Unit 3 - Transport of oxygen and carbon dioxide Flashcards
How many oxygen molecules is one haem group capable of binding to?
One Oxygen molecule
How many haem groups does one haemoglobin molecule contain?
4
Give the equation for haemoglobin binding to Oxygen
Hb + 4O2 ⇌ HbO8
What is formed when haemoglobin binds to oxygen?
Oxyhaemoglobin
How does Oxygen get from the alveoli into the blood?
Diffuses from alveoli into blood capillaries down a concentration gradient
What occurs to the Hb once the first molecule of O2 has been taken up by it?
The Hb changes shape
Why does Hb change shape once the first molecule of O2 has been taken up?
- enables Hb to take up the 2nd O2 more quickly
- the 3rd O2 quicker still
- 4th O2 even more quickly
- allows a concentration gradient to be maintained as no free oxygen is dissolved into the blood
What is positive cooperactivity?
- Hb which changes shape once 1st molecule of O2 is taken up
- enables 2nd, 3rd, 4th O2 molecules to be taken up more quickly
Where is oxyhaemoglobin transported to?
Respiring tissues
When oxyhaemoglobin is transported to respiring tissues what happens?
It releases O2 molecules
What is the determining factor for whether O2 is picked up or released?
The partial pressure of O2 (pO2)
What is an oxygen dissociation curve?
a way of showing how the binding of O2 varies at different pO2
What is the shape of the oxygen dissociation curve?
An ‘S’ shape
What does the ‘S’ shape of the oxygen dissociation curve mean for change in pO2?
For a relatively small change in pO2 there is a large change in the % of Hb saturated with O2
What is the x axis for an oxygen dissociation curve?
p(O2) (kPa)
What is the y axis for an oxygen dissociation curve?
% Hb saturated with O2