B3.1.8—Leaf tissue distribution
Dicot leaf tissues are arranged so light capture, gas diffusion, water supply and sugar transport occur in coordinated epidermal, mesophyll and vascular layers.
- Syllabus
- First assessment 2025
- Objective
- B3.1.8
- Level
- HL
Exam analysis
Chance of appearing4%of analysed past papers
Latest appearanceNovember 2015
Most common paperPaper2
Typical marks1–8
Common command terms
- Draw
- Explain
Scoring notes
- Common mistake
- Drawing individual cell detail when a plan diagram should show tissue distribution and relative positions.
Recent exam appearances
November 2015Paper2 ["HL"] · TZ07(a)[ 5 ]B3.1.8—Leaf tissue distribution
November 2014Paper2 ["HL"] · TZ06(c)[ 8 ]B3.1.8—Leaf tissue distribution
May 2013Paper2 ["HL"] · TZ15(a)[ 4 ]B3.1.8—Leaf tissue distribution
November 2012Paper1 ["HL"] · TZ031[ 1 ]B3.1.8—Leaf tissue distribution
Practice this objective
Coverage 2012–2015 · Updated 15 Jul 2026
Concept essentials
- Palisade mesophyll lies near the upper leaf surface and is rich in chloroplasts.
- Spongy mesophyll contains air spaces for internal gas diffusion.
- Xylem supplies water to leaf tissues, while phloem transports photosynthetic products.
- A plan diagram shows tissue distribution and labels, not detailed organelles.