Loading…
Loading…
GCSE Biology · key term
A comparison of an object's surface area with its volume, showing how much surface is available for each unit of volume.
Used by AQA and OCR
Specification 4.1.3.1 · Paper 1
Revise: Surface Area to Volume Ratio and Exchange SystemsThe larger cubes have a greater total surface area, but their volume has increased even more rapidly. Their surface area to volume ratio has therefore fallen. This distinction matters: “larger surface area” and “larger surface area to volume ratio” do not mean the same thing.
Specification B2.2e · Paper 1 (Foundation), Paper 3 (Higher)
The amount of surface available compared with the volume of an object or cell.
Revise: Red blood cells and plasmaIts biconcave shape gives it a large surface area to volume ratio. This provides a large membrane area across which oxygen can diffuse.
Do not confuse total surface area with surface area to volume ratio. A larger organism can have a greater total surface area but a smaller surface area to volume ratio.
When explaining the need for a transport system, link a low surface area to volume ratio to insufficient exchange and long diffusion distances. A transport system does not remove the need for diffusion.
A biconcave shape gives a large surface area to volume ratio; do not confuse this with simply saying that the whole cell is large.
Create a free account to read GCSE Biology revision notes for your exam board and track your progress.