Unicellular Organisms
- In order for any organism to function properly, it needs to exchange substances, such as food molecules and waste products, between itself and its environment
- This exchange of substances occurs across the cell membrane
- There are three transport processes that living organisms use for exchange: diffusion, osmosis and active transport
- Unicellular (single-celled) organisms like amoeba have very large surface areas (SA) in comparison to their volumes
- This means that the distance between the surface of the organism to its centre is very small
- As a result, unicellular organisms do not need to have specialist exchange surfaces or transport systems; as diffusion, osmosis and active transport through the cell membrane occur at a sufficient rate to meet the organisms needs
Unicellular organisms such as amoeba do not require transport systems due to their large surface area to volume ratio
