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15 Cards in this Set
- Front
- Back
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Haemoglobin is |
Conjugated globular protein made of 4 polypeptide chain, each with iron containing haem prosthetic group |
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How many oxygen molecules does each Haemoglobin binds to? |
4 oxygen molecules |
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How does oxygen bind to Haemoglobin and form what? |
Loosely to form oxyhaemoglobin |
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How does Haemoglobin carries oxygen? |
Erythrocytes enter capillaries in alveoli , Oxygen diffuses into erythrocytes and binds to Haemoglobin Arrangement of Haemoglobin means as one oxygen binds to haem group, Haemoglobin changes shape and easier for next oxygen to bind Oxygen bind to haem group so free oxygen concentration stays low so maintain steep concentration gradient |
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What does the oxygen dissociation curve shows? |
Affinity of Haemoglobin for oxygen |
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At high partial pressure of oxygen in lungs |
Haemoglobin is loaded with oxygen rapidly |
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Small drop in oxygen levels in respiring cells |
Oxygen released rapidly |
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Partial pressure of co2 rises |
Haemoglobin gives up oxygen more easily |
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What change in affinity of Haemoglobin due to co2 known as? |
The Bohr shift |
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Fetal Haemoglobin |
Fetal Haemoglobinhas higher affinity for oxygen so oxygen transfer from adult to Fetal Haemoglobin Lower partial pressure of oxygen in placenta Fetal receives oxygen for respiration and maintain oxygen concentration gradient
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Three ways to transport carbon dioxide |
5% dissolve in plasma 10-20% combine with amino acid in polypeptide chain of Haemoglobin to from carbaminohaemoglobin 75-85% converted to hydrogen carbonate ions in cytoplasm of red blood cells |
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How is CO2 converted to hydrogen carbonate ions? |
CO2 reacts with water to from carbonic acid Carbonic acid dissociates to form hydrogen ions and hydrogen carbonate ions Catalysed by carbonic anhydrase |
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What happens after hydrogen carbonate ions form ? |
Negatively charged hydrogen carbonate ions diffuse out of erythrocytes Negatively charged chloride ions diffuse in to maintain electrical balance of cell Known as chloride shift |
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What happens to carbons dioxide in lungs? |
Hydrogen carbonate ions diffuses back into erythrocytes And react with hydrogen to form carbonic acid Carbonic acid broken down into CO2 and water and diffuses into lunges Chloride ions moves back into plasma |
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How does Haemoglobin help to prevent changes in pH? |
Act as a buffer bu accepting free hydrogen ions to form Haemoglobinic acid |
