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another bio question

Discussion in 'DAT Discussions' started by teefRcool, Jul 23, 2006.

  1. teefRcool

    teefRcool Senior Member
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    why does CO have a better affinity to hemoglobin than O2
     
  2. cryptozoologist

    cryptozoologist Junior Member
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    because in your cells where metabolism of glucose is happening and CO2 is high, presence of CO2 induces hemoglobin travelling through nearby capillaries to dump O2 and pick up CO2. O2 then used for respiration. CO2 then transported to lungs. CO2 transported in form of bicarbonate ion primarily through reaction in blood cells.

    bicarbonate changed back to CO2 at lung epithelium when O2 binds to hemoglobin (creating H+ change) which drives a change back to CO2. CO2 dumped at lungs via simple diffusion (less CO2 in air than in your cells).

    http://www.elmhurst.edu/~chm/vchembook/261carbondioxide.html
     
  3. teefRcool

    teefRcool Senior Member
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    Your talking about carbon dioxide, but the question asks carbon monoxide.
     
  4. sgdorfl90

    sgdorfl90 Senior Member
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    you don't need to know it, but it has to do with steric hindrance and the ability of CO to fit in nicely into a cavity. You will never be asked why on the DAT, just know its like 250 X more....if you want detailed explanation about which carbon and all that, google it.
     
  5. 4thQtrDreams

    4thQtrDreams Good times, for a change.
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    Hemoglobin's oxygen-binding capacity is decreased in the presence of carbon monoxide because both gases compete for the same binding sites on hemoglobin, carbon monoxide binding preferentially in place of oxygen. Carbon dioxide occupies a different binding site on the hemoglobin.

    The binding of oxygen is affected by molecules such as carbon monoxide (CO) (for example from tobacco smoking, cars and furnaces). CO competes with oxygen at the heme binding site. Hemoglobin binding affinity for CO is 200 times greater than its affinity for oxygen, meaning that small amounts of CO dramatically reduces hemoglobin's ability to transport oxygen. When hemoglobin combines with CO, it forms a very bright red compound called carboxyhemoglobin.
    Hemoglobin binds oxygen only slightly, which is good, because it
    needs to carry it around through the blood but then needs to let go of it at the destination. Carbon monoxide binds to the iron in hemoglobin much more easily and sticks to it very tightly. So if there is oxygen and carbon monoxide " fighting" for spaces in the hemoglobin, CO will win and as it circulates, it doesn't let go
     
  6. teefRcool

    teefRcool Senior Member
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    Awesome explanation thanks guys
     

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