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Flashcards in Transport Of O₂ Deck (11):


carries 4 oxygen molecules
4 sub units
4 polypeptide chains
haem (non-protein) group in each = iron ion Fe²⁺
iron ion has high affinity (attraction to oxygen)


haemoglobin ___________ curve is _ shaped.
___ is plotted against ___

% saturation with O₂


use what key words when talking about haemoglobin and oxygen?

associates/dissociates with
binds with


how is the concentration of oxygen measured?

by relative pressure it contributes to mixture of gases
this is the partial pressure of oxygen or pO₂ also called oxygen tension
units kPa


What is the partial pressure of oxygen (pO₂)?

the relative pressure that it contributes to a mixture of gases


What is oxygen tension?

partial pressure of oxygen


What happens at low oxygen tension?

Haemoglobin doesn't readily associate with oxygen because the haem group is in the middle so oxygen molecules can't reach it. So there is a low saturation level of haemoglobin at low oxygen tensions.


What happens when oxygen tension rises?

The diffusion gradient into haemoglobin molecules increases.
When the first O₂ associates, a conformational change in haemoglobin occurs, then it easily allows more O₂ to bind. This causes the steepness of the curve as pO₂ rises.


What happens at high oxygen tension?

as approaches 100% saturation of haemoglobin, the curve levels off


_____ in lungs is _________, and ______ in ____ is _______ to _________

oxygen tension
high to produce close to 100% saturation
oxygen tension
cause oxygen to dissociate from oxyhaemoglobin


Fetal haemoglobin has a ___________ so the curve ___________.
This is because ______________.
In the placenta _______________.

higher affinity for oxygen

for haemoglobin dissociation, is to the left of the adult haemoglobin curve (is steeper so associates more easily to oxygen as low pO₂)

fetal haemoglobin must be able to associate with oxygen in an environment where oxygen tension is low enough to make adult haemoglobin dissociate with oxygen.

pO₂ is low, fetal H will absorb O₂ from surrounding tissues making pO₂ even lower, so O₂ diffuses from mother's blood fluid to placenta, reducing pO₂ in mother's blood. This makes maternal haemoglobin release more oxygen.