When haemoglobin is exposed to different partial pressures of oxygen, how does it bind to it?
Unevenly
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How is the amount of gas present in a mixture of gases measured?
By its partial pressure
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What units are used for measuring the partial pressure of a gas?
KiloPascals (kPa)
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How can the partial pressure of oxygen be represented?
pO2
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Under different partial pressures of oxygen haemoglobin changes its...?
Affinity for oxygen
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What does the oxygen dissociation curve show?
The relationship between the saturation of haemoglobin with oxygen and the partial pressure of oxygen
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What shape does the oxygen dissociation curve have?
Sigmoid 's' shape
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How many parts can the graph be split into?
3
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Part 1: Why is the curve shallow?
Due to the haemgroups on the haemoglobin molecule being close together, it is difficult for the first oxygen molecule to bind
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What does part 1 of the graph show?
There is a low saturation of haemoglobin with oxygen and a low partial pressure of oxygen
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What does the binding of the first oxygen molecule do?
It induces the other subunits to bind to an oxygen molecule
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Part 2: Why does the gradient of the graph steepen?
The binding of the first oxygen molecule changes the quaternary structure of the haemoglobin molecule, making it easier to bind with the second oxygen molecule
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What does part 2 of the graph show?
It takes a smaller increase in the partial pressure of oxygen to bind the second oxygen molecule
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Part 3: Why does the gradient of the curve reduce and the graph flatten off?
The binding of the fourth molecule should in theory be the easiest but it isn't. This is due to the probability of binding with an oxygen molecule decreases as there are less oxygen binding sites available
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What does the graoh look like with a high CO2 concentration?
Shifted to the right
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Why is the graph shifted to the right?
The haemoglobin has a lower affinity for oxygen
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What is the affinity for oxygen and CO2 concentration when the graph is shifted to the left?
Affinity for oxygen is high and CO2 concentration is low
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The higher the concentration of CO2, how does the pH change?
The lower the pH
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How does a lower pH affect the function of haemoglobin?
The shape changes to one which has a lower affinity for oxygen
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How does haemoglobin adapt to a higher rate of respiration?
Higher rate of respiration -> More CO2 produced by tissues -> pH is lowered -> Greater haemoglobin shape change -> Oxygen readily unloaded -> More oxygen available for respiration
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When the temperature is raised- how does the oxygen dissociation curve move?
It shifts to the right
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What is the effect of an increased temperature on oxygen dissociation?
A higher temperature denatures the bond between oxygen and haemoglobin so oxygen is dissociated more readily
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Other cards in this set
Card 2
Front
How is the amount of gas present in a mixture of gases measured?
Back
By its partial pressure
Card 3
Front
What units are used for measuring the partial pressure of a gas?
Back
Card 4
Front
How can the partial pressure of oxygen be represented?
Back
Card 5
Front
Under different partial pressures of oxygen haemoglobin changes its...?
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