mass transport

• what is haemoglobin made up of?

  • two beta polypeptide chains
  • two alpha helices
• what does oxygen bind to on a haemoglobin molecule?

  the haem (Fe2+) group
• how many oxygen molecules can one haemoglobin molecule carry?

  four
• what is the partial pressure of oxygen?

  the concentration of dissolved oxygen in cells
• what happens to partial pressure of oxygen as the concentration of oxygen increases?

  partial pressure increases
• what is dissociation

  when oxygen is released from oxyhaemoglobin at the respiring tissues
• how is haemoglobin in animals that live at high altitude adapted

  • they have a higher affinity for oxygen
• how is haemoglobin in animals that have a high metabolic rate

  • they have a lower affinity for oxygen
• what is the meaning of a double circulatory system?

  blood flows through the heart twice in one circuit
• which arteries supply blood to the heart

  coronary arteries
• which direction do the arteries carry blood

  away from the heart
• which type of blood vessel has valves

  veins