Flashcards
Transport of Oxygen by Haemoglobin
Cards in this deck (11)
- 1Describe what happens as the first oxygen molecule binds to the hgb. What might this look like on a graph?At first the shape of the hgb makes it difficult for the oxygen to bind to on of its sites on its 4 polypeptide sub units as they're closely united. This means at low oxygen concentrations, little oxygen binds to hgb = shallow gradient on graph.
- 2The first oxygen molecule has binded to the haemoglobin (hgb) what happens to it after the oxygen has binded?Due to the first oxygen molecule binding to the haemoglobin, the quarternary structure of the hgb molecule has changed, causing it to change shape. This makes it easier for the other sub units to bind to an oxygen molecule
- 3Describe what happens as the second and third oxygen molecules bind to the hgb. What might this look like on a graph?As it is easier for the other sub units to bind to an O2 molecule = takes a smaller increase in the partial pressure of oxygen for the second one to bind. This is known as 'positive cooperativity' as binding of the first O2 molecule makes it easier for the second. This all means the gradient of the curve would steepen.
- 4After the binding of the third O2 molecule, what changes to make the 4th O2 molecule harder to bind to, and what does this make the graph look like?After binding the third molecule, the situation changes and it harder for the 4th O2 molecule to bind purely due to probability as with more occupied sites, it is harder to find an empty one to bind to. This gradient of the curve reduces and flattens off.
- 5The further to the left the oxygen dissociation curve is...the greater the affinity of hgb for oxygen
(so it loads oxygen more readily but unloads less easily) - 6The further to the right the oxygen dissociation curve is...the lower the affinity of hgb for oxygen
(so it loads oxygen less readily but unloads more easily) - 7Describe in steps what happens with hgb and oxygen at the surface of gas exchange- CO2 constantly being removed
- pH is slightly raised
- Hgb changes shape due to different conditions to one that loads O2 readily
- Shape also increases affinity for O2 = isn't released while being transported in blood - 8Describe in steps what happens with hgb and oxygen at the respiring tissues- In the tissues, CO2 is being produced by respiring cells
- CO2 is acidic in solution = pH of blood within tissues is lowered
- Lower pH changes shape of hgb into one with lower affinity for O2
- Hgb releases O2 into respiring tissues - 9Complete the sentence: A low carbon dioxide concentration ...shifts the oxygen dissociation curve to the left
- 10Complete the sentence: A high carbon dioxide concentration ...shifts the oxygen dissociation curve to the right
- 11Mice have a large surface area to volume ratio and tend to lose heat repidly. What does this mean about their hgb?To maintain their body temperature, the mice tissues respire more and so their hgb releases oxygen easier to the tissues to keep up their rate of respiration and keep the mouse warm
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- AS - Level Biology (7 - Mass Transport) Flashcards on Transport of Oxygen by Haemoglobin, created by Bee Brittain on 17/04/2016.
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- Bee Brittain
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