Transport in and out of organisms

• • 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: