Oxygen Transport Flashcards
What is the structure of haemoglobin?
It is a protein made up of four polypeptide chains. Each chain contains a haem group which contains iron.
What is oxygen association/loading?
When oxygen binds with haemoglobin and forms oxyhaemoglobin.
What does oxygen affinity mean?
The tendency of a molecule to bind to oxygen.
What does the partial pressure of oxygen mean?
the concentration of oxygen
What effect does a change in the partial pressure of oxygen have on haemoglobin affinity for oxygen?
As the partial pressure increases the oxygen affinity increases and oxygen loads onto haemoglobin more to form oxyhaemoglobin.
Where does oxygen association happen?
In the alveoli where the partial pressure of oxygen is high more oxygen loads onto the haemoglobin to form oxyhaemoglobin.
Why is the partial pressure of oxygen in the alveoli high?
Oxygen enters the capillaries at the alveoli.
Where does oxygen dissociation happen?
At respiring cells where the partial pressure of oxygen is low oxygen unloads from oxyhaemoglobin to form haemogoblin.
Why is the partial pressure of oxygen at respiring cells low?
It is used for respiration.
What is an oxygen dissociation curve?
Does it show how saturated the haemoglobin is at any given partial pressure?
Why does the graph curve upwards?
Where the partial pressure is high, haemoglobin has a high affinity for oxygen so the saturation is high. Where the partial pressure is low, haemoglobin has a low affinity for oxygen so the saturation is high.
Why is the graph S-shaped?
When the haemoglobin binds with the first oxygen molecule it changes shape which makes it much easier for other oxygen molecules to bind to it. This increases the saturation of the haemoglobin rapidly and the curve becomes steeper. The curve then levels off because at high saturation it gets harder for other oxygen molecules to bind.
How does the partial pressure of carbon dioxide affect haemoglobin affinity for oxygen?
When it is high the affinity is low so oxygen unloads.
How does an increase in the partial pressure of CO2 affect the oxygen dissociation curve?
The saturation of oxygen decreases at a given partial pressure of oxygen so the graph shifts to the right.
What factors affect the oxygen affinity of haemoglobin?
- partial pressure of oxygen.
- Partial pressure of CO2
- saturation of the haemoglobin.
