Lecture 13 Flashcards
What does a heme consist of?
Porphyrin ring with an iron attached to it which binds oxygen
Myoglobin vs haemoglobin
Myoglobin just one subunit haemoglobin 4 chain subunits each with a haem group to bind oxygen
Myoglobin binding is hyperbolic
Haemoglobin binding is sigmoidal
T state vs R state haemoglobin?
R state has higher affinity. Oxygen binding stabilises the R state which encourages further binding.
How is oxygen binding between myoglobin and haemoglobin different?
Co-operative vs consistent. Co-operative binding means that oxygen binding makes it easier for more to bind and gives curve a sigmoidal shape.
What is the advantage of co-operative binding and sigmoidal binding curve?
Binds oxygen well in lungs and release it well in tissues
What does 2,3 BPG do (bisphosphoglycerate)
Reduces binding affinity by stabilising low affinity state and so allows oxygen to be given up in tissues more easily
Why does running at altitude make you more fit?
More 2,3 BPG made
What is the Bohr effect?
Oxygen released easier when H+ and CO2 present. This means that at metabolically active tissues oxygen is released more easily
How does carbon monoxide poisoning work?
Binds to haemoglobin very strongly. Must use hyperbaric chamber with high O2 pressure to compete with CO
Why is it important that fetal haemoglobin is different?
Stronger affinity for O2 allows it to take it from mother
Sickle cell anaemia cause?
Mutation of glutamate to valid. A hydrophilic swapped for hydrophobic= sticky pocket and molecules stick together
What is thalassaemia?
Imbalance between number of alpha and beta chains
