O2 Dissosocitation Curve

Question 1

Describe the plateau

Answer 1

Between 70-100 mmHG
Once HB is fully saturated it cannot accept anymore O2 and it is not very soluble in solution (Henry’s) so no increase in saturation occurs

Question 2

Describe the factors affecting the curve

Answer 2

Increase in
Pco2
Temperature
pH
2,3 BPG
This will reduce HB affinity for 02 unloading it where it is most needed, becoming deoxyhaemoglobin and facilitating co2 to transported to the lungs (haldane effect).
This causes a shift to the right in the graph called the Bohr effect

The opposite effect on these factors will cause a shift to the left.

Question 3

Describe them HB molecule

Answer 3

2 alpha polypeptide chains
2 beta polypeptide chains
Each containing a heme group bearing an iron molecule which can reversible bind with O2
1RBC can carry 250 million HB which carries 4 O2 = 1 billion O2 molecules

Question 4

Describe the steep portion of the graph

Answer 4

Between 10-50 mmhg
Where HB has high affinity for O2 readily accepting it becoming HBo2. As the first molecule binds positive cooperation facilitates binding.