Oxygen Dissociation Curves

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Flashcards by , created about 6 years ago

AS Biology2 (The Variety of Life) Flashcards on Oxygen Dissociation Curves, created by sammi_taylor01 on 05/28/2013.

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Created by sammi_taylor01 about 6 years ago
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Question Answer
What is oxygen measured in in oxygen dissociation curves? partial pressure (kPa) Normal atmospheric pressure is 100kPa, as oxygen counts for 21% of the atmosphere, it's partial pressure would be 21kPa.
At low concentrations of oxygen, why is it harder for the molecule to load oxygen? Due to the four polypeptide chains being so close together
Once the first molecule of O2 is loaded.. It is easier for the other three O2 molecules to be absorbed by the haem group.
If haemoglobin has a lot of oxygen it is called.. Similarly for when it doesn't have a lot of oxygen it's called.. 1-saturated 2- unsaturated
What causes the shape of different haemoglobin molecules change? Due to different conditions/environments.
The further to the left the dissociation curve... The higher it's affinity, therefore the more readily it loads oxygen but the less easily it releases oxygen.
The further to the right the dissociation curve... The lower the affinity for oxygen and therefore the less easily it loads oxygen but the more readily it releases it to respiring tissues.
What effect does the presence of carbon dioxide have on the affinity for oxygen? Increased carbon dioxide concentrations decreases the molecules affinity for oxygen, therefore the less readily it loads oxygen but the more readily unloads.
In the lungs what is the dissociation for oxygen? High affinity due to the low concentrations of CO2 therefore more easy for the molecule to load oxygen and less readily unloads.
In the tissues what is the oxygen dissociation curve like? Low affinity for oxygen due to the high concentrations of carbon dioxide from the respiring tissues, therefore the more easily it unloads oxygen but less readily loads it.
What pH is dissolved carbon dioxide therefore what effect does this have on haemoglobin? slightly acidic, therefore alters the shape of the molecule so more loosely bound to the oxygen molecules meaning more readily unloads it.
Therefore, if low pH changes the shape of the molecule so it releases oxygen more readily, what's the effect of high pH (low concentration of CO2) on the dissociation curve? High pH alters the shape of the molecule so that it more readily loads the oxygen (it's in high concentration) and less readily unloads it.
Describe the statement 'the more active the tissue, the more readily oxygen is unloaded'. the more active, the more it respires, the more CO2 present, low pH alters shape to low affinity for oxygen, unloads O2 more easily, more O2 available for respiration.
In a pregnant woman, where would the babies oxygen dissociation curve be? To the left, in order for it to pick up oxygen more readily.
What is the oxygen dissociation curve of a rat in comparison to a Plaice (that lives on the bottom of the sea). Rat- low affinity for oxygen as it's active and needs to be able to easily unload oxygen to respiring muscles. Plaice- high affinity as it's in a low oxygen environment and isn't very active, so needs to be able to hold onto oxygen and not release it readily