B1.1.6—Cellulose structure and function
May 2016Paper1 ["HL"] · TZ04[ 1 ]B1.1.6—Cellulose structure and function

Coverage 2016–2024 · Updated 15 Jul 2026

Cellulose scales weak attractions into strong fibres

  1. β-glucose monomers join by β-1,4 glycosidic bonds.
  2. Alternate monomers are rotated 180°, producing a straight, unbranched chain.
  3. Parallel chains form many hydrogen bonds.
  4. Chains bundle into microfibrils; microfibrils combine into fibres.
Straight beta-glucose chains joined by many hydrogen bonds, bundled into a microfibril within a plant cell wall.

Each hydrogen bond is weak, but many acting in parallel give high tensile strength. Cellulose therefore resists stretching and helps a water-filled plant cell maintain its shape without bursting.

Carbohydrate summary: follow monomer to biological job

Starting form Linkage or arrangement Emergent form Main job
α-glucose α-1,4 with optional α-1,6 branches amylose, amylopectin, glycogen energy storage
β-glucose alternating β-1,4 chain; hydrogen-bonded bundles cellulose fibres tensile support
short surface sugars attached to protein or lipid; exposed outside glycocalyx markers recognition, adhesion, signalling

Condensation builds a covalent linkage and releases water; hydrolysis consumes water and breaks that linkage. Which enzyme acts depends on the bond and substrate.

For a structure–function explanation:

  1. name the monomer or functional group
  2. identify the linkage and three-dimensional arrangement
  3. state the resulting property
  4. connect that property to the biological job

Cellulose structure and function

[ 3 ]

Describe how cellulose is formed from monosaccharides.

Concept essentials

  • Cellulose is made from beta-glucose monomers joined by 1,4 glycosidic bonds.
  • Alternating glucose orientation creates straight, unbranched chains.
  • Hydrogen bonding between chains forms strong microfibrils.
  • Cellulose provides structural strength in plant cell walls.