[OLD] Haemoglobin Flashcards
Describe the structure of haemoglobin? List at least 3 facts
A protein containing 4 polypeptide chains.
Quaternary structure
Each polypeptide contains a haem group, which contains iron
What are the units for partial pressure of oxygen?
pO2
What are the terms sometimes used to describe the binding and releasing of oxygen by haemoglobin?
loading and unloading
Explain why it is important for haemoglobin to be soluble.
so it can be transported in the blood
Red blood cells contain some enzymes. Explain why the enzymes cannot be synthesised in red blood cells.
it does not contain a nucleus
4 key points of haemoglobin structure
4 interlocking globin subunits
each with a porphyrin ring
contains Fe2+
each ring carries one O2 molecule
advantages of the sigmoidal curve
Lower affinity at low partial pressures of oxygen
> unloads oxygen to the tissues more readily
Higher affinity at high partial pressures of oxygen
> more efficient at loading oxygen in lungs
what is the Bohr effect?
In a CO2-rich environment (i.e. at respiring tissue), more oxygen dissociates from oxyhaemoglobin
Oxygen dissociation curve shifts to the right
Advantage of the Bohr effect
when a muscle is respiring more it receives an increased amount of oxygen.
what in haemoglobin binds to oxygen?
the Fe2+ ion in the haem group
how are red blood cells adapted to transport oxygen?
no nucleus, Golgi, rer, mitochondria contains haemoglobin biconcave shape flexible membrane small size
why is binding to the first o2 difficult?
low diffusion gradient to haem group in centre of molecule
what does binding of the first o2 do?
produces a conformational change in shape
where do foetuses get oxygen from?
it’s mothers blood across the placenta
does foetal haemoglobin have a higher or lower affinity for oxygen than adult haemoglobin?
higher
