5 - Mass Transport Flashcards
Define haemoglobin
Protein in a RBC that transports oxygen
Haemoglobin has …. polypeptide chains
4
What does haemoglobin form with oxygen?
Oxyhaemoglobin
Describe the structure of haemoglobin (5)
Made of 4 subunits Each subunit has a haem group Each haem group has Fe2+ The shape changes when O2 bonds The shape changes when the pH is lowered
Why is haemoglobin made of 4 subunits?
4 O2 molecules can be transported
Why is blood red?
The haem group contains Fe2+
Why does haemoglobin have an affinity for oxygen?
Contains Fe2+ (bond)
Why does the shape of haemoglobin change when O2 is bonded to it?
Other oxygen molecules can load easily
When does the shape of haemoglobin change? (2)
O2 bonded to it
pH is lowered
Why does the shape of haemoglobin change when the pH is lowered?
Oxygen molecules unload in respiring tissue
Process of transporting oxygen by haemoglobin (3)
1 - Readily associate with O2 at surface where gas exchange happens
2 - Readily dissociate from O2 at respiring tissues
3- Does this by forming oxyhaemoglobin
O2 concentration where gas exchange happens
Low
O2 concentration where respiring tissues are
High
CO2 concentration where gas exchange happens
High
CO2 concentration where gas respiring tissues are
Low
Affinity where gas exchange happens
High
Affinity where gas respiring tissues are
Low
Result where gas exchange happens
Oxygen attached
Result where respiring tissues are
Oxygen released
Define affinity
Ability of haemoglobin to bind to oxygen
Equation about haemoglobin
Loading
Hb + 4O2 -> HbO8
Shape of the oxygen dissociated curve
S
Describe the oxygen dissociated curve
1 - Near tissues. Hard to load as low O2 concentration
2 - Changes shape so happens easier
3 - Near lungs - hard to load but high affinity
Does the curve go left or right in foetal haemoglobin?
Left