haemoglobin

    Cards (13)

    • oxygen is carried around the body by haemoglobin in red blood cells
    • red blood cells contain haemoglobin
    • haemoglobin is a large protein with a quaternary structure
    • it is made of four polypeptide chains
    • each chain has a prosthetic haem group attached, which contains an iron ion (makes it red)
    • haemoglobin has a high affinity for oxygen
    • each haemoglobin molecule can carry four oxygen molecules
    • in the lungs, oxygen joins to haemoglobin in red blood cells to form oxyhaemoglobin
    • red blood cells are biconcave discs with a large surface area to volume ratio
    • red blood cells do not contain a nucleus to provide more space inside the cell for haemoglobin so they can transport as much oxygen as possible
    • the four globin subunits are arranged so the hydrophobic R groups are facing inwards, maintaining the 3D spherical shape, and the hydrophilic R groups are facing outwards, to maintain solubility
    • each prosthetic haem group contains an iron ion which reversibly combines with oxygen to form oxyhaemoglobin
    • red blood cells are also known as erythrocytes
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