Adaptations of red blood cells

• Biconcave discs:

  • Increases their surface area which increases diffusion of oxygen across the cell membrane
• Packed with haemoglobin:

  • Haemoglobin binds to oxygen
  • Contains an atom of iron (Fe) which gives the pigment its red colour, and is brightest when there is lots of oxygen bound to the haemoglobin
• No nucleus:

  • Allows more space for more haemoglobin