Haemoglobin & Oxygen dissociation Flashcards
Why is haemoglobin described as a conjugated protein?
It is a protein bound to an inorganic group. (Haem group)
In terms of the quarternary structure, what is haemoglobin made up of?
4 subunits. 2 alpha + 2 beta.
Each subunit has 1 haem group (Fe)
What is the name given to haemoglobin in which all 4 subunits are bound to oxygen?
Oxyhaemoglobin
What is the chemical formulae of oxyhaemoglobin?
Hb(O2)4
What is the term given to the change of haemoglobins shape when oxygen binding occurs?
Positive cooperativity.
What does positive cooperativity mean?
That the binding of oxygen increases haemoglobins affinity for O2.
How many hb per RBC?
300 million.
What determines the percentage saturation of haemoglobin.
The number of subunits that have O2 bound to them.
e.g. 1/4 = 25%
2/4 = 75%
What is this graph called?
What is the shape curve know as?
Oxygen dissociation curve
Sigmoid curve
Define pO2.
Partial pressure of oxygen.
The amount of oxygen gas dissolved in the blood.
a) Low affinity. Few haem groups bonded with O2
b) Affinity increasing due to positive cooperativity,
c) Hb saturated. Becomes Oxyhaemoglobin.
What is it called when the oxygen dissociation curve shifts to the right?
Bohr effect
What is the Bohr effect?
Oxyhaemobglobin can release O2 more readily at high concentrations of CO2,
(Haemoglobins oxygen affinity is reduced.)
What happens to oxygen affinity around tissues?
Cells respire creating CO2.
High concentrations of CO2 reduce the oxygen affinity of Hb.
This allows O2 to be more readily given up.
Good because cells need a shit load of O2.
When haemoglobin is at the lungs what is the state of its oxygen affinity.
The area near the lungs is a low CO2.
Hb’s affinity for O2 is higher and thus:
Releases O2 less readily
or
Bind to O2 more readily
