oxyhaemolobin and carbaminohaemoglobin

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Red blood cells contain haemoglobin


  • 4 subunits each contain a polypetide protein and heam group and heam group has an affinty for oxygen.
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taking up and releasing oxygen

Taking up oxygen

  • Oxygen absorbed by the blood enters the blood plasma then enters the blood plasma then enters the red blood cells. Here taken up by the haemoglobin.
  • Oxygen molecules leave so a steep diffusion gradient created
  • Diffusion gradient allows more oxygen to enter the cells

Releasing oxygen

  • cells need oxygen for aerobic respiration there oxyhaemoglobin must release oxygen this is called dissociation
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Haemoglobin unloading

unloading occurs in tissue capillaries where;

  • pp02 is ------ low
  • pco2 is ------ high
  • blood ph ----- lower
  • temperature ----higher Tt is difficult for the third oxygen molecules to diffuse and associate with the last heam group so therefore it is difficult to gain 100% saturation of all the heamoglobin molecules. Even when oxygen tension is very high so therefore the curve levels off when saturation becomes 100%.
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Carriage of carbon dioxide

Carbon dioxide can be transported in 3 different ways;

  • 5% is dissolved directly in to the plasma
  • 10% combined directly is with haemoglobin to form a compound called Carbamniohaemoglobin
  • 85% is transported in the form of hydrogen carbonate ions (hco3-)

Hydrogen carbonate ions are formed;

co2 diffuses into the blood some enters the red blood cells and combines with water to form carbonic acid which is catalysed by carbonic anhydrase

co2 + H2O -------------> H2OC03

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Carriage of carbon dioxide

Co2 + H2o -------------> H2Co3

the carbonic acid dissociates to release H ions and hydrogencarbonate Hco3-

H2Co3 -------------> Hco3- + H+

  • hydrogen carbonate ions diffuse out of the red blood cell into the plasma
  • Charge inside the red blood cell maintained by the chloride shift
  • the H+ ions can become acidic so it is taken up by haemoglobin to produce Haemoglobinic acid. Haemoglobin acts as a Buffer!
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Bohr effect

Increased ppco2, lower ph and increased temperature all have the effect to push the curve to the right more is unloaded which is the Bohr effect

  • Haemoglobin has a lower affinity for oxygen as the oxygen is trying to supply the body with more oxygen
  • more Co2 is gained as the body is respiring
  • Oxygen is needed to the respiring tissues
  • LESS AFFINITY for oxygen as it gives it up!
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Natalie Beard

Great, again, the font does need to be bigger, espsically the first page :P I really don't know why somebody rated this at 1 star, i'm giving it four :P


lo hahahahahahahaha nat

great revision caRD

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