Diffusion in Multicellular Organisms
- Large, multicellular organisms like humans have relatively small surface areas (SA) in comparison to their volumes (in comparison to single-celled organisms)
- This means that the distance between the surface of the organism to its centre is relatively large
- This is why larger organisms usually have exchange surfaces and transport systems; as diffusion, osmosis and active transport cannot happen sufficiently to meet a larger organism’s needs otherwise
Many cells which are adapted for diffusion have increased surface area in some way – eg root hair cells in plants and cells lining the ileum in animals