carbon dioxide concentration

• partial pressure of carbon dioxide (pCO2) 


  a measure of the concentration of CO2 in a cell.
• Haemoglobin gives up its oxygen more readily at a higher pCO2
• Bohr affect

  When cells respire they produce carbon dioxide, which raises the CO2. This increases the rate of oxygen unloading. The saturation of blood with oxygen is lower for a given pO2 meaning that more oxygen is being released
• the Bohr effect

  A) low

  B) medium

  C) high

  
• CO2 transport in the blood

  1. CO2 diffuses into red blood cells

  2. CO2 reacts with water to form carbonic acid, catalysed by carbonic anhydrase

  3. Rest of CO2 binds directly to haemoglobin and is carried to the lungs

  4. Carbonic acid dissociates to give H+ and HCO3- ions

  5. H+ ions cause oxyhemoglobin to unload oxygen

  6. H+ ions form haemoglobinic acid

  7. HCO3- ions diffuse out of red blood cells and are transported in blood plasma

  8. Chloride ions diffuse into red blood cells to maintain charge balance (chloride shift)

  9. In lungs, low pCO2 causes HCO3- and H+ to recombine into CO2

  10. CO2 diffuses into alveoli and is breathed out
• Carbonic anhydrase


  • Enzyme that catalyses the reaction of CO2 and water to form carbonic acid
• Haemoglobin


  • Carries CO2 to the lungs
  • Unloads oxygen when H+ ions bind to it
• Haemoglobinic acid


  • Compound formed when H+ ions bind to haemoglobin
• Chloride shift


  • Diffusion of chloride ions into red blood cells to maintain charge balance
• formation and splitting of carbonic acid

  A) carbon dioxide + water

  B) carbonic anhydrase

  C) carbonic acid

  D) hydrogen ions

  E) hydrogencarbonate ions

  
• unloading of oxygen

  A) Cl-

  B) HCO3-

  C) hydrogen ions

  D) oxyhemoglobin

  E) haemoglobonic acid

  F) oxygen