Transport Into & Out of Organisms (OCR GCSE Combined Science A (Gateway): Biology): Revision Note

Transport Into & Out of Organisms

• In order for any organism to function properly, it needs to exchange substances between itself and the 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

• Organisms must take in:

  • Oxygen

    • For respiration

  • Water

    • Needed for transport and in many cellular reactions

  • Dissolved food molecules

    • Used to release energy, as well as for growth and cell repair

  • Mineral ions

    • Organisms need vitamins and minerals in small amounts, to help use other nutrients efficiently

  • Plants must also take in carbon dioxide

    • For photosynthesis

• Organisms need to remove waste substances such as urea and carbon dioxide

  • If waste substances build-up within an organism, they can have negative effects due to their toxicity

Unicellular organisms such as amoeba do not require transport systems due to their large surface area to volume ratio