3.3.1 Surface area to volume ratio

• The smaller the surface area to volume ratio, the higher the metabolic rate as larger organisms tend to move more so therefore respire more.
• Ways large organisms compensate for low SA:V ratio include:

  • folding in the surface of the cell membrane
  • long, thin or elongated shaped cells
  • specialised gas exchange surface
• The larger the organism, the smaller the surface area to volume ratio, so the rate of diffusion of gases such as oxygen is slower.