AQA A Level Biology复习笔记3.4.5 The Bohr Shift

The Bohr Shift

 

  • Changes in the oxygen dissociation curve as a result of carbon dioxide levels are known as the Bohr effect, or Bohr shift
  • When the partial pressure of carbon dioxide in the blood is high, haemoglobin’s affinity for oxygen is reduced
    • This is the case in respiring tissues, where cells are producing carbon dioxide as a waste product of respiration
    • This occurs because CO2 lowers the pH of the blood
      • CO2 combines with water to form carbonic acid
      • Carbonic acid dissociates into hydrogen carbonate ions and hydrogen ions
      • Hydrogen ions bind to haemoglobon, causing the release of oxygen
  • This is a helpful change because it means that haemoglobin gives up its oxygen more readily in the respiring tissues where it is needed
  • On a graph showing the dissociation curve, the curve shifts to the right when CO2 levels increase
    • This means that at any given partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher levels of CO2

The-Bohr-Effect

The dissociation curve shifts to the right as a result of the Bohr effect. This means that any given partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher CO2 levels.

 

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