CHEM 112 Lecture Notes - Bicarbonate, Red Blood Cell, Heme

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Lower atm pressure / fewer molecules present / less o2 reaches tissues. Body adapts to changes by increasing: heart rate and resting breathing rate, blood plasma, red blood cell production and number of blood capillaries. Haemoglobin hb has 4 subunits, each subunit contains 2 parts: haem ring of atoms linked to fe2, globin polypeptide chain, sequence of amino acids affects o2 carrying properties. Oxyhaemoglobin hbo2 from lungs dissociates in respiring tissues: o2 diffuses into body cells while hb is transported back to lungs. Features of red blood cells that allow them to transport o2 more efficiently: biconcave disc larger surface area to volume ratio for diffusion, absence of nuclei/other organelles more room for haemoglobin. Co2 produced in tissues diffuses into blood plasma. There it reacts with h2o in the plasma and in the cytoplasm of red blood cells: co2 + h2o h2co3(carbonic acid) h+ + hco3- (hydrogen carbonate) Thus, most co2 is transported in blood as hco3-