B2.3.6—Surface area-to-volume ratios
Surface area-to-volume ratio limits cell size because exchange depends on surface area while metabolic demand rises with volume during growth.
- Syllabus
- First assessment 2025
- Objective
- B2.3.6
- Level
- HL
Exam analysis
Chance of appearing4%of analysed past papers
Latest appearanceMay 2017
Most common paperPaper1
Typical marks1–2
Common command terms
- Identify
- Explain
- Outline
- State
Scoring notes
- Common mistake
- Saying surface area-to-volume ratio increases as a cell grows.
Recent exam appearances
May 2017Paper2 ["HL"] · TZ23(d)[ 1 ]B2.3.6—Surface area-to-volume ratios
May 2015Paper1 ["HL"] · TZ21[ 1 ]B2.3.6—Surface area-to-volume ratios
May 2014Paper2 ["HL"] · TZ22(c)[ 2 ]B2.3.6—Surface area-to-volume ratios
May 2013Paper1 ["HL"] · TZ24[ 1 ]B2.3.6—Surface area-to-volume ratios
Practice this objective
Coverage 2013–2017 · Updated 15 Jul 2026
Concept essentials
- Surface area affects the rate of exchange across the cell boundary.
- Volume affects metabolic demand and waste or heat production.
- As a cell grows without changing shape, surface area-to-volume ratio decreases.
- Low surface area-to-volume ratio can limit diffusion and therefore cell size.